Topsoil and Raised Bed Soil Calculator

Fill a raised bed or top-dress a lawn. Enter the size and depth to see cubic yards and bags.

For a raised bed, use the bed height.
New soil settles 10% to 20% in the first season.

How the calculation works

cubic feet = length × width × (depth in inches ÷ 12) × number of beds

The settling allowance is added on top, and the total is divided by 27 for cubic yards. Bagged soil is usually sold in 0.75, 1, 1.5 or 2 cubic foot bags.

Worked example

One 8 × 4 foot raised bed, 12 inches deep, holds 32 cubic feet. With 15% extra for settling, that's 36.8 cubic feet, or 1.36 cubic yards. In bags, that's 37 bags of 1 cu ft or 19 bags of 2 cu ft.

What to fill a raised bed with

Plain topsoil gets dense in a raised bed. A common mix is about 60% topsoil, 30% compost and 10% coarse material such as perlite or pine bark fines. Many landscape suppliers sell a ready-made "garden blend" by the yard that's cheaper than bags for beds over about 1 cubic yard.

Frequently asked questions

How much does a yard of topsoil cover?

One cubic yard covers 324 square feet at 1" deep, 108 square feet at 3" deep, and 54 square feet at 6" deep.

How many bags of soil for a 4 × 8 raised bed?

A 4 × 8 bed that's 12" deep holds 32 cubic feet: about 32 one-cubic-foot bags before settling, or 37 with a 15% allowance. A bed 6" deep needs half that.