Raised bed soil calculator
Fill the bed, not the truck twice.
Calculate how much soil, compost, and bagged mix you need for a raised garden bed. Use inside dimensions, choose your fill depth, compare bagged versus bulk costs, then copy a shopping list before you head to the nursery.
Quick formula
Length × width × depth in feet = cubic feet of soil.
That same 4 × 8 × 12 inch bed needs about 1.19 cubic yards, 823 quarts, or 16 two-cubic-foot bags.
Your soil estimate
One bed: 32 cu ft • Total beds: 1
Total cubic feet
32
Cubic yards
1.19
Quarts
823
2 cu ft bags
16
Bagged estimate
$144
Bulk estimate
$65
Shopping list
1 raised bed(s), 8 ft × 4 ft × 12 in deep Total soil: 32 cu ft (1.19 cu yd) Bagged option: 16 bags at 2 cu ft each Mix: 16 cu ft topsoil, 9.6 cu ft compost, 6.4 cu ft aeration
Depth guide
- 6 inches: shallow greens, herbs, and top-offs.
- 10–12 inches: most annual vegetables.
- 18–24 inches: deep-rooted crops or poor native soil.
Simple fill mix
For a general vegetable bed, start around 50% screened topsoil, 30% compost, and 20% aeration such as coarse sand, perlite, leaf mold, or aged bark fines.
- Topsoil: 16 cu ft
- Compost: 9.6 cu ft
- Aeration: 6.4 cu ft
Use inside dimensions
Measure the actual soil cavity, not the outside lumber footprint. Thick boards can change the soil volume enough to matter when buying bags.
Choose depth by crop
Leafy greens can work in shallower beds, but tomatoes, peppers, carrots, and deep-rooted crops usually want more room and better drainage.
Compare bagged vs bulk
Bagged mix is convenient for one bed. Bulk delivery is often better when you are filling several beds or building a larger lawn-to-garden conversion.
Raised bed FAQ
Soil volume questions people ask before buying materials
Use these rules of thumb to sanity-check the calculator and avoid overbuying compost, underfilling beds, or choosing a depth that does not match your crop plan.
How do I calculate soil for a raised bed?
Multiply inside bed length by width by soil depth in feet. A 4 by 8 foot bed filled 12 inches deep needs 32 cubic feet of soil.
How many cubic feet are in a cubic yard of soil?
One cubic yard equals 27 cubic feet. Divide total cubic feet by 27 when comparing bagged soil with bulk soil delivery.
How many bags of soil fill a 4 by 8 raised bed?
A 4 by 8 bed filled 12 inches deep needs 32 cubic feet. That is 16 two-cubic-foot bags, 11 three-cubic-foot bags, or about 1.19 cubic yards.
Is it cheaper to buy raised bed soil in bulk or bags?
Bulk soil is often cheaper for multiple beds, but delivery fees and access matter. Bagged soil can be simpler for one small bed or when you need to move materials through a tight yard.
What is a good raised bed soil mix?
A practical starting mix is roughly half screened topsoil, thirty percent compost, and twenty percent aeration or structure material such as leaf mold, aged bark fines, coarse sand, perlite, or pumice.
Next step
Turn the soil estimate into a planting plan.
Once you know the bed volume, pick crops that match the season and depth. Start with tomatoes, basil, lettuce, or the Three Sisters guild, then use seasonal guides to time planting.