Gravel Calculator

Enter your dimensions above and the calculator returns the answer in the units suppliers actually sell in — cubic yards, cubic feet, tons and bags.

Typical gravel depth by application

Gravel is sold by the cubic yard from a landscape yard, or by the bag for small patches; crushed stone is the usual choice for driveways and decorative gravel for beds.

What the numbers assume

The result uses a bulk density of 105 lb per cubic foot and a default waste allowance of 10%. Both are typical values, not measurements of your material — bagged products and different aggregate sources vary by 10% or more. Change the waste field if your subgrade is uneven or you are pouring against forms with complex edges.

Gravel compacts as much as 20% under traffic, so a 4-inch loose layer settles to about 3¼ inches. Order by the compacted depth you want, not the loose depth you see in the truck.

Costs shown are material only, based on a national average price you can edit. They exclude delivery, short-form fees, equipment rental and labour.

A driveway is four layers, and only two of them are stone

A gravel driveway that lasts is not a pile of gravel. It is a structure built from the bottom up, and every layer has a job.

Subgrade — the native soil, stripped of topsoil and anything organic, graded and compacted before anything else goes down. This is the layer that actually carries the truck. Soft spots, buried stumps and tree roots telegraph through the stone above them within a season or two.

Geotextile — a woven fabric, not the thin non-woven landscape fabric sold for beds, laid directly on the subgrade. It stops stone punching down into soft soil and fines pumping up into the voids. It does not change the volume you order, which is why the methodology page keeps it out of the calculation, but on clay it roughly doubles how long the surface survives.

Base — ¾-inch minus, road base, or crushed stone with the fines left in. The fines are the point: they let the material compact into a semi-locked, load-spreading layer instead of a loose pile of pebbles. Four inches compacted is the norm under a car driveway, six under anything heavier.

Surface — clean crushed stone with no fines, usually a single-size grade like ¾-inch clean. It sits on the base, sheds water, and is the layer you rake and top up.

Both get sold as "gravel," and they are not interchangeable. Base with fines locks up under a plate compactor; clean stone never locks up, which is what you want on top and exactly wrong underneath. Order six yards of clean stone hoping it becomes a base and you will rebuild the driveway next year. For pavers on top instead of stone, the paver base calculator gives base depth by traffic load. If the subgrade itself has to come up first, that material is fill — the fill dirt calculator covers the volume.

Compaction is the difference between what you order and what you get

Crushed stone compacts up to 20% under a plate compactor and traffic. A four-inch loose layer settles to about three and a quarter inches — the biggest gap between the number a homeowner calculates and the number that survives contact with a real driveway.

The default waste allowance here is 10%, which is generous for a decorative top dressing. For a driveway built in lifts, where every layer gets watered and compacted, the multiplier that shows up in the field is closer to 20%, because what you order has to be the loose volume that compacts down to the depth you specified. The waste field is editable, and it is the honest place to put that difference.

Worked through: a four-inch compacted layer over 360 square feet is 360 × 0.333 = 120 cubic feet, or 4.44 cubic yards in place. To still have that after compaction you need 120 ÷ 0.8 = 150 cubic feet of loose stone, or 5.56 cubic yards. On that one layer the gap is 1.1 yards — the sort of shortfall that turns into a second delivery fee and a lost Saturday.

Compaction is not something you can buy your way out of with more stone. It happens in lifts no deeper than three or four inches, each watered lightly and run over with a plate compactor or roller until the surface rings rather than thuds. Dumping eight inches at once and compacting the top leaves the bottom loose.

Yards, tons and truckloads

Gravel gets quoted two ways. A landscape yard sells by the cubic yard, a volume. A quarry or aggregate supplier often sells by the ton, a weight. For the same crushed stone the two are interchangeable at 105 lb per cubic foot: 27 cubic feet to the yard, so 2,835 lb, or about 1.4 tons per cubic yard. Five yards is roughly seven tons. River rock and pea gravel are lighter, closer to 1.2 tons per yard, so a ton price from one supplier is not comparable to a yard price from another until you know which stone is being quoted. Ask which unit you are buying in, and whether delivery is included.

Truckloads are where units meet reality. A tandem-axle dump truck carries about 12 cubic yards, around 17 tons of crushed stone. Past that the load runs into the 80,000 lb legal gross weight limit for US highways, so bigger orders arrive split across two trucks or on a tri-axle. Every trip usually carries its own fee or minimum.

Site access decides as much as price. A loaded dump truck needs a firm, wide approach with no overhead wires where the bed goes up, and somewhere it can spread as it drives out — spreading from the truck saves hours of wheelbarrow work. If the truck cannot get in, the stone is dropped at the kerb and that labour is yours. Where the drive meets a road, that transition is usually concrete, and the concrete calculator sizes it.

What a cubic yard actually covers

Coverage falls off in a straight line with depth, because volume is area times depth. One cubic yard is 27 cubic feet, so an inch deep covers 324 square feet. At two inches it is 162 square feet, at three inches 108, at four inches 81, at six inches 54. Most driveways land between 80 and 110 square feet per yard — the three-to-four-inch range a top layer occupies.

A full example: a 12 × 30 ft driveway, 360 square feet, with a four-inch base and a four-inch surface.

• Surface layer: 4.44 cubic yards in place, 5.56 yards loose at a 20% compaction allowance.
• Base layer: the same again, 5.56 yards loose.
• Total to order: about 11 cubic yards, weighing roughly 15.5 tons at 1.4 tons per yard.
• At the $52 per cubic yard default that is about $570 in stone before delivery. The default is a US national average and it is editable, so put your own yard's number in first.

Topping up an existing drive instead of building one halves it: two inches over the same area is about 2.8 yards loose. It is the cheap version of the job, and the one that fails fastest when the base underneath is already gone. The material calculator runs these numbers across every material, and the river rock calculator is a different number again — lighter per yard, usually two to three times the price.

The edges fail first

The outermost six inches of a gravel driveway take the turning loads and have nothing on the outside holding them in. Stone migrates sideways, the edge rounds off, and once it loses height the layers beside it lose confinement: the surface spreads and ravels, and potholes form at the edge first. Almost every "the gravel keeps disappearing" complaint is an edge problem, not a stone problem.

A real edge is one of three things. Steel or aluminium edge restraint, spiked through into the base, is the permanent answer wherever a vehicle turns. A compacted shoulder of the same stone works on a low-traffic drive if you maintain it. A pressure-treated timber or a line of larger stone, buried a third of its depth, holds a path or a light drive for years. Native soil on its own is not an edge, especially on a slope.

Grading is the other half of keeping edges intact. Shape the surface with a two percent fall away from the centre — about a quarter inch per foot — so water runs off. Water that sits in a gravel drive in November is ice in February, and ice lifting the surface is how a driveway that looked fine in autumn becomes a rutted mess by spring.

Get the base right, compact it in lifts, contain the edges, and grade for water, and a gravel driveway will outlast the truck that delivered it. Skip any one of those and the stone you paid for ends up in the grass at the edge within two winters.