Topsoil calculator
How much topsoil or compost for a new lawn, garden beds or raised beds.
How it works
Area × depth gives the volume. We add 10% because loose soil settles and compacts once it's raked and watered. Weight uses about 1.3 tonnes per m³ for topsoil and 0.6 for compost; damp soil is heavier, so change the density if your supplier gives one.
Worked examples
A new lawn, 10 × 5 m, with 100 mm of topsoil: 5 m³, or 5.5 m³ with 10% extra, about 7.2 tonnes delivered loose.
Two raised beds, 8 × 4 ft and 12 in deep: 64 cu ft, or 70.4 cu ft with extra. That is 36 bags of 2 cu ft, or about 2.6 cu yd loose. Many people fill raised beds with a topsoil and compost mix; run the calculator twice with each material's share of the depth.
How deep?
- New lawn from seed or turf: about 4 in (100 mm) of good topsoil is a common target.
- Levelling or top-dressing a lawn: a thin layer, often well under 1 in (25 mm) at a time.
- Raised beds: use the bed's height, less any drainage layer.
Bags, bulk bags or loose
Small jobs suit bags. For anything over about a cubic yard (0.75 m³), loose delivery or bulk bags are usually much cheaper. In the UK, topsoil is often sold in bulk bags by weight, so compare using the tonnage figure.
Common questions
How much topsoil do I need for a lawn?
Multiply the lawn area by the depth. At 4 in (100 mm), every 100 sq ft needs about 1.2 cu yd, and every 10 m² needs about 1 m³, before extra.
Reviewed by Alex Rowan, Editor. Last reviewed . How we calculate · Report a problem