Mulch volume formula
volume = length × width × depth × beds × (1 + extra %)Imperial depth is converted from inches to feet before volume is calculated. Cubic feet are divided by 27 for cubic yards.
Mulch calculator
Estimate bulk cubic yards or cubic meters and full bags for one or more equal rectangular beds.
Enter bed dimensions
Split curved or irregular beds into smaller rectangles for a practical estimate.
Measure depth after deciding what stays in the bed
Existing mulch, settled organic material, plant crowns, edging height, and drainage influence the practical added depth. Deeply burying trunks or stems can damage plants even when the volume calculation is correct.
- Measure separate beds and add them rather than guessing one bounding rectangle.
- Confirm bag volume because similarly sized bags may use different units.
- Ask how the supplier rounds bulk orders and whether material is sold loose.
Match depth to the job
Existing beds being refreshed usually need less material than new beds. Too much mulch against trunks, stems, siding, or foundations can trap moisture; follow local horticultural guidance.
Before ordering mulch
Measure planted areas rather than the entire lot and account for large structures or ground cover that will not be mulched. Bag volume and bulk delivery increments vary. This estimate does not determine an appropriate mulch type or depth for a particular plant or site.