Raised Bed Soil Calculator
Enter your bed's length, width and height to see how much soil it needs in cubic feet, cubic yards and bags, and how much of each ingredient to buy for a soil mix.
Soil for common raised bed sizes
Filled to the top. Soil settles, so beds are usually topped up after the first few waterings.
| Bed | Cubic feet | Cubic yards | 1.5 cu ft bags |
|---|---|---|---|
| 4 × 4 ft, 12 in tall | 16 | 0.59 | 11 |
| 4 × 8 ft, 6 in tall | 16 | 0.59 | 11 |
| 4 × 8 ft, 12 in tall | 32 | 1.19 | 22 |
| 4 × 8 ft, 18 in tall | 48 | 1.78 | 32 |
| 3 × 6 ft, 12 in tall | 18 | 0.67 | 12 |
| 4 × 12 ft, 12 in tall | 48 | 1.78 | 32 |
| 2 × 8 ft, 12 in tall | 16 | 0.59 | 11 |
Tips for filling raised beds
- Deep beds: for beds over 18 inches tall, many gardeners fill the bottom third with logs, branches and leaves, then soil on top. It saves money and breaks down over time.
- Buy bulk for big jobs: more than a cubic yard is much cheaper as a bulk "garden mix" or "raised bed mix" from a landscape supplier than in bags.
- Top up each spring with 1–3 inches of compost: see the compost calculator.
Beds filled? See when to plant each vegetable for your area, or look up your last frost date by ZIP code, at our sister site, My Frost Dates.
Frequently asked questions
How much soil do I need for a 4 × 8 raised bed?
A 4 × 8 foot bed that is 12 inches tall holds 32 cubic feet of soil, about 1.2 cubic yards or 22 bags of 1.5 cubic feet. At 6 inches tall it needs half that.
What is the best soil mix for a raised bed?
A common, affordable mix is about half topsoil, 30% compost and 20% of something for drainage such as perlite or coarse sand. A lighter soilless mix uses equal parts compost, peat moss or coco coir, and vermiculite.
Can I fill a raised bed with just compost or just topsoil?
It's not ideal. Pure compost is too rich and dries out; pure topsoil compacts. A blend drains well and holds nutrients.