Mulch Calculator
Find how much mulch to buy for a garden bed at your chosen depth, in bags or cubic yards.
About the Mulch Calculator
Enter the area to cover, the depth and the bag size. The calculator gives the mulch needed in cubic yards or cubic metres and the number of bags.
Mulch is usually spread 5–8 cm (2–3 in) deep: enough to suppress weeds and hold moisture without smothering roots. Keep it a few centimetres away from stems and tree trunks. Bulk mulch is sold by the cubic yard or cubic metre; bags are often 2 ft³ or 50 L.
The formula
Volume = area × depth; 1 yd³ = 27 ft³ = 0.7646 m³
Worked example
100 ft² of beds, 3 inches deep
- 100 × 3 ÷ 12 = 25 ft³
- = 0.93 yd³
- 13 bags of 2 ft³
Questions people ask
How deep should mulch be?
2–3 inches (5–8 cm) for most beds; up to 4 inches for paths.
How much does a cubic yard cover?
About 108 ft² at 3 inches deep, or 162 ft² at 2 inches.