Artificial Grass Calculator: Roll Length
Measure rectangular lawn sections and choose a roll width and cut direction. Compare lawn area with separate cut lengths and full-width purchase area.
How the estimate works
Lawn area = sum(length × width) for complete, non-overlapping rectangular sections. Cut rectangle dimensions = measured dimensions + explicitly supplied extras (blank adds zero). For each explicitly chosen direction, along = that adjusted dimension and across = the other adjusted dimension. Across must not exceed the supplied roll width. Cut length = along without a rounding step; otherwise independently ceil(along / explicit positive step) × step, using safe whole-number arithmetic and never returning a shorter cut. Total cut length = sum of these separate cuts, with no offcut pooling. Full-width bought area = total cut length × roll width. Known area alone cannot determine cut length.
Deterministic rectangular quantity arithmetic only. No area exclusions from measured cuts, automatic joined strips, offcut reuse, or full-roll/piece inventory guarantee. Lawn area, extra-adjusted rectangle area and full-width bought area are different quantities. Every active section needs explicit direction and confirmation; missing facts or any non-fitting across-width measurement withhold all purchase totals. This is not a fitting layout, product recommendation or sufficient-order guarantee.
Reading your result
Lawn area is the ground you measured. Full-width bought area includes the whole roll width for every separate cut, so it can be larger. Total cut length is a sum of separate cuts, not a promise that one continuous piece or a joined layout will fit.
Worked example
Hypothetical rectangle: 4 m length × 3 m width gives 12 m² of lawn. With an explicitly supplied 4 m roll width, length direction and complete-rectangle confirmation, and no extras or rounding step, the separate cut is 4 m long and the full-width bought area is 16 m². Choosing width direction instead gives a 3 m cut and 12 m² bought area because the 4 m across-width dimension fits exactly. These are arithmetic examples, not fitting advice or prefilled values.
What to measure
Measure complete rectangular lawn sections without subtracting holes, and confirm that separate sections do not overlap. Choose whether each cut runs along its named length or width, then confirm these are the complete rectangles for this calculation. Supply the roll width and only your own trimming extras or positive length-rounding step. Blank extras mean before fitting extra; no trimming allowance or direction is assumed. Known area gives an area result only.
Why is bought area different from lawn area?
Each separate cut uses the entire supplied roll width. Its full-width bought area is cut length × roll width, not simply the lawn area or an assumed waste percentage.
Can I use a known area?
Yes, for an area result. An area alone does not specify rectangular dimensions or direction, so it cannot determine an actual cut length or purchase total.
Are trimming extras included?
Only extras you explicitly enter. Blank extras add nothing and the rectangles are before fitting extra. Extras are total additions to the named dimensions, not automatically doubled edge allowances.
What happens if a rectangle is too wide?
After explicit extras, the across-width measurement must fit the supplied roll width. If it does not, all purchase totals are withheld pending a supplier fitting/layout check; the calculator does not invent joined strips or rotate the chosen direction.
Can I subtract a hole or reuse an offcut?
Not in measured cut rectangles: a hole does not shorten a full cut. Each section has a separate cut and rounding operation; no offcuts are pooled or credited.
Does this give a count of full rolls?
No. It shows separate cut quantities, total linear cut length and full-width bought area only. It does not allocate stock rolls or guarantee inventory, usable pieces, fitting or a sufficient order.
Where the numbers come from
Formula v1.0. Numerical product facts start blank unless you explicitly apply a verified option. Supplier facts checked 14 November 2026; they do not establish stock, delivery, suitability or a final order.
- Grass Warehouse — Lunar 20mm Artificial Grass — checked 2026-11-14
- Grass Warehouse — Hestia 40mm Artificial Grass — checked 2026-11-14
- Forever Green Lawns — Bahamas 30mm Pile — checked 2026-11-14
Other garden quantities
Turf · Grass Seed · Gravel and topsoil · Raised-bed soil · Plan a patio (a separate project)