A gravel driveway is one of the most common bulk material jobs, and the amount comes down to two things: the area and how deep you go. A fresh top layer needs far less than a full build from bare ground, so the first decision is which one you are doing.
Pick the depth
For a fresh surface layer over an existing, sound base, 3 to 4 inches of stone is typical. For a full build on bare soil, you need a deeper structure: a compacted sub base of crusher run, often 4 to 6 inches, topped with a 2 to 3 inch finer surface stone. A full build can easily total 6 to 8 inches once both layers are in.
Work out the volume
Multiply length by width by depth in feet, then divide by 27 for cubic yards. Convert depth from inches to feet by dividing by 12, then convert to tons using your stone density.
Worked example one: a top up
A 20 by 30 foot driveway at 4 inches: 20 times 30 is 600 square feet, times 0.333 feet is 200 cubic feet, divided by 27 is about 7.4 cubic yards. At roughly 1.4 tons per cubic yard, that is about 10.4 tons of crushed gravel.
Worked example two: a full build
The same 20 by 30 driveway built from bare ground with 6 inches of total stone: 600 square feet times 0.5 feet is 300 cubic feet, divided by 27 is about 11.1 cubic yards, or roughly 15.5 tons. Split that between a thicker crusher run sub base and a finer surface stone on top.
Order by the ton
Suppliers usually sell gravel by weight, so confirm the density of your chosen stone to convert your cubic yards to tons accurately. Crushed stone and crusher run differ, and moisture adds weight, so the 1.4 figure is a starting point, not a guarantee.
Tips for a driveway that lasts
- Compact each layer rather than dumping it all at once. A plate compactor on the sub base makes a real difference to how the surface holds up.
- Crown the surface slightly, higher in the middle, so water runs off to the sides rather than pooling and washing ruts.
- Add edge restraints or a defined border to keep the gravel from migrating into the lawn over time.
- Use angular crushed stone, not smooth pea gravel, for the surface so it locks together under tyres.