Topsoil & raised bed calculator
Turn bed dimensions into a soil order you can discuss with a supplier. Use the unfilled depth for an existing raised bed, or the planned added layer for a new landscape bed.
The interactive calculator requires JavaScript. The formula and worked example below are available without it. No sign-up is required.
How to use this calculator
- Measure the inside dimensions or the actual area receiving soil.
- Measure the remaining fill depth, leaving any planned space at the top.
- Enter the bag volume and an allowance only if your supplier or site plan calls for one.
The formula
Cubic feet = square feet × unfilled depth in inches ÷ 12. Cubic yards = cubic feet ÷ 27. Whole bags = volume including allowance ÷ bag volume, rounded up.
Worked example
An empty raised bed measuring 8 × 4 ft with 12 inches of fill space holds 32 cubic feet: about 1.185 cubic yards, or 16 two-cubic-foot bags before any allowance.
Use inside dimensions
Raised-bed walls take up space. Measure from the inside faces and check depth at several locations. For an existing bed, calculate only the empty space instead of ordering for the full wall height.
Volume does not select the soil mix
A vegetable bed, a lawn repair, and a landscape bed may need different materials. University of Minnesota Extension discusses soil mixtures for raised beds. Ask about the intended plants, drainage, and soil-test information before buying.
Keep settlement separate from measurement
The extra allowance is your explicit adjustment, not a universal settlement rate. Existing fill, moisture, soil texture, and handling can change the delivered quantity needed. Do not use this volume calculation to design grading around a foundation.
Common questions
Is topsoil the same as raised bed soil?
No. This tool measures volume for either, but it does not make the materials interchangeable. Choose a suitable mix for the plants and site, then use its bag volume or bulk units.
How much soil fills a 4 × 8 raised bed?
At 12 inches of unfilled depth, a 4 × 8 ft bed takes 32 cubic feet, or approximately 1.185 cubic yards. A partially filled bed needs less.
Can I calculate several beds together?
Yes, if the fill depth is the same. Add their measured areas and use the square-feet option. Calculate different depths separately and add the resulting volumes.
Sources & method
Calculations use the formulas shown above. These references inform the planning guidance; they do not endorse this tool. References checked on .
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