Quick answer
Multiply length × width × depth in feet and divide by 27 for cubic yards, then add for compaction: Penn State's road center compacts 8 inches of loose aggregate to 6, so order about a third more than the finished depth. A 12 × 50 ft driveway 6 inches deep (compacted) takes 11.1 cubic yards finished, about 14.8 cubic yards loose, or roughly 21 tons at 1.4 tons per cubic yard. County and state standards call for 6 to 13 inches of stone in total.
How deep to build it
There is no national driveway standard. Road agencies and counties set a minimum depth, and the more detailed ones put a thicker base of larger stone under a surface layer of finer gravel.
- FHWA's gravel roads guide calls for a surface layer of at least 3 inches, on top of a base deep enough for the loads, and says any total over 4 inches should go down in separate layers so each can be compacted.
- Canyon County, Idaho requires new driveways to have 9 inches of pit-run subbase plus a 4-inch compacted base of ¾-inch-minus gravel: 13 inches in all, 12 ft wide.
- Wisconsin DOT's standard rural entrance with a gravel surface uses 6 inches of dense-graded base aggregate, more on clay.
- Mason County, Michigan requires at least 6 inches of processed road gravel.
Soft or clay soil needs more depth. FHWA recommends at least 6 inches for the first layer when it goes over a geotextile fabric, and notes that each layer should be at least twice as thick as the largest stone in it. Your county or town may have its own driveway standard, especially where the driveway meets the road.
Which gravel
Gravel is sold by size number under the AASHTO M43 standard. Maryland's Department of the Environment lists, for example:
| Size | Stone size |
|---|---|
| #3 | 2 to 1 inch |
| #4 | 1-1/2 to 3/4 inch |
| #57 | 1 inch down to about 3/16 inch (No. 4 sieve) |
| #8 | 3/8 inch down to No. 8 sieve |
Those are clean, washed stone with the fines screened out. For a driving surface, road agencies use dense-graded aggregate, a mix of sizes down to fines that packs into a hard layer; suppliers often sell it as crusher run, road base or ¾-inch minus, and the names vary by region. Ask the supplier for their driveway base and surface material.
Order extra for compaction
Gravel arrives loose and packs down when it is rolled or driven on. FHWA warns that ordinary compaction often shrinks the volume by 30 percent or more, and that people too often calculate from the loose depth. A 30 percent shrink means ordering about 43 percent more than the finished volume; FHWA's figure includes settling under traffic over time. Penn State's Center for Dirt and Gravel Road Studies places its road aggregate 8 inches loose to finish at 6 inches, or 6 inches loose to finish at 4-1/2: about a third more loose stone than the finished depth, compacted with at least a 10-ton vibratory roller. With a plate compactor or a small rented roller, FHWA advises spreading and compacting layers no more than about 4 inches deep loose. Your supplier can give the figure for their material.
Worked example
A driveway 12 ft wide and 50 ft long, with 6 inches of finished, compacted gravel:
- Volume: 12 × 50 × 0.5 = 300 cubic feet, ÷ 27 = 11.1 cubic yards compacted.
- Loose stone to order, at 8 inches loose for 6 compacted: 11.1 × 8 ÷ 6 = 14.8 cubic yards.
- Weight, if your supplier sells by the ton: 14.8 × 1.4 = about 21 tons. The 1.4 tons per cubic yard is the factor our gravel calculator uses, from Nebraska DOT's figure for chip seal aggregate; your supplier's figure for their stone is the one to use.
The gravel calculator does the volume and tons for any size, and the cubic yards to tons guide covers other materials.
How many truckloads
Texas DOT's seal coat manual says single-axle dump trucks normally carry 6 cubic yards of aggregate, and tandem-axle trucks 12 or 14 cubic yards. The example above, about 15 cubic yards, is more than one truck: three single-axle loads, or two tandem loads. Legal weight limits can cap a load below the bed's volume, so ask the supplier how many loads it will take.
Frequently asked questions
How deep should a gravel driveway be?
Published standards range from 6 inches (Mason County, Michigan; Wisconsin DOT rural entrances) to 13 inches (Canyon County, Idaho: 9 inches of subbase plus a 4-inch base). FHWA calls for at least 3 inches of surface gravel on top of an adequate base, and more depth on soft soil.
How much extra gravel should I order for compaction?
About a third more than the finished depth: Penn State's road center places 8 inches loose to finish at 6. FHWA warns that over time compaction can shrink volume by 30 percent or more, so on soft ground or for a long-lasting job, order closer to half again as much.
How many tons of gravel for a 50 ft driveway?
For a 12 ft wide driveway with 6 inches of compacted gravel, about 14.8 cubic yards of loose stone, roughly 21 tons at 1.4 tons per cubic yard. Your supplier's weight per yard may differ.
What is the best gravel for a driveway?
Dense-graded aggregate, a mix of stone sizes down to fines that compacts into a hard surface, often sold as crusher run, road base or ¾-inch minus.
Calculators for this
Gravel
Find how much gravel, crushed stone, pea gravel or river rock you need in tons, cubic yards and bags for driveways, paths and patios.
Cubic Yard
Convert length, width and depth to cubic yards for dirt, gravel, mulch, sand or fill.
Asphalt
How many tons of asphalt do you need?
Published 2026-11-08. Sources: FHWA, Gravel Roads Construction & Maintenance Guide (FHWA-OTS-15-0002, 2015); Penn State Center for Dirt and Gravel Road Studies, Driving Surface Aggregate tech bulletin (2025); Canyon County, Idaho, private road and driveway construction packet; Wisconsin DOT, SDD 8D22 entrances; Mason County Road Commission (Michigan), driveway standards; Maryland Department of the Environment, Guide to Common Construction Materials (AASHTO M43 sizes); Texas DOT, Seal Coat and Surface Treatment Manual: haul trucks; Nebraska DOT, Estimating material quantities. See how we calculate.