Gravel Calculator (Volume & Weight Estimate)
Free tool to estimate how much gravel or crushed stone you need. Enter your area (rectangular or circular) and fill depth to get the volume (m³/ft³) and weight (kg/tons) by material type.
What is a gravel calculator?
This free tool estimates the volume and weight of gravel or crushed stone you need before ordering, for projects like driveways, garden beds, edging, and drainage. It supports two area shapes — rectangular (driveways, paths) and circular (flower beds, standalone areas) — so you only need to enter the dimensions and the fill depth to get the volume (m³/ft³) and, based on the material you pick, the weight (kg/tons).
Gravel bulk density varies a lot by type: rounded river rock tends to be lighter, while crushed stone and general sand-mixed gravel tend to be heavier for the same volume. You can choose from five common materials (general gravel, crushed stone, pea gravel, river rock, and sand), or enter a custom density if you know the exact figure from a supplier catalog. Since real installs always have some loss from compaction and unloading, you can add an optional waste margin (10% by default).
How to use the gravel calculator
- Choose the area shape Pick rectangular for driveways and paths, or circular for flower beds and standalone areas.
- Choose a unit system Pick metric (m, cm) or imperial (ft, in), whichever is easier to measure with.
- Enter the dimensions and depth Enter the length and width (or diameter) and the fill depth you want, based on actual measurements.
- Choose the material type Pick gravel, crushed stone, pea gravel, river rock, or sand, or use custom if you know the exact density.
- Read the result The volume (m³/ft³) and weight (kg/tons), including your waste margin, are calculated instantly.
Tips for getting more out of it
- Gravel suppliers usually price by weight (tons) rather than volume, so it helps to quote the weight figure when placing your order.
- For driveways, a fill depth of about 8-10cm (3-4in) is a common target to prevent settling; for decorative garden gravel, 3-5cm (1-2in) is usually enough.
- River rock is lighter than crushed stone for the same volume, so picking the wrong material type can throw off your order if you're buying by weight.
- If you're also laying a base layer of crushed stone or weed barrier under your gravel, calculate that base thickness separately rather than folding it into your fill depth.
Use cases
Driveway or walkway gravel
Use the rectangular shape to estimate crushed stone or gravel for a driveway or entrance path.
Decorative gravel around flower beds
Use the circular shape to estimate pea gravel or river rock for a flower bed or around a tree.
Drainage trench backfill
Use the rectangular shape to estimate the crushed stone needed to backfill a drainage trench or french drain.
Sandbox or dog run base
Use the rectangular shape with sand selected to estimate how much sand a sandbox or dog run needs.
Glossary
- Bulk density
- The weight per unit volume of a granular material like gravel, measured including the air gaps between particles. It is lower than the density of the solid mineral itself.
- Crushed stone
- Angular gravel produced by mechanically crushing rock. Its sharp edges interlock well, making it common for road base and footing backfill.
- River rock
- Naturally rounded gravel smoothed by rivers or ocean waves over long periods. Its smooth appearance makes it popular for decorative garden use.
- Waste margin
- An extra percentage added to the calculated volume to cover losses from spillage, compaction, and measurement error that a pure geometric calculation cannot account for.
- Base course
- A layer of crushed stone laid and compacted beneath a driveway or path for stability, distinct from any decorative gravel layered on top.
- US ton (short ton)
- A unit of weight used mainly in the US, equal to 2,000 pounds (about 907.18kg). It differs from the metric ton (1,000kg) used internationally.
Frequently asked questions
Side Note — Every pebble carries the memory of a place thousands of miles away
Gravel forms when rock is tumbled by rivers or ocean waves over long stretches of time, wearing down sharp edges into smooth, rounded shapes. Each pebble carries a record of the volcanic activity that formed its parent rock and the river path that carried and shaped it along the way. Geologists sometimes study gravel deposits to reconstruct where ancient rivers once flowed, which means a handful of garden gravel can hold tens of thousands to millions of years of geological history.
The "bulk density" concept used in this tool is specific to granular materials like gravel and crushed stone. A given volume of gravel feels lighter than the same volume of water because of the air trapped between particles. Uniformly sized pea gravel packs with more air gaps and stays lighter, while crushed stone with a mix of particle sizes fills those gaps more and tends to be heavier. That is why this tool treats the required weight as something that changes with material type, even at the same volume.
In Japanese rock gardens (karesansui), white gravel and river rock have long been raked into patterns to represent flowing water. The rippled lines, called samon, symbolize waves and currents and are said to have a calming effect on anyone viewing them. It is a striking example of how a practical building material like gravel has also found a place expressing spirituality within a cultural art form.