Enter the area and the depth you plan to spread. The calculator turns it into cubic feet, cubic yards for bulk delivery and the number of bags for a lawn topdressing or a garden bed.
Compost formula
Volume (cu ft) = area (sq ft) × depth (in) ÷ 12 Cubic yards = cubic feet ÷ 27 Bags = cubic feet ÷ bag size, rounded up
Worked example: topdressing a 50 × 20 ft lawn at 1/4 in
- Area: 1,000 sq ft.
- Volume: 1,000 × 0.25 ÷ 12 = 20.8 cu ft.
- Cubic yards: 0.77, or 21 bags of 1 cu ft.
Compost per 1,000 sq ft
| Depth | Cu ft | Cu yd |
|---|---|---|
| 1/4 in | 20.8 | 0.77 |
| 1/2 in | 41.7 | 1.54 |
| 1 in | 83.3 | 3.09 |
| 2 in | 166.7 | 6.17 |
| 3 in | 250 | 9.26 |
How thick to topdress a lawn
Clemson Cooperative Extension advises applying no more than 1/2 in of topdressing at a time so the grass is not smothered. Thin layers can be repeated. For new garden beds, compost is often worked into the top few inches of soil; follow local extension advice and a soil test.
Questions
How much compost for 1,000 sq ft?
About 0.77 cu yd at 1/4 in or 1.54 cu yd at 1/2 in.
Is compost sold by the yard?
Bulk compost is usually sold by the cubic yard; bagged compost by the cubic foot.
How many bags make a cubic yard?
27 bags of 1 cu ft or 18 bags of 1.5 cu ft.
Sources
- HGIC 1227: Topdressing a Home Lawn, Clemson Cooperative Extension.
Used for: No more than 1/2 in of topdressing applied at a time.