SettingsSettings for this calculationUS
Waste is set to 5% by hand. Pick a tier above to replace it, or keep your own figure.
The area the resin bound surface covers.
Break an irregular drive into rectangles and triangles, measure each twice and add them up. The area multiplies through the stone, the resin, the primer and the labour, so it is worth getting right before anything else.
Tools needed: Tape measure
How thick the finished resin bound layer is laid.
Depth follows the stone: at least three times its largest particle, or the surface has too little interlock and ravels. Footpaths in 1–3 mm stone are commonly laid at around 12–15 mm (about 1/2 to 5/8 in), and drives in 2–5 mm stone at around 18 mm (about 3/4 in); the system's data sheet has the binding figure. The small sample board a salesman carries is laid thinner still and says nothing about a drive.
The top size of the aggregate: 5 mm (about 3/16 in) for a 2–5 mm blend.
It sets the least depth the surface can be laid to, three times this size, and the page states how the depth you entered compares.
How much a loose-filled volume of this particular dried stone weighs — from its supplier.
A measured property of the specific stone (BS EN 1097-3, ASTM C29), and different stones at the same size do not weigh the same, so take it from the supplier's sheet. The default, 1,550 kg/m³ (97 lb/ft³), is a placeholder of the usual order for dried natural aggregate, not any product's figure.
The weight of dried stone one Part A and Part B kit is proportioned for — on the kit.
Two-part systems are sold so that nobody measures a ratio on site: each resin kit is matched to a set weight of stone, often supplied with it in bags. That weight is on the kit and in its data sheet; the default is a placeholder of the usual order, not any system's figure. The resin percentage is built into the kit, which is why this page never asks for it.
Extra stone for dips in the base, edges and what is left in the mixer.
An old tarmac or concrete base is never flat, and every dip is filled at the laid depth plus the dip. A base that was surveyed and made good needs less; a tired drive with ruts needs more, or regulating before the resin goes down.
Resin kits to order
13 kits
The depth entered is 3.7 times the largest stone; the trade's working rule is at least three. Every kit is mixed whole — Part A, Part B and its matched stone together — so the order is a count of kits, with the resin percentage already inside each one. Both the stone's density and each kit's stone are the product's own figures, so enter them from the system's data sheet.
- Stone at the laid depth
- 2,600.51 lb
- Stone with the allowance
- 2,730.54 lb
- Stone in whole kits
- 2,860 lb
- Area one kit covers at this depth
- 36.38 ft²
- Least depth for this stone — three times its largest size
- 0.6 in
They open the calculator with your figures already in it
Resin Bound Surfacing Calculator: 13 kits — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Stone = area × laid depth × the loose bulk density of that specific dried aggregate, a measured property — BS EN 1097-3 (loose bulk density and voids) or ASTM C29 (bulk density and voids in aggregate) — not a figure from a generic coverage chart
- Two-part resin bound systems are supplied as matched kits — Part A, Part B and the stone they are proportioned for — and are mixed whole in a forced-action mixer; kits = stone needed ÷ the stone one kit is matched to, rounded up, never split
- The trade's working rule is a laid depth of at least three times the largest stone: commonly 1–3 mm stone at around 12–15 mm for footpaths, and 2–5 mm stone at around 18 mm for domestic drives. The binding figure is the system's own data sheet; there is no British Standard for resin bound surfacing
Inputs used
- Area to Surface
- 430 sq ft
- Laid Depth
- 0.75 in
- Largest Stone Size in the Blend
- 0.2 in
- Loose Bulk Density of the Dried Stone
- 96.76 pcf
- Stone One Resin Kit Is Matched To
- 220 lb
- Allowance for an Uneven Base and Loss (%)
- 5
Intermediate steps
- Stone at the laid depth
- 2,600.51 lb
- Stone with the allowance
- 2,730.54 lb
- Stone in whole kits
- 2,860 lb
- Area one kit covers at this depth
- 36.38 ft²
- Least depth for this stone — three times its largest size
- 0.6 in
Confidence note: The depth entered is 3.7 times the largest stone; the trade's working rule is at least three. Every kit is mixed whole — Part A, Part B and its matched stone together — so the order is a count of kits, with the resin percentage already inside each one. Both the stone's density and each kit's stone are the product's own figures, so enter them from the system's data sheet.
What this calculation does not cover
- A surface, not a structure. Resin bound carries no load of its own; the tarmac, concrete or new permeable build-up beneath it does, and cracks, soft spots or a failing base come straight through. Survey and core the base first — the site's resin bound guide says what to look for.
- The stone's loose bulk density and the stone each kit is matched to are the product's figures, and the defaults here are placeholders of the usual order. Enter both from the system you are buying, or the kit count is a guess.
- Primer for the base, edge restraints, day-joint edging and any regulating course are not counted, and neither is the base work itself.
- Pot life, temperature and moisture decide whether each kit cures, and none of them is a quantity. Dried stone that has taken on water, a damp base or rain inside the cure window ruins a batch outright.
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.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-21 · v1.0.0
Regulatory standards & verification citations3
- Stone = area × laid depth × the loose bulk density of that specific dried aggregate, a measured property — BS EN 1097-3 (loose bulk density and voids) or ASTM C29 (bulk density and voids in aggregate) — not a figure from a generic coverage chart
- Two-part resin bound systems are supplied as matched kits — Part A, Part B and the stone they are proportioned for — and are mixed whole in a forced-action mixer; kits = stone needed ÷ the stone one kit is matched to, rounded up, never split
- The trade's working rule is a laid depth of at least three times the largest stone: commonly 1–3 mm stone at around 12–15 mm for footpaths, and 2–5 mm stone at around 18 mm for domestic drives. The binding figure is the system's own data sheet; there is no British Standard for resin bound surfacing
Which documents these citations point at
Standards referenced: ASTM C29 (ASTM International, United States); BS EN 1097-3 (European Committee for Standardization, as published in the UK by BSI, European (EN)).
Cite this page
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