Raised Bed Soil Calculator
Soil Volume for Common Raised Bed Sizes
Rectangular beds at 12" depth, 2 cu ft bags
| Bed Size | Cubic Feet | Cubic Yards | 2-cu-ft Bags |
|---|---|---|---|
| 4×4 ft | 16.0 | 0.59 | 8 |
| 4×8 ft | 32.0 | 1.19 | 16 |
| 4×12 ft | 48.0 | 1.78 | 24 |
| 3×6 ft | 18.0 | 0.67 | 9 |
| 2×8 ft | 16.0 | 0.59 | 8 |
| 6×6 ft | 36.0 | 1.33 | 18 |
How We Calculate This
This raised bed soil calculator uses established formulas and industry-standard data to provide accurate estimates.
- Enter your specific values into the calculator fields above
- Our algorithm applies the relevant formulas using your inputs
- Results are calculated instantly in your browser — nothing is sent to a server
- Review the detailed breakdown to understand how each factor affects your result
These calculations are estimates based on standard formulas. For critical decisions, always consult a qualified professional.
How to Convert Oven Recipes to Air Fryer
Calculate the total volume of soil mix needed based on your raised bed dimensions. Convert to bags or bulk delivery amounts.
The basic rule:
- Rectangular: volume = length × width × depth (in feet)
- Circular: volume = π × (diameter/2)² × depth
- Convert inches to feet: divide depth by 12
- 1 cubic yard = 27 cubic feet
- Soil mix weighs approximately 40 lbs per cubic foot
For beds deeper than 18 inches, you can fill the bottom third with logs, branches, or straw (hugelkultur method) to save on soil cost and improve drainage.
When Would You Use This Calculator?
This raised bed soil calculator is designed for anyone who needs quick, reliable estimates without complex spreadsheets or professional consultations.
- When you need a quick estimate before committing to a purchase or project
- When comparing different options or scenarios side by side
- When planning a budget and need to understand potential costs
- When you want to verify a quote or estimate you've received from a professional
- When teaching or learning about the concepts behind these calculations
Frequently Asked Questions
How deep should a raised bed be?
Minimum 6 inches for lettuce and herbs, 12 inches for most vegetables, 18-24 inches for root crops like carrots and potatoes. If placed on hard ground or concrete, go deeper since roots can't penetrate below.
What soil mix should I use?
A popular mix is 1/3 topsoil, 1/3 compost, and 1/3 aeration (perlite, vermiculite, or coarse sand). Mel's Mix from Square Foot Gardening uses 1/3 peat moss, 1/3 vermiculite, 1/3 blended compost.
Is bulk delivery cheaper than bags?
Yes, usually by 50-70%. Bulk soil costs $30-60 per cubic yard delivered, while bagged soil at $5-8 per 2 cu ft bag costs $67-108 per cubic yard equivalent. Bulk makes sense for anything over 1 cubic yard.
How much does the soil settle?
New soil settles 10-20% in the first season. Plan to top off your beds annually with 1-2 inches of compost, which also replenishes nutrients.