Soil Calculator
Estimate how much soil you need for a garden bed, lawn repair, raised planter, or landscaping project.
Tip: Suppliers often round up to the nearest 0.5 cubic yard for delivery.
Why a soil calculator matters
Getting soil quantities right saves money, labor, and multiple delivery trips. If you order too little, your project pauses halfway through. If you order too much, you pay to move and store material you may never use. A simple soil calculator gives you a practical estimate before you place an order.
This page focuses on the most common use case: rectangular areas such as raised beds, lawn patches, and landscape zones. You enter length, width, and depth, then apply a small extra percentage to cover compaction and settling.
How the soil calculation works
Base formula
The core volume formula is:
Volume (ft³) = Length (ft) × Width (ft) × Depth (ft)
Because depth is usually measured in inches, the calculator converts depth to feet first:
Depth (ft) = Depth (in) ÷ 12
Converting to cubic yards
Most bulk soil vendors price by cubic yard.
Volume (yd³) = Volume (ft³) ÷ 27
Adding waste or settling
After the base volume, the calculator adds your percentage buffer:
Adjusted volume = Base volume × (1 + waste% / 100)
Understanding the output
- Cubic feet: useful for bagged soil comparisons.
- Cubic yards: common for truck delivery and supplier pricing.
- Cubic meters: useful for metric planning.
- Estimated weight: helps plan hauling and wheelbarrow loads.
- Estimated cost: displayed when you enter price per cubic yard.
Typical soil density reference
Soil density changes with moisture, composition, and compaction. Use these values as practical starting points:
| Soil Type | Approx. Density (lb/ft³) | Notes |
|---|---|---|
| Light potting mix | 35–45 | Very loose, high organic content |
| Topsoil (screened) | 65–85 | Good default range for garden projects |
| Compost blend | 45–65 | Lighter than mineral soil |
| Wet clay-heavy soil | 85–110 | Can be substantially heavier when wet |
Example: raised bed project
Suppose your bed is 12 ft long, 4 ft wide, and needs 8 inches of soil.
- Depth in feet: 8 ÷ 12 = 0.667 ft
- Volume in cubic feet: 12 × 4 × 0.667 = 32.0 ft³
- Volume in cubic yards: 32.0 ÷ 27 = 1.19 yd³
- With 10% extra: 1.19 × 1.10 = 1.31 yd³
You would typically order about 1.5 cubic yards to stay safe, depending on supplier increments.
Common mistakes to avoid
1) Forgetting unit conversion
Depth must be converted from inches to feet before volume is computed in cubic feet.
2) Ignoring compaction and settling
Freshly placed soil settles over time, especially after watering. Add 5% to 15% extra in most cases.
3) Using dry-weight assumptions for wet material
If your supplier delivers wet soil, weight can be much higher. Check vehicle limits and unloading conditions.
4) Not accounting for irregular areas
For curved or complex spaces, divide the area into smaller rectangles, calculate each, then add totals.
Quick planning checklist before ordering soil
- Measure length and width at multiple points for accuracy.
- Confirm target depth after grading and existing soil condition.
- Choose your soil type (topsoil, compost blend, planting mix).
- Apply waste/settling percentage.
- Verify price, delivery minimums, and truck access.
- Round up to supplier increments (often 0.5 yd³).
Final thoughts
A reliable soil estimate makes your landscape or gardening project smoother from start to finish. Use the calculator above to get volume, weight, and cost in one place, then confirm final quantities with your local supplier based on their material specs and delivery rules.