Gravel Calculator, Cubic Yards & Tons for Your Driveway

The formula

• Cubic feet = length (ft) × width (ft) × (depth (in) ÷ 12)
• Cubic yards = cubic feet ÷ 27
• Tons = cubic yards × density (1.3 to 1.5 tons/yd³ by gravel type)
• Bags = cubic feet ÷ 0.5 cu ft, rounded up
• Total cost = (tons × price per ton) + delivery fee; order 10 to 15% extra for compaction

A worked example

A 20×20 ft two car driveway at 4 inches deep: 400 × 0.333 = 133.3 cubic feet, or 4.94 cubic yards. At crushed stone's 1.4 tons per cubic yard that is 6.9 tons; with a 15% compaction allowance, order 8 tons. At $40 a ton plus $60 delivery the job costs $380, far less than buying 267 half cubic foot bags at the big box store.

More about the Gravel Calculator

From measurements to tons: the math

Start with volume. Length × width × (depth in feet) gives cubic feet, a 12×50 foot driveway at 4 inches deep is 600 × 0.333 = 200 cubic feet. Divide by 27 for cubic yards: 7.4. Then comes the part most calculators fudge: multiplying by the material's bulk density to get tons.

Density varies by stone type and moisture. Dry crushed stone runs about 1.4 tons per cubic yard, pea gravel a little less at 1.3, and dense crusher run up to 1.5. The calculator carries five presets so you are converting with the right figure, and 7.4 yards of crushed stone lands at roughly 10.4 tons.

Pick the right gravel for the job

Not all stone behaves the same. Crusher run, mixed sizes with stone dust, packs into the hardest driving surface, which is why it is the default driveway choice. Crushed stone (#57, mostly ¾ inch) locks together for base and middle layers. Pea gravel rolls underfoot, so it suits paths and patios, not driveways.

River rock and washed stone are for water, not weight: French drains, dry creek beds and drainage behind retaining walls. Decomposed granite compacts into a firm natural looking path. Match the stone to the job before you worry about the tonnage, the wrong gravel at the right price is still wrong.

Depth rules by project

Depth is where driveway projects fail. A top up over a sound existing drive needs 2 to 3 inches of fresh stone. A working driveway over a firm base wants 4 to 6 inches. A new build over bare subgrade needs 6 to 8 inches total, built in compacted layers, never one deep dump.

Paths and patios get 2 to 3 inches of pea gravel or decomposed granite. Drainage trenches take 6 to 12 inches of river rock, and French drains want 6 to 8 inches of washed stone wrapped in filter fabric. Shallow base depth is the usual reason a gravel drive develops ruts and potholes within a season.

Compaction: the hidden extra

Loose gravel is not finished gravel. It settles 10 to 20 percent under tires and rain, which means a bed intended to finish at 4 inches must be laid deeper or topped up. Ordering from the finished depth alone reliably leaves the job short, and thin.

Add 10 to 15 percent to your order, and lay deep drives in 2 to 4 inch lifts, compacting each before the next. A single 8 inch dump never densifies at depth and will rut in the first wet season. The calculator's tonnage figure is your starting point; the compaction allowance is what you actually order.

Bags vs bulk, and the delivery sting

Bagged gravel at big box stores costs $4 to $8 per 0.5 cubic foot bag, $200 to $430 per cubic yard. Bulk from a quarry runs $25 to $50 a ton, or roughly $35 to $70 a yard. Bags make sense under about a cubic yard: a small French drain, a path repair. Anything bigger, get a quarry quote.

Watch the delivery line: most suppliers deliver 5+ ton loads, and smaller drops carry a $50 to $150 surcharge. Enter your delivery fee above so the total is honest. Pouring a slab nearby too? Our <a href="/concrete-calculator/">concrete calculator</a> prices that base the same way, and our <a href="/grass-seed-calculator/">grass seed calculator</a> works out the pounds for any lawn edging the drive. See the full <a href="/home-garden/">Home & Garden collection</a> for soil, fencing and lawn tools.

A garden path worked from tape measure to tonnage

Suppose you are graveling a path 12 feet long and 3 feet wide at 2 inches deep. The area is 36 square feet, and 2 inches is one sixth of a foot, so the volume is 36 multiplied by one sixth, exactly 6 cubic feet. Divided by 27, that is about 0.22 cubic yards. At 1.4 tons per cubic yard for crushed stone, the path needs roughly 0.31 tons before any allowance is added.

Now add the 15 percent compaction allowance this calculator encourages. A tenth and a half more brings 0.31 tons to about 0.36 tons, so in practice you order a half ton bag or the nearest amount your supplier sells, because nobody delivers 0.36 of anything. Seeing the true figure first still matters: it tells you a half ton carries a sensible margin, while a full ton would leave you landscaping the excess into every bed you own.

What one cubic yard covers at three common depths

Coverage figures make a useful lie detector for quotes and for your own arithmetic. One cubic yard is 27 cubic feet. Spread 2 inches deep, which is one sixth of a foot, it covers 27 divided by one sixth, or 162 square feet. At 3 inches deep it covers 108 square feet, and at 4 inches it covers 81 square feet. Doubling the depth exactly halves the coverage, every time, with no exceptions for optimism.

Use those three numbers as a pocket check before ordering anything. A 200 square foot area at 3 inches deep must need a little under 2 cubic yards, because 200 divided by 108 is about 1.85. If a calculator session, a supplier, or your own spreadsheet claims 4 yards for that job, a depth was probably entered in feet instead of inches, or an area got measured twice. Catching the error takes ten seconds with the coverage figures and saves a very literal tonne of regret.

Three ordering mistakes that strand a half finished job

The first mistake is measuring the hole and forgetting the edges. If edging boards sit inside your measured rectangle, the gravel area is the inside of the edging, but if the gravel runs up and over a border, the footprint grows on every side. The second mistake is mixing units mid calculation, entering a depth of 3 as feet in one line and inches in another, which multiplies an order by twelve and has genuinely happened to careful people.

The third mistake is ordering the exact calculated weight with no allowance and no plan for the leftover problem in reverse. Gravel compacts underfoot, the first rain settles it into every hollow, and a job calculated to the last kilogram finishes visibly thin in its busiest patches. A modest stated allowance, plus knowing where any genuine surplus could usefully go, such as a muddy gate corner, turns both failure modes into non events before the truck arrives.

How to use the Gravel Calculator

1. Enter the length and width of the area in feet and the gravel depth in inches.
2. Pick your gravel type, crusher run, crushed stone, pea gravel, river rock or decomposed granite.
3. Add the price per ton and any delivery fee to get the full project cost.
4. Click Calculate, order tons in bulk, or buy bags for jobs under about a cubic yard.