Bulk mulch or bags?
Measure the bed and enter the depth of the new mulch layer. If mulch is already present, calculate only the top-up depth you plan to add. Divide curved beds into smaller rectangles for a closer estimate.
Length (ft) × width (ft) × depth (in) ÷ 324 = cubic yards
In metric units: length (m) × width (m) × depth (cm) ÷ 100 = cubic meters.
A worked example
A 20 ft × 12 ft bed with 3 in of new mulch needs 2.22 cubic yards, or exactly 30 bags of 2 cubic feet. With 10% extra, allow 33 bags.
Mulch depth and coverage
Use enough mulch to cover soil without piling it against trunks or stems.
| Project or depth | Planning reference |
|---|---|
| Annual top-up | 1–2 in |
| Established bed | 2–3 in |
| Weed suppression | 3–4 in |
| 1 cubic yard at 3 in | about 108 sq ft |
Before you order
Check the volume printed on the bag, not its weight. This calculator accepts cubic-foot or liter bags and always rounds the bag count up. Keep mulch clear of trunks and stems; choose the appropriate depth for your planting and material.