✓Depth has a large effect on volume, so measure it carefully.
✓Convert inches to feet before calculating cubic feet.
✓Weight depends on material density and moisture, so tonnage is an approximation unless supplier data is available.
Cubic feet = length × width × depth in feetCubic yards = cubic feet ÷ 27Weight in pounds = cubic yards × bulk densityTons = pounds ÷ 2,000 1. Measure the area and finished depth
For a rectangle, multiply length by width. For curved or irregular areas, divide the project into simpler shapes or use a measured area if you already know it.
The depth should represent the planned material layer. Compaction and base preparation can change how much loose material is needed on site.
2. Convert depth before calculating volume
A 3-inch gravel layer is 0.25 feet. Multiplying feet by unconverted inches produces an incorrect cubic-foot result.
For metric projects, convert dimensions to metres and calculate cubic metres directly.
3. Use density only when you need weight
Bulk density varies with stone type, grading, void space and moisture. If the supplier sells by the ton, use its published conversion or density whenever possible.
The same volume of two different gravel products can have different weights.
4. Distinguish delivered material from compacted finished volume
Loose delivered gravel may settle or compact after placement. A simple calculator estimates geometric volume, not the exact compaction behavior of a specific aggregate.
For driveways or engineered bases, confirm the required layer system and compaction specification separately.
Example: 12 ft × 12 ft area at 3 in deep
- Area
- 144 sq ft
- Depth
- 3 in
- Waste allowance
- 5%
- Bulk density
- 2,800 lb/yd³
The base volume is about 1.33 cubic yards. With a 5% allowance it is about 1.40 cubic yards. At 2,800 lb/yd³, that planning volume weighs about 1.96 tons.
Run your own numbers in the Gravel Calculator →What to avoid
- Using inches as feet
- Assuming one universal tons-per-yard conversion
- Ignoring the difference between loose and compacted material
- Using a landscaping estimate as a pavement design specification
Before you order
- Measure area
- Choose layer depth
- Convert units
- Calculate volume
- Use supplier density if weight is needed
- Confirm delivery or compaction requirements