Gravel Calculator
Convert area and depth into cubic yards and tons of gravel or crushed stone, including a compaction allowance.
Estimates are for planning. Confirm quantities against your measured site and product packaging before ordering, and follow local building codes.
How to measure the area
For a straight driveway or pad, it’s length times width with a long tape or measuring wheel. Measure the width at both ends and the middle; driveways are rarely as uniform as they look, and three readings averaged beats one optimistic one.
Irregular areas split into rectangles. An L-shaped drive is two rectangles. A driveway with a flared apron at the road is the main rectangle plus a rough rectangle for the flare (average the narrow and wide ends for its width). A circular pad uses radius times radius times 3.14. Sketch it, label each piece, and add the square footages.
Depth depends on the job. A walkway or patio base wants 2 to 3 inches per material layer. A new residential driveway needs more than people expect: 4 inches of compacted base plus 2 to 3 inches of top stone is a common spec, and on soft ground the base alone can be 6 to 8 inches. A refresh of an existing driveway might only need 1 to 2 inches of new top stone. Run the calculator once per layer if your base and top courses are different materials, because you’ll order them separately anyway.
The formula and what it assumes
Cubic yards equals area in square feet, times depth in inches divided by 12, divided by 27, then multiplied by 1 plus the compaction percentage (15% by default). The first part is plain geometry: inches to feet, area times depth for cubic feet, 27 cubic feet to the yard. The compaction multiplier is the part gravel-specific: you order loose volume, but the finished depth you measured is compacted volume, so the order has to be bigger than the hole.
Tons is then yards times 1.4, the standard conversion for crushed stone. That’s an approximation. Dry pea gravel runs nearer 1.3 tons per yard, dense or wet crushed stone up to 1.5, so confirm with your quarry, especially on big orders where a tenth of a ton per yard adds up.
Assumptions to keep in mind. The formula treats depth as uniform, so crowned driveways (slightly higher in the middle for drainage) need a touch extra. The 15% default suits crusher run and similar graded material; clean #57 compacts less, closer to 10%, while fines-heavy base on soft ground can hit 20%. And the calculation covers one layer of one material. A proper driveway is built in lifts: spread 3 to 4 inches loose, compact it with a plate compactor or roller, then spread the next lift. Dumping 8 inches at once and driving on it never compacts properly at the bottom.
Buying tips
Bagged gravel at home centers comes in 0.5 cubic foot bags weighing about 50 pounds, at $4 to $8 each. That’s $216 to $430 per cubic yard equivalent, which is why bags only make sense for jobs under about half a yard: a small French drain run, paver leveling, filling a few post holes.
Bulk crushed stone from a quarry or landscape yard runs roughly $20 to $50 per ton for common materials like crusher run and #57, with decorative stone higher. Delivery adds $50 to $150 depending on distance, often free or discounted above a tonnage threshold. A single-axle dump truck carries about 8 to 10 tons, a tandem 14 to 18, so a typical 2-car driveway refresh fits in one load. As with mulch, the delivery fee sets the break-even: above roughly half a yard to a yard, bulk wins decisively.
What pros do on a new driveway: strip the topsoil, compact the subgrade, lay woven geotextile fabric on anything soft or clay-heavy, then build up crusher run in compacted 3 to 4 inch lifts, finishing with 2 inches of #57 on top. The fabric stops the base from sinking into mud, the crusher run fines lock into a hard crust, and the clean #57 sheds water and looks tidy. They also order a quarter to half ton extra rather than paying a second delivery fee for a shortfall, and they have the driver tailgate-spread the load along the drive instead of dumping one pile, which saves hours of wheelbarrow work.
Frequently asked questions
How many tons of gravel are in a cubic yard?
Roughly 1.4 tons per cubic yard for crushed stone, which is how most quarries price it. Lighter materials like dry pea gravel run closer to 1.3; wet or dense stone can push 1.5. Always ask your supplier for their material's weight, since they sell by the ton but you measured in yards.
What's the difference between #57 stone and crusher run?
Crusher run (also called CR-6, ABC, or road base) mixes crushed stone with fines, so it compacts into a hard, almost paved base layer. #57 stone is clean, uniform 3/4 to 1 inch rock with no fines, so it drains freely and stays looser. Driveways typically use crusher run as the base and #57 as the top course.
Why does the calculator add 15% for compaction?
Loose gravel loses volume when you compact it. A 4 inch loose lift packs down to roughly 3.5 inches, so without the allowance you'd come up short. Crusher run with fines compacts more than clean stone; 10 to 20 percent covers the normal range.
Do I need landscape fabric under a gravel driveway?
On soft, clay, or wet soil, yes. A woven geotextile keeps the gravel from being pumped down into the subgrade and the mud from rising up, which is the main reason driveways 'eat' their gravel every couple of years. On well-drained, firm soil it's optional but cheap insurance at about $0.30 to $0.60 per square foot.