About this calculator
The Gravel Calculator turns the size of your area into the amount of gravel to order: cubic yards, tons and 0.5 cubic foot bags. It works for driveways, paths, patios, drainage trenches and garden beds, in US or metric units.
How to calculate how much gravel you need
- Measure the area. Enter length and width, or choose Circle and enter the diameter.
- Enter the depth. Use inches (or centimetres in metric mode).
- Choose the material. Heavier stone means more tons for the same volume.
- Keep the waste allowance at 10 percent unless your supplier advises otherwise, and add a price to see the cost.
The gravel formula
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27. Divide depth in inches by 12 to get feet. Tons = cubic yards × the material's weight per cubic yard, which is about 1.4 tons for most crushed stone.
Example: a 20 ft × 10 ft driveway section, 4 inches deep, is 20 × 10 × (4 ÷ 12) = 66.7 cubic feet, or 2.47 cubic yards. Adding 10 percent gives 2.72 cubic yards, which is about 3.8 tons at 1.4 tons per yard.
How far does a cubic yard of gravel go?
| Depth | Area covered by 1 cubic yard |
|---|---|
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
Things to watch out for
- Weight varies. Stone type, size and moisture all change tons per cubic yard. Ranges of roughly 1.2 to 1.5 tons are common, so check your supplier's figure.
- Base layers compact. Gravel under pavers or a driveway settles when compacted, so order a little extra.
- Suppliers sell by the ton or the yard. Use the weight result for ton pricing and the volume result for cubic yard pricing.
- Irregular areas. Split the shape into rectangles and circles, calculate each, and add them up.
Frequently asked questions
About 1.4 tons for typical crushed stone. Pea gravel and river rock are a little lighter, and road base is a little heavier. Check the exact figure with your supplier.
Multiply length by width in feet, then by depth in feet (inches divided by 12), and divide by 27 to get cubic yards. A 4 to 6 inch layer is common for a driveway.
A cubic yard is 27 cubic feet, so it equals 54 bags of 0.5 cubic foot.
Adding 5 to 10 percent covers spills, uneven ground and compaction. Use the waste percentage box to include it.
Yes. Choose Circle, enter the diameter, and the calculator uses the area of the circle.