How the roll count is worked out
The lawn area is length multiplied by width. Dividing that by the area one roll covers gives the number of rolls, and the waste allowance is added before the count is rounded up.
Most UK rolls cover about 1 square metre, though some are 0.6 square metres and some are supplied in larger slabs. Check the supplier's figure and enter it.
The count rounds up because a part roll is not sold. A lawn of 20.5 square metres needs 21 rolls at 1 square metre each, before any waste.
Worked example
A lawn 5 metres by 4 metres is 20 square metres. At 1 square metre per roll that is 20 rolls, and adding 5 per cent for edges gives 21 rolls.
A garden with curved borders loses more to cutting. Measure the area as a set of rectangles that cover the lawn, and accept that the offcuts are waste.
Timing and preparation matter more than the count
Turf has to be laid within about 24 hours of delivery in warm weather, and sooner in summer. Order it for the day you can lay it, not the day before.
The ground needs 100 to 150 mm of improved topsoil, firmed but not compacted, and watered before laying. Turf laid on dry, loose soil shrinks away at the joints and dies at the edges.
Water daily for the first two weeks. The most common reason new turf fails is not the quantity, it is drying out in the first ten days.
Limits of this calculator
It measures area only. It does not tell you how much topsoil to buy, which is a separate volume calculation.
It does not account for slopes, which need pegging, or for shaded areas that need a different turf species.
It does not include the cost. Turf is priced per square metre or per roll, and delivery is often charged by the pallet.
For US pallet coverage in square feet, use the US turf calculator.
Inputs for the turf calculator
Lawn length
Length of the area to turf in metres.
Lawn width
Width of the same area in metres.
Coverage per roll
Square metres on one roll. Most UK rolls cover about 1 m².
Waste allowance
Extra for cuts at edges and corners. Five per cent is normal.
CALCULATOR QUESTIONS
UK turf calculator questions
How much does a roll of turf cover?
Usually about 1 square metre, though 0.6 square metre rolls and larger slabs are also sold.
How quickly must turf be laid?
Within about 24 hours of delivery, and sooner in hot weather. It heats up and deteriorates in the roll.
How much topsoil do I need?
About 100 to 150 mm of improved topsoil across the whole area, which is a separate volume calculation.
Can I lay turf over an old lawn?
Not successfully. The old surface needs removing, and the soil below needs loosening and feeding first.