Mulch & compost
Estimate mulch volume for beds, borders and tree rings. See equivalent units and every active assumption.
Enter project dimensions.
Calculated quantities for your project.
Enter measurements and calculate to see the result.
Direct answer
Calculate mulch volume from the surface area to be covered and the layer depth you choose. It works for bark, woodchip and other loose mulches without assuming that those products share a density.
Use it for garden beds, borders and tree surrounds. Calculate areas with different products or depths separately so the ordering record remains clear.
Measure only exposed soil to receive mulch. Deduct paving, dense groundcover and large plant bases where appropriate. For a tree ring, use the outer circle minus any unmulched inner circle as two calculations.
Mulch is usually a surface covering; compost is commonly used as a growing-medium component or amendment. The two should not be merged solely because both are organic materials.
A circular bed has a 4.0 m outer diameter. A 1.0 m diameter inner circle remains unmulched. Areas are π × 2² = 12.566371 m² and π × 0.5² = 0.785398 m². Net area is 11.780972 m²; at 50 mm, volume is 0.589049 m³.
The example uses geometry only. It does not insert a density, package size, recommended depth or supplier tolerance.
Mulch may be sold loose, in litres or in bags with stated capacity. Enter that exact capacity for package counts and do not infer it from a marketing name.
The calculator does not recommend application depth, determine plant compatibility or predict decomposition and settlement.
Yes. Use the capacity printed on the specific product.
No. Any allowance is an explicit planning choice, not a predicted decomposition rate.
Review BulkMeasure’s calculation methodology, learn how to measure an area, and read about volume, density and estimated weight. Browse the calculator directory when another material or project better matches the job.