Landscaping · updated 2026
Raised Garden Bed Soil Calculator
A raised bed is a box of soil — length × width × depth gives cubic feet directly, no density tables needed. This raised bed calculator takes your bed's dimensions and returns soil volume, 1.5-cu-ft bag counts, and the 2×10 boards to build it, with 2026 costs. It assumes 12-in deep beds, the standard; root vegetables want deeper.
12 in standard; 18–24 in for carrots and other root vegetables
Show the math
Volume = 8 × 4 × (12 ÷ 12) = 32 cu ft
Bags = ⌈32 ÷ 1.5⌉ = 22 (1.5-cu-ft bags)
Boards = 2 × ⌈8 ÷ 8⌉ + ⌈4 ÷ 8⌉ = 3 (8-ft 2×10s; short sides cut from one board)
Cost = 22 × $6–$9/bag + 3 × $15–$25/board
What the numbers mean
The calculator converts your measurements into a practical purchase quantity using a documented coverage or spacing assumption.
Any whole-unit quantity is rounded up so the result does not leave you short during the project.
Use the cost range as a planning baseline and confirm the final quantity, availability, and delivery charge with your local supplier.
2026 material prices
| Material | 2026 average price | Note |
|---|---|---|
| Raised bed soil, 1.5-cu-ft bag | $6.00 – $9.00 / 1.5-cu-ft bag | Blended for drainage and fertility |
| 2×10×8-ft board, pressure-treated | $15.00 – $25.00 / 8-ft board | Each |
| 2×10×8-ft board, cedar | $25.00 – $40.00 / 8-ft board | Lasts longest; best for edibles |
Wave 1 Batch 3 content price guide, Sep 2026. 2026 U.S. national averages. Prices vary by region and retailer — confirm locally before buying.
Pro tips
- Fill the bottom third of deep beds with logs and branches (hugelkultur) — it cuts soil cost and feeds the bed for years.
- Line the inside with landscape fabric — it holds soil in while letting water drain out.
- 12 in suits most vegetables; go 18–24 in for carrots, parsnips, and potatoes.
- Avoid old railroad ties for edible beds — stick to cedar or new pressure-treated lumber.
- Level the ground first; a tilted bed sheds water off the low side and starves the high side.
- An 8×4×12-in bed needs 32 cu ft of soil (22 bags) and 3 eight-ft boards — about $175–$275 all-in.
Common questions
Frequently asked questions
How much soil for an 8×4×12-in raised bed?
8 × 4 × 1 = 32 cu ft → 22 one-and-a-half-cu-ft bags, plus 3 eight-ft 2×10 boards.
How about a 4×4 bed?
16 cu ft → 11 bags, and 3 boards (2 × 1 + 1).
Can I use regular topsoil?
It's heavy and compacts — use raised-bed mix, or cut topsoil 50/50 with compost.
How deep should a raised bed be?
12 in for most vegetables; 18–24 in for root crops.
What wood should I use?
Cedar lasts longest; new pressure-treated is fine and cheaper — avoid old railroad ties for edibles.
What does an 8×4 bed cost to fill and build?
$132–$198 in soil plus $45–$75 in lumber — roughly $175–$275.
Related calculators
Planning estimates only. Prices are 2026 U.S. national averages and vary by region — confirm with your local supplier before buying.