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Landscaping & YardCompost Calculator — How Much Compost Do I Need?
Enter the area and how thick you want to spread compost to get cubic yards and the number of standard bags — for top-dressing beds, amending soil, or feeding a lawn.
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How this calculator works
Volume = area × depth. We convert to cubic yards and divide the cubic feet by 1.5 (a common bag size) to count bags. Compost is light, so bulk delivery is economical for larger jobs.
What changes how much you need
- Top-dressing a lawn: ¼–½ inch. Amending beds: 1–3 inches worked into the soil.
- Raised beds: blend roughly 1 part compost to 3 parts topsoil.
- Bag sizes vary (1, 1.5, and 2 cu ft) — check the label and adjust.
- Compost settles and breaks down; reapply seasonally.
Frequently asked questions
How thick should I spread compost?
¼–½ inch to top-dress a lawn, or 1–3 inches dug into garden beds.
How many bags of compost in a yard?
About 18 bags at 1.5 cubic feet each (27 ÷ 1.5), or ~14 bags at 2 cubic feet.
Can I fill a raised bed with only compost?
It’s best mixed — pure compost holds too much water and settles. Blend about 1 part compost to 3 parts topsoil.