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How far the lawn runs away from where it is mostly seen from — usually the house.
Measure from the side nearest the main view to the far side. For a curved or irregular lawn, measure the smallest rectangle that encloses it, lined up with the house: grass is bought in rectangles and cut to curves on site, so what is cut away is real waste and belongs in the order.
Tools needed: Tape measure
How wide the lawn is from side to side, as seen from the main view.
Measure at the widest point. When the rolls run away from the view, as they usually do, this is the measurement the roll widths are laid across — so it decides how many pieces and joins the lawn takes.
Tools needed: Tape measure
The width the grass you are buying comes in, in the widths of the measurement system you have chosen.
Artificial grass is cut to length off a roll of fixed width. Where it is sold in metric widths that is usually 4 m, with 2 m for narrow spaces and some products; in the US it is usually 15 ft, with some products at 12 ft. The two are not the same roll — a 15 ft roll is wider than a 4 m one — so switching the measurement system switches the roll, and can change the order.
The direction every piece is laid in — which fixes the way the pile faces.
Artificial grass has a pile that leans one way along the roll, and it looks fuller and greener seen from the direction it faces. So every piece is laid the same way, conventionally with the pile facing the house or wherever the lawn is mostly seen from, and a piece is never turned to use up an offcut — it would show as a band of a different shade. The result also shows what laying the rolls the other way would take, so the cost of keeping the pile facing the view is visible.
Extra on the length of every piece, and on the width the pieces must cover, so the grass can be trimmed in place.
Artificial grass is cut oversize and trimmed to the edging once it is down, and the factory edge is cut off both sides of every join, so the pieces must be longer and together wider than the lawn. Installers commonly allow 5 to 10 cm (2 to 4 in) at each edge; on a garden-sized lawn that is a few per cent, which is the default. It is also why a lawn measured at exactly two roll widths takes three: two widths leave nothing to trim.
The length of join one cartridge, tub or kit of adhesive covers — printed on the product.
Only the product knows this figure. Cartridges commonly state a few metres of join each, and tubs and two-part kits a great deal more; the default is a placeholder of that order, not any product's figure, so replace it with the one on the adhesive you buy.
Artificial grass to buy
509.9 ft²
The lawn takes 2 pieces side by side and 1 join; the tape runs the full length of each, and the adhesive is counted from the join length each pack covers, as entered. Laid across the main view instead, the rolls would take 39% more grass and 1 join — but the pile would face sideways to the view.
- Pieces to cut, each one full roll width
- 2 pieces
- Length of each piece
- 17 ft
- Roll width
- 15 ft
- Joins between the pieces
- 1 join
- Joining tape, the full length of every join
- 17 ft
- Adhesive, at the join length each pack covers
- 2 packs
- Lawn area
- 379.5 ft²
- Grass bought beyond the lawn area
- 34.35 %
- Perimeter to fix down
- 79 ft
- Rolls laid the other way: grass to buy
- 710.7 ft²
- Rolls laid the other way: joins
- 1 join
They open the calculator with your figures already in it
Artificial Grass and Synthetic Turf Calculator: 510 ft² — 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)
- Artificial grass is sold cut to length off rolls of fixed width — commonly 4 m and 2 m where it is sold in metric widths, and 15 ft, with some products at 12 ft, in the US — so a lawn takes whole widths laid side by side, each cut to the lawn's length with extra for trimming
- Every piece is laid with its pile running the same way, conventionally facing the main view, because a piece turned the other way shows as a band of a different shade; offcuts therefore cannot be turned to fill a gap. Pieces are joined over joining tape with adhesive, after the factory edge is trimmed from both sides of the join
- Adhesive = total length of the joins ÷ the join length one pack covers, which is the manufacturer's figure printed on the product
Inputs used
- Lawn Depth, Measured Away From the Main View
- 16.5 ft
- Lawn Width, Measured Across the Main View
- 23 ft
- Roll Width
- 15 ft wide
- Roll Width, From the Product
- 16.5 ft
- Which Way the Rolls Run
- Away from the main view, so the pile faces it (usual)
- Trimming Allowance (%)
- 3
- Join Length One Pack of Adhesive Covers
- 11.5 ft
Intermediate steps
- Pieces to cut, each one full roll width
- 2 pieces
- Length of each piece
- 17 ft
- Roll width
- 15 ft
- Joins between the pieces
- 1 join
- Joining tape, the full length of every join
- 17 ft
- Adhesive, at the join length each pack covers
- 2 packs
- Lawn area
- 379.5 ft²
- Grass bought beyond the lawn area
- 34.35 %
- Perimeter to fix down
- 79 ft
- Rolls laid the other way: grass to buy
- 710.7 ft²
- Rolls laid the other way: joins
- 1 join
Confidence note: The lawn takes 2 pieces side by side and 1 join; the tape runs the full length of each, and the adhesive is counted from the join length each pack covers, as entered. Laid across the main view instead, the rolls would take 39% more grass and 1 join — but the pile would face sideways to the view.
What this calculation does not cover
- A rectangle. For a curved or irregular lawn, enter the smallest rectangle that encloses it, lined up with the direction the rolls run; for an L-shape, enter each rectangle separately with the rolls running the same way in both. Offcuts from one part can only fill another where their pile runs the same way.
- Each piece is one continuous length off the roll. A lawn longer than the longest piece the supplier can cut needs a join across each width as well, which this page does not add.
- The joins are counted and taped here, not placed. Keep them out of the line people walk along where you can, and away from where water runs across the lawn, even if that means an extra piece.
- The adhesive count rests on the join length each pack covers, which is the product's own figure. Adhesive used to glue the edges to a hard border, or to fix the whole lawn to concrete or decking, is not included.
- The ground beneath is not counted: the excavation, the crushed-stone sub-base and the finer laying course over it, the weed membrane, the edging, the pins or nails around the perimeter, and any sand infill the product calls for.
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
- Artificial grass is sold cut to length off rolls of fixed width — commonly 4 m and 2 m where it is sold in metric widths, and 15 ft, with some products at 12 ft, in the US — so a lawn takes whole widths laid side by side, each cut to the lawn's length with extra for trimming
- Every piece is laid with its pile running the same way, conventionally facing the main view, because a piece turned the other way shows as a band of a different shade; offcuts therefore cannot be turned to fill a gap. Pieces are joined over joining tape with adhesive, after the factory edge is trimmed from both sides of the join
- Adhesive = total length of the joins ÷ the join length one pack covers, which is the manufacturer's figure printed on the product
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