Gravel Calculator
Work out how much gravel you need by volume, weight, bags and cost.
Results update as you type.
About this calculator
A gravel calculator estimates the volume of gravel or aggregate needed to fill an area to a given depth, then converts that to weight, bags and cost. It multiplies the area (length × width) by the depth to get cubic feet, converts to cubic yards by dividing by 27, and to weight in US tons using a typical gravel density of about 1.4 tons per cubic yard. Loose gravel settles and spreads unevenly, so a small waste allowance is included by default.
Worked example: a 20 × 10 ft area is 200 sq ft. At 2 inches deep that is 200 × (2 ÷ 12) = 33.3 cubic feet, about 1.23 cubic yards, weighing roughly 1.23 × 1.4 ≈ 1.7 US tons. Enter a price per cubic yard and it multiplies through for the delivered cost.
Ordering by the yard is almost always cheaper than bags once you pass a fraction of a yard, so the tool shows both. Use it for gravel driveways, paths, drainage beds, patios and French drains — adjust the density field if your supplier quotes a different figure for the stone you are buying.
Frequently asked questions
How deep should a gravel layer be?
For a decorative bed 2 inches is usual; for a walkway 2–3 inches; for a driveware base plan on 4–6 inches, often in two compacted layers. Deeper layers need proportionally more gravel, which the depth field handles directly.
How much does a cubic yard of gravel weigh?
About 1.4 US tons (roughly 2,800 lb) for typical crushed stone, though it ranges from 1.3 to 1.7 tons depending on stone type and moisture. Adjust the density field if your supplier quotes a different figure.
Should I buy gravel in bags or by the yard?
Bags suit small jobs under about a third of a cubic yard; beyond that, bulk delivery by the cubic yard is far cheaper per unit. The calculator shows both so you can compare.
How many tons of gravel do I need for a driveway?
Work out the area (length × width) and depth — a driveway base is usually 4–6 inches — to get cubic yards, then multiply by the density (about 1.4 tons per cubic yard). A 40 × 12 ft drive at 4 inches is about 5.9 cubic yards, roughly 8.3 tons.
How do I convert cubic yards of gravel to tons?
Multiply cubic yards by the density in tons per cubic yard. The default 1.4 suits typical crushed stone; pea gravel is a little lighter (around 1.25–1.4) and wet or dense stone heavier (up to 1.7). Set the density field to match your material.
Does the type of gravel change how much I need?
The volume you need is fixed by the area and depth, but the weight changes with the stone — lighter pea gravel weighs less per cubic yard than dense crushed rock. If you buy by the ton, adjust the density; if you buy by the yard, the volume is what matters.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/gravel/curl
curl "https://calculator.free/api/v1/gravel/?length=20&width=10&depth=2"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/gravel/?" + new URLSearchParams({
"length": "20",
"width": "10",
"depth": "2"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.