Garden soil and topsoil calculator

This calculator works out how much topsoil, compost, or garden soil you need to fill a raised bed, border, or planting area. Enter the length, width, and depth, and it returns the volume in cubic metres and litres, the approximate weight, and how many 50-litre bags or bulk bags to buy.

How much soil do I need?

The volume is length × width × depth. Topsoil weighs roughly 1.3 tonnes per cubic metre, though this varies with moisture and how much organic matter it contains. For new beds, a depth of 20–30 cm suits most vegetables and flowers; for laying or topping up a lawn, 2.5–5 cm is usually enough.

Bags vs bulk

Small jobs are easiest with 50-litre bags, but for anything over about 1 m³ a delivered bulk bag is far better value. To plan what to grow in the bed, use our plant spacing calculator, and to feed it, the fertiliser calculator.

Frequently asked questions

How many litres of soil in a cubic metre?

There are 1,000 litres in one cubic metre, so a 1 m³ order equals twenty 50-litre bags.

Disclaimer: Estimates only. Soil density varies — confirm quantities with your supplier.