Compost Calculator – Volume, Weight, Bags & Coverage
Enter your area, pick an application preset (like lawn topdressing or garden bed), and set a depth. The calculator shows compost volume in metric and imperial units, estimated weight, bag counts, coverage per bag, and convenient wheelbarrow and truckload equivalents. Presets keep it simple while you can still edit depth to match your project.
How to Use
- Choose Unit System and Area Shape (or enter a direct area).
- Select an Application to auto-fill a sensible depth, then adjust if needed.
- Pick a Bag Size and set Waste and Density if you want weight estimates.
- Click Calculate to get volume, bag counts, coverage, loads, and weight.
Coverage Examples (quick reference)
- 1.5 ft³ bag covers ~18 ft² @ 1" · 9 ft² @ 2" · 6 ft² @ 3"
- 2.0 ft³ bag covers ~24 ft² @ 1" · 12 ft² @ 2" · 8 ft² @ 3"
- 3.0 ft³ bag covers ~36 ft² @ 1" · 18 ft² @ 2" · 12 ft² @ 3"
Formulas & Assumptions
- Rectangle area = L × W; Circle area = π × (D/2)².
- Volume = Area × Depth; Waste applied as V × (1 + waste%).
- Weight = m³ × density; conversions: 1 yd³ = 27 ft³; 1 m³ = 35.3147 ft³; 1 ft³ = 28.3168 L.
- Bag coverage (ft²) ≈ (bag ft³ × 12) ÷ depth in inches.
Related Tools
You may also find these helpful: Topsoil Calculator, Sand Calculator, and Gravel Calculator.