CALCULATION METHOD
How much gravel do I need?
Measure the area and finished depth, then select a gravel type. This gravel estimator also works as an aggregate calculator for the listed materials. It converts volume to cubic yards and uses bulk density to estimate tons. Compaction and waste are shown separately so you can see why the order amount is larger than the finished volume.
Net volume = length × width × depth
Order volume = net volume × compaction factor × waste factor
Order weight = order volume × bulk density
Gravel driveway example
A 40 ft × 12 ft driveway at 4 inches deep has a finished volume of 5.93 cubic yards. Using general gravel at 105 lb/ft³, plus 10% for compaction and 5% for waste, the estimated order is about 6.8 cubic yards or 9.7 short tons.
Typical gravel densities
Bulk density varies with stone type, gradation, moisture, and supplier. The values below are planning defaults, not purchase specifications.
| Material preset | Density used | Approx. tons/yd³ |
|---|---|---|
| General gravel | 105 lb/ft³ | 1.42 |
| Crushed stone / road base | 100 lb/ft³ | 1.35 |
| Pea gravel | 102 lb/ft³ | 1.38 |
| River rock | 95 lb/ft³ | 1.28 |
| Crushed limestone | 105 lb/ft³ | 1.42 |
Compaction is not the same as waste
Compaction allowance accounts for loose aggregate settling into a smaller finished volume. Waste covers uneven excavation, spillage, and measurement error. Keep them separate and replace the defaults with project or supplier values when available.
Inch Calculator gravel weight ranges and the FHWA Gravel Roads Maintenance and Design Manual. Accessed September 10, 2026.