Tool · raised beds
Raised bed soil calculator
Volume first, bags second. Enter the bed's internal dimensions and the depth of soil you want; the calculator returns cubic feet, cubic metres and the number of bags at two common sizes.
Enter your bed dimensions to get the volume, the bag count and a cost estimate.
The formula
Volume (ft³) = length (ft) × width (ft) × depth (in) ÷ 12. One cubic metre is 35.31 cubic feet; a 2 cu ft bag is about 56.6 litres.
Why the bag count is not the whole story
- Soil settles after the first season: add 10–15% for a new bed.
- Drainage matters more than richness: a mix with coarse material drains better than topsoil alone.
- Root crops want 30–40 cm; herbs and salad are fine at 20 cm.
- Buy by volume, not by bag, once the bed is larger than about 1 m³.