Dirt calculator
Soil for raised beds, or fill dirt for a hole or a low spot, in cubic yards and bags.
2 raised beds of 8 ft × 4 ft filled 12 in deep need 64 cubic feet of soil: 2.37 cubic yards or 43 bags of 1.5 cu ft.
Measure
You need
64.0 ft³ · about 1.90 tons
Mix: 1.66 yd³ topsoil + 0.71 yd³ compost
Your shopping list
Bags
43 bags
Bulk, by the yard
2.37 yd³m³
Delivered or picked up at a landscape supplier
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How it is calculated
- Volume8 ft × 4 ft × 12/12 ft × 2 = 64.0 ft³
- Cubic yards64.0 ÷ 27 = 2.37 yd³
- Bags64.0 ÷ 1.5 ft³ = 43 bags
- Mix2.37 × 70 % topsoil, × 30 % compost
Soil for common raised beds
| Bed | ft³ at 6 in | ft³ at 12 in | yd³ at 12 in | 1.5 cu ft bags |
|---|---|---|---|---|
| 2 × 4 ft | 4 | 8 | 0.30 | 6 |
| 3 × 3 ft | 5 | 9 | 0.33 | 6 |
| 4 × 4 ft | 8 | 16 | 0.59 | 11 |
| 2 × 8 ft | 8 | 16 | 0.59 | 11 |
| 3 × 6 ft | 9 | 18 | 0.67 | 12 |
| 4 × 8 ft | 16 | 32 | 1.19 | 22 |
| 4 × 10 ft | 20 | 40 | 1.48 | 27 |
| 4 × 12 ft | 24 | 48 | 1.78 | 32 |
Topsoil and compost for a 4 × 8 bed
| Soil height | Total yd³ | Topsoil yd³ | Compost yd³ |
|---|---|---|---|
| 6 in | 0.59 | 0.41 | 0.18 |
| 8 in | 0.79 | 0.55 | 0.24 |
| 12 in | 1.19 | 0.83 | 0.36 |
| 18 in | 1.78 | 1.24 | 0.53 |
Frequently asked questions
How much soil do I need for a 4 × 8 raised bed?
32 cubic feet (1.19 yd³) to fill it 12 inches deep, 16 cubic feet (0.59 yd³) at 6 inches: length × width × soil height, in feet.
How deep should a raised bed be?
Most plants need at least 6 to 12 inches of soil (Iowa State University Extension). Leave 1 to 2 inches below the rim for mulch, and loosen the ground under a shallow bed so roots can go deeper.
What soil mix should I put in a raised bed?
About 70 % topsoil and 30 % compost, or equal parts topsoil, compost and coarse sand (Iowa State University Extension). For a 4 × 8 bed 12 inches deep: 0.83 yd³ of topsoil and 0.36 yd³ of compost.
How many bags of soil for a raised bed?
Divide the cubic feet by the bag size. A 4 × 8 bed 12 inches deep holds 32 ft³: 32 bags of 1 cu ft, 22 of 1.5 cu ft or 16 of 2 cu ft.
How much does a yard of dirt weigh?
About 0.80 short tons, or 1,600 lb, for loose fill dirt or topsoil, and 1.10 tons for clay (New Mexico EMNRD, from the BLM handbook). Wet soil weighs more.