The layers
- Subgrade
- The native soil, cleared of topsoil and organic material and shaped so water runs off. This isn't something you order, but the driveway depends on it.
- Base
- Large angular stone (for example #2) or a compactable road base. It spreads wheel loads.
- Surface
- Smaller angular stone (for example #57) that drives and drains well.
How deep?
| Use | Total depth | Layers |
|---|---|---|
| Residential, light use | 4–6 in | 2–3 in #2 base + 2–3 in #57 top |
| Residential, heavy use | 8 in + | Thicker base |
| Commercial | 10–12 in | 6–8 in #2 + 2–3 in #57 + 2–3 in fine top (#8 or crusher run) |
This is one supplier's guidance, not a standard. Soft or wet soil, steep slopes and heavy vehicles call for more. When in doubt, ask a local supplier or contractor who knows the ground.
Choosing the stone
Angular crushed stone locks together; rounded stone (pea gravel, river rock) rolls. That's why driveway guidance generally uses crushed stone. See types and sizes for what the numbers mean.
Compaction and ordering
Loose stone settles when it's compacted and driven on. A gravel-roads manual prepared for the Federal Highway Administration reports a “30% or greater reduction in volume” from ordinary compaction in many areas source. If you design to a compacted depth, order more loose stone — a 30% reduction means about 43% more (1 ÷ 0.7). The driveway calculator has a separate compaction allowance for each layer.
Working out the quantity
For a 60 ft × 10 ft driveway with 3 in of base and 3 in of surface, a 20% compaction allowance and 5% waste, the calculator gives 7.0 yd³ per layer — 14.0 yd³, about 19.85 US tons at 105 lb/ft³. Use your supplier's densities to firm that up.
Estimating cost
Stone prices vary a lot by region, material and delivery distance, so we don't publish prices. To estimate your own:
- Get quotes per ton or per yard for each layer's stone, and the delivery charge.
- Enter each price in the driveway calculator (per ton, per yard or per tonne); it multiplies by that layer's quantity.
- Add the items the calculator doesn't cover: excavation, geotextile, edging, culverts, equipment hire or labour.
Bulk loads often have minimum orders or delivery charges that don't scale with quantity, so compare the totals, not just the unit price.
After installation
Gravel surfaces need occasional regrading and top-ups as stone gets pushed aside or pressed into the base. To size a top-up, measure the area and the depth you want to add, and use the gravel calculator.