Using the Mulch Calculator
Use the bed's length and width in meters and the depth in centimeters. For several beds, calculate each area separately or combine areas that share the same depth. The extra allowance is a percentage added to the calculated volume.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Length (m)
- 5
- Width (m)
- 4
- Depth (cm)
- 5
- Extra allowance (%)
- 10
- Bulk density (kg/m³)
- 400
Example result
- Volume (m³)
- 1.1
- Volume (cubic yards)
- 1.4387457
- Estimated mass (kg)
- 440
Method and assumptions
Length × width × depth, plus the selected allowance. Density is user supplied and varies with material and moisture.
Turn an estimate into an order
A geometric quantity is a starting point for purchasing. Check whether the supplier sells by bag, box, mass or bulk volume, and use the stated coverage or yield to convert the result. Round only after accounting for the chosen allowance and packaging increments. For irregular spaces, divide the job into simpler sections and combine quantities with the same units.
Common question
Should I use the same depth for every planting area?
The calculator does not choose a horticultural depth. Enter the depth appropriate to the material and planting situation you are planning. If areas need different depths, calculate them separately before adding the volumes.
Guide updated .