Gravel Calculator
Gravel is sold by the ton but planned by the area — this calculator bridges the gap. Enter length, width and depth, pick your material, and get the tonnage to order plus the cubic-yard volume and a coverage check. It covers crushed stone, pea gravel, river rock and decomposed granite, each with its own bulk density, so driveway, patio-base and drainage-bed estimates come out right the first time.
3–4 in typical for driveways; 2 in for walkways.
Densities are quarry rules of thumb; your supplier may differ.
Crushed stone needed
2.78ton
- Volume
- 1.85yd³
- Total weight
- 5,556lb
- Coverage at this depthSquare feet one ton covers at your chosen depth.
- 72ft²
How it was calculated
- Volume: 20 ft × 10 ft × 0.250 ft = 50.00 ft³ = 1.85 yd³.
- Tonnage: 1.85 yd³ × 1.5 t/yd³ (crushed stone) = 2.78 tons.
- Coverage check: one ton covers ≈ 72.0 ft² at 3.0 in depth.
How it works
Volume comes first: length × width × depth (in feet) gives cubic feet; divide by 27 for cubic yards.
Tonnage = cubic yards × the material's bulk density in tons per cubic yard — 1.5 for crushed stone, 1.4 for pea gravel, 1.45 for river rock, 1.3 for decomposed granite.
The coverage check inverts the math: ft² per ton = (27 ÷ density) ÷ depth in feet. It is a quick way to sanity-check a supplier's quote.
Densities are bulk rules of thumb that include air voids between stones; compacted-in-place weight runs a little higher.
Worked examples
20 × 10 ft driveway at 3 inches, crushed stone
Volume = 200 × 0.25 = 50 ft³ = 1.85 yd³. Tonnage = 1.85 × 1.5 = 2.78 tons — order 3 tons. Coverage check: one ton covers 72 ft² at 3 in, and 200 ÷ 72 = 2.78 tons. Consistent.
12 × 8 ft walkway at 2 inches, pea gravel
Volume = 96 × 0.1667 = 16 ft³ = 0.59 yd³. Tonnage = 0.59 × 1.4 = 0.83 tons, about 1,660 lb. Most suppliers have a 1-ton minimum, so expect to order a full ton.
How to measure
- Measure the area after edging is set — edging defines the real boundary, not your sketch.
- For curved beds, measure the longest length and widest width, then shave 10–15% off the area for the curve.
- Decide depth by use: 2 in for walkways, 3–4 in for driveways, 6+ in for a compacted base under pavers.
- Measure depth from the finished grade down, not from the top of loose soil.
- For sloped areas, measure depth at the shallowest point and add half a ton — stone migrates downhill.
Assumptions & limitations
Planning estimate
- Bulk densities (crushed stone 1.5, pea gravel 1.4, river rock 1.45, decomposed granite 1.3 tons/yd³) are an industry rule of thumb; actual density varies with quarry, stone size and moisture.
- Volume assumes a flat, uniform depth — crowned driveways and dished areas need manual adjustment.
- Weight is loose bulk weight; compacted stone weighs more per yard because voids collapse.
- This is a planning estimate only — not a substitute for code compliance or professional design. Structural base depths for driveways should follow local standards.
Frequently asked questions
A 20 × 10 ft driveway at 3 inches needs about 2.8 tons of crushed stone (order 3). The general rule: multiply area in ft² by depth in feet, divide by 27 for yards, then multiply by the stone's density — roughly 1.5 tons per yard for crushed stone.
It depends on depth. A ton of crushed stone covers about 72 ft² at 3 inches, 54 ft² at 4 inches, or 108 ft² at 2 inches. Coverage = (27 ÷ density) ÷ depth-in-feet, which this calculator shows for your exact depth.
Crushed stone has angular faces that lock together — best for driveways and bases. Pea gravel is small, rounded stone that shifts underfoot — better for walkways, patios and decorative beds. Crushed stone is also slightly denser per yard.
Order 5–10% extra for driveways and beds with curves or slopes, where stone migrates or edges spill. Gravel stores indefinitely, so a half-ton leftover is useful for future top-ups rather than waste.
Most quarries and landscape suppliers have a 1-ton (sometimes 2-ton) minimum for delivery, and delivery fees are often flat — so combining projects into one order saves money. Small walkway jobs under a ton are usually handled with bagged stone from a garden center.