How Much Gravel Do I Need for a Driveway or Patio Base?

A 10 x 10 ft patio base 4 inches deep needs 1.23 cubic yards of gravel, about 1.73 tons. A 12 x 50 ft gravel driveway built 8 inches deep needs 14.81 cubic yards, about 20.74 tons. In both cases, order roughly 10 to 15% more, because crushed stone compacts and spreads.

The formula is the same for any area: square feet × depth in inches ÷ 12 ÷ 27 = cubic yards, and cubic yards × 1.4 = tons. The Gravel Calculator does this for rectangles, circles and triangles, and the tables below use the same 1.4 tons per cubic yard so the numbers match.

Gravel per 100 Square Feet by Depth

A 100 sq ft area is a 10 x 10 ft patio or a 4 x 25 ft path. Multiply by your own area in hundreds of square feet.

Turned around, one ton of gravel covers about 116 sq ft at 2 inches, 77 sq ft at 3 inches, 58 sq ft at 4 inches and 39 sq ft at 6 inches.

Tons vs Cubic Yards

Suppliers sell gravel by the ton, by the cubic yard, or both. Convert with the stone's weight per cubic yard:

The 1.4 figure is an average. Real gravel and crushed stone commonly weigh somewhere around 1.3 to 1.5 tons per cubic yard, depending on the rock, the size of the pieces and how wet it is. If your supplier tells you the weight per yard for the exact product you are buying, use that instead. The tons here are US short tons of 2,000 lb.

How Deep Should the Gravel Be?

These are common practices for firm, well-drained soil. Clay, soft or wet ground usually needs a deeper base, and in that case a grading contractor can tell you what works locally. For slabs, see how thick a concrete slab should be, which covers the base under each type of slab.

Worked Example: A Paver Patio Base

A 12 x 12 ft patio is 144 sq ft. At 4 inches deep:

At 6 inches, the same patio needs 2.67 cu yd (3.73 tons) before the extra. You also need about 1 inch of bedding sand on top, covered in the paver patio materials list, along with the paver count. The Paver Calculator works out the base and sand together.

Worked Example: A New Gravel Driveway

A 12 x 50 ft driveway is 600 sq ft. Gravel driveways are built in layers: larger crushed stone underneath for strength, and a smaller stone on top for a firm, smooth surface. Calculate each layer separately with its own depth.

A 12 in build on the same footprint needs 22.22 cu yd, about 31.11 tons before extra. Ask your supplier how many tons fit in one truckload. Large orders may need more than one delivery, and a single big load dumped in the wrong place can be hard to move.

How Much Extra for Compaction?

The calculator gives the volume of the finished layer and does not add anything. Loose stone settles when you compact it and spreads into low spots and edges, so order about 10 to 15% more than the calculated amount. Use the higher figure for compacted bases under pavers and slabs, and around 10% for loose decorative gravel. Compact in lifts of about 2 to 3 inches with a plate compactor rather than all at once; a single thick layer stays loose at the bottom.

Which Type of Gravel?

Names vary by region, so describe the job when you call the supplier.

Bags vs Bulk

Small jobs can use bagged gravel or paver base, often sold in 0.5 cu ft bags. A 10 x 10 ft base at 4 inches is 33.33 cu ft, which is 67 bags of that size. Beyond a small path or a few patio repairs, bulk delivery is usually much easier. Check delivery minimums and whether the truck can reach the drop spot without damaging a lawn or driveway.

Before You Dig

Call 811 (or your local utility locating service) a few days before you excavate. Remove sod and topsoil down to firm ground, and lay landscape fabric where you want to keep gravel from sinking into the soil. For driveways on slopes, poor drainage or soft clay, a grading contractor can size the base and drainage properly.

The Short Answer

Multiply your area in square feet by the depth in inches, divide by 324 for cubic yards, and multiply by 1.4 for tons. Then add 10 to 15%. The Gravel Calculator does it in one step, and if you are pouring concrete on top, how many bags of concrete you need covers the slab itself.