Compost Calculator

What the compost calculator computes

The compost calculator converts the size of the area you're covering and the depth you want into a cubic yard total for compost, so you know how much to order before delivery day. Compost is sold by the cubic yard, not by the ton, so the calculator is built around volume rather than weight. Enter the length and width of your beds or lawn area in feet and the depth you plan to spread in inches, and the tool returns the cubic yards of compost to order.

Behind the numbers, the calculator uses compost's typical density, about 37 pounds per cubic foot, to estimate the weight of your order alongside the volume. That weight figure helps you plan truck access and confirm the load matches what you expect when it arrives. For product details on the finished material, see the Compost page.

Depth guidance for compost

How deep to spread compost depends on what you're using it for. As a soil amendment worked into an existing bed or lawn before planting, 2 to 3 inches tilled into the top 6 to 8 inches of soil is typical. As a topdressing on established turf or around existing plants, 1/4 to 1/2 inch is usually enough, since a thicker layer can mat down and block air and water movement. A new garden bed built largely from compost blended with topsoil often calls for a deeper layer, closer to 3 to 4 inches, before mixing.

Whatever depth you choose, enter it into the calculator in inches along with your length and width in feet, and it converts the area and depth into cubic yards for you.

Compost density and the yards to tons conversion

Compost is lighter and looser than soil or stone, which is part of why it's priced and delivered by the cubic yard instead of the ton. A cubic yard of compost weighs roughly 1,000 pounds, or about half a ton, based on a density near 37 pounds per cubic foot. That's noticeably lighter than topsoil or gravel on a yard for yard basis, so don't assume the same weight applies across materials.

If you need the weight in tons for a specific load or delivery truck, run your total through the cubic yards to tons converter, once you have your cubic yard figure from this page.

Ordering tips and overage for compost

Order a little more compost than the calculator's raw number. Beds settle, spreading is never perfectly even, and coming up a few cubic yards short means a second delivery. Adding about 10 percent on top of the calculated volume covers most projects without leaving a large surplus pile behind. Round up to the nearest half or full cubic yard as well, since compost is typically sold and delivered in those increments rather than fractional amounts.

If you're blending compost into existing topsoil across a large bed, calculate the compost and topsoil volumes separately using their own depths, then add the two totals together for your full order. Confirm site access for a bulk delivery truck before your delivery date so the load can be dropped where you need it.