Artificial grass, carpet and decking calculator

Four steps: what you're fitting, your area, your flooring, your total. You choose whether to add 5% for cuts, and we show the delivered price before you commit.

  1. 1 What you're fitting
  2. 2 Your area
  3. 3 Your flooring
  4. 4 Your total

What are you fitting?

Pick a range to start. Everything after this depends on it, because roll widths and board sizes differ by material.

This is the calculator we use ourselves when a customer sends a sketch. It works out how much artificial grass, carpet or composite decking a space needs and shows the delivered price at trade rates, before you commit to anything.

How the artificial grass calculator works

Artificial grass is sold by the roll width, not by the square metre of your garden. Every range comes in 2m and 4m rolls, most in 5m, some in 3m and 1m, cut to the length you need. So a 3m by 6m lawn cut from a 4m roll is 4m by 6m, 24 square metres, not 18. The calculator tries both orientations of your measurements against every roll width the range is made in and picks the cheapest piece with no join. Add 5% for cuts on the last step if the shape is awkward; it is never added silently.

Composite decking and carpet

Decking divides the area by the cover of one board, 3.6m by 150mm or 4.8m by 150mm, and rounds up to whole boards. The composite decking price list adds the frame, clips and fascia to that figure. Carpet works like grass, from 4m and 5m rolls, and the how much artificial grass do I need guide walks through the measuring with diagrams.

Prices in the calculator are the live shop prices including VAT: artificial grass from £7.49 to £21 per square metre, composite decking priced per 3.6m or 4.8m board, with free delivery over £190 and £30 below that. The artificial grass price list has every range on one table, and free samples let you check the colour before the roll is cut.

Calculator questions

How do I calculate how much artificial grass I need?

Measure the two longest sides of the space in metres. Pick the first roll width that covers the shorter side (a 3.4m garden takes a 4m roll), then order that width by the longer side plus 10cm for trimming. The calculator does this for every width the range is made in and shows the cheapest piece with no join.

Why is the area bigger than length times width?

Because the grass is cut from a fixed-width roll. A 3m by 6m lawn is 18 square metres of garden but 24 square metres of a 4m roll, and you pay for the roll width. A range made in 3m wide would cost 18 square metres for the same lawn, which is why the width pages matter.

Does the calculator include a waste allowance?

Only if you tick it. The last step offers 5% for cuts, shown as its own line. A plain rectangle with straight edges does not need it; curves, steps and borders usually do.

How much does artificial grass cost for an average garden?

A 4m by 6m lawn is 24 square metres: £180 in Rocco 18mm at £7.49, £216 in Dan 38mm at £8.99, £504 in Dluxe 40mm at £21, all including VAT with free delivery. Add roughly £6 to £8 per square metre for base materials if you lay it yourself, or £25 to £45 per square metre for a fitter.

How many composite decking boards do I need?

Area in square metres divided by 0.54 for 3.6m boards or 0.72 for 4.8m boards, rounded up, plus one or two spares. A 3.6m by 3m deck is 20 boards of 3.6m. The calculator does the division and the decking price list adds the joists, clips and fascia.