Gravel Calculator

How to use

1. Pick a shape: rectangle, circle, triangle, or enter the area directly if you already know it.
2. Enter the length and width (or diameter, or base and height), in feet or meters.
3. Choose a project preset such as driveway, path, patio base or drainage, or type your own depth. The preset fills in a sourced typical depth for that job.
4. Pick a gravel type from the material list. Each one has a different typical weight per cubic yard.
5. Check the result: cubic yards, tons, bag count and an order line you can round up before you call a supplier.

How it works

The calculator turns your shape into a volume first. For a rectangle it multiplies length by width by depth; for a circle it uses the area of a circle; for a triangle it uses base times height divided by two. You enter depth in inches, and the calculator converts it to feet by dividing by 12, since gravel depth is usually much smaller than length and width. It then divides the volume in cubic feet by 27, the number of cubic feet in a cubic yard, to get cubic yards.

To get weight, the calculator multiplies the cubic yards by the density of the gravel you picked, in tons per cubic yard. Density isn’t one fixed number. It depends on the stone’s size, how angular or rounded it is, and how wet or compacted it is, so every material carries a typical value plus a realistic minimum and maximum. A crushed, angular stone like crusher run packs down harder than a rounded stone like pea gravel, which is one reason their typical densities differ.

Two adjustments matter for a real order. First, an extra percentage for waste, compaction and settling. Each material starts with its own default, which you can change, since a compactable crushed stone behaves differently than a rounded, loose gravel. Second, rounding: the order line rounds volume up to the next half cubic yard and weight up to the next half ton, because many suppliers sell in half-yard or half-ton steps, not exact decimals. Bag counts round up too, since a partial bag still means buying a whole one.

Limits to keep in mind: this tool assumes a flat area at a constant depth. A sloped driveway or an area with a dip needs more material than the flat-area math gives, so add a separate area for the low spot using “Add another area” instead of applying one depth across the whole space. Irregular shapes are best handled with the “Area” shape, using your own measured square footage. And because gravel density varies with moisture and compaction, treat the weight and bag numbers as a solid planning estimate, not an exact figure. A supplier can weigh your actual load and adjust the bill from there.

Gravel depth guide by project

These depths come from aggregate suppliers, paver installers and driveway contractors, and are built into the project presets above.

A home driveway on firm ground usually needs 4 to 6 inches of gravel in total, so the light-use preset covers it. For heavy trucks or soft ground, build three layers: pick a driveway preset and the calculator lists the tons of base, middle and top stone for your area.

Worked example

1. Area: 38.5 ft × 3.5 ft = 134.75 sq ft
2. Depth: 3 in ÷ 12 = 0.25 ft
3. Volume: 134.75 sq ft × 0.25 ft = 33.69 cu ft
4. Extra for settling: 33.69 cu ft × 1.10 = 37.06 cu ft
5. Cubic yards: 37.06 ÷ 27 = 1.37 cu yd (1.05 m³)
6. Weight: 1.37 cu yd × 1.4 tons per cu yd = 1.9 tons (1.7 tonnes)
7. Order: round up to 2 tons, or 75 bags of 0.5 cu ft

Questions people ask

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