Short answer: A bed of 100 square feet covered 3 inches deep needs about 0.93 cubic yards, or 25 cubic feet of mulch. That is about 13 bags of 2 cubic feet each.
| Bed area | 2 inches deep | 3 inches deep | 4 inches deep |
|---|---|---|---|
| 50 sq ft | 0.31 | 0.46 | 0.62 |
| 100 sq ft | 0.62 | 0.93 | 1.23 |
| 200 sq ft | 1.23 | 1.85 | 2.47 |
| 500 sq ft | 3.09 | 4.63 | 6.17 |
The formula
Multiply the bed area in square feet by the depth in feet, which is inches divided by 12. That gives cubic feet. Divide by 27 for cubic yards. A depth of 2 to 3 inches suits most beds, and 3 to 4 inches helps suppress weeds.
Bags or bulk?
Bags are convenient for small beds. Once you need more than about 2 cubic yards, which is 14 bags of 2 cubic feet or more, bulk delivery is usually cheaper and quicker. Keep mulch a couple of inches back from tree trunks and house walls.
Worked example
A bed 25 ft by 4 ft covered 3 inches deep holds 25 cubic feet, or 0.93 cubic yards. With 5% extra for settling, order 0.97 cubic yards, which is 14 bags of 2 cubic feet.
Use the Mulch CalculatorEnter your own measurements and get an exact amount.
Frequently asked questions
How much does a cubic yard of mulch cover?
About 108 square feet at 3 inches deep, or about 162 square feet at 2 inches.
How many bags of mulch are in a cubic yard?
13.5 bags of 2 cubic feet, so buy 14.
How deep should mulch be?
Two to three inches for most beds. Deeper layers can smother roots.
More quick answers
Related calculators
Figures are typical planning values. Material sizes, densities and local requirements vary, so confirm with your supplier before ordering.
Last updated October 11, 2026.