Gravel calculator: tons and cubic yards

How to use the gravel calculator

Pick the job at the top; each starts with the stone and depth most people use, so the answer is there before you type. Put in your length and width, change the stone or depth if yours differ, and add a layer when the job has two, like crushed stone under paver sand. The big tile is the tons to order, rounded up to the half ton yards sell by. The other tabs time the work by hand and by machine, and size stone backfill around a pool.

How it’s figured

Area times depth gives the cubic yards that end up in the ground. Loose stone shrinks when it is compacted or walked on, so the calculator orders extra for each stone, then turns yards into tons with that stone’s weight.

Worked example. A 12 by 50 foot driveway at 4 inches of crusher run: 600 × 4 ÷ 12 ÷ 27 = 7.4 cubic yards finished. Crusher run packs down about 25 percent, so order 9.26 yards. At 1.5 tons a yard that is 13.9 tons: order 14, one tandem dump truck.

Imperial or metric. Press Metric at the top to work in meters, centimeters, cubic meters and metric tonnes; the page converts what you already typed. The math is done in feet and US tons and only the units change, with exact factors: 1 foot is 0.3048 m, 1 inch is 2.54 cm, a cubic yard is 0.764554857984 m³, and a US (short) ton is 2,000 lb, or 0.90718474 of a metric tonne (1,000 kg). In metric the same driveway, 15 by 3.6 m at 10 cm of crusher run, is 5.4 m³ finished, 6.75 m³ to order and about 12 tonnes (order 12.5).

The settling allowance is what this calculator adds for compaction: 25 percent for crusher run, 20 for stone dust, 15 for sand, 5 for clean stone like #57 and pea gravel, almost nothing for river rock and none for rip rap. It does not add extra for waste or an uneven subgrade; if your ground is soft or rutted, add 5 to 10 percent yourself.

Which stone for which job

The quickest way to choose is to ask one question: should water drain through it, or should it pack hard? Crusher run (sold as Item 4 around Buffalo, CR-6 or 21A in Virginia, DGA, QP, road base or ¾-inch minus elsewhere) is crushed stone with its dust left in. The dust locks it into a hard base for driveways, sheds, patios and pavers, but water runs off it, not through it. #57 stone is the same rock washed and screened to about ¾ to 1 inch with no fines, so it drains: French drains, foundation drains, shed pads, pool backfill and a driveway’s top coat. #2 and #3 are 1 to 3 inch stone for the bottom of a driveway on soft ground; some regions also sell #1, up to 4 inches. #8 and #89 are ⅜-inch chips for between flagstones and under some permeable pavers. Pea gravel is small and round, comfortable underfoot for paths, play areas and dog runs, but it rolls, so it needs an edge. River rock is larger round stone for dry creek beds and splash areas. Stone dust (screenings) makes a firm path surface. Rip rap is 6 to 12 inch stone for banks and culvert outlets.

Sizes follow ASTM D448 and AASHTO M 43, so one quarry’s #57 matches the next; local names don’t. Ask for the size and whether it has fines. More in #57 stone or crusher run?

Why the weight changes the truck

Most stone weighs 1.3 to 1.5 tons per cubic yard. Crusher run is near the top because its dust fills the gaps; round river rock and big rip rap are near the bottom because they don’t pack. Sand gains weight when it is wet: about 1.35 tons a yard dry and 1.5 damp. That 10 percent is the difference between one load and two on a single-axle truck, and suppliers sell by the ton, so always order by weight. A half-ton pickup carries about a ton safely; a single-axle dump truck about 6; a tandem about 14; a tri-axle about 20. Check your state’s limits and the truck’s own rating.

The work: by hand or with a machine

Fourteen tons is 28,000 pounds, and by hand every pound goes through your shovel. The Canadian Centre for Occupational Health and Safety puts a sensible shovel load at 11 to 15 pounds and a steady pace at about 15 scoops a minute, with rests: about 2,300 shovelfuls. A 6 cubic foot wheelbarrow holds more stone than you should push; at 250 pounds a load that is 2¼ cubic feet of crusher run, or 112 trips. Call it 18 hours of shoveling, walking and raking for one person. A skid steer does the same pile in about 2½ hours, setup included, and you lift nothing; a mini skid steer or a stand-on loader fits through a 36 to 42 inch gate, and many rental stores carry them; a power wheelbarrow saves the pushing, not the shoveling. Type your rental quote to see what each saved hour costs. On a driveway, ask the truck to spread it from the tailgate.

Backfilling an inground pool with stone

Dirt pushed back around a new pool keeps settling for a year or more, and the patio or deck poured on top sinks with it. Clean crushed stone settles far less, drains water away from the walls and needs little compacting, which is why pool builders backfill with it. Fiberglass maker River Pools names #68 clean stone and says most of its installs use 40 to 60 tons; many builders use #57. The amount is the over-dig, the ring of empty space around the walls: the outer outline minus the pool, times the average depth. A 16 by 32 foot pool, 3½ to 6 feet deep, with 2 feet of over-dig, takes about 54 tons of #57. Your pool maker’s install guide wins on the stone, the over-dig and any base under the shell, because the warranty depends on it.

Sand under pavers and around the yard

Under pavers the usual build is compacted crushed stone, then 1 inch of washed concrete sand screeded flat; add it here as a second layer. Paver guides prefer concrete sand to stone dust for that bedding layer. For polymeric joint sand, mason sand, play sand and every other kind, by the bag or the ton, use the sand calculator.

Where the numbers come from

Stone weights are the middle of suppliers’ conversions and match the old calculator; your quarry’s figure beats ours. Sizes follow ASTM D448 and AASHTO M 43. The shovel load and pace are from the CCOHS shoveling fact sheet; barrow loads, walking, raking and machine rates are estimates built on those limits and landscapers’ reported rates. The play-area depth is the CPSC playground handbook’s common figure; pool stone is from River Pools. No prices are built in.

Tips and common mistakes

• Order by the ton, and ask the yard for its tons-per-yard figure if you think in yards.
• Compact crusher run in lifts of 2 to 3 inches with a plate compactor; one thick layer stays soft underneath.
• Don’t use #57 alone as a driveway surface on a slope: without fines it rolls.
• Lay landscape fabric under paths and drains so the stone doesn’t sink into the soil.

Questions

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