Calculate compost volume needed to spread over a garden or lawn area.
Equivalent bags
Bulk vs bagged
Usage Tip
A quarter inch top-dressing is plenty for an established lawn; rake it in so it reaches the soil rather than smothering the grass.
The result is cubic yards for bulk ordering.
How much compost do I need?
Measure the area you are covering, decide how deep the compost layer should be, and convert that to volume. Multiply the area in square feet by the depth in feet to get cubic feet, then divide by 27 for cubic yards. Because most gardeners buy bags, this calculator also converts the result into the number of 1 and 2 cubic foot bags — and compares bagged against bulk delivery so you can see which is cheaper before spring optimism takes over.
Compost depth guide
How deep to spread depends on the job. A light top dressing is a dusting; filling a new bed is several inches.
| Use | Depth |
|---|---|
| Lawn top dressing | 1/4 to 1/2 in |
| Light soil amendment | 1 in |
| Vegetable garden | 2 to 3 in |
| New garden bed | 4 to 6 in |
| Raised bed fill | by bed height (often 8 to 12 in) |
Compost coverage chart
One cubic yard of compost spreads over different areas depending on depth. This is the figure people search for most:
| Depth | One cubic yard covers |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
How many bags of compost per cubic yard?
A cubic yard is 27 cubic feet, so it equals 27 of the standard 1 cubic foot bags, about 18 of the 1.5 cubic foot bags, or roughly 14 of the 2 cubic foot bags. Bulk delivery is usually cheaper per yard once you need more than 10 to 15 bags — the calculator shows the crossover.
Compost for raised beds
For a raised bed, the depth is the fill height. A 4 by 8 ft bed filled 10 in deep needs about 27 cubic feet, or one cubic yard — a single bulk scoop, or 27 one-cubic-foot bags. Many gardeners blend compost with topsoil rather than filling with pure compost, which is rich enough to use as an amendment rather than a sole growing medium.
Compost for vegetable gardens
Vegetable beds love compost. Spread 2 to 3 in over the surface and work it into the top few inches each season. A 100 sq ft plot at 2 in needs about 0.6 cubic yards, or roughly 17 one-cubic-foot bags.
Frequently asked questions
How much compost do I need for a garden bed?
Spread 2 to 3 in for an existing bed. Multiply area by depth in feet, divide by 27 for cubic yards, or use the bag count this tool gives.
How many bags of compost in a cubic yard?
27 one-cubic-foot bags, about 18 of the 1.5 cubic foot bags, or roughly 14 two-cubic-foot bags.
How deep should compost be?
A quarter to half inch for lawn top dressing, 2 to 3 in for vegetable gardens, and 4 to 6 in for a brand new bed.
Is bagged or bulk compost cheaper?
Bulk is usually cheaper per yard once you need more than 10 to 15 bags, but bagged is easier to handle for small jobs. The calculator compares both.
Can I fill a raised bed with pure compost?
It is better to blend compost with topsoil. Pure compost is very rich and can stay too wet; a mix of compost and soil grows better and settles less.
How much does a yard of compost weigh?
Roughly 1,000 to 1,600 lb depending on moisture, so plan your vehicle and delivery accordingly.
Mulch Calculator · Gravel Calculator · Sod Calculator
Coming soon: Topsoil Calculator · Raised Bed Calculator · Landscape Fabric Calculator
Estimates are for planning. Compost settles and varies in density by source and moisture; buy a little extra for settling, and blend with soil rather than filling beds with pure compost. Confirm bulk pricing and delivery minimums with your supplier.