For round beds, measure the diameter and use it as both length and width, then reduce the result by about 20%.
How to use the mulch calculator
- Measure the length and width of the bed in feet.
- Pick a depth: 2 inches to top up, 3 inches for new beds, 4 inches to suppress weeds.
- Choose your bag size and check the bag and bulk prices.
The formula
Cubic yards: length × width × depth (in) ÷ 12 ÷ 27. A shortcut is length × width × depth (in) ÷ 324.
Bags: cubic feet ÷ bag size.
Mulch needed for common bed sizes (3 in deep)
| Bed size | Cubic yards | 2 cu ft bags |
|---|---|---|
| 10 × 10 ft | 0.93 | 13 |
| 10 × 20 ft | 1.85 | 25 |
| 5 × 50 ft | 2.31 | 32 |
| 20 × 20 ft | 3.70 | 50 |
| 25 × 40 ft | 9.26 | 125 |
Frequently asked questions
How many bags of mulch are in a cubic yard?
About 13.5 bags of 2 cu ft, or 9 bags of 3 cu ft. A cubic yard is 27 cubic feet.
How deep should mulch be?
2 to 3 inches for most garden beds. Up to 4 inches helps suppress weeds, but deeper than that can smother roots.
How much area does a cubic yard of mulch cover?
About 108 sq ft at 3 inches deep, or about 162 sq ft at 2 inches.
Is bulk mulch cheaper than bags?
Usually, once you need more than about 2–3 cubic yards, even after a delivery fee.
Results are estimates for planning and budgeting. Always confirm measurements and product coverage before you buy, and follow local building codes.