Gravel calculator, yards, tons and bags.

A gravel calculator works out how much stone fills an area to a depth. Volume is length times width times depth, with every size in the same unit. Gravel is usually sold by the ton, so the volume is then multiplied by a density to give a weight. This one handles rectangles, circles and an area you already know, adds extra for compaction and waste, and shows cubic yards, cubic feet, cubic metres, short tons, tonnes and bags.

How to use the gravel calculator

1. Pick the Shape: "Rectangle (length and width)", "Circle", or "An area I already know".
2. Pick the Length unit and the Depth unit. They can differ, so you can measure a driveway in feet and its depth in inches. You can type 12.5, a fraction like 3 1/2, or feet and inches like 12'6".
3. Type the sizes and the Depth. Type "How many of them" if you have several beds the same size.
4. Pick the Stone. The list holds the stones in the Washington State DOT table. For anything else, such as pea gravel, river rock or limestone, pick "Other stone" and type the density in "Density (ask your supplier)".
5. Set "The volume I typed is" to "Laid in place, compacted" for a layer you will spread and roll, or "Loose, as delivered" if you measured the pile.
6. Set "Compaction extra (%)" and "Waste extra (%)". Waste starts at 10, and compaction at 0. Both are yours to set.
7. Read "Gravel needed", the Weight in short tons and tonnes, and, if you picked a bag size, the number of Bags.
8. Type a Price a ton, a cubic yard or a bag to see the cost. Copy result and Copy link keep the work.

Worked example: a 20 by 10 ft driveway strip, 4 inches deep

• Same units. 4 inches is 4 ÷ 12 = 0.3333 ft.
• Volume. 20 × 10 × 0.3333 = 66.67 cubic feet, which is 66.67 ÷ 27 = 2.47 cubic yards.
• With 10% waste. 66.67 × 1.10 = 73.33 cubic feet, or 2.72 cubic yards.
• Weight. With "Crushed surfacing base course" laid and compacted, the table gives 3,700 lb per cubic yard. 2.716 × 3,700 = 10,049 lb, which is 5.02 short tons or 4.56 tonnes.
• In the truck. The same table gives 2,950 lb per cubic yard loose, so the same weight is 10,049 ÷ 2,950 = 3.41 cubic yards of loose stone.
• Bags. With 0.5 cubic foot bags, 73.33 ÷ 0.5 = 146.7, so 147 bags. The calculator always rounds bags up.

Where the densities come from

Exhibit 620-1 of the Washington State DOT Design Manual (M 22-01.23, September 2024), checked 18 Oct 2026, lists the unit dry weight of gravel base and surfacing materials in pounds per cubic yard, as loose truck measure and as compacted on the roadway.

These are dry weights for Washington State materials. The exhibit says to correct for water content by multiplying by one plus the free water as a decimal, which is what the "Water in the stone (%)" box does, and it says to add 10% to the quantity if the material is to be stockpiled. Stone from other places and other quarries has other densities, so no density is built in for pea gravel, river rock, limestone or sand. Ask your supplier for the figure printed on their ticket or data sheet.

How far does a cubic yard go?

A cubic yard is 27 cubic feet. Spread 1 foot deep it would cover 27 square feet, so at a depth in inches it covers 27 ÷ (depth ÷ 12) = 324 ÷ depth square feet. The table on the page works this out for each depth.

Circles and metric sizes

A round bed 8 ft across and 3 inches deep is π × 4 × 4 × 0.25 = 12.57 cubic feet, or 0.47 cubic yards. In metric, 5 m by 3 m at 10 cm deep is 5 × 3 × 0.1 = 1.5 cubic metres. A cubic yard is exactly 0.764554857984 cubic metres, so that is 1.5 ÷ 0.7646 = 1.96 cubic yards.

Tips and common problems

• Tons or short tons. The page shows short tons of 2,000 lb, and tonnes of 1,000 kg. Check which your supplier means.
• Loose against compacted. A yard of loose stone weighs less than a yard laid and compacted. That is why the page asks what your volume means.
• Compaction. The percent is your own margin. The page does not choose one, because it depends on the stone and how you compact it.
• Sub-base depth. Check the depth with your supplier or your local rules for the job. This page only does the arithmetic.

For slabs and footings, use the concrete calculator. To work out the area of an odd shape first, the square footage calculator adds pieces and takes cut-outs away. The unit converter changes tons, tonnes and pounds.