Turf Calculator (UK)
Last updated: 12 August 2026
Work out how much turf and topsoil you need for a new lawn. Enter the area, choose your topsoil depth, and get rolls, tonnes and bulk bags.
How the calculation works
A standard UK turf roll measures about 1.64m × 0.61m, covering one square metre, so rolls needed ≈ lawn area plus a wastage allowance for cutting around curves and edges.
Topsoil volume = area × depth. We convert to tonnes using a typical screened topsoil density of about 1.55 tonnes per cubic metre, then to 850kg bulk bags. Loose, dry soil is lighter; wet soil is heavier.
How much topsoil for a lawn?
| Depth | Per m² | 50 m² lawn |
|---|---|---|
| 50mm (top-up) | 0.08 tonnes | ~4 tonnes / 5 bulk bags |
| 100mm (standard) | 0.155 tonnes | ~7.8 tonnes / 10 bulk bags |
| 150mm (poor ground) | 0.23 tonnes | ~11.6 tonnes / 14 bulk bags |
For a new lawn, 100mm of good screened topsoil over a broken-up, weed-free base is the usual specification. Anything less and the turf struggles to root in dry spells.
Laying turf: timing and aftercare
Turf is best laid in autumn or spring when the ground is warm and moist. Lay it the day it arrives — stacked rolls heat up and yellow within 24–48 hours. Water thoroughly for the first two to three weeks and keep off it until the roots knit, which you can test by lifting a corner.
Frequently asked questions
How much does a roll of turf cover?
A standard UK turf roll is about 1.64m x 0.61m and covers exactly 1 square metre. So a 50 square metre lawn needs 50 rolls plus 5 to 10% extra for cutting around curves and edges.
How much topsoil do I need for a new lawn?
Allow 100mm of screened topsoil for a new lawn, which is about 0.155 tonnes per square metre. A 50 square metre lawn needs roughly 7.8 tonnes, or about 10 bulk bags.
How many bulk bags of topsoil per square metre?
One 850kg bulk bag covers roughly 5.5 square metres at 100mm deep, or about 11 square metres at 50mm deep.
When is the best time to lay turf in the UK?
Autumn is ideal — warm soil and reliable rainfall help roots establish before winter. Spring is the next best window. Avoid laying in midsummer heat or when the ground is frozen.
How long does turf take to root?
Typically two to three weeks in good growing conditions. Test by gently lifting a corner: if it resists, the roots have knitted. Keep foot traffic off and water daily until then.
Related calculators
Topsoil Calculator
Topsoil in m³, tonnes and bulk bags for lawns and beds.
Decking Calculator
Boards, joists and screws for a timber or composite deck.
Block Paving Calculator
Paving blocks, sub-base and sand for a driveway or patio.
Estimates are for guidance only. Material dimensions, densities and coverage vary by supplier — always confirm quantities before ordering, and consult a qualified professional for structural work.