Soil Calculator
Calculate exact topsoil, garden soil, and potting mix volumes in cubic yards, cubic feet, and bag counts for raised beds and garden planters.
Total Soil Volume
How to Use This Soil Calculator
Filling raised beds or topdressing lawns requires calculating total soil volume before buying bulk soil or bagged topsoil. Use this tool with simple steps:
- Planter Shape: Select rectangular for standard 4x8 ft raised garden beds or circular for round containers.
- Bed Dimensions: Enter garden length, width, or planter diameter in feet or meters.
- Soil Depth: Enter soil depth in inches or centimeters (standard raised vegetable beds require 10 to 12 inches of soil).
- Soil Bag Size: Select bag size (topsoil commonly comes in 0.75 cu ft bags, while potting mix comes in 1.5 cu ft bags).
Soil Volume Formulas & Mix Ratio Benchmarks
Soil volume calculations use three-dimensional cubic measurement formulas converted into cubic yards or retail bag counts:
Volume Formula (Rectangular Beds)
Length x Width x Depth converted to cubic yards:
Cubic Yards = (Length x Width x (Depth / 12)) / 27
Mel's Mix Raised Bed Ratio
Standard raised bed soil recipe recommendations:
1/3 Peat Moss + 1/3 Vermiculite + 1/3 Mixed Compost
Raised Bed Soil Requirement Quick Reference Table
Estimated soil volume requirements for popular raised garden bed dimensions at a 12-inch soil depth.
| Bed Dimensions | Depth | Cubic Feet | Cubic Yards | Bags (0.75 cu ft) |
|---|---|---|---|---|
| 3 x 3 ft Small Bed | 12 Inches | 9 cu ft | 0.33 Yards | 12 Bags |
| 4 x 4 ft Square Bed | 12 Inches | 16 cu ft | 0.59 Yards | 22 Bags |
| 4 x 8 ft Standard Bed | 12 Inches | 32 cu ft | 1.19 Yards | 43 Bags |
| 4 x 12 ft Large Bed | 12 Inches | 48 cu ft | 1.78 Yards | 64 Bags |
Frequently Asked Questions
How deep should soil be in a raised garden bed?
Most vegetables require 8 to 12 inches of quality soil depth for healthy root development. Deep taproot crops like carrots and tomatoes benefit from 12 to 18 inches of rich soil depth.
How many bags of soil are in a cubic yard?
One cubic yard equals 27 cubic feet. That converts to 36 bags of 0.75 cu ft topsoil or 27 bags of 1.0 cu ft garden soil.
What is the difference between topsoil, garden soil, and potting mix?
Topsoil is raw screened earth used for filling deep holes and grading lawns. Garden soil is topsoil enriched with organic compost for ground garden beds. Potting mix is lightweight soil-free medium (peat moss, perlite, bark) designed for container drainage.
How much does soil settle after watering?
Freshly filled raised beds settle by approximately 10 to 15 percent after thorough watering. Filling beds slightly above the rim accounts for natural soil compaction.
