A gravel calculator turns three measurements — length, width and depth — into the cubic yards, tons and bags you need to order. Enter your area above and GravelGenie does the math instantly, adding a 10% allowance for settling and spillage. Most projects sit between 2 and 4 inches deep.
How do you calculate how much gravel you need?
To calculate gravel, multiply the area (length × width, in feet) by the depth (in feet) to get cubic feet, then divide by 27 to get cubic yards. Multiply cubic yards by about 1.4 to get tons. A 200-square-foot area at 4 inches deep works out to roughly 2.5 cubic yards, or about 3.5 tons.
The full method is four short steps:
- Find the area. For a rectangle, multiply length by width in feet. For a circle, use π × radius². Odd shapes can be split into rectangles and added together.
- Convert depth to feet. Divide inches by 12 — so 3 inches is 0.25 feet, and 4 inches is 0.333 feet.
- Multiply for volume. Area × depth gives cubic feet. Divide by 27 to reach cubic yards, the unit most bulk suppliers use.
- Convert to tons. Multiply cubic yards by the material’s density — about 1.4 for standard gravel. Then add ~10% for waste.
That last step is where a plain volume calculator falls short: order stone by weight and you need the density right. GravelGenie stores a tested density for every gravel type, so switching from crushed stone to pea gravel updates the tonnage automatically. For a full worked walkthrough, see how much gravel do I need.
How much does a ton (or cubic yard) of gravel cover?
One ton of standard gravel covers roughly 100 square feet at 2 inches deep, about 65 square feet at 3 inches, or 50 square feet at 4 inches. A cubic yard covers about 160 square feet at 2 inches or 80 square feet at 4 inches. Coverage shrinks as depth grows, because deeper layers hold more volume per square foot.
| Depth | 1 ton covers | 1 cubic yard covers |
|---|---|---|
| 2 inches | ~100 sq ft | ~160 sq ft |
| 3 inches | ~65 sq ft | ~108 sq ft |
| 4 inches | ~50 sq ft | ~80 sq ft |
| 6 inches | ~33 sq ft | ~54 sq ft |
These are planning figures — a rounded pea gravel or a light crushed limestone will cover a touch more ground per ton than a dense river rock, because it weighs less per cubic yard.
What depth of gravel do you need?
For a walking path or decorative bed, 2 inches is plenty; for a patio base or a dog run, use 3 inches; for a driveway top layer, 4 inches; and for drainage trenches, 4–6 inches. Going deeper than a project needs wastes money and can make loose gravel rut and migrate underfoot.
| Project | Typical depth | Notes |
|---|---|---|
| Decorative bed / mulch replacement | 2 in | Over landscape fabric |
| Garden & walking path | 2–3 in | Edge it to stop spread |
| Patio / shed base | 3–4 in | Compact in layers |
| Driveway top layer | 4 in | Over a compacted base — see the driveway calculator |
| French drain / drainage | 4–6 in | Use clean, angular stone |
Cubic yards vs tons — which should you order in?
Suppliers sell gravel by the ton (weight) or by the cubic yard (volume), and both describe the same pile of stone. Bulk aggregate is usually priced per ton, while bagged gravel and topsoil are sold by volume. GravelGenie shows both figures at once, so you can match whatever number your supplier quotes without doing a conversion in the yard.
Why does the same volume vary in weight? Moisture is the biggest factor — wet gravel can weigh 10–15% more than dry — followed by stone size and shape. That is exactly why buying by weight needs a trustworthy density, and why we publish ours on the about page. When in doubt, give your supplier the cubic yards and let them convert to their own tonnage.
How many bags of gravel are in a cubic yard?
A cubic yard equals 27 cubic feet, so it takes about 54 half-cubic-foot bags — the common 50-pound bag size — to fill one cubic yard. Bagged gravel costs several times more per cubic yard than bulk delivery, so bags really only make sense for small jobs under roughly half a yard, or where a truck simply can’t reach.
The calculator reports bag count alongside yards and tons, so you can compare a run to the store against a bulk drop-off before you commit. For anything over about a cubic yard, bulk almost always wins on price — the cost per ton guide breaks down where the money goes.
How to avoid ordering the wrong amount
The two classic mistakes are forgetting compaction and measuring only the easy dimension. Gravel compacts as it settles, so a driveway that measures 4 inches loose finishes closer to 3 inches — order for the loose depth. And an L-shaped or curved area needs to be split into simple shapes and added up, not guessed. A few quick habits keep you covered:
- Measure twice, at the widest points, and sketch the shape before you calculate.
- Keep the default 10% waste — bump it to 15% on sloping or uneven ground.
- Check the supplier’s delivery minimum; many charge a flat fee under 1–3 tons.
- Subtract large obstacles (a raised bed, a manhole) from the area.
- If you’re between two depths, round the depth up, not the area.