How much mulch do I need?
Short answer
One cubic yard of mulch covers about 108 square feet at 3 inches deep. A 20 × 10 ft bed at 3 inches takes about 1.85 cubic yards, or 25 bags of 2 cubic feet.
Work it out for your numbers
Mulch needed
1.85 cubic yards
- Bags to buy
- 25 2 cu ft bags
- Volume
- 50 cubic feet
- Area covered
- 200 sq ft
How far a cubic yard goes
| Depth | Square feet per cubic yard |
|---|---|
| 1 inch (top-up) | 324 |
| 2 inches | 162 |
| 3 inches | 108 |
| 4 inches | 81 |
Bags in a cubic yard
| Bag size | Bags per cubic yard |
|---|---|
| 1.5 cu ft | 18 |
| 2 cu ft | 13.5 |
| 3 cu ft | 9 |
The math
Length × width × depth in feet (inches ÷ 12) gives cubic feet. Divide by 27 for cubic yards, or by the bag size for bags, and round up. A 10 × 10 ft bed at 3 inches is 25 cubic feet: just under a yard, or 13 bags of 2 cubic feet.
How deep?
- 2 to 3 inches suits most beds. Deeper can smother roots and hold too much moisture.
- Topping up last year’s mulch usually takes only about an inch. Measure what’s there before ordering a full depth.
- Keep mulch a few inches away from tree trunks and plant stems. Piling it against them invites rot and pests.
Bulk or bags?
Bags are easier for small beds and keep well. For a couple of yards or more, bulk delivery is usually cheaper and saves a lot of plastic. Ask about the delivery fee and where the truck can dump it.
Common questions
How many bags of mulch are in a yard?
13.5 bags of 2 cubic feet, 9 of 3 cubic feet, or 18 of 1.5 cubic feet.
How much area does a yard of mulch cover?
About 108 square feet at 3 inches deep, or 162 at 2 inches.
How deep should mulch be?
2 to 3 inches for most beds, and about an inch to refresh existing mulch.
Updated October 29, 2026. Figures are estimates for planning. Check product labels and local codes before you buy or build.