How the gravel calculator works
Gravel gets ordered two ways, and the two never quite agree. A quarry weighs your truck and sells you tons; a landscape yard scoops a loader bucket and sells you cubic yards. Your project, meanwhile, is measured in feet and inches. This calculator translates between all three: measure the area (a rectangle, a circle, or a triangle), enter the depth in inches, pick the stone, and you get cubic yards, tons, and half-cubic-foot bags, each rounded up, because running short halfway through a driveway is the one outcome nobody wants.
The step people skip is the weight. Volume is plain geometry, but tons depend on the stone, and stone is heavier than it looks: heavy enough that a single cubic yard outweighs what a half-ton pickup is rated to carry. So every answer comes with a weight range, a working figure, and a label saying where each number came from, and if you enter your truck's payload, the number of trips it takes to haul it safely.
The formula
cubic yards = area × depth in inches ÷ 12 ÷ 27
tons = cubic yards × pounds per cubic yard ÷ 2,000
bags = cubic feet ÷ 0.5
Area is in square feet. Dividing the depth by 12 turns inches into feet, so area times depth is cubic feet, and dividing by 27 turns cubic feet into cubic yards, because a cubic yard is 3 feet by 3 feet by 3 feet. The pounds per cubic yard depend on the stone: 2,800 for #57 crushed stone, 3,000 for pea gravel and river rock, 2,600 for sand, and for road base and decomposed granite a compacted figure, because those two are measured after the plate compactor has done its work. Half a cubic foot is a common bag size for gravel and sand, so a cubic yard is 54 of them.
Worked example
A 12 by 20 foot parking pad, 4 inches of #57 crushed stone. The area is 240 square feet. Times 4 inches, divided by 12, is 80 cubic feet, and divided by 27 is 2.96 cubic yards. At 2,800 pounds a yard that is 8,296 pounds, or 4.15 tons. Rounded up, the answer reads about 4.2 tons of crushed stone: 3.0 cubic yards, and since most quarries sell by the half ton, you would ask for 4.5. The honest range, from the lightest lab measurement to a wet load, runs 3.52 to 4.44 tons.
Hauling it yourself? Even the best-rated version of the F-150, with 2,440 pounds of payload, would need 4 trips for a wet load of 8,877 pounds, carrying no more than about 0.81 cubic yards a trip. In bags it is 160 of them at about 52 pounds each.
A 12 by 16 foot paver patio, 4 inches of compacted road base plus 1 inch of bedding sand. The base is 2.37 compacted cubic yards; at 3,700 pounds a compacted yard that is 4.39 tons, so the answer reads about 4.4 tons of road base: 2.4 cubic yards once compacted. Loose off the truck it is about 3.13 cubic yards, and you spread it about 5.3 inches deep so the plate compactor can bring it down to 4. The bedding sand is 16 cubic feet: about 32 half-cubic-foot bags of sand, 0.77 tons.
A cubic yard of gravel outweighs a half-ton pickup's payload
This is the fact worth knowing before you back up to the pile. A cubic yard of #57 crushed stone weighs about 2,800 pounds, and pea gravel about 3,000. The best payload rating of any version of the Ford F-150 is 2,440 pounds (Ford's 2025 towing guide), the Ram 1500 2,360, and the Chevrolet Silverado 1500 2,260. Those are the best-case versions, usually a regular cab with a long bed; Ford's own table runs as low as 1,405. So a single cubic yard is more than the truck is built to carry, even though it barely covers the bottom of the bed and looks like nothing at all.
Nothing is wrong with the truck, and nothing is wrong with you for guessing. A pickup bed is sized for bulky things like furniture and mulch, and stone is most of a solid rock: a cubic yard of solid limestone would weigh about 4,489 pounds, and a yard of crushed stone is simply that rock with 47 percent air mixed in. Even at the light end of the lab measurements, typical loosely poured sand and natural gravel still outweigh all three trucks' best ratings. The best F-150 is full at 0.87 cubic yards of crushed stone, and the 1,405 pound version at half a yard.
Two numbers decide a safe load, and both are printed on paper you can hold. The first is on the tire and loading sticker on the driver's door frame, which federal rules require to say "the combined weight of occupants and cargo should never exceed" a stated number of pounds; you and your passengers count against it. The second is the scale ticket from the quarry. Enter your payload above and the calculator plans the trips against the heavy, wet end of the range.
What gravel weighs, and where our numbers come from
Published gravel weights disagree by a third, so we label every number, the same way our dumpster calculator does. MEASURED means a public agency measured it. REPORTED means a quarry publishes it for its own stone. EDITORIAL means it is our pick, shown in public.
The measured floor comes from the Alabama Department of Transportation, which lists a lab-measured loose unit weight for every aggregate it approves. Across 79 crushed limestones the median is 88 pounds a cubic foot (2,376 pounds a yard); across 51 natural gravels, 93 (2,511 a yard); across 63 concrete sands, 95 (2,565 a yard). That is typical stone loosely poured into a lab measure, so it is the light end. The quarries' own order calculators run higher, because stone in a truck is damp and settled: Luck Stone's uses 103.7 pounds a cubic foot, which is 2,800 pounds a yard, and Rogers Group uses 1.4 tons for crushed stone, 1.5 for gravel, and 1.3 for sand. Those are our working figures. Our heavy end adds 7 percent for a wet load, about the most water Wisconsin DOT's researchers found in loose base stone.
Leaning heavy is deliberate. If your stone turns out lighter than our working figure, the tons you ordered cover a little more ground than planned, and the truck carried less than we warned. If we leaned light, you would run short and overload the truck. Only one of those mistakes is cheap.
One more thing the lab numbers show, and it surprises people: the size of the stone barely changes the weight. Sand grains are a small fraction of the size of gravel, yet Alabama's concrete sands and natural gravels both come out about 42 percent air, because a pile of similar-sized pieces leaves about the same fraction of gaps whether the pieces are marbles or bowling balls. What changes the weight is shape and mix. Angular crushed stone props itself open and runs about 47 percent air, which is why a yard of pea gravel outweighs a yard of #57. And a mix of big pieces with fines, like crusher run, fills its own gaps, which is why it compacts so hard.
Road base and compaction: why you buy more than the hole holds
Crusher run, road base, ABC, DGA, 21A: different regional names for crushed stone that keeps its dust and fines. It arrives loose and gets compacted in place, so the depth you design for is the finished depth, and the stone you buy has to be more than the finished hole. Wisconsin DOT's standard specification pays for base aggregate at 1.85 tons per compacted cubic yard, and its 2023 research measured 1.79 to 1.98 on real projects. Loose off the truck, the same stone runs about 1.4 tons a yard (the same researchers measured loose base at 90 to 104 pounds a cubic foot before its water), so it packs down by a factor of 1.32. Penn State's Center for Dirt and Gravel Road Studies lands in the same place from the other direction: its road surface aggregate goes down 8 inches loose to finish at 6, a factor of 1.33.
That is why this calculator asks for the finished depth for road base and decomposed granite, works out the tons from the compacted weight, and then tells you the loose depth to spread. Weight does not change when stone is compacted, only volume does, so buying by the ton is the reliable way to order it. If a yard sells it by the cubic yard, ask what one of their yards weighs.
Decomposed granite gets the same treatment, with one honest caveat: we could not find a producer that publishes its weight. DG is small crushed granite with its own fines, the same recipe as road base, so we borrow the finest road base Wisconsin DOT measured, 1.80 to 1.86 tons a compacted yard, and label it editorial.
How deep should gravel be?
| Job | Depth | Where it comes from |
|---|---|---|
| Paver patio or walkway: compacted base | At least 4 inches over well-drained soil; thicker on wet or weak soil and in cold climates | CMHA (formerly ICPI) Tech Note PAV-TEC-002 |
| Paver driveway: compacted base | At least 6 inches over well-drained soil | CMHA Tech Note PAV-TEC-002 |
| Bedding sand under pavers | 1 inch, screeded, not compacted | CMHA Tech Note PAV-TEC-002 |
| DG or crushed fines path | 3 inches compacted over 4 to 6 inches of compacted base; 4 over 8 to 12 for vehicles | Kafka Granite installation guide |
| Gravel driveway surface | 6 inches compacted (spread 8 loose); over fabric on poor soil, 6 inches of base stone first | Penn State Center for Dirt and Gravel Road Studies |
| Drain pipe | At least 3 inches of #57 stone around the pipe | CMHA Tech Note PAV-TEC-002 |
| Behind a retaining wall | At least 12 inches of free-draining stone | CMHA Tech Note SRW-TEC-004 |
| Loose pea gravel path | 2 to 3 inches | EDITORIAL: deeper round stone rolls underfoot |
A layered driveway is just this table stacked: add up each layer as its own job. Run the base course (road base at its compacted depth) and the surface course (#57, crusher run, or pea gravel) through the calculator separately, and add the tons. If you are also filling a bed or hauling away what you dig out, our cubic yard calculator and dumpster size calculator use the same 27 cubic feet to the yard, and the concrete calculator takes over when the job needs a slab.