The formula
How it works
Estimate how much gravel you need for a driveway, path or drainage layer, from its length, width and depth. The calculator gives both the volume and the approximate weight in tons, since gravel is often sold by weight.
FAQ
How deep should a gravel layer be?
About 2 inches (5 cm) is enough for a decorative path, while a driveway that takes vehicles usually wants 4 inches (10 cm) or more, often over a compacted base layer.
Why is weight shown as well as volume?
Gravel is commonly sold by the ton, not the cubic yard. The weight depends on the type of stone, but a rough density of 1.4 tons per cubic yard works for most crushed gravel.
Should I order extra gravel beyond the calculated amount?
Yes — adding 5 to 10% extra covers compaction, an uneven sub-base and minor spillage, so you are not left short partway through the job.
What size gravel should I use?
Smaller stone like pea gravel or 3/8-inch chips suits paths and decorative areas, while larger crushed stone (3/4 inch or more) compacts better under driveways and heavy loads.
Do I need a base layer before adding gravel?
For paths a layer of landscape fabric over compacted soil is usually enough, but driveways benefit from a compacted sub-base of larger crushed stone before the top layer goes down.
How does gravel compare to sand or mulch for this kind of project?
Gravel drains well and resists erosion, making it better for driveways and drainage, while sand suits paver joints and mulch is better for garden beds — each is calculated the same way from area and depth.
Does moisture affect how much gravel I need?
Not the volume calculation itself, but damp gravel is heavier per load than dry gravel, so if you are buying by weight, ask your supplier whether their density figure already accounts for moisture.
About the gravel calculator
This calculator estimates the gravel you need to fill an area to a given depth, in both volume and weight. Gravel is used for driveways, paths, patios and drainage, and it is usually sold either by the cubic yard or, more often, by the ton. Because the two are related by the density of the stone, working out the volume first and then converting to weight lets you order confidently whichever way your supplier prices it.
How to use it
Choose your units, then enter the length, width and depth of the area you are filling. The calculator returns the volume in cubic yards or cubic metres and the approximate weight in tons. For example, a 20 ft by 12 ft driveway filled 4 inches deep needs about 3 cubic yards, which is roughly 4 tons of gravel. Add a little extra for settling and compaction, especially on a driveway that will carry vehicles.
The formula
The volume is length times width times depth, , with the depth converted to the same unit. The weight is then the volume times the gravel’s density, . This calculator uses a typical density of about 1.4 tons per cubic yard for crushed gravel; heavier stone weighs more, so treat the tonnage as an estimate and check with your supplier for a specific product.
Where it is used
Homeowners and landscapers use it to order gravel for driveways, garden paths, French drains and decorative borders. Builders use it for sub-bases under paving and concrete, where a compacted gravel layer spreads the load. Because gravel yards price by weight, the tonnage figure is what you take to the supplier, while the volume helps you picture how much material will actually arrive.