Raised Bed Soil Calculator
A bed is just a box — length by width by depth, then order by the cubic yard.
Volume to order1.1852 cubic yards32 cu ft · 0.9061 m³
Weight1.2186 US tons1,105.5 kg · 2,437.2 lb · 1.1055 tonnes
MaterialTopsoil1,220 kg/m³, about 76 lb/ft³
Cubic feet32
Cubic metres0.9061
In 50 lb bags49if buying bagged rather than bulk
Area covered32 sq ft2.9729 m²
Depth12 in304.8 mm
One cubic yard covers27 sq ftat 12 in deep
The method
volume = area × depth; weight = volume × density
Depth in inches, volume in yards
This is where the arithmetic usually goes wrong. A cubic yard is 27 cubic feet, so spread 4 inches deep it covers 81 square feet — not 27. Divide the depth in inches by 12 before multiplying, or work in a single unit throughout.
Order by volume when you can and treat the weight as a cross-check. Loose densities vary by about 10% between quarries and rise sharply when the material is wet, so a ton of gravel is a less definite quantity than a cubic yard of it.
Add a compaction allowance for anything that will be rolled or tamped. Crusher run and road base typically lose 20–25% of their loose volume once compacted.