Measure inside edges
Use the usable inside length, width or diameter—not the outside frame. Compare common bed sizes.
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Raised Bed Soil Calculator
Know exactly how much soil to buy. Calculate volume, bags, mix ingredients, and cost for every garden bed.
✓ Imperial & metric✓ Multiple beds✓ Shopping list
1STEP ONE
Enter your garden bed
Garden bed 1
This bed: 18.0 cu ft
2STEP TWO
Plan your purchase
Choose your depth
Most vegetables perform well with 10–12 inches of quality soil. Read the full depth guide.
Choose a balanced mix
Combine structure, mature compost and drainage—not just one material. See the soil mix guide. Calculate compost separately.
RAISED BED SOIL GUIDE
How much soil do I need for a raised garden bed?
For a rectangular raised bed, multiply the inside length by the inside width and the soil depth. Keep every measurement in the same unit, then convert the result to cubic feet or cubic yards. This calculator handles those conversions automatically, adds multiple beds, and rounds bag quantities up so you do not run short.
Length × Width × Soil Depth × Quantity = Soil Volume
Common soil depths
6 inches — leafy greens and shallow-rooted herbs.
10–12 inches — versatile for most vegetables.
18–24 inches — deep roots or poor soil beneath the bed.
Plan the purchase
A 6 × 3 ft bed filled 12 inches deep requires 18 cubic feet. With 5% extra, plan for 18.9 cubic feet, or 13 bags at 1.5 cubic feet each.
Frequently asked questions
Should I fill a raised bed to the top?
Leave one or two inches below the rim for watering and mulch. New soil also settles, which is why the calculator can add 5–10% extra.
How many soil bags equal one cubic yard?
One cubic yard equals 27 cubic feet: 36 bags at 0.75 cu ft, 27 bags at 1 cu ft, 18 bags at 1.5 cu ft, or 14 bags at 2 cu ft after rounding up.
What soil mix should I use?
A practical starting point is 40% screened topsoil, 40% mature compost and 20% aeration material. Plant needs and local conditions may require adjustments.
Does this work for circular beds?
Yes. Choose Circle, enter the inside diameter and soil depth, and the calculator uses the circular volume formula automatically.