Compost Calculator
Compost is wetter and heavier than mulch, at about 30 lb per cubic foot.
Volume to order1.2346 cubic yards33.333 cu ft · 0.9439 m³
Weight0.4942 US tons448.4 kg · 988.4 lb · 0.4484 tonnes
MaterialCompost475 kg/m³, about 30 lb/ft³, wetter than mulch
Cubic feet33.333
Cubic metres0.9439
In 50 lb bags20if buying bagged rather than bulk
Area covered200 sq ft18.5806 m²
Depth2 in50.8 mm
One cubic yard covers162 sq ftat 2 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.