The layers
A driveway that lasts a decade is built in layers, not dumped in one:
- Base: 6–8″ of large crushed stone (2–3″ minus), compacted. This is the structural layer that spreads vehicle loads.
- Surface: 3–4″ of smaller stone (3/4″ minus or crusher run), compacted. This is what you drive on — the fines in crusher run lock it together.
On firm, sandy soil you can shave an inch or two off the base. On clay or soft ground, go thicker — or lay geotextile fabric under the base to stop the stone from migrating down into the mud. Fabric is the cheapest insurance in driveway building.
Crowned, not flat
Grade the driveway with a slight crown (about 2% fall from center to edges) so water sheets off instead of pooling. Standing water is what kills gravel driveways — it softens the base and carves ruts.
Maintenance math
Even a well-built gravel driveway needs a fresh 1–2″ of surface stone every 2–4 years. Budget for it with the gravel calculator — topping up is cheap, rebuilding is not.
Worked example: a 12 ft by 100 ft driveway
That driveway is 1,200 square feet. A 7 inch compacted base is about 25.9 cubic yards before compaction allowance, and a 3.5 inch surface layer is about 13 cubic yards, for roughly 39 cubic yards in total. Gravel is usually sold by the ton, and a cubic yard of crushed stone weighs roughly 1.3 to 1.4 tons, so the order is in the region of 50 to 55 tons split between the two stone sizes. That surprises most people the first time, and it is why a quote that sounds high per ton can still be correct. Run your own length and width through the gravel calculator layer by layer, using compacted depth, and let it apply the compaction factor rather than ordering loose depth.
Depth by soil: one table worth keeping
| Firm sand or gravel soil, good drainage | 4 to 6 inches base plus 3 inches surface |
| Average loam | 6 inches base plus 3 to 4 inches surface |
| Clay or soft, wet ground | 8 inches base over geotextile fabric plus 3 to 4 inches surface |
| Heavy vehicles, deliveries, or a farm lane | Add 2 inches to the base on any soil |
These are planning depths for a private driveway, not an engineered road section. If the ground pumps or feels spongy underfoot in spring, treat it as clay even if the surface looks like loam.
Compaction is not optional
Loose stone compacts by roughly 20 to 30 percent under a roller or plate compactor and under traffic. Spreading the full depth in one lift and driving on it compacts the top and leaves the bottom loose, which later shows up as ruts that follow your tire tracks exactly. Spread each layer, compact it, then add the next. Wetting the surface lightly before compacting helps the fines lock together in crusher run. If you skip renting a compactor, expect the first year of driving to do the compacting for you, and budget extra surface stone to fill the settling.
Drainage mistakes that undo good depth
A driveway that is deep enough will still fail if water has nowhere to go. Keep the crown, keep ditches or swales open at the edges, and never let the surface end up lower than the ground beside it, which turns it into a long shallow pond. Where a driveway meets a garage or a road, check that meltwater and storm water flow away from buildings rather than toward them. Most premature gravel failures traced in hindsight are water failures, not stone failures.
Content reviewed October 2026. Frost depth and local rules vary; check local requirements for work in a road right-of-way.