How many tons is a cubic yard of gravel?

About 1.35 to 1.4 tons for crushed stone. Pea gravel is lighter at roughly 1.25 to 1.3; dense-graded base with fines can reach 1.5. Confirm with your supplier for the exact product.

How much gravel for a 12x40 driveway?

At 4 inches, about 5.9 cubic yards or 8.3 tons before compaction — closer to 10 tons ordered once compaction is allowed for. A properly built driveway with 8 to 12 inches of layered stone needs two to three times that.

Do I need to add extra for compaction?

For dense-graded base with fines, yes — 20 to 25 percent. For clean washed drainage stone, no; it does not meaningfully compact.

How deep should a gravel driveway be?

8 to 12 inches of stone built in compacted layers, coarse at the bottom and dense-graded on top. A single thin layer over soft subgrade will rut within a year.

How Many Tons of Gravel Do I Need?

Gravel is measured in cubic yards and sold in tons, and the conversion is roughly 1.4 tons per cubic yard for crushed stone. Work out the volume from area times depth, convert, then add 20 to 25 percent if the material is going to be compacted — because a compacted base is measured after compaction and delivered before it.

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Yards to tons

Crushed stone weighs roughly 2,700 pounds per cubic yard, so one cubic yard is about 1.35 to 1.4 tons. Pea gravel and washed river rock are lighter, nearer 1.25 to 1.3 tons; crusher run and dense-graded base with fines are heavier, up to 1.5. Ask the quarry for the figure for the specific product, because a 10 percent difference on a 20 ton order is two tons of stone.

The volume itself is the easy part. Area in square feet times depth in feet, divided by 27, gives cubic yards — a 12 by 40 foot driveway at 4 inches is 480 × 0.333 ÷ 27, or 5.9 cubic yards, which is about 8.3 tons before compaction.

The compaction allowance

This is where estimates go wrong. Dense-graded base compacts by 20 to 25 percent as it is rolled or plate-compacted: four inches of finished base takes about five inches of loose stone to build. Order the finished volume and the driveway ends up thin.

Clean, open-graded stone — washed drainage rock with no fines — barely compacts at all, so no allowance is needed for a French drain or a dry well. Knowing which of the two you are buying matters more than the exact percentage, and the distinction is easy: if the pile has dust in it, it will compact.

The same logic runs backwards for excavation. Soil swells when you dig it, typically 20 to 30 percent, so the dirt coming out of a trench fills more truck volume than the hole suggests.

Depths that actually work

A gravel driveway wants 8 to 12 inches of total stone in layers, not one deep dump: a coarse base of 3 to 4 inch stone at the bottom, a middle layer of crusher run, and a finish course of dense-graded base or 3/4 inch minus on top, each compacted before the next goes down. A single 4 inch layer of pretty stone over soft ground becomes ruts in a season.

A paver or slab base is 4 to 6 inches of compacted dense-graded base for a patio and 6 to 8 for anything a vehicle uses, plus an inch of bedding sand for pavers. A French drain trench is filled with clean washed stone around the pipe, wrapped in filter fabric, with the fabric folded over the top so silt cannot migrate in and kill the drain.

Whatever the application, the base is what the surface is standing on. Spending on a thicker base and a thinner surface is almost always the better trade.

Ordering and delivery

Stone is delivered by the ton on trucks with a practical maximum around 20 tons for a tandem and more for a tri-axle. Below about 5 tons you may pay a minimum-load charge that makes small orders expensive per ton, and above one truckload the price per ton usually drops.

Check that the truck can reach where the pile needs to be, and where it will be dumped: a 20 ton pile in the wrong place is a day of wheelbarrowing. Confirm the dump site, the turning space and any overhead wires before the delivery arrives, not while it is reversing.

Common questions

How many tons is a cubic yard of gravel?: About 1.35 to 1.4 tons for crushed stone. Pea gravel is lighter at roughly 1.25 to 1.3; dense-graded base with fines can reach 1.5. Confirm with your supplier for the exact product.
How much gravel for a 12x40 driveway?: At 4 inches, about 5.9 cubic yards or 8.3 tons before compaction — closer to 10 tons ordered once compaction is allowed for. A properly built driveway with 8 to 12 inches of layered stone needs two to three times that.
Do I need to add extra for compaction?: For dense-graded base with fines, yes — 20 to 25 percent. For clean washed drainage stone, no; it does not meaningfully compact.
How deep should a gravel driveway be?: 8 to 12 inches of stone built in compacted layers, coarse at the bottom and dense-graded on top. A single thin layer over soft subgrade will rut within a year.

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Updated 09/03/2026