Free raised garden bed planning tool
Raised Bed Soil Calculator
Enter the inside dimensions of your garden bed to calculate cubic yards, cubic feet, bags and ingredient amounts for your soil mix.
Enter your raised bed
Optional soil mix
Adjust the percentages to match your recipe. They must total 100%.
Your soil mix percentages must total 100%.
Enter values greater than zero, including at least one raised bed.
Total soil to order
Mix amounts
- Topsoil
- 0.78 yd3
- Compost
- 0.39 yd3
- Aeration material
- 0.13 yd3
Includes 10% extra for settling across 1 bed.
How Much Soil Does a Raised Bed Need?
Measure the inside length, width and the depth you actually plan to fill. Multiply those measurements to get volume. This calculator also multiplies by the number of identical beds and can add 5% or 10% for settling.
Measure inside the boards, not outside edge to outside edge. If the bottom contains logs, branches or another filler, enter only the remaining depth that will actually contain soil.
Raised Bed Soil Volume Chart
The order amounts below include 10% extra for settling.
| Inside size | Base volume | Order volume | 0.75 ft3 bags |
|---|---|---|---|
| 4 x 4 x 1 ft | 16 ft3 / 0.59 yd3 | 0.65 yd3 | 24 |
| 4 x 8 x 1 ft | 32 ft3 / 1.19 yd3 | 1.30 yd3 | 47 |
| 4 x 8 x 1.5 ft | 48 ft3 / 1.78 yd3 | 1.96 yd3 | 71 |
| 3 x 6 x 1 ft | 18 ft3 / 0.67 yd3 | 0.73 yd3 | 27 |
| 4 x 12 x 1 ft | 48 ft3 / 1.78 yd3 | 1.96 yd3 | 71 |
A Practical Raised Bed Soil Mix
A starting mix of 60% screened topsoil, 30% finished compost and 10% aeration material is easy to calculate and adjust. The best recipe depends on your existing soil, climate and crops, so treat the mix calculator as a purchasing estimate rather than a universal growing prescription.
Avoid filling a deep bed with pure compost or potting mix. A mineral soil component adds structure, while mature compost supplies organic matter. Check the quality and source of bulk materials before ordering.
Working on a lawn or ground-level bed?
Use the main calculator for topsoil depth, tons, bags and bulk cost, or estimate the compost portion separately.
Raised Bed Soil Calculator FAQ
How much soil do I need for a 4 x 8 raised bed?+
A 4 x 8 ft bed filled 12 inches deep needs 32 cubic feet, or 1.19 cubic yards. With 10% extra, order about 1.30 cubic yards or 47 bags of 0.75 cubic feet.
Should I calculate the inside or outside dimensions?+
Use the inside dimensions. Measuring outside the boards overestimates the space that soil can occupy.
How deep should soil be in a raised garden bed?+
Many vegetables grow well with 10 to 12 inches of good soil, while deep-rooted crops may benefit from 18 inches or more.
How many bags equal one cubic yard of soil?+
One cubic yard equals 27 cubic feet: 36 bags at 0.75 cubic feet, 27 one-cubic-foot bags, or 18 bags at 1.5 cubic feet.
Should I add extra soil for settling?+
Adding 5% to 10% is practical because loose soil settles after watering.