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 Calculator
Grow Bag Soil Calculator
Convert grow bag gallons into cubic feet, liters, dry quarts, and bag counts.
Preset: container or grow-bag volume
Formula: grow bag ft³ = gallons × 0.133680556 × quantity
Worked example: 10 × 15-gallon grow bags plus 6 × 10-gallon grow bags equals 210 gallons, or about 28.07 ft³.
Adjust the live inputs above before copying the shopping list, printing the result, or buying material.
How to use this calculator
- Confirm the preset and unit labels.
- Replace every default that differs from your bed, container, bag, price, or planting plan.
- Review volume, bag count, cost, warnings, and rounding.
- Check package labels and local conditions before purchasing or planting.
What to verify
- Assuming the labeled gallon size equals exact filled volume.
- Packing media so tightly that useful volume changes.
- Using dense garden soil where a lighter container mix is needed.
Page-specific notes
- Grow bag ratings are nominal.
- Shape, folding, compaction, and fill line change real fill.
Planning assumptions and sources
Container pages use volume math, but real fill depends on pot shape, drainage, media texture, and fill line.
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.
- University of Maryland Extension: Growing Vegetables in Containers and Salad Tables A: Container media volume, drainage, watering, crop variety, seed-packet spacing, and container-size considerations.
- University of Maryland Extension: Growing Media (Potting Soil) for Containers A: Container media guidance; dense topsoil/garden soil is not the default for containers.
- Oregon State Extension: Container gardening without yard space A: Use lightweight potting soil for containers; avoid heavy garden soil or topsoil in typical pots.
- Oregon State Extension: Container gardening basics A: Container drainage, potting soil structure, and fill-line/watering reservoir considerations.
- University of Maryland Extension: Container volume examples A: Grow bag and container volume examples; actual fill varies with shape, folding, and fill line.
- University of Maryland Extension: Container seed spacing reminder A: For containers and raised-bed planning, follow seed packet spacing, depth, and timing for the crop.
- University of Maryland Extension: Growing Vegetables in Containers A: Container volume and plant-size guidance; notes that dense garden soil can restrict air and water movement in containers.
- University of Maryland Extension: Types of Containers for Growing Vegetables A: Minimum container volume and depth ranges for large, medium, and shallow crops; useful for container page boundaries.
- Oregon State Extension: How to use compost in gardens and landscapes A: Compost bag sizes, bulk cubic yards, 27 ft³ per yd³, and annual compost planning ranges.
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.