Plank & Plot

Gravel Calculator

For landscaping work: garden paths, patios, shed pads, and gravel driveways. Enter the area and depth, pick the stone, and see how many cubic yards and tons to order.

Project

Area

Length
ft
in
Width
ft
in

100 sq ft

in
Compaction, weights, and prices
%
Added to crusher run and decomposed granite, which pack down when tamped.

Weight from your supplier

tons per cu yd

Example prices, change them to yours

$
$
0 if you haul it yourself.
cu ft
$

1.5 tons of pea gravel

You need 25 cu ft for 100 sq ft at 3 in, about 1.25 tons.

  • Bulk, delivered$1531.5 tons at $45 a ton plus $85 delivery.
  • 0.5 cu ft bags$30050 bags holding 25 cu ft.

Estimated cost$153

Bulk is cheaper for this job, even with the $85 delivery fee. At these prices, bulk always costs less above about 10.5 cu ft. Weights vary by quarry, so check the tons per yard with your supplier. Prices are examples.

Show the math
  1. Area: 100 sq ft
  2. Gravel: 100 sq ft × 3 in = 25 cu ft in place
  3. Weight: 0.93 cu yd × 1.35 tons per cu yd = 1.25 tons
  4. Order of pea gravel: 1.25 tons, rounded up to the next half ton = 1.5 tons
  5. Bags: 25 cu ft ÷ 0.5 cu ft = 50, rounded up to 50

How to use this gravel calculator

  1. Choose the project. “Path, patio, or bed” is one layer of one kind of stone. “Driveway” sets up two layers, a base and a top, which you can change.
  2. Measure each area in feet. Use several rectangles for an L-shaped path, or a circle for a fire pit pad.
  3. Pick the stone and enter the depth you want when the job is done. For crusher run and decomposed granite, that’s the depth after tamping. The calculator adds extra so you order enough loose stone to get there.
  4. Open “Compaction, weights, and prices” if your supplier quotes a different weight per cubic yard, or to enter your prices and delivery fee. The prices that are filled in are only examples.

Use “Copy link” to send the numbers to your supplier or save them for later.

How the calculator works

in place     = area × depth ÷ 12                 cubic feet
to order     = in place × 1.11                   crusher run and DG only
cubic yards  = cubic feet ÷ 27
tons         = cubic yards in place × weight per cubic yard
bulk order   = tons, rounded up to the next half ton
bags         = cubic feet to order ÷ 0.5, rounded up

Gravel is sold by the cubic yard or by the ton, and the conversion between them depends on the stone. These are the weights we start with:

Stone Tons per cubic yard Where the number comes from
Pea gravel 1.35 A 50 lb bag of Quikrete All-Purpose Gravel holds 0.5 cubic feet, or 100 lb per cubic foot
#57 crushed stone 1.4 FHWA lab tests: 1.29 loose, 1.47 fully packed
Crusher run or road base 1.6 Maine DEP, for a compacted cubic yard of road gravel
Decomposed granite 1.5 GraniteCrete’s math sheet
River rock 1.3 Our estimate

We couldn’t find a published weight for river rock that we could check, so 1.3 is our estimate. Larger rounded stones leave more air between them, so we put river rock near the loose end of the FHWA results for the coarsest stone in its tests, No. 5, which ranged from 1.28 to 1.48 tons per cubic yard.

The compaction allowance comes from Maine DEP’s landowner manual, which multiplies by 1.11 to end up with 3 inches of compacted road gravel. We apply it to crusher run and, as our own call, to decomposed granite, since both are tamped. You can change it.

The driveway layers follow the same manual. It calls for a coarser, free-draining base under a surface layer with enough fines to pack hard and shed water. Where fabric goes straight onto native ground, it asks for at least 6 inches of base and 4 to 6 inches of surface gravel. For a full road on poor soil it suggests a 12 to 18 inch base. Our preset uses the thinner end: 6 inches of #57 stone under 4 inches of crusher run. That pairing is common for home driveways, but it’s our choice, not an engineering spec.

A worked example

Say you’re building a 10 × 50 foot gravel driveway with the preset layers.

  • Base: 500 square feet × 6 inches = 250 cubic feet, or 9.26 cubic yards. At 1.4 tons per yard that’s 12.96 tons, so you order 13.
  • Top: 500 square feet × 4 inches = 166.7 cubic feet in place, or 6.17 cubic yards. Add 11% for compaction and you order 6.85 cubic yards. The weight is 6.17 × 1.6 = 9.88 tons, so you order 10.
  • Total: 23 tons in two deliveries.

At the example prices, 13 tons of #57 at $42 plus $85 delivery is $631, and 10 tons of crusher run at $32 plus $85 is $405, or $1,036 together. The same stone in 0.5 cubic foot bags would take 870 bags, which is why the calculator doesn’t price bags for driveways.

Gravel for common projects

Cubic yards to order and tons, using the weights above:

Project Stone Cubic yards Tons
Garden path, 20 × 3 ft 3 in pea gravel 0.56 0.8
Walkway, 40 × 4 ft 3 in decomposed granite 1.64 2.2
Patio, 12 × 12 ft 4 in pea gravel 1.78 2.4
Shed pad, 12 × 10 ft 4 in #57 stone 1.48 2.1
Dry creek bed, 30 × 3 ft 4 in river rock 1.11 1.4
Driveway, 50 × 10 ft 6 in #57 stone + 4 in crusher run 16.11 22.8
Driveway, 80 × 12 ft 6 in #57 stone + 4 in crusher run 30.93 43.9

Even the smallest job here, a 3 × 20 foot path, works out cheaper delivered than in bags at our example prices. Bags can only win below about 10.5 cubic feet, roughly a 6 × 7 foot area at 3 inches.

Tips for ordering and spreading gravel

  • Ask your supplier how they convert yards to tons. Wet stone weighs more, and one quarry’s #57 can be heavier than another’s. Enter their number under “weights.”
  • Use crushed stone, not rounded gravel, where cars drive. Angular pieces lock together, while round ones roll out from under tires and leave ruts.
  • Put a woven geotextile fabric under a driveway or path on soft ground. It keeps the stone from mixing into the soil below, so the base stays thick.
  • Crown the driveway so water runs off. Maine DEP suggests about 1/2 inch of rise per foot of width on flat or gently sloping roads.
  • Tamp crusher run and decomposed granite when they’re slightly damp. Crushed stone with fines packs hardest at the right moisture, so mist it if it has dried to dust.
  • Check how many tons one truck can carry before you schedule delivery. A big driveway may need two loads, and each one usually has its own fee.

Frequently asked questions

How much does a cubic yard of gravel weigh?

Between about 1.3 and 1.6 tons, depending on the stone. Pea gravel is about 1.35 tons, #57 crushed stone about 1.4, decomposed granite about 1.5, and compacted crusher run about 1.6. Moisture and the quarry change these numbers, so ask your supplier what they use.

How many tons of gravel do I need for a driveway?

For a 10 × 50 foot driveway with 6 inches of #57 stone under 4 inches of compacted crusher run, about 23 tons: 13 of #57 and 10 of crusher run. As a rule of thumb, every 100 square feet of crusher run at 4 inches compacted weighs about 2 tons.

How many bags of gravel are in a ton?

With 50 lb bags, 40 bags make a ton. A typical 50 lb bag of small gravel holds 0.5 cubic feet, so a cubic yard takes 54 bags. That is why bags only make sense for small jobs like a planter or a few square feet of path.

Does gravel compact after it is spread?

Crushed stone with fines, such as crusher run and decomposed granite, packs down a lot when tamped. Maine DEP multiplies by 1.11 to get 3 inches of compacted road gravel. Clean stone like #57 and pea gravel settles much less. In FHWA lab tests, #57 stone got only about 14% denser even on a vibrating table, so we add nothing for clean stone unless you choose to.

Can I use pea gravel on a driveway?

It works on a flat driveway, but it ruts. Rounded stone rolls out from under tires. The Maine DEP landowner manual recommends crushed gravel for the driving surface, because its angular edges lock together and pack well.

Sources

  1. Gravel Road Maintenance Manual: A Guide for Landowners on Camp and Other Gravel Roads, Maine Department of Environmental Protection (April 2016). Multiply by 1.11 for compaction; a compacted cubic yard of gravel weighs about 1.6 tons; at least 6 in of base and 4 to 6 in of surface gravel over fabric; crushed rather than rounded gravel; 1/2 in of crown per foot.
  2. Strength Characterization of Open-Graded Aggregates for Structural Backfills (FHWA-HRT-15-034), Table 7, Federal Highway Administration (June 2015). No. 57 aggregate weighed 95.4 lb per cu ft loose and 108.7 lb per cu ft at maximum density (1.29 to 1.47 tons per cu yd).
  3. GraniteCrete Math Sheet (revised July 29, 2024), GraniteCrete. 1 cubic yard of decomposed granite equals 1.5 tons.
  4. Quikrete 0.5 Cu. Ft. 50 Lb. All-Purpose Gravel, Do it Best (retail listing). A 50 lb bag holds 0.5 cu ft, which works out to 1.35 tons per cubic yard for small gravel.

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