The bath rim falls six millimetres and nothing on the wall can absorb it
There is a 600 by 300 in your left hand and a notched trowel in your right, and the question holding the job up is not which corner to start in. It is what the first course is measured from. A bathroom wall offers more datums than any other wall in the house — finished floor, bath rim or tray upstand, ceiling, window head and sill, niche head and base, the top of a half-height run — and one grid of courses can honour exactly one of them. Everything else lands on a joint by luck, or gets cut around at whatever height it happens to sit.
So the first hour goes on measuring how far from ideal each of those datums is. Six millimetres of fall along a bath rim is ordinary, and some of it is deliberate, because a bath is bedded to drain. Eleven millimetres across a ceiling is ordinary too. Plumb both faces of every internal corner, straightedge each wall in three places, and write every reading on a sketch with its sign — a plus and a minus at opposite ends of one wall is a different problem from two pluses. None of it is a defect adhesive will fix. Each is a quantity you are about to spend.
Cut a rod before you cut a tile
Everything below depends on the module, and the module is not what the box says. A tile sold as 600 by 300 is made to a tolerance — ANSI A137.1 tabulates the facial dimension variation and the warpage a joint has to absorb — and a batch can run a millimetre under or over across a whole pallet. Lay ten tiles face up with the spacers you will actually use, push the run tight, measure it once with a steel tape and divide by ten. In the room worked through here that gives 602 across and 302 up.
Then make the rod: a length of 50 by 25, or a strip ripped off 18 mm ply, longer than the tallest wall. Mark it in modules from one end and nick it with a knife every fifth mark so it reads at arm's length from a step. Hold it against everything — floor to ceiling on all four walls, floor to rim, rim to ceiling, the window sill and head, the pencil line where the niche is going. Each reading tells you where the part-course falls if you anchor there.
Ten minutes of that finds what would otherwise surface on the fourth course of the second wall, by which point it is a demolition rather than a decision. Then get the grid off the rod and onto the walls: carry the course marks round the internal corners with a level, and tick both ends of every wall rather than one, because adhesive buries a pencil mark mid-wall within the hour and a grid re-established from a tiled edge inherits the error already in it.
The floor decides where the bottom course lands
Every vertical measurement in this room is taken from a floor that does not exist yet. A deck with a 6 mm backer board, a 3 mm bed and a 9 mm tile finishes 18 mm higher than the surface you are standing on, so a bath rim measured off bare boards is 18 mm wrong — most of the way to a joint. Settle the build-up, mark finished floor level at both ends of all four walls, and only then strike anything. The order of work has two honest answers: walls first leaves the bottom course cut to a level line with the floor butted to it through a sealant joint, so the floor can be lifted later without touching a wall, while floor first is quicker and marries the two grids where people look.
If the same tile goes on both, check first that it is rated for floor use, because many wall tiles are not and the fact that it cuts and sticks the same way says nothing about whether it will take a heel. Where it is rated the offcuts cross over between the two schedules — the only place on this job where waste actually falls — and the two grids can be lined through. Line them through on the wall you see from the door and let the other three land where they land: a grid agreeing on three walls and disagreeing on the fourth reads as an accident, one agreeing only where you look reads as intent.
The floor is a separate schedule with its own box count — about 3.1 square metres here once the bath footprint comes out. The lay pattern selector does the real work, since pattern moves waste further than tile size does; the floor's own setting out belongs to the floor tiling guide rather than to this page.
Net area of floor or wall.
Long side of the tile.
Short side of the tile.
How the tiles are laid.
From the supplier's data.
Tiles required
36 tiles
Keep the spare tiles. A batch-matched replacement in five years is worth more than the box it came in.
- Boxes to order
- 6 boxes
- Tiles before waste
- 32.5 tiles
- Waste applied
- 10 %
- Area covered by the boxes
- 144 ft²
- Spare after the job
- 0 tiles
They open the calculator with your figures already in it
Floor & Wall Tile Calculator: 36 tiles — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Nothing checks that the tile and the pattern belong together. A tile with any edge of 15 in (about 380 mm) or more falls under a tighter substrate flatness rule — TCNA asks for 1/8 in in 10 ft — and the offset on a long plank is held to roughly a third of its length, because a half-bond sets the neighbouring tile's high point against your tile's crown and produces lippage. This will happily return a herringbone count for a 1200 mm plank over a floor that cannot take it.
- Movement joints sit outside the count. The same TCNA and BS 5385 documents cited above for the waste figures also call for a soft joint at every perimeter and wall abutment, around columns and fixed penetrations, and across the field at intervals — roughly 8 to 10 m indoors, and much closer over a heated screed or outside. Those joints take sealant and a profile rather than grout, and a floor tiled hard into its walls tents at the first hot spell.
A wall honours one anchor, and the rest have to move
Take the worked room: 2.4 by 1.8 metres, ceiling 2350 above finished floor, a 1700 bath along the long wall with the shower over it, rim at 560, course module 302. Anchor on the ceiling and seven full courses run down to 236, leaving that whole 236 as a cut course at the floor, with joints at 2048, 1746, 1444, 1142, 840 and 538. Anchor on the rim instead and five full courses run up to 2070 with a 280 mm cut against the ceiling, plus one course down and a 258 mm cut at the floor. Same room, same tile, two different walls.
The ceiling-anchored version puts a joint at 538, twenty-two millimetres below a rim at 560 — a 22 mm strip of tile lying along the top of the bath for the whole length of the shower, in a width that snaps in the cutter and will not hold enough adhesive to bed. The rim-anchored version puts a full course on the rim, drives one part-course to the ceiling where 280 mm reads as full from below, and takes the other behind the bath panel. That trade is the whole exercise, and it is made in a sketchbook rather than on a wall.
Then eye level, which is the check nobody writes down. Standing in a shower, the band from roughly 1500 to 1700 carries the valve, the riser bracket and the niche, and it is the only part of the wall anybody studies. In the rim-anchored grid a full course spans 1466 to 1768, so no joint crosses the fittings and no narrow strip runs past a chrome escutcheon. Put the rod against that band before committing: it is the one height where a 40 mm sliver is unforgivable, and no sequence of stages will prompt you to look at it.
The useful half of the argument is that some datums move. The rim and the ceiling do not. The niche does, and so do the window board, the shower valve and the top of a half-height run — which inverts the usual order of trades, because the niche framing has to be positioned off the tile grid and that puts the tiler in the room before the carpenter closes the wall. A 300 by 600 niche with its base on the joint at 1164 and its head on the joint at 1768 sits between full courses. The same niche 160 mm lower gives a 142 mm strip beneath and a 160 mm strip above, the upper one running straight across the band anybody in the shower is looking at, and neither recoverable once the boards are on.
| Anchored on | Full courses | Part-course | Where the part-course sits | What it costs elsewhere |
|---|---|---|---|---|
| The ceiling | 7, measured down from 2350 | 236 mm | At the floor, mostly behind the bath panel | A joint at 538 puts a 22 mm strip along a rim at 560, the length of the bath |
| The finished floor | 7, measured up from 0 | 236 mm | Tight to the ceiling, and reads as full from below | A joint at 604 puts a 44 mm strip along the same rim, upside down |
| The bath rim at 560 | 1 below the rim, 5 above | 258 mm and 280 mm | One at the floor, one at the ceiling | Two cut courses instead of one — and neither of them at eye level |
Full tile in the corner, or split the difference
With the courses fixed, the horizontal axis is a three-way choice with arithmetic behind it. Take the wall run and the horizontal module; let n be the whole number of tiles that fit and r be what is left over. A full tile hard into one corner gives the far corner a cut of r. Centring on n full tiles gives both corners r halved. Dropping to n minus one full tiles gives both corners r plus a module, halved. Those three widths are the entire menu on any wall, and the answer is the largest of them that is not itself a full tile.
The floor under that rule is about a third of the tile's width, and it is trade convention rather than a clause in anything: a narrower strip snaps in the cutter more often than it survives, carries too little tile to bed against a wall trying to shed it, and reads as a mistake to someone who could not say why. The odd two or three millimetres belong to the perimeter joint, which takes sealant rather than grout.
Fifty millimetres of wall length can change the answer completely, which is the part worth internalising. On an 1800 wall at a 602 module r is 596, and a corner start leaves a cut nobody would identify as a cut. Add fifty millimetres and r collapses to 44, so the same corner start drives a splinter into the far corner; the fix is to drop to two full tiles and take 323 at each end. Nothing about the room changed except a dimension you did not choose.
The options also consume different amounts of tile. When both ends of a wall are cut to the same width, one tile yields both pieces, so a centred layout on a wide wall genuinely buys less tile than a corner start. When one end takes a full tile and the other a cut, the offcut is worth something only if another cut on the job wants that width — which the sketch answers before ordering, and which is the reason to draw all four walls rather than the one you are standing at. Last comes the corner itself: one wall's tile face runs past the other wall's cut edge, and the face you meet first through the door is the one that should be uncut.
| Wall run | Full tiles | Left over | Full tile into a corner | Centred | Which to take |
|---|---|---|---|---|---|
| 2400 mm, the bath wall | 3 (1806 mm) | 594 mm | One 594 mm space at the far end | 297 mm at both ends | Corner start — one cut instead of two, and the far one reads as full |
| 1800 mm, the end wall | 2 (1204 mm) | 596 mm | One 596 mm space | 298 mm at both ends | Corner start, unless this is the wall you see from the door |
| 1850 mm, the same wall in an older house | 3 (1806 mm) | 44 mm | A 44 mm splinter | 323 mm at both ends, on two full tiles | Centre it — this is the case the rule exists for |
| 1200 mm, over a vanity | 1 (602 mm) | 598 mm | One 598 mm space | 299 mm at both ends | Either — take the one that puts a full tile behind the mirror |
| 900 mm, the shower return | 1 (602 mm) | 298 mm | One 298 mm space beside a full tile | 450 mm at both ends, with no full tile at all | Either — a 298 leaves a usable 300 offcut, two 450s leave two useless 148s |
Three tiles in four carry a cut edge
The area comes off the setting out rather than off a tape. Eight point four metres of perimeter by 2.35 high is 19.7 square metres gross; deduct the door at about 1.5 and the window at about 0.5, add the reveals back, and call it 17.9 square metres of tiled face. At 0.18 square metres a tile, that is a hundred positions before a single cut is made.
The waste allowance comes off the edge, not the area, and this is where a wall parts company with a floor for good. Four wall panels give roughly 35.6 metres of outline, the door opening adds 4.8 and the window 3.0 — about 43 metres of edge around 17.9 square metres of tiling. A floor of the same area is a little over four metres square and has under seventeen. Two and a half times the edge per square metre is the answer when somebody asks why the allowance is higher on the smaller job.
Counting the cut positions makes it concrete. Top course and bottom course are fourteen each. Four internal corners with at least one side of each cut is four columns of eight. The door surround takes about thirteen, the window ten, the niche eight. Roughly three tiles in four in a small fully tiled bathroom carry a cut on at least one edge — which is why ten per cent is the wrong allowance here, fifteen is closer to honest, and a spare box from the same batch is arithmetic rather than caution.
Net face area and the tile's measured size — the one off the rod, not the one off the box — against the waste factor the edge count justifies. Fifteen per cent is the defensible figure for a small fully tiled bathroom, and it is the count of cut positions that earns it rather than the square metres.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The floor or wall area the tile will cover.
The length of one tile.
The width of one tile.
Extra tiles for cuts around edges, corners, and breakage.
Tiles needed
242 tiles
- Area per tile
- 1 sq ft
They open the calculator with your figures already in it
Tile Layout Calculator: 242 tiles — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- A COUNT, NOT A SETTING-OUT. Where the first tile goes decides how many are cut and how narrow the perimeter cuts are, and a room centred on its own axis can waste a whole row more than one started from a datum line. This multiplies area by a waste factor and never places a tile.
- One waste factor for a room that has none. Cuts cluster at the perimeter, around a threshold and at every pipe, so a small bathroom full of edges runs a far higher real waste than a large open floor at the same percentage.
- Assumes one tile size throughout. A border, a feature strip or a change of tile at a threshold each carry their own coverage and their own cutting, and none of them is in this figure.
- Grout joints never enter the count: the divisor is the bare tile face, `tileAreaFt2 = tileLengthFt * tileWidthFt`, so a 1.5 mm (0.06 in) rectified joint and a 6 mm (0.24 in) one return exactly the same number of tiles. A joint makes each tile cover slightly more floor than its own face, so the figure sits a little above what the finished grid needs rather than below it.
- The arithmetic is one area divided by another, not a set-out — nothing compares the room's length and width against the tile, so the model cannot know how many tiles get cut or whether the offcut from one edge is any use at the opposite one. Large-format and plank tiles are where that bites hardest, because a single awkward cut writes off a big piece.
- Only the product of the two tile dimensions is used, so swapping Tile Length and Tile Width changes nothing: a straight grid, a running bond, a herringbone and a 45-degree diagonal all compute identically. Pattern reaches the answer only through the waste percentage, and you have to raise that yourself.
- The waste field is clamped between 5% and 25%, so there is no way to model a job with genuinely no cuts, and no way to push past 25% for a room full of angles or a mosaic border — anything beyond that has to be added to the order by hand.
- Area to Tile is taken exactly as typed: nothing is deducted for an island, a hearth, a bath panel or a shower tray, and nothing is added for a threshold, a step or the return into a doorway. Splitting an irregular room into rectangles and adding them up stays the reader's job.
- A single tile size is read, so borders, feature strips, cove base and bullnose trim sit outside the count, and the waste percentage is spent on cuts and breakage rather than held back as spare tiles for a repair years later.
Bond, and the wall that shows every bow
An offset bond is the default on a rectangular wall tile, and the offset is not a half. Most manufacturers' fixing instructions limit it to about a third on tiles over 300 mm long, and the reason is warpage: a tile bowed along its length carries its high point at the middle, and a half bond parks that high point hard against the end of its neighbour, where the step is both most visible and most felt. ANSI A137.1 tabulates the permitted warpage the joint has to absorb, and on a wall you have one fewer remedy than on a floor, because you cannot stand on a tile to close the step.
A stack bond runs every joint straight through, so every millimetre of facial size variation is read along a two metre line by whoever is standing in the shower; it wants a rectified tile and a background made flat rather than adequate. Standing the same tile on end swaps the modules to 302 across and 602 up, and every figure in this article changes with it. A diagonal or herringbone field turns each of those 43 metres of edge into a 45 degree cut, and a triangular offcut from one edge almost never fits another. Forty-three metres at a 600 mm tile is seventy-two perimeter positions, each losing about half a tile: roughly six and a half square metres of extra waste on a room with 17.9 to cover, a third again on top of the field. The pattern selectors here put a straight lay at ten per cent and a herringbone at twenty, and on a wall the honest allowance sits above the top of that band. That is not an argument against a diagonal bathroom — it is the price of one, and it belongs in the quotation rather than in the second delivery.
It is written around a room's perimeter, so on a wall you feed it the total edge of the tiled panels instead — corners, ceiling line, floor line and every reveal. What comes back is the extra on top of a base tile count, not a replacement for one.
The total perimeter of the room to be tiled diagonally.
The side length of a single square tile.
The area of a single tile.
Extra diagonal corner-cut waste
32.9 ft²
This estimates the ADDITIONAL waste specific to diagonal corner cuts, on top of your tile layout calculator's base tile count — it is not a replacement for that count.
- Perimeter tile positions requiring a corner cut
- 68
They open the calculator with your figures already in it
Diagonal Tile Layout 45° Corner Cut Waste Calculator: 32.94 ft² — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Half a tile per position is an average that assumes the offcut is scrap. In a plain rectangular room the triangle cut off at one wall is often the exact piece wanted at the opposite wall, and a setter who plans the cuts recovers much of it, so this figure is an upper bound there. In a room with alcoves, returns and doorways nothing matches up and the real waste runs above half.
- The setting-out point decides how much of each perimeter tile survives, and it is not in this calculation at all. Shifting the diagonal origin a little turns a row of unusable slivers into generous triangles, and slivers cost more than the geometry suggests — a narrow diagonal cut breaks on the saw more often than it survives, so it is scrapped and cut again. The perimeter length is fixed; where the grid starts is not.
- Assumes every offcut is interchangeable. Directional tile, a wood-look plank, a stone with a run of vein, or a rectified tile laid to a matched pattern cannot simply be turned around to fill the opposite wall, so the offcut recovery that keeps waste near half is unavailable. On top of that sits the breakage rate on long diagonal cuts in hard porcelain, which is a separate loss from the geometric waste counted here.
The batten, and the membrane you must not screw through
The batten carries the first full course while the adhesive grabs, and it goes under that course rather than at the floor, because the bottom course is a cut and a cut course cannot carry a field. In the worked room its line is struck at 563 — three millimetres above a rim at 560, leaving the sealant joint. Fix it level. Not parallel to the bath: level. The rim's six millimetres of fall are then absorbed by a silicone joint tapering from three to nine, a joint whose whole purpose is to absorb movement and which nobody will ever measure, rather than by a course of tiles that fifty people will sight along.
Then the expensive part. In a tanked shower the wall carries a bonded waterproof membrane — brush-applied or sheet, specified to ANSI A118.10 in the American system, with the wet area provisions in BS 5385-4 — and a batten screwed through it puts eight holes in the only thing keeping water out of the stud bay. No sequence avoids this cleanly, since tanking and battening both precede tile. Keep the fixings outside the tanked zone where the geometry allows; or support the first course on proprietary wall wedges bedded into the adhesive instead; or repair every hole with the membrane system's own patch detail, photographed, before a tile goes near it. The tanking belongs to the wet room guide; what belongs here is that the setting-out method has to be chosen with the membrane in mind.
What the batten is made of matters less than whether its top edge is straight, since a bowed batten prints its bow into the first course and every course above inherits it. Screws rather than nails, because it has to come off without levering against tiles that are three days old. Leave it until the adhesive has genuinely set — in a cold bathroom in February, longer than the bag implies, which is most of the reason a fast-setting class exists in the BS EN 12004-1 designations. Then strip it, make good the fixings, and cut the bottom course last, scribed to the floor as it actually finished.
- Mark finished floor level on all four walls from the floor build-up, not from the deck you are standing on.
- Carry the rod's course marks round every internal corner with a level, so all four walls read one grid.
- Strike the line for the bottom of the first full course, and check it against the rod at both ends of every wall before fixing anything to it.
- Fix the batten level, sight along its top edge for bow, then set a second batten as a plumb rule at the corner you are starting from.
What the wall will carry, and what it will not straighten
A tiled wall is the only tiling surface in the house where mass is a design input, because it is held up by adhesion rather than gravity. BS 5385-1 tabulates a maximum weight of tiling for each background, and the ranking is worth carrying even when the figures are not: gypsum plaster takes the least, plasterboard more, a sand and cement render more again, and a tile backer board whatever its manufacturer certifies. Read the current figure from the standard rather than from memory, then do the arithmetic before choosing the background. Nine millimetre porcelain at a bulk density near 2,400 kg per cubic metre is about 21 kilos a square metre, and a three millimetre cementitious bed adds four and a half. Call it 26. A twenty millimetre marble is nearer sixty.
Inside an enclosure the choice narrows to a cementitious backer unit to ANSI A118.9, a coated glass mat gypsum panel to ASTM C1178 or an equivalent proprietary board, with the International Residential Code's wall covering provisions setting what is permitted. Flatness then has no rescue, because you cannot pour a levelling compound down a vertical plane: whatever bow the straightedge found comes out of the background, or is absorbed in a bed whose stated maximum thickness is usually thinner than the bow people try to bury in it. ANSI A108.02 sets the substrate requirements and BS 8000-11 the workmanship.
Gravity is against you for the first four hours
On a floor the tile is trying to sit still. On a wall it is trying to slide down and fall off, and it has about an hour in which to be stopped. BS EN 12004-1 classifies adhesives by the properties that decide whether it is: C for cementitious against D for a dispersion, 1 or 2 for normal or improved, T for reduced slip, E for extended open time, F for fast setting, S1 or S2 where the background moves. The T is the letter a wall tiler is actually buying, and it is awarded on the slip test in BS EN 1308 rather than on a claim in a brochure.
The tub of ready-mixed paste is the most common wrong purchase in a domestic bathroom. It is perfectly good behind a basin and wrong in a shower, in a way that takes about a year to appear: a dispersion adhesive cures by losing water to the air and to the background, and behind an impervious porcelain tile on a tanked wall there is nowhere for that water to go. Continuous wet areas take a cementitious adhesive, and BS 5385-4 is where that requirement lives rather than in advice given across a trade counter.
Quantity follows the notch. A 600 by 300 wants a 10 mm square notch at roughly five kilos a square metre, and the back-buttering a shower's coverage requirement makes unavoidable adds about a third — some 116 kilos over 17.9 square metres, so six twenty-kilo bags before any dubbing out and seven with it. Coverage percentages, ribbed backs and skinned beds are worked through in the floor tiling and wet room guides. What changes up a wall is that you comb only what you can reach comfortably, two or three tiles' worth, and check the leading edge against the plumb batten every second course — a millimetre of drift per course is invisible at course three and eight millimetres out of plumb by the ceiling.
Notch and back-buttering are the two inputs that move the answer; a 600 by 300 on a shower wall is a 10 mm notch with buttering, which is not the same bag count as the same tile dry-laid on a hallway floor.
Net tiling area.
Notch size governs how much adhesive stays on the wall.
A skim coat on the tile back as well as the substrate.
Weight of the bags you are buying.
Adhesive required
3 bags
Coverage rates are typical for cement-based adhesive. Check the specific product — rates vary by 20% between brands and between standard and lightweight formulations.
- Adhesive required
- 133.13 lb
- Coverage rate
- 1.02 lb/ft²
- Bag size
- 50 lb
- Surplus in the last bag
- 16.87 lb
They open the calculator with your figures already in it
Thinset & Tile Adhesive Calculator: 3 bags — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- An uneven substrate consumes considerably more than these figures. Levelling first is cheaper than filling with adhesive, and it performs better.
- Does not cover a levelling compound, a decoupling membrane or a waterproofing layer, all of which are separate materials.
The spacers are doing structural work
On a floor a spacer holds a gap. On a wall it also holds a load, because until the adhesive grabs every tile in a course is standing on the one below it and the spacer is the thing in compression. That changes which sort you buy: a cross spacer pushed flat into the joint sits at the depth the grout needs and has to be pulled from a joint whose tile is still green, while a T-spacer or a wedge sits proud at the face and comes away clean. Wedges earn their keep on the first course over a bath rim, holding three millimetres along a rim that falls six.
Levelling clips hold the face flush against a tile trying to slump, which on a 600 format is the difference between a wall you can sight along and one you can feel with a flat hand. Snap them off along the joint rather than across it, and snap them the next day: a clip broken out of a green wall takes the tile with it. The count is small enough to get wrong — a hundred positions plus fifteen per cent is 115 tiles, and at the usual sharing factor of two and a half spacers per tile that is about 290, which is two bags of 250 rather than one. Every one of them comes out before grouting.
Run it on the same tile count and the same waste percentage as the layout above, so the two agree — a spacer count worked from a different waste figure is exactly the small inconsistency that sends someone back to the merchant on grouting morning.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The floor or wall area to be tiled, measured as for the tile count.
The length of one tile; with the width, it sets how many tiles there are to space.
The width of one tile.
The estimating factor used to convert tile count into spacer count.
Extra tiles (and therefore spacers) for cuts around edges, corners, and breakage.
Tile spacers needed
605 spacers
Spacers-per-tile varies by tile size and layout pattern, and the direction is the opposite of the intuitive one: a straight grid meets four tiles at every intersection, so one cross spacer serves four corners, while a running bond meets three at a T-junction and so needs MORE spacer positions per tile, not fewer. Raise the factor for a staggered layout rather than lowering it. Buy an extra bag if in doubt, since spacers are inexpensive relative to a shortage causing a project delay.
- Tile count
- 242
They open the calculator with your figures already in it
Ceramic/Porcelain Tile Spacer Count Calculator: 605 spacers — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- THE 2.5 FACTOR IS A GRID ASSUMPTION, and the pattern you are laying decides whether it holds. A running bond meets three tiles at a T-junction rather than four at a cross, a herringbone meets tiles at every other edge, and a large-format tile laid with levelling clips uses a clip per edge rather than a spacer per corner. Same tile count, materially different spacer count.
- Spacers are consumed, not just placed. Ones that sink into the adhesive, ones that will not come back out of a narrow joint and ones that snap on removal all leave the count — the bag you buy is not the number that ends up between tiles.
- Says nothing about the joint width, which is the decision this calculation sits underneath. Spacer size is set by the tile's edge, its rectification and the substrate's movement, and a spacer count is useless if the width is wrong.
- Assumes the spacer is a cross sitting in a corner. Large-format tile is not set that way: much above 400 mm (16 in) on a side it goes down with a lippage control system — a clip in the joint at intervals along every tile EDGE with a wedge or cap driven onto it — so the quantity follows the length of the joints, not the number of corners, and the clips snap off and are thrown away while the wedges come back. Run a 600 x 300 floor through this page and you order the right count of the wrong product.
- Counts the joints between tiles and not the joint around the outside of them. The perimeter gap at every wall, column and threshold is held open with its own spacers or wedges while the field sets, and that gap is what gives the floor somewhere to go when it expands — close it up because the bag ran out and the only direction left is up.
Every arris in a bathroom is a decision
A fully tiled bathroom has more external corners than any other room of its size: both arrises of the boxing round the soil stack, full height; the three arrises of a window reveal; the outer return of the enclosure; the top of any half-height run; and the four arrises of a niche, which is the fiddliest metre and a half on the job. In the worked room that is about ten metres before any allowance — five two-and-a-half metre sticks, six once the niche corners have each eaten a stick end.
Mitre or trim is the decision, and looks settle it less often than people expect. A mitred porcelain arris is the better-looking answer and also a knife edge of unglazed biscuit that chips the first time a shower screen swings into it; a trim is insurance with a visible line. Inside an enclosure a third consideration usually decides it: a mitre is a joint that has to be sealed and stays sealed only as long as the silicone in it, whereas a trim has a joint behind its leg for the membrane and the adhesive to close between them. Choose before the tiles are ordered, because a mitred job cuts its arris pieces from full tiles and a trimmed one does not.
Then two smaller decisions. The profile is sized on the tile plus its bed rather than the tile alone — nine plus three here, so a 12.5 rather than a 10 — and a wall dubbed out anywhere makes that sum local. Material is a cleaning question rather than a strength one: anodised aluminium survives everything in a domestic bathroom except a limescale remover left sitting on it.
Count only the edges you are not solving with a mitre or a shaped piece, add the allowance the niche corners deserve, then convert the total into whole sticks — any run you want unjointed has to fit inside one.
SettingsSettings for this calculation
Waste is set to 8% by hand. Pick a tier above to replace it, or keep your own figure.
The total length of tile edges that will be exposed and need trim protection.
Extra trim material for corner miters and offcuts.
Edge profile needed
105.8 ft
They open the calculator with your figures already in it
Tile Edge Profile (Trim Strip) Linear Footage Calculator: 106 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Part of a profile system is sold by the piece, not by the length. Molded outside corners, inside corners and end caps are separate items, and they are what finishes a return cleanly — a site-cut miter in an anodized or powder-coated profile leaves a raw cut edge on show at the exact corner everyone looks at. Count corners and stops off the drawing alongside the linear total.
The joints that get grout, and the joints that must not
Quantity first, because it is smaller than people expect and that is the point. A 600 by 300 at a 2 mm joint carries just under five metres of joint in every square metre — one over 0.302 plus one over 0.602 — and at two millimetres wide by nine deep that is about 0.09 litres a square metre, a little over a litre and a half for the whole room. Two kilos and a bit. Grout is the cheapest material on the wall and the most looked at, which is the argument for two bags of one batch rather than one bag and a top-up in a fortnight.
Then the joints that are not grout at all, and a bathroom has more of them per square metre than anywhere else in the building. Wall to wall, wall to ceiling, wall to floor, wall to bath rim, wall to tray, and the four internal corners inside the niche are all movement joints taking a flexible sealant. Grouting an internal corner is the most repeated mistake in the trade: it cracks, because the two planes move independently, and the crack is the route water takes into the stud bay. The movement joint guidance in the TCNA Handbook and BS 5385-1 is the reference, elastomeric sealants are specified to ASTM C920, and a shower wants a sanitary grade with a fungicide in it.
Grout first, cure for the period the bag states rather than the period the programme wants, then silicone — laid into a green joint it traps the water the grout is still giving up and fails from behind, invisibly. Then say at handover what nobody says: the silicone is a maintenance item with a life measured in a few years rather than the life of the tiling, and the grout will discolour whatever colour it starts, a dark one showing limescale and a white one showing everything else. Grout is classified in BS EN 13888 and internationally in ISO 13007, and in a domestic bathroom the class matters more than the shade.
Give it the wall's net tiled area and the tile as it really is — 600 by 300, not a square near it — with the 2 mm joint and a depth of 9 mm. The joint length above is what it works from, so it comes back with the litre and a half as kilograms, and the bags that is.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The tiled area — the surface, not the tiles ordered.
The long side of one tile, as sold.
The short side of one tile; the same as the length for a square tile.
The gap between tiles — the spacer size.
How deep the grout goes — normally the tile's thickness.
The weight of one volume of grout once mixed and packed into the joint.
Grout left in the bucket, on the float and washed off the face.
Grout needed
3.051 lb
About 1 × 25 lb bag(s). The joint volume is geometry and is as good as the sizes entered; the mass follows the density, which varies by product.
- Share of the surface that is joint
- 0.98 %
- Joint volume
- 0.03 ft³
- Before the allowance
- 2.77 lb
- Allowance at 10%
- 0.28 lb
- 25 lb bags
- 1 bag
They open the calculator with your figures already in it
Grout Calculator: 3.05 lb — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- The joints are counted on a straight grid. A herringbone, a brick bond or a mix of tile sizes lays the same joint area only approximately, and an irregular stone or hexagonal tile has a different joint geometry altogether.
- Joint depth is taken as full to the tile face. Where adhesive has squeezed up into the joints and set, the grout goes less deep and less is used — and the joint is weaker for it.
- Movement joints take a flexible sealant, not grout — at internal corners, where tiling meets a bath or shower tray, round the edges, and at intervals across a large floor — and grout put into them cracks. They are counted here as grout, so on a room with many of them the figure reads slightly high.
- Density varies by product, and a sanded or epoxy grout can be heavier than the default. A bag's own consumption chart, where it gives one, is the better figure for that product.
The order these have to be settled in
Each one closes off the next: the floor build-up fixes the datum, the datum fixes the courses, the courses fix the cuts, and only once the cuts are known does anything get counted.
- Finished floor level, marked on all four walls — Board plus bed plus tile above the deck. Every vertical dimension in the room is measured from it, and a bath rim taken off bare boards is out by the whole build-up.
- The module, off ten tiles rather than off the box — Lay ten with the spacers you will use, measure the run once, divide by ten. Mark a rod with it and hold that rod against the ceiling, the rim, the window and the pencilled niche.
- The anchor, and the two heights it must not spoil — One datum gets the full course. Check the 1500 to 1700 band and the top of the bath rim before committing — those are the two places a narrow strip is unforgivable.
- End cuts, chosen from the three widths the wall offers — The leftover for a corner start, half of it, or half of it plus a module for the two centred options. Take the largest that is not a full tile and not under about a third of one.
- Tile, at the waste the edge count justifies — Roughly three tiles in four in a small bathroom carry a cut edge, which is why fifteen per cent rather than ten, plus a spare box from the same batch.
- Adhesive, spacers, trim and grout against the settled layout — Notch and back-buttering set the bags, the spacer count has to use the same waste figure as the tile count, trim converts to whole sticks, and grout follows joint length rather than area.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.