How Much Topsoil Do I Need for a New Lawn?

Screened topsoil spread 100mm deep, with 20% extra because it settles.

Page last reviewed 26 October 2026 by the UkToolCalc team

A 20m² lawn (5 × 4m) needs about 2.4m³ of topsoil at 100mm deep: 4 bulk bags of 0.75m³, weighing about 3.2 tonnes.

Topsoil by lawn size

100mm deep, 20% extra for settling, 0.75m³ bulk bags.

Lawn area	Topsoil	Bulk bags	Weight	Or 40L bags
10 m²	1.2 m³	2	1.6 t	30
20 m²	2.4 m³	4	3.2 t	60
30 m²	3.6 m³	5	4.9 t	90
50 m²	6.0 m³	8	8.1 t	150

Topsoil (m³) = area (m²) × depth (m) × 1.2 20m² at 100mm: 20 × 0.1 × 1.2 = 2.4m³

Laying turf on top? The turf calculator counts the rolls. Clearing old soil first? The skip size calculator picks the skip.

How deep should topsoil be for a lawn?

100–150mm of good topsoil is ideal for a new lawn. Turf or seed on less than about 50mm dries out quickly in summer.

Why add 20% to topsoil?

Loose topsoil settles and compacts once it's raked, rolled and watered. Ordering about 20% extra stops you ending up short.

How much does a bulk bag of topsoil cover?

A 0.75m³ bulk bag covers about 7.5m² at 100mm deep before settling, or about 6m² once you allow 20% for it.