Soil Calculator
Calculate how much topsoil or compost you need to fill raised beds or level ground.
About the Soil Calculator
Enter the bed's area and depth and the bag size. The calculator gives the volume of soil in cubic yards or cubic metres and the number of bags.
For raised beds, multiply length × width × depth. Fresh soil settles by roughly 10–20%, so add extra or top up after a few weeks. A common raised-bed blend is about 60% topsoil, 30% compost and 10% grit or perlite.
The formula
Volume = area × depth; 1 yd³ = 27 ft³ = 0.7646 m³
Worked example
A 100 ft² raised bed filled 12 inches deep
- 100 × 1 ft = 100 ft³ = 3.7 yd³
- 67 bags of 1.5 ft³
Questions people ask
How deep should a raised bed be?
At least 30 cm (12 in) for most vegetables.
How many bags fill a bed?
Divide the volume by the bag size; the result is shown above.