Gravel Calculator

This gravel calculator works out how much gravel a project needs and what it will cost. Give it the area you want to cover and how deep the gravel should sit, pick a material, and it returns the volume and the weight.

You can describe the area three ways: as a single total, as a rectangle you measure by length and width, or as a circle you measure across. Add a price and it estimates the spend and the number of bags too.

How the gravel calculation works

Gravel is bought by volume or by weight, and both come from the same two measurements: the area you are covering and how deep the layer is.

Volume is simply area multiplied by depth:

Weight then follows from the material's density, which is its mass per unit of volume:

The calculator keeps everything in consistent units behind the scenes, so you can enter feet, meters, inches, or yards and read the answer back in cubic yards, tons, or whichever unit you prefer.

Working out the area

For a plain rectangle, the area is the length times the width. For a circle, it is pi times the radius squared, and the radius is half the diameter.

If your space is an odd shape, break it into rectangles and circles, add the pieces together, and enter the total under the total-area option.

A worked example

Say you are covering a 20 by 15 foot area, which is 300 square feet, with a 3 inch layer of gravel.

Three inches is a quarter of a foot, so the volume is 300 times 0.25, or 75 cubic feet. That is about 2.8 cubic yards.

At a typical gravel density of about 105 pounds per cubic foot, 75 cubic feet weighs roughly 7,875 pounds, which is close to 4 US short tons. The calculator does this arithmetic for any numbers you enter.

How deep should the gravel be?

Depth drives the whole result, so it is worth getting right. A layer that is too thin shifts and shows the ground below; too thick wastes material.

These depths are common starting points. Loose decorative gravel can sit shallower, while driveways that carry vehicles need more and often a separate base layer.

Gravel density and weight

Density is what turns a volume into a weight, and it changes with the material and how wet it is. Dry, loose gravel is lighter than a sand and gravel mix, and wet material is heavier still.

The presets below cover the common cases. If your supplier gives an exact figure, choose the custom option and type it in.

These are loose densities for material as delivered. Once gravel is laid and compacted it settles a little, which is one reason to order a small amount extra.

Estimating the cost and bags

Suppliers price gravel in different ways: by the cubic yard or cubic meter, by the ton, or by the bag. Turn on the cost option and pick the basis that matches your quote.

When you price by the bag, enter how much one bag holds, either as a volume such as cubic feet or as a weight such as pounds. The calculator divides the job into whole bags and rounds up, since you cannot buy part of a bag.

The estimate covers the material only. Delivery, labor, edging, and a base layer are extra, and bulk loads are usually far cheaper per ton than bagged gravel for anything larger than a small bed.

Order a little extra

It is normal to add five to ten percent to the amount you order. Gravel compacts under its own weight and traffic, some is lost to spillage and uneven ground, and running short mid-project means a second delivery.

The waste option adds your chosen percentage on top and shows the amount to order, while the headline figures stay as the exact quantity the space needs.

What gravel is and where it is used

Gravel is a loose mix of rock fragments, larger than sand but smaller than cobbles. It is one of the most widely used construction materials, going into concrete, roads, drainage, and landscaping.

Around the home it makes driveways, paths, and patios, borders flower beds, and drains wet spots because water passes freely through the gaps between the stones. Pea gravel, crushed stone, and river rock are common types, each with a slightly different look and feel.

These figures are estimates for planning. Actual quantities vary with ground conditions, compaction, and how the material is spread, and prices depend on your supplier and location.