Raised Bed Soil Calculator
Enter your bed dimensions to get the exact soil volume in cubic feet, yards, and bags — plus a proven 60/30/10 mix breakdown.
Fill 1–2″ below the rim so soil doesn't wash out.
Standard bagged garden soil size.
Perlite, coarse bark, or coconut coir.
How it works
Length × width × fill height gives cubic feet. We convert to cubic yards for bulk delivery and divide by 1.5 for standard bagged soil. The 60/30/10 breakdown — topsoil, compost, aeration material — is a widely used mix that drains well while holding nutrients.
Formula: Length × Width × Height÷12 = cubic feet (÷ 27 = yards; ÷ 1.5 = bags)
Good for
- Vegetable and herb beds
- New raised beds and planter boxes
- Topping up settled beds each spring
- Square-foot gardening setups
Tips
- Soil settles 10–15% in the first season — top up with compost rather than overfilling day one.
- For beds deeper than 18″, fill the bottom third with coarse organic material (logs, branches) to save soil.
- Skip 'garden soil' bags for containers — raised beds want a lighter mix than in-ground amendments.
References
Estimates use standard industry volume math. Cross-check your numbers against the pros:
Related calculators
Sod Calculator
Enter your lawn dimensions to get the square footage, rolls, and pallets of sod to order — with a margin for edge cuts and curves.
Open calculator →Grass Seed Calculator
Enter your lawn size and grass type to get the pounds of seed you need — for a brand-new lawn or overseeding thin turf.
Open calculator →Concrete Slab Calculator
Enter your slab dimensions to get cubic yards, the number of 80-lb bags, and an optional cost estimate — with a waste margin so you don’t run short.
Open calculator →Raised Bed Soil Calculator FAQ
How much soil for a 4×8 raised bed?
A 4×8 ft bed filled 12″ deep needs 32 cubic feet — about 1.19 cubic yards or 22 bags at 1.5 cu ft each. At that volume, a bulk delivery is usually cheaper than bags.
What's the best soil mix for raised beds?
A common recipe is roughly 60% topsoil, 30% compost, and 10% aeration material like perlite or coarse bark. It drains freely but still holds moisture and nutrients for vegetables.
How deep should a raised bed be?
Most vegetables are happy with 12 inches of good soil. Root crops like carrots and parsnips prefer 12–18 inches. Beds over open ground can be shallower since roots continue downward.