Mulch keeps moisture in, keeps weeds down and finishes off a garden bed. Enter the bed size and the depth you want to see how many cubic yards to order in bulk or how many 2 ft³ and 3 ft³ bags to buy.
Formula
Cubic yards = Area (ft²) × Depth (in) ÷ 324
324 is the number of square feet one cubic yard covers at 1 inch deep (27 ft³ × 12). In metric, volume (m³) = area (m²) × depth (m).
Worked example
A 12 ft × 10 ft bed at 3 inches deep needs 120 × 3 ÷ 324 = 1.11 yd³ of mulch. With 5% extra that is about 16 bags of 2 ft³, or 11 bags of 3 ft³.
How thick should mulch be?
2–3 inches (5–7.5 cm) is right for most beds. Use up to 4 inches for weed control on bare ground, and keep mulch a few inches away from tree trunks and plant stems.
Frequently asked questions
How many bags of mulch are in a yard?
One cubic yard equals 13.5 bags of 2 ft³ or 9 bags of 3 ft³.
How much area does a yard of mulch cover?
About 162 ft² at 2 inches deep, or 108 ft² at 3 inches deep.
Last updated · Calculations checked by automated tests· Editorial policy