Gravel Calculator

How to use this calculator

1. Choose feet and inches or meters and centimeters.
2. Describe the area: length × width, a circle (diameter), or enter the area directly if you already know it.
3. Enter the depth of the layer.
4. Pick a material. Each has a typical density in tons per cubic yard; choose Other to enter your supplier’s figure.
5. Set the extra allowance for compaction and waste (10% by default).
6. Optionally open Cost and enter a bulk price per ton or per cubic yard, any delivery fee, and a bag price.

You get the weight in tons, the volume in cubic yards, the number of 0.5 cubic foot bags, and a table of the same job in every material on the list.

The formula

Gravel is measured by volume but usually sold by weight, so there are two steps: find the cubic yards, then multiply by the material’s density.

Dividing by 324 does two conversions at once: inches to feet (÷ 12) and cubic feet to cubic yards (÷ 27). The extra allowance multiplies the volume before the weight is worked out.

Worked example

The default is a 20 × 12 foot parking pad with 4 inches of crushed stone and 10% extra:

1. Area: 20 × 12 = 240 sq ft.
2. Volume: 240 × 4 ÷ 12 = 80 cubic feet.
3. Add 10%: 80 × 1.1 = 88 cubic feet.
4. Cubic yards: 88 ÷ 27 = 3.26 cubic yards.
5. Weight: 3.26 × 1.4 = 4.56 tons, about 9,126 pounds.
6. Bags: 88 ÷ 0.5 = 176 bags of 0.5 cubic feet.

At the example bulk price of $50 a ton, that’s $228 of stone before delivery. In 0.5 cubic foot bags at $6 each, the same job costs $1,056, which is why bags make sense only for small jobs.

A smaller job: a 30 × 3 foot pea gravel path, 3 inches deep with 10% extra, needs 0.92 cubic yards, about 1.28 tons, or 50 bags.

Typical densities

These are the planning values the calculator uses for dry, loose material. They fall within the 75 to 110 pounds per cubic foot that the Portland Cement Association gives for the bulk density of normal-weight aggregate; topsoil is lighter.

The topsoil figure is based on the USDA Natural Resources Conservation Service’s rule of thumb of about 1.33 grams per cubic centimeter for a silt loam with half its volume as pore space, which works out to about 1.12 tons per cubic yard. Real soils range widely with texture, organic matter and moisture.

Water adds weight fast. Sand straight from an uncovered pile after rain can weigh noticeably more than the dry figure, so if you’re paying by the ton, ask whether the material is washed and how wet it is.

How deep to go

• Decorative beds and dry creek beds: 2 to 3 inches of river rock or pea gravel, usually over landscape fabric.
• Paths and patios: 2 to 3 inches of pea gravel or decomposed granite. Pea gravel rolls underfoot, so edge it well.
• Paver base: 4 to 6 inches of compacted crusher run, topped with an inch of sand. Use 15% to 20% extra because compaction squeezes the layer down.
• Driveways: built in layers, commonly a base of larger stone and a top layer of crushed stone, each 4 to 6 inches. Run the calculator once per layer.

Bulk or bags?

Bagged gravel, pea gravel and sand come in 0.5 cubic foot bags, which weigh about 50 pounds each; QUIKRETE’s 50 lb All-Purpose Gravel is listed at about 0.5 cubic feet. That’s 54 bags per cubic yard. Bags are handy for a few square feet of path or for filling around fence posts, but for anything over about a cubic yard, bulk delivery from a quarry or landscape yard is usually cheaper and spares your back. Bulk prices are quoted per ton or per cubic yard; the calculator handles either, so you can compare quotes directly.

Tips for ordering

• Order slightly over. Running short means a second delivery fee. The extra allowance covers uneven ground and spillage.
• Ask for the supplier’s conversion. “How many tons in a yard of your #57?” gives you a density to enter under Other.
• Check truck minimums and access. A loaded dump truck is heavy; make sure it can reach the spot without damaging your lawn or septic system.
• Concrete instead? If the pad will be paved, the concrete calculator works out cubic yards and bags of mix. For mulch beds next to the gravel, use the mulch calculator.

Assumptions and limitations

• Densities are typical values, not your supplier’s measurement. They vary with rock type, particle size and moisture.
• The area is treated as flat with an even depth. For an irregular area, add up its parts with the square footage calculator and use the I know the area option.
• Bag counts assume 0.5 cubic foot bags. Some products come in other sizes; divide the cubic feet in the result by your bag size.
• Prices are editable examples, not quotes.

Sources

• USDA NRCS: Soil Quality Indicators, Bulk Density
• Portland Cement Association, Design and Control of Concrete Mixtures (EB001), chapter on aggregates: bulk density of normal-weight aggregate, 75 to 110 lb/ft³
• QUIKRETE All-Purpose Gravel product page and 50 lb bag listing, about 0.5 cu ft

Updated November 2026. Results are estimates for educational purposes and depend on the inputs you provide.