Raised bed soil calculator
Enter your bed size and how many beds you’re filling. The result includes extra for the settling that happens after the first watering.
Soil needed
35.2 cubic feet
- Bags to buy
- 24 1.5 cu ft bags
- Bulk order
- 1.3 cubic yards
How it works
Each bed’s volume is length × width × depth (in feet). The calculator multiplies by the number of beds, then adds your settling allowance. Fresh soil sinks noticeably after it’s watered in, so filling only to the exact volume usually leaves the bed short.
Bag count is cubic feet divided by the bag size, rounded up. Bulk soil is sold by the cubic yard (27 cubic feet).
Example
With bed length 8 ft, bed width 4 ft, soil depth 12 in, number of beds 1, extra for settling 10%, bag size: 1.5 cu ft bag, the answer is 35.2 cubic feet.
Tips before you buy
- Most vegetables grow well in 10–12 inches of loose soil. Deep-rooted crops like tomatoes appreciate more.
- In a tall bed, you can fill the bottom third with branches, leaves or old logs and use less purchased soil.
- Many gardeners fill beds with a blend of topsoil and compost rather than straight bagged potting mix, which is pricier and dries out quickly.
- Once you need more than about a cubic yard, get a quote for bulk delivery. It is often cheaper than bags.
Common questions
How many bags of soil fill a 4×8 raised bed?
A 4×8 bed filled 12 inches deep holds 32 cubic feet. That’s about 22 bags of 1.5 cu ft, or 24 bags if you add 10% for settling.
How much does soil settle in a raised bed?
Fluffy bagged soil commonly settles 10–20% in the first few weeks. Plan to top it up after the first good soaking.
How many cubic feet are in a cubic yard of soil?
27. One cubic yard fills a 4×8 bed about 10 inches deep.