How Much Gravel for a Driveway

How deep should a gravel driveway be?

Depth comes down to two things: what drives on the driveway, and what's underneath it. Firm, well-drained soil, such as sandy or gravelly ground, supports a thinner build. Clay, silt, or ground that stays wet needs a thicker base, and usually a layer of geotextile fabric, because soft soil lets the stone sink and mix with mud.

Depths are after compaction. Loose gravel settles when it's compacted and driven on, which is one reason to order about 10% more than the calculated volume.

How the layers work

Each layer does a different job, so each uses a different stone. A standard two-layer driveway looks like this in cross-section:

• Subgrade. This is the native soil after you strip the sod and topsoil. Organic soil compresses and holds water, so it has to go. The subgrade is shaped and compacted before any stone goes down, because the finished surface can only be as even as what's under it.
• Geotextile fabric. Woven stabilization fabric separates the stone from the soil. On firm, sandy ground you can skip it. On clay or wet ground it's one of the cheapest ways to make a driveway last, because it stops the base from being pushed down into the mud a little more every year.
• Base layer. Large, angular crushed stone (or crusher run) locks together when compacted and spreads each wheel load over a wider area of soil. This is where most of your tonnage goes.
• Surface layer. Smaller stone fills the top and gives you something smooth to drive on. Material with fines, such as crusher run or #411 (#57 stone mixed with stone dust), compacts into a hard crust. Clean #57 drains faster but stays loose and can rut.

For new driveways on soft ground, many builders use three layers instead of two: about 4 in of #3 stone at the bottom, 4 in of #57 in the middle, and a 2–3 in top layer of crusher run or #411. To estimate a three-layer build in the Driveway Calculator, enter the two lower layers together as the base depth, or run each layer through the Gravel Calculator if you'll order them separately.

How much gravel for common driveway sizes

This table uses a standard 6 in build (a 4 in base plus a 2 in surface layer) and the same assumptions as the Driveway Calculator: compacted driveway stone at about 2,800 lb per cubic yard (1.4 tons), plus 10% extra for waste.

For an 8 in build, multiply by 1.33; for a 12 in build on soft soil, double the figures. For a tapered, curved, or circular driveway, use the calculator's trapezoid, circle, or ring shapes.

How to calculate it yourself

The math is the same for any driveway. Here it is for a driveway 12 ft wide and 50 ft long:

1. Multiply length by width to get the area: 50 × 12 = 600 ft².
2. Convert each layer's depth to feet by dividing by 12: 4 in = 0.333 ft and 2 in = 0.167 ft.
3. Multiply the area by each depth: 200 ft³ for the base and 100 ft³ for the surface.
4. Add the layers and divide by 27 to get cubic yards: 300 ft³ ÷ 27 = 11.1 yd³.
5. Add 10% for compaction, spillage, and dips in the subgrade: 11.1 × 1.1 = 12.2 yd³.
6. If your supplier sells by the ton, multiply by the stone's weight per yard: 12.2 × 1.4 ≈ 17.1 tons.

Building a gravel driveway, step by step

1. Check for utilities and permits. In the US, call 811 a few days before you dig so buried lines are marked. Ask your town whether you need a permit, especially for the apron where the driveway meets the road or if it crosses a ditch.
2. Mark the layout. Stake both edges and run string lines. Plan on 10–12 ft of width for a single lane and 20–24 ft for two cars side by side, and make curves generous: vehicles cut corners and will push gravel off a tight bend.
3. Strip and excavate. Remove sod, topsoil, and roots down to firm subsoil, typically 6–8 in for a standard build and more for a thicker one. Aim for a finished surface level with or slightly above the surrounding ground, so water drains away from the driveway rather than into it.
4. Shape and compact the subgrade. Grade it with a crown, higher in the center than at the edges, or with a steady cross-slope on a hillside. Gravel road manuals recommend about 1/2 in of fall per foot of width (roughly 4%). Compact it with a plate compactor or roller, and dig out any soft spots and refill them with stone.
5. Lay fabric if you need it. On clay or wet soil, roll woven geotextile over the whole subgrade, overlapping the seams by a foot or more.
6. Spread and compact the base. Place base stone in lifts of no more than about 4 in, compacting each one before adding the next. A thick layer compacted all at once stays loose at the bottom.
7. Add the surface layer. Spread 2–3 in of surface stone, keep the crown, and compact it. A light spray of water helps crusher run and #411 bind into a hard surface.
8. Finish the edges and drainage. Edging made of steel, timber, or stone keeps gravel out of the lawn. Where the driveway crosses a ditch or a natural drainage path, a culvert carries the water under it instead of across it.

Resurfacing an existing driveway

If the base is still sound, with no deep ruts or soft spots that pump up mud, you only need a new surface layer. Fill potholes with base stone and compact them first, so the new layer isn't just filling holes, then spread 1–2 in of surface gravel over the whole driveway. A 12 × 50 ft driveway at 2 in takes about 4.1 yd³ including waste, or 5–6 tons depending on the stone.

Most gravel driveways need a fresh top layer every 2–4 years, depending on traffic, snow plowing, and how much rain runs across them. Regrading once a year to restore the crown makes each top-up last longer.

Common mistakes

• Building on topsoil or sod. Organic material compresses and rots, and the gravel sinks with it.
• Skipping compaction. Loose stone shifts and settles unevenly under the first heavy loads, leaving ruts.
• Using rounded stone. Pea gravel and river rock roll against each other instead of locking together. They make a poor driving surface and a worse base.
• Ignoring drainage. Water is the main cause of potholes: it softens the base, and traffic does the rest. A crown and a clear path for runoff prevent most of them.
• Ordering the exact calculated volume. Compaction, spreading losses, and dips in the subgrade use up more stone than you'd expect. Add 10%, or 15% on soft or uneven ground.

Choosing a gravel type

Angular crushed stone is the standard for both layers because its fractured faces lock together. Pea gravel looks good but rolls underfoot and under tires, so save it for paths. See types of gravel and sizes for a full comparison, and how much gravel costs to budget the job.

Related guides and calculators

• Driveway Calculator →
• Gravel Calculator →
• Types of gravel and sizes →
• How much does gravel cost? →
• Gravel coverage chart →

Frequently asked questions