Artificial (Fake) Grass Calculator

Work out how much artificial grass to order for your lawn, and what goes under it. Some call it fake grass or synthetic grass.

Made by BuildersCount · Last checked 4 Oct 2026 · Our sources

Measure your lawn

LengthmWidthm

Roll widths your seller has

Namgrass and Perfectly Green sell rolls 2 m and 4 m wide. Some grass also comes 5 m wide.

Which way do the strips run?

Lay every strip the same way. If the pile must face your house, pick the way that does that.

MOT Type 1 depth

Two makers: 50–70 mm (Namgrass); 50 mm on free-draining soil, up to 100 mm on clay (Perfectly Green).

Your answer

Order about

19.8m² of grass

For a 15.0 m² lawn: 2 strips (4 m + 2 m wide), each 3.3 m long, laid along the width. That is 32% more than the lawn. It covers trimming and any spare width.

1 join: about 3.3 m of joining tape. Fewer joins: 4 m needs 21.2 m² with no joins.

2.3

tonnes of MOT Type 1

75 mm, packed

0.45

tonnes of sharp sand

20 mm on top of it

75–120

kg of kiln-dried sand

up to 5 bags of 25 kg

15.0

m² of weed membrane

the lawn area, plus small overlaps

tubes of joining glue

310 ml, about 3 m of join each

edge pins

16.0 m of edge

You can use granite dust instead of sharp sand. The tonnes shown are for sharp sand.

Sand on top is a choice, not a must. We show the 5–8 kg per m² range from Namgrass and LazyLawn. Namgrass says homes with pets can do without it.

One 310 ml tube covers about 3 m of joining tape (Artificial Lawn Supply).

We found only one supplier's figure: Artificial Grass GB nails every 150–300 mm. We use 5 per metre. Skip them if you fix to timber edging.

We show the layout with the least grass. Namgrass points the pile towards the house, so that may decide which way your strips run.

What the grass costs

Artificial grass

£396

19.8 m² × £20

Price per m²£

£20 per m² (with VAT) is our mid-range figure. It sits inside Checkatrade's £14–£24 band and LazyLawn's £8.99–£31.74 shelf prices (2 sources, Oct 2026). Type your seller's price.

Quick answers

Roll widths: UK makers sell rolls 2 m and 4 m wide, cut to the length you need. Some grass comes 5 m wide.
Extra for trimming: Add at least 300 mm to each length, says Perfectly Green.
A 5 × 3 m lawn: Buy 19.8 m²: strips of 4 m + 2 m, each 3.3 m long, with 1 join.
Sand infill on top: Plan 5–8 kg per m² if you brush kiln-dried sand in. It is optional.
Weight: About 2.4–2.8 kg per m² for a 35–40 mm pile, from Namgrass and LazyLawn figures.

How to work it out

Measure the length and width of the lawn at its longest and widest points.
Each strip is cut to the side it runs along, plus 300 mm for trimming.
Lay strips side by side to cover the width. Use 4 m and 2 m strips with the least waste.
Grass to buy = total strip width × strip length. We pick the layout with the least grass; your pile direction may change which way you lay it.
Joins: one less than the number of strips. Each join is one strip long.

Lawn: 5 × 3 m = 15 m²
Strips run along the width: 3 + 0.3 = 3.3 m long
4 m + 2 m = 6 m wide
6 × 3.3 = 19.8 m², 1 join
No joins: one 4 m strip = 21.2 m²

Roll widths: planning the strips

Artificial grass comes off a roll 2 m or 4 m wide. You choose the length. So you buy whole strips, and cut off what you don't need.

Trim: add at least 300 mm to every length (Perfectly Green).
Same way: lay all strips with the pile facing one way, or the joins show.
Mix widths: Namgrass covers a 5.2 × 6 m lawn with two strips. They are 4 m and 2 m wide, each 6 m long. With our trim, that is 37.8 m². If your pile can run the other way, it needs 33 m².

Artificial grass to buy for common lawns
Lawn	Buy	Strips	Joins	Glue tubes
3 × 3 m	13.2 m²	4 m	0	0
4 × 3 m	13.2 m²	4 m	0	0
5 × 3 m	19.8 m²	4 m + 2 m	1	2
5 × 4 m	21.2 m²	4 m	0	0
6 × 4 m	25.2 m²	4 m	0	0
8 × 5 m	42.4 m²	4 m + 4 m	1	2
10 × 5 m	53.0 m²	4 m + 4 m + 2 m	2	4

Least grass, with 300 mm trim on each strip. Glue: one 310 ml tube per 3 m of join.

Fewer joins can cost more grass. For a 5 × 3 m lawn, one 4 m strip has no join but needs 21.2 m². The calculator shows both.

Materials you need to lay or install artificial turf

Dig out: LazyLawn digs out about 50 mm of turf first.
Base: 50–100 mm of MOT Type 1, packed down. Our Type 1 calculator gives tonnes and bulk bags.
Top layer: up to 20 mm of sharp sand or granite dust. See our sand calculator.
Weed membrane: the lawn area, with small overlaps.
Joins: joining tape the length of each join, and glue. A tub kit of 5 kg glue with 10 m of tape cost £50 with VAT, on offer. It is usually £59.
Fixings: nails or pins round the edge, or fix to timber edging.
Infill (optional): kiln-dried sand, 5–8 kg per m².

How deep should the sand be under artificial grass?

Keep it thin: up to 20 mm of sharp sand or granite dust, on top of the packed Type 1. LazyLawn and Namgrass both lay a thin layer like this.

Checking a fitter's quote? Our artificial grass vs turf cost calculator prices the whole job, fitted or DIY.

How much does artificial turf weigh?

Garden grass with a 35–40 mm pile weighs about 2.4–2.8 kg per square metre (m²). Namgrass gives 2.4 kg for its Pragma grass. LazyLawn's Lazy Signature is 2.83 kg.

A 4 × 5 m piece (20 m²): about 48–56 kg.
A full 4 m × 25 m roll (100 m²): about 240–280 kg. LazyLawn's full rolls are 25 m long.

Cheap grass can weigh less. A 40 mm budget grass on B&Q's site weighs about 1.5 kg per m².

Questions people ask

How much artificial or fake grass do I need?

Cut each strip to the side it runs along, plus 300 mm. Add 2 m and 4 m strips until they cover the other side. A 5 × 3 m lawn needs 19.8 m².

Which way should artificial grass face?

Lay every piece with the pile running the same way, or the joins show. Namgrass points it towards the house. In a front garden, Perfectly Green points it to the road.

Can you buy artificial grass by the metre?

Yes. B&Q cuts some grass to size in store, priced per metre off a 4 m wide roll. Namgrass cuts lengths in 10 cm steps.

How much infill does artificial grass or turf need?

If you use it, brush in 5–8 kg of kiln-dried sand per m². So one 25 kg bag does 3–5 m². Our sand calculator has more on sand.

How thick is artificial turf?

Its thickness is the pile height, the length of the blades. Garden grass is about 28–40 mm. Namgrass's garden grasses are 30–40 mm, and LazyLawn's 28–38 mm.

How do you join artificial grass?

With joining tape and glue under the seam. You need 1 m of tape per metre of join. A 310 ml tube of glue covers about 3 m of tape.

How many pins or nails does artificial grass need?

One UK supplier, Artificial Grass GB, nails the edge every 150–300 mm. That is about 3–7 nails per metre. Or you can fix the edge to timber edging.

Do you need a membrane under artificial grass?

Yes. Namgrass, LazyLawn and Artificial Grass Direct all lay a weed membrane. LazyLawn pins it every 0.75 m round the edge.

Where our numbers come from

Made by BuildersCount. Last checked 4 Oct 2026.

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