Topsoil Calculator

What This Calculator Does

This topsoil calculator works out how much soil you need to fill a lawn, raised bed, border or planter — in cubic yards, cubic metres, tonnes and bags. It's for gardeners, landscapers and anyone topping up beds or laying a new lawn who wants to order the right amount and avoid paying for extra deliveries.

How to Use

1. Choose imperial or metric units.
2. Enter the length and width of the area you're filling.
3. Enter the depth of topsoil you want to add.
4. Read off the volume, approximate weight and number of bags.

Worked Example

Say you're topping up a border that is 5 m long, 2 m wide, to a depth of 100 mm (0.1 m):

1. Volume = 5 × 2 × 0.1 = 1 m³.
2. At roughly 1.2 tonnes per m³ that's about 1.2 tonnes.
3. In 25 kg bags that's around 48 bags — so a bulk (dumpy) bag would be far better value.

Tips

• New lawns: 100-150 mm (4-6 in) of topsoil over prepared ground.
• Raised beds and borders: 150-300 mm (6-12 in).
• Topsoil weighs about 1.1 tons per cubic yard or 1.2 tonnes per m³ — more when wet.
• Bulk bags are usually far cheaper per tonne than small bags for anything over about 0.5 m³.