How to calculate compost
Cubic yards = Area (sq ft) × Depth (in) ÷ 12 ÷ 27
Example: top-dressing a 2,000 sq ft lawn with ¼ inch of compost needs 2,000 × 0.25 ÷ 12 = 41.7 cubic feet — about 1.5 cubic yards.
How much compost to use
| Use | Depth |
|---|---|
| Top-dressing an existing lawn | ¼–½ in |
| Before seeding or sodding (mix into top 4–6 in) | 1–2 in |
| Amending vegetable and flower beds | 2–3 in |
| Mulching around plants | 1–2 in |
Building new raised beds? Use the raised bed soil calculator instead.
Frequently asked questions
How much compost do I need for 1,000 sq ft?
About 0.8 cubic yards at ¼ inch, 1.5 yards at ½ inch, and 3.1 yards at 1 inch.
How much does a yard of compost weigh?
Roughly 800–1,400 lb, depending on moisture and what it is made from.
How many bags of compost are in a cubic yard?
27 bags of 1 cu ft, or 13.5 bags of 2 cu ft.
When should I top-dress my lawn with compost?
After aerating in early fall or spring, so the compost settles into the holes.
Related calculators
These figures are estimates for planning only. Material weights and coverage vary by supplier, moisture and compaction. Always confirm quantities and prices with your supplier before ordering. See our terms & disclaimer.