What the guides say
| Guidance | Figure | Source |
|---|---|---|
| Road base under a driveway | 4 to 6 in, in 2 in lifts | hellogravel.com |
| Three-layer gravel driveway, total | 12 to 18 in, each layer 4 to 6 in | angi.com (archived) |
| Paver driveway base | 6 in minimum | cmha.org |
Soft, wet or clay soil needs the deeper end. A driveway that carries delivery trucks or RVs needs more than one that only sees cars.
Tons per 100 sq ft by depth
| Depth | Cubic yards | Tons of crusher run | Tons of No. 57 |
|---|---|---|---|
| 2 in | 0.62 | 0.93 | 0.80 |
| 4 in | 1.23 | 1.85 | 1.59 |
| 6 in | 1.85 | 2.78 | 2.39 |
| 8 in | 2.47 | 3.70 | 3.18 |
| 12 in | 3.70 | 5.56 | 4.77 |
Crusher run at 1.5 t/yd³; No. 57 at FHWA's loose 1.29 t/yd³.
Common questions
Is 4 inches of gravel enough for a driveway?
Hello Gravel's lower figure for road base under a driveway is 4 inches; Angi's three-layer method is much deeper. Firm, well-drained ground can get by with less than soft ground.
Related calculators
Sources
- https://hellogravel.com/products/road-base/
- https://web.archive.org/web/20230601114804/https://www.angi.com/articles/how-to-make-gravel-driveway.htm
- https://www.cmha.org/news-and-insights/proper-concrete-paver-base-and-depth-what-to-know-and-why-it-matters/
- https://selectsg.com/how-much-does-a-yard-of-crushed-stone-weigh/
- https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/15034/003.cfm