Soil Volume Calculator

Enter dimensions to find how much soil, compost, or fill you need.

Length (feet)

Width (feet)

Depth (inches)

Number of beds

Volume per bed (cu ft) —

Total volume (cu yd) —

Bags needed (1 cu ft bags) —

Bags needed (2 cu ft bags) —

Volume = L × W × (D/12) cubic feet. Divide by 27 for cubic yards. Bulk delivery is usually cheaper for orders over 3 cubic yards.

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Common Raised Bed Sizes

Bed Size	Depth	Soil Needed
4×4 ft	12"	5.3 cu ft (0.20 cu yd)
4×8 ft	12"	10.7 cu ft (0.40 cu yd)
4×8 ft	18"	16.0 cu ft (0.59 cu yd)
4×12 ft	12"	16.0 cu ft (0.59 cu yd)
3×6 ft	10"	5.0 cu ft (0.19 cu yd)

How to Calculate Soil for Raised Beds

To calculate soil volume, multiply length times width times depth (convert depth from inches to feet first). The result is in cubic feet. Divide by 27 to convert to cubic yards.

For raised beds, a good fill mix is 60% topsoil, 30% compost, and 10% perlite or vermiculite. Soil settles 10-15% over the first season, so consider slightly overfilling new beds.

Formula: volume (cubic feet) = length (ft) × width (ft) × depth (ft). Convert depth in inches to feet first (divide by 12). A 4×8 raised bed filled to 12 inches: 4 × 8 × 1 = 32 cubic feet. Divide by 27 to convert to cubic yards: 32/27 ≈ 1.19 cu yd.

Recommended fill mix for raised beds: 60% topsoil, 30% compost, 10% coarse perlite or vermiculite for drainage. This is the "Mel's Mix" variant — adjust the compost ratio up to 50% if you're using inexpensive topsoil that may compact. Pure compost collapses over one season.

Soil settles 10–20% after the first season as organic matter decomposes. Slightly overfill on first install. Annual top-dressing with 1–2 inches of compost replaces what compresses and is consumed by plants.

Cost estimate: bagged topsoil costs $3–6 per cubic foot; bulk delivery averages $25–50 per cubic yard. For 1.19 cu yd: bagged = $114–$228; bulk = $30–$60. Bulk is far more economical for beds over 20 cubic feet. (Prices are estimates; verify locally.)