Soil Calculator
Work out how much topsoil, garden soil or raised bed mix you need, in cubic yards for a bulk delivery or in bags from the store.
Soil for common raised bed sizes
Volume to fill each bed to the top, before settling:
| Raised bed | Cubic feet | Cubic yards | 1.5 cu ft bags | 2 cu ft bags |
|---|---|---|---|---|
| 2 × 4 ft, 12 in deep | 8.0 | 0.30 | 6 | 4 |
| 3 × 6 ft, 12 in deep | 18.0 | 0.67 | 12 | 9 |
| 4 × 4 ft, 6 in deep | 8.0 | 0.30 | 6 | 4 |
| 4 × 4 ft, 12 in deep | 16.0 | 0.59 | 11 | 8 |
| 4 × 8 ft, 6 in deep | 16.0 | 0.59 | 11 | 8 |
| 4 × 8 ft, 11 in deep | 29.3 | 1.09 | 20 | 15 |
| 4 × 8 ft, 12 in deep | 32.0 | 1.19 | 22 | 16 |
| 4 × 8 ft, 18 in deep | 48.0 | 1.78 | 32 | 24 |
| 4 × 12 ft, 12 in deep | 48.0 | 1.78 | 32 | 24 |
How deep should the soil be?
| Use | Soil depth |
|---|---|
| Top-dressing an existing lawn | ¼–½ in |
| New lawn (seed or sod) | 4–6 in |
| Flower beds | 6–8 in of loosened soil |
| Raised beds: lettuce, herbs, greens | 6–8 in |
| Raised beds: tomatoes, peppers, squash | 12 in or more |
| Raised beds: carrots, potatoes, root crops | 12–18 in |
How to calculate soil
- Area: length × width in feet (3.1416 × radius² for a round bed).
- Cubic feet: area × depth in inches ÷ 12. A 4 × 8 bed 12 in deep: 32 × 12 ÷ 12 = 32 cu ft.
- Cubic yards: cubic feet ÷ 27. 32 ÷ 27 = 1.19 yd³.
- Bags: cubic feet ÷ the bag size. 32 ÷ 1.5 = 22 bags.
- Add 10–20% because bagged and bulk soil settles once it's watered.
Measure your beds with a tape measure. Mulching on top? The mulch calculator works out the next layer.
Frequently asked questions
How much soil do I need for a 4x8 raised bed?
A 4 × 8 ft bed 12 inches deep holds 32 cubic feet of soil, about 1.19 cubic yards. That's 16 bags of 2 cu ft or 22 bags of 1.5 cu ft. For a common 11 inch tall kit, it's 29.3 cu ft. Buy 10 to 20% extra: new soil settles after watering.
How many bags of soil are in a yard?
A cubic yard is 27 cubic feet, so it takes 36 bags of 0.75 cu ft topsoil, 27 bags of 1 cu ft, 18 bags of 1.5 cu ft or 13.5 bags of 2 cu ft. Above 1 or 2 yards, bulk soil delivered by the yard is usually much cheaper.
How much does a yard of topsoil weigh?
About 1 to 1.2 tons (2,000 to 2,400 lb) when dry and loose, and more when wet. That's why suppliers deliver it by truck: a pickup truck usually carries about 1 cubic yard at most.
How deep should topsoil be for a new lawn?
4 to 6 inches of good topsoil gives grass roots room to grow. For top-dressing an existing lawn, spread only ¼ to ½ inch so the grass isn't smothered.
Can I fill a raised bed with only topsoil?
It works, but a raised bed mix drains and feeds plants better. A common blend is about 60% topsoil, 30% compost and 10% coarse material like perlite or pine bark fines. For deep beds, the bottom third can be filled with logs, branches or leaves to save soil.
For other materials by volume, see the cubic yard calculator and the gravel calculator.