Interactive raised bed calculator
Enter bed size. Get soil volume, bags, cost, and a shopping list.
Default example: one 4×8×12 in bed, 10% settling, and 2 ft³ bags. Results update automatically as inputs change.
More planners: mix, containers, spacing, top-off, depth, cost, multi-bed, shapes
Raised Bed Soil & Planting Planner
Raised Bed Soil Calculator
Enter bed size and bag size to estimate soil volume, bags, bulk order size, cost, and a copyable shopping list before buying materials.
Formula
Raised bed volume = length × width × effective depth × number of beds × settling allowance. Soil bag count = ceil(required cubic feet ÷ bag cubic feet).
Example calculation
A 4 ft × 8 ft × 12 in raised bed equals 32 ft³, or 1.19 yd³. Two beds with 10% settling need 70.4 ft³, or 2.61 yd³.
Default example
The calculator opens with a 4×8×12 in single-bed example, 10% settling, and a 2 ft³ bag size so users can understand the result immediately.
Common raised bed sizes
| Bed size | 12 in deep soil | Planting squares | Use case |
|---|---|---|---|
| 4×4 | 16 ft³ | 16 | Compact square-foot garden |
| 4×6 | 24 ft³ | 24 | Medium backyard bed |
| 4×8 | 32 ft³ | 32 | Highest-value standard layout |
| 2×8 | 16 ft³ | 16 | Narrow side-yard bed |
| 3×6 | 18 ft³ | 18 | Reachable narrow bed |
Related calculators
Planning assumptions and sources
Homepage sources show why BedSoil should behave like a task-first calculator: users compare dimensions, bag labels, cubic yards, and local growing assumptions before buying soil.
BedSoil keeps deterministic volume math separate from gardening assumptions. Cubic-foot, cubic-yard, liter, quart, gallon, and bag-count calculations come from your inputs; crop spacing, crop depth, mix ratio, and container advice are planning aids that need product labels, seed packets, local Extension guidance, and soil-test context.
- Old Farmer's Almanac Soil Calculator A: Competitor pattern: raised bed or pot dimensions produce a soil quantity estimate.
- Gardener's Supply Co. Garden Soil Calculator A: Competitor pattern: shape and dimensions produce cubic feet, cubic yards, or quart outputs.
- Lowe's Mulch and Soil Calculator A: Retail estimator pattern; supports clear planning-tool boundary language.
- Kellogg Garden Organics Soil Calculator A: Project type, dimensions, depth, and bag selection pattern for soil estimates.
- University of Minnesota Extension: Raised bed gardens A: Raised bed placement, water access, sunlight, access, fill, and soil-mix considerations.
- University of Maryland Extension: Soil to Fill Raised Beds A: Raised bed fill scenarios, hard-surface depth guidance, topsoil limits, soil testing, and lead caution.
- NIST: Approximate Conversions from U.S. Customary Measures to Metric A: Source provenance for U.S. customary and metric unit conversion factors.
- University of Maryland Extension: Understanding Your Soil Test Report A: Soil reports show pH, phosphorus, potassium, magnesium, calcium, organic matter, and lab recommendations; calculators should not replace lab interpretation.
- USDA National Agricultural Library: Raised Beds & Container Gardening A: Trust hub for raised beds, containers, growing media, water, light, and related resources.
Source library coverage
The project source library now contains 39 curated references. This page shows the sources most relevant to the active calculator mode; 30 additional references cover SERP patterns, containers, compost, soil testing, amendments, and related crop assumptions.
Always check product labels, seed packets, local extension guidance, soil tests, delivery minimums, drainage, and site conditions before purchasing materials or planting.
FAQ
How much soil do I need for a 4x8 raised bed?
A 4×8 bed filled 12 inches deep needs 32 cubic feet, or about 1.19 cubic yards, before any settling allowance.
How many bags of soil do I need for a raised bed?
Divide the required cubic feet by the bag volume in cubic feet, then round up. The calculator does this automatically.
Should I add extra soil for settling?
Many gardeners add 10–15% for initial settling, especially when compost-heavy material is used.
What is the difference between cubic feet and cubic yards?
One cubic yard is 27 cubic feet. Bulk soil is usually sold by the cubic yard; bags are often labeled in cubic feet, dry quarts, or liters.
Is 40 lb of soil the same as 40 quarts?
No. Pounds measure weight, while quarts measure volume. Soil weight changes with moisture and material density.
How deep should a raised bed be?
Six to eight inches can work for shallow greens and herbs. Tomatoes, peppers, squash, and longer root crops usually benefit from 12 inches or more.
Disclaimer
BedSoil results are planning estimates for buying and mixing soil. They are not agricultural, engineering, pest, disease, fertilizer, or crop-yield advice. Check product labels, local material quality, drainage, bed construction, climate, and crop variety before purchasing materials.