Gravel Calculator

How much gravel do I need?

Gravel is sold by volume or weight, but projects are measured in length and width. To get from one to the other, multiply the area’s length, width, and desired depth to get a volume, convert that to cubic yards (or cubic meters), then multiply by the density of the stone to get tons (or tonnes). Because most landscape and aggregate yards price bulk gravel by the ton, the weight is shown as the headline figure, with the volume and the equivalent number of retail bags beside it.

For a rectangle, two tape measurements are enough. For a curved bed, an L-shaped driveway or a path that wanders around the house, split the area into simple shapes and add them up — the square footage calculator for irregular areas handles that — then enter the total as length × 1 ft (or 1 m) here.

Formula & methodology

Volume = Length × Width × Depth, with depth converted to the same unit as length and width before multiplying (inches ÷ 12 for feet, centimeters ÷ 100 for meters). A waste/compaction allowance (default 10%) is then added, since loose gravel settles once it’s spread and rolled, and some always ends up in the lawn or under the edging. Cubic feet ÷ 27 gives cubic yards.

Weight is that volume × the selected material’s typical density — 105 lb per cubic foot for bank-run gravel, for example — divided by 2,000 lb per US ton. In US mode the bag count assumes standard 0.5 cubic foot retail bags, rounded up because a store won’t sell you 0.3 of a bag. Open “Show the math” under the results to see every step with your own numbers.

Outside the US, switch to metric: lengths go in meters, depth in centimeters, and results come out in cubic meters and metric tonnes. Metric stone bags are sold by weight rather than volume, so choose 20 kg or 25 kg and the count is based on the stone’s weight. Your existing measurements are converted when you switch.

Worked example: a 40 × 12 ft driveway

Say you’re topping a single-car driveway 40 ft long and 12 ft wide with 4 inches of crushed stone, and you want 10% extra for compaction.

1. Area: 40 ft × 12 ft = 480 sq ft.
2. Volume: 480 sq ft × (4 ÷ 12) ft = 160 cu ft, or 5.93 cu yd.
3. Add 10%: 160 × 1.10 = 176 cu ft = 6.52 cu yd.
4. Weight: 176 cu ft × 100 lb/cu ft = 17,600 lb ÷ 2,000 = 8.8 tons.
5. In bags: 176 ÷ 0.5 = 352 bags — a good illustration of why driveways are bought in bulk.

Most suppliers sell in whole or half tons, so you would order 9 tons. If the same driveway used bank-run gravel instead, the volume stays at 6.52 cu yd but the weight rises to about 9.3 tons because that material is denser.

Gravel coverage by depth

Quick reference for how far a cubic yard goes, and how much it takes to cover a 100 sq ft patch (10 × 10 ft), using bank-run gravel at 1.42 tons per cubic yard and no waste allowance.

Metric rule of thumb: 1 m³ covers 20 m² at 5 cm deep, 10 m² at 10 cm, and about 6.7 m² at 15 cm.

Gravel types & density

Density is what turns a volume into a weight, and it is the main reason two quotes for “a yard of stone” can differ by a few hundred pounds. Rounded, washed stones such as pea gravel and river rock leave more air gaps and weigh less per yard than bank-run gravel, which carries sand and fines that fill those gaps.

Densities are typical approximations — actual density varies with moisture content and stone type. Ask your supplier for exact figures on large orders.

How deep should gravel be?

Depth drives the order more than anything else: going from 2 to 4 inches doubles it. These are typical depths, not specifications — a site with soft clay, heavy vehicles or a local code requirement may need more.

• Walkways and garden paths: commonly 2–3 inches (5–7.5 cm) of pea gravel or fine crushed stone over landscape fabric. Deeper loose stone is harder to walk on.
• Decorative cover and beds: about 2 inches is usually enough to hide the soil. For planted beds, compare against organic cover with the mulch and topsoil calculator.
• Driveways: typically 4–6 inches (10–15 cm), often built in layers with larger base stone below and a finer top course. New driveways on soft ground are frequently deeper.
• Under a slab or patio: 4 inches (10 cm) of compacted base is a common minimum; once the base is sized, work out the pour itself with the concrete slab calculator.

Gravel cost

As a rough 2026 US range, bulk gravel runs about $20–$75 per ton before delivery, depending on the stone and your region, and delivery is often a flat $50–$200 per load. Prices vary by region — get local quotes. At those rates the 9-ton driveway above would cost roughly $180–$675 in material plus delivery.

Plain crushed stone and bank-run gravel sit toward the low end; washed, screened or decorative stone toward the high end. Some suppliers quote per cubic yard instead of per ton — divide the yard price by the tons-per-yard figure in the table above to compare them fairly.

Tips for ordering gravel

• Order a little extra — most suppliers round up to the nearest half or full yard/tonne anyway, and topping up later costs a second delivery fee.
• For a gravel driveway, 4–6 inches (10–15 cm) of compacted base gravel is typical.
• For a slab base, 4 inches (10 cm) is a common minimum — check your local building code.
• Bagged gravel is convenient for small jobs, but bulk delivery is cheaper per ton for anything over ~1–2 cubic yards. Bag counts round up, since an opened bag can’t go back on the shelf.
• Ask whether the yard measures by weight (scale ticket) or by loader bucket, and confirm the truck can reach the drop spot without crossing a septic field or soft lawn.
• Outside the US, quantities are usually quoted in tonnes or cubic meters and bags come in 20–25 kg sizes; use metric mode to match.