Mulch, gravel and soil calculator
A 20 × 10 ft bed covered 3 inches deep needs 1.85 cubic yards, which is 25 bags of 2 cu ft or 17 bags of 3 cu ft. Enter your bed and depth for mulch, gravel or topsoil.
Material
For a ring around a tree, work out the full circle, then add the trunk circle on the square footage calculator as a subtraction.
Odd-shaped beds: add up the pieces on the square footage calculator and type the total here.
Depth and bags
The list always shows 2 and 3 cu ft bags. Gravel and soil often come in other sizes, so type the cubic feet printed on your bag.
How it is worked out
- AreaLength × width in feet: 20 × 10 = 200 sq ft. For a circle, π × (diameter ÷ 2)².
- VolumeMultiply by the depth in feet: 200 × (3 ÷ 12) = 50 cu ft. Divide by 27 for cubic yards: 1.85 cu yd.
- BagsDivide the cubic feet by the bag size and round up: 50 ÷ 2 = 25 bags, or 50 ÷ 3 = 16.7, so 17 bags.
How deep? Clemson University's Home & Garden Information Center says fine wood and bark mulches should be no more than 2 to 3 inches deep, and coarse pine bark nuggets can go as deep as 4 inches. The University of Maryland Extension says to keep mulch about 3 inches away from tree trunks.
Why no tons? Gravel and soil are often sold by the ton, but their weight per yard changes with the stone, the moisture and how packed it is. We did not find a published density we could cite, so this calculator gives volume only. Ask your supplier how many tons make a yard of the product you buy.
Sources: Clemson HGIC, Mulch; University of Maryland Extension, Mulching Trees and Shrubs; NIST Handbook 44, Appendix C.
How far a cubic yard goes
One cubic yard is 27 cu ft. Spread it thinner and it covers more ground.
| Depth | One cubic yard covers | One 2 cu ft bag covers | One 3 cu ft bag covers |
|---|---|---|---|
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft |
Mulch for common bed sizes
3 inches deep unless noted.
| Bed area | Cubic yards | 2 cu ft bags | 3 cu ft bags |
|---|---|---|---|
| 100 sq ft, 2 in deep | 0.62 | 9 | 6 |
| 100 sq ft | 0.93 | 13 | 9 |
| 200 sq ft | 1.85 | 25 | 17 |
| 300 sq ft | 2.78 | 38 | 25 |
| 500 sq ft | 4.63 | 63 | 42 |
| 1,000 sq ft | 9.26 | 125 | 84 |
Questions people ask
- How many bags of mulch make a yard?
- 13.5 bags of 2 cu ft (so buy 14) or exactly 9 bags of 3 cu ft. A cubic yard is 27 cu ft. See bags of mulch per yard for more sizes.
- How much area does a yard of mulch cover?
- 108 sq ft at 3 inches deep, 162 sq ft at 2 inches. The formula is 27 ÷ (depth in inches ÷ 12).
- Should I buy bags or bulk?
- Compare the price of the bags on the list with the bulk price per yard plus delivery. The list shows both so you can price them side by side.
- Can I use this for gravel and topsoil?
- Yes. The volume math is the same for any loose material. If your gravel or soil comes in a different bag size, type it in "Your bag size". For tons, ask the supplier for their weight per yard.