How much compost do I need?
Compost improves garden soil, feeds lawns when top dressed, and fills raised beds when blended with soil.
Enter the length, width, and depth of your area above. The calculator shows cubic yards, cubic feet, an estimated weight in tons, and the number of 1 cubic foot bags if you buy bagged compost. Add a price per cubic yard and it also estimates the cost.
Cubic yard calculator for compost
This cubic yard calculator for compost works for any shape. Pick rectangle for most beds and slabs, circle for round areas, or trench for narrow runs. Open the price estimator under the calculator to add your supplier price, delivery fee, and tax. For a full cost breakdown, see the compost cost calculator.
Compost weight and bags per cubic yard
A planning value for compost is 1,000 pounds per cubic yard, which is 0.50 US tons. Moisture, particle size, and compaction move that number, so treat it as a starting point.
| Measure | Value |
|---|---|
| Pounds per cubic yard | 1,000 |
| US tons per cubic yard | 0.50 |
| Kilograms per cubic yard | 454 |
| Cubic yards per US ton | 2.00 |
| Cubic feet per US ton | 54.00 |
| 1 cubic foot bags per cubic yard | 27.0 |
How far does a cubic yard of compost go?
Coverage depends only on depth. The deeper the layer, the less area a cubic yard covers. The suggested depth for compost is 1 to 4 inches, and 2 inches is a common choice.
| Depth (inches) | Square feet covered | Square yards covered |
|---|---|---|
| 1 | 324 | 36.0 |
| 2 | 162 | 18.0 |
| 3 | 108 | 12.0 |
| 4 | 81 | 9.0 |
| 6 | 54 | 6.0 |
| 8 | 40 | 4.5 |
| 12 | 27 | 3.0 |
Compost needed for common areas at 2 inches deep
| Area | Square feet | Cubic yards | US tons | 1 cubic foot bags |
|---|---|---|---|---|
| 5 by 5 ft | 25 | 0.15 | 0.08 | 5 |
| 8 by 10 ft | 80 | 0.49 | 0.25 | 14 |
| 10 by 10 ft | 100 | 0.62 | 0.31 | 17 |
| 10 by 20 ft | 200 | 1.23 | 0.62 | 34 |
| 12 by 12 ft | 144 | 0.89 | 0.44 | 24 |
| 15 by 20 ft | 300 | 1.85 | 0.93 | 50 |
| 20 by 20 ft | 400 | 2.47 | 1.23 | 67 |
| 20 by 30 ft | 600 | 3.70 | 1.85 | 100 |
| 30 by 40 ft | 1,200 | 7.41 | 3.70 | 200 |
| 50 by 50 ft | 2,500 | 15.43 | 7.72 | 417 |
Worked example: 20 by 8 feet at 2 inches
The area is 20 feet times 8 feet, or 160 square feet. A depth of 2 inches is 0.17 feet. Volume is 160 times 0.17, which is 26.67 cubic feet. Divide by 27 to get 0.99 cubic yards. At 1,000 pounds per cubic yard that weighs about 0.49 US tons. With 10 percent extra, order 1.09 cubic yards.
Tips for ordering compost
- Top dress a lawn with about a quarter to half inch of compost.
- Work 2 to 3 inches into new garden beds to improve the top 6 inches of soil.
- Mature, dark, crumbly compost smells earthy, not sour.
Compost is light for its volume, so a pickup truck can carry several cubic yards.
Frequently asked questions
How many cubic yards of compost do I need?
Multiply length, width, and depth in feet, then divide by 27. A 20 by 8 foot area at 2 inches deep needs about 0.99 cubic yards.
How much does a cubic yard of compost weigh?
About 1,000 pounds, or 0.50 US tons, as a planning value. Ask your supplier for the exact figure.
How deep should compost be?
Most projects use 1 to 4 inches. 2 inches is a common choice.
How many square feet does a cubic yard of compost cover?
162 square feet at 2 inches deep, and 324 square feet at 1 inch.
How many bags of compost make a cubic yard?
About 27 bags of the 1 cubic foot size, which yields about 1 cubic feet each.