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.
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Important Estimate Disclaimer
These calculations are general planning estimates only. Actual aggregate quantities may vary due to compaction rates, settlement, moisture content, and excavation depth.
See our Methodology and Data Sources for details.
Base preparation, drainage requirements, and load-bearing needs may alter total material requirements.