Soil Calculator
Work out how much soil or potting mix you need for raised beds, round pots and planters, and lawn topdressing, in cubic feet, cubic yards, bags, quarts and liters, with a topsoil and compost mix split.
Soil calculator
Raised beds (length and width in feet, depth in inches)
| Length | Width | Depth (in) | How many |
|---|---|---|---|
Round pots and planters (inches)
| Diameter | Soil depth | How many |
|---|---|---|
Lawn topdressing
How much soil do I need?
For a raised bed, length × width in feet × depth in inches ÷ 12 = cubic feet. An 8 × 4 ft bed 12 inches deep holds 32 cubic feet, about 1.19 cubic yards. Potting mix bags are often sold in quarts or liters: one cubic foot is about 29.9 quarts or 28.3 liters.
- Raised bed mixes commonly blend topsoil with compost (for example 60/40 or 50/50), sometimes with a coarse material for drainage. Your local extension service can suggest a mix for your area.
- Settling: new soil settles, so many gardeners add about 10–20% extra.
- Topdressing a lawn usually uses a thin layer, about ¼ inch, of compost or screened soil.
Common questions
How much soil do I need for a 4x8 raised bed?
32 cubic feet at 12 inches deep, or 16 cubic feet at 6 inches.
How many quarts of soil are in a cubic foot?
About 29.9 quarts (dry measure is about 25.7 dry quarts; potting mix bags generally use 29.9 liquid quarts).
How many bags of soil do I need?
Divide the cubic feet by the bag size. 32 cu ft is 32 bags of 1 cu ft or 22 bags of 1.5 cu ft.
What's the best soil mix for raised beds?
A blend of topsoil and compost is common. Extension services often recommend mixing in compost so organic matter is roughly a quarter to half of the mix.
How deep should a raised bed be?
Most vegetables do well in 8–12 inches of soil; root crops like 12 or more.
Sources
Related
General information, not financial, tax or legal advice. Check important numbers with the official source before acting on them.