How much artificial grass do I need?
Artificial grass is bought by area but sold in rolls of fixed width, and the gap between those two facts is where most orders go wrong. A garden of 30 square metres cannot always be covered by 30 square metres of grass, because the shape decides how much is cut away.
This guide shows the measuring method we use, then how the roll widths turn your area into a quantity and a price.
7 minute read · Updated November 2026
Measure the shape, not just the size
Sketch the lawn and break it into rectangles. For each rectangle record the longest length and the widest width, in whole metres, because artificial grass is cut to the measurement you give us. Measuring round beds as squares is deliberate: you cannot fit a rectangle of grass around a curve without waste, so plan to cut the curve out of a rectangle.
- Measure to the edge of the final lawn, not to the old turf edge.
- Add 50mm to each dimension for trimming into the edging.
- Measure in at least three places for length and width; gardens are rarely square.
- Record slopes separately: a lawn on a slope needs more length than the plan suggests.
Square metres
Area is length multiplied by width. For several rectangles, add the areas together. Irregular shapes are usually best treated as a large rectangle with the offcuts counted as waste, because those offcuts cannot be joined invisibly.
Roll widths decide the joins
A roll is a fixed width and a length cut from it. If your garden is wider than the roll, it is covered with two or more strips laid side by side and joined with tape and adhesive. Each join is a line in the lawn, so the aim is the fewest joins in the least conspicuous places.
- Lay strips along the longest dimension where possible: fewer joins, less waste.
- A join running away from the house and towards a border is less visible than one across the middle.
- Stagger joins rather than aligning them, so no continuous line appears.
- Avoid a join where a table, goal or path crosses the lawn.
Waste allowance
Some waste is normal. Simple rectangular gardens with a roll width that divides cleanly need very little; curved, angled or stepped gardens need more. Cutting to fit around a curved border from a rectangle can waste a band along the whole edge.
| Garden shape | Waste to plan for | Why |
|---|---|---|
| One rectangle that fits one strip | Minimal, 50–100mm per edge to trim | The roll is cut once and laid |
| Two strips side by side | One joining allowance plus trimming | Each strip is cut to length |
| L-shaped or stepped | A band equal to the offset | The step has to be cut out of a rectangle |
| Curved or angled borders | The largest band, often the full curve depth | Curves are cut from rectangular pieces |
An example
A lawn 5.2m wide by 6.4m long is 33.28m². It is wider than a single 4m strip, so it becomes two strips of 6.4m, plus trimming allowance. That is 12.8m of 4m-wide roll, or 51.2m² of grass for a 33m² garden, because the second strip is only partly used. Whether that is wasteful depends on the roll width available, which is why the width matters as much as the price.
Check the order before paying
- 01
Re-measure at both ends
Confirm the length and width at the widest points, in whole metres.
- 02
Confirm the roll direction
Grass has a pile direction. All strips must run the same way or the join will show as a colour change.
- 03
Add the fixing materials
Joining tape, adhesive and edging are ordered alongside the grass. See accessories.
- 04
Keep the plan
Grass is cut to your measurements, so the order is final once confirmed. Check twice.
Where to go next
Questions answered in this guide
Related buying guides
Royal Grass roll widths explained
Why width decides the joins and the price.
How much does Royal Grass cost?
The full basket from lawn to installation.
Grass calculator
Work out area, rolls and price.