Gravel Calculator

Ordering gravel by guesswork almost always ends in a second delivery — or a pile of leftover rock nobody wants. This calculator converts your area and depth into cubic yards, cubic feet, and tons, using a supplier- and DOT-sourced density instead of a rounded-off average. Enter the length and width of the space, pick a depth (or tap a preset for a walkway, patio base, or driveway), and the results update as you type. Add a price per yard or ton and you'll get an estimated cost range too. Whether you're topping off a garden path or ordering a dump-truck load for a driveway base, the numbers below are the ones to bring to the counter.

Your area

Price (optional)

Enter your dimensions above to see results.

How it's calculated

The calculator first finds the volume of the area in cubic feet: length (ft) × width (ft) × depth (in ÷ 12). That's converted to cubic yards by dividing by 27, since a cubic yard is 3 ft × 3 ft × 3 ft. A waste percentage is added on top to cover spillage and an uneven sub-base, and the adjusted cubic yardage is multiplied by gravel's density (tons per cubic yard) to get the weight in tons. Bag counts divide the adjusted cubic feet by each bag's yield; truckloads divide the adjusted cubic yards by the truck's capacity.

Worked example

A 10 ft × 10 ft walkway at 3 inches deep: volume = 10 × 10 × (3 ÷ 12) = 25 cubic feet. In cubic yards, that's 25 ÷ 27 = 0.93 yd³. Adding a 10% waste factor: 0.93 × 1.10 = 1.02 yd³. At 1.375 tons per cubic yard, that's 1.02 × 1.375 = 1.40 tons — or 1.32–1.48 tons across the full 1.30–1.45 density range, and higher still if the material is wet or compacted. In 0.5 cu ft bags, the adjusted 27.5 cu ft (25 × 1.10) needs 55 bags.

How deep should it be?

Depth is the number most people guess wrong, because it depends on what the gravel is doing structurally, not just how it looks. A 2" layer is a topping — enough to cover a walkway or refresh existing gravel, but too thin to bear weight or resist rutting on its own. 3" is the standard base under patio pavers or a low-traffic path, deep enough to bridge minor grade irregularities. 4" or more is a driveway base, and in freeze-thaw climates or clay soils, contractors often go to 4–6" of compacted base plus a topping layer to keep the surface from heaving. Whatever depth you use, measure it after compaction, not as a loose pile — loose gravel settles 10-20% once driven or walked on, which is exactly what the waste factor above is partly compensating for.

Common mistakes

  • Measuring depth as the loose pile height instead of the compacted depth — gravel settles 10-20% once compacted or driven on.
  • Using one density figure for every gravel type. Pea gravel, crusher run, and drainage stone can differ by 30% or more in weight per yard.
  • Skipping the waste factor on irregular or sloped areas, where cutting and spillage run higher than a clean rectangle.
  • Ordering bagged gravel past the point it's cheaper than bulk — bagged material typically costs 2-3x more per ton once you're past roughly a ton.
  • Forgetting sub-base prep. A gravel layer poured straight onto unprepared soil migrates into the ground and needs regular topping-off.

Where the density figure comes from

North Bay Materials lists gravel and sand at 1.30–1.40 tons/yd³; Select Sand & Gravel lists crushed stone at 1.35–1.4 tons/yd³. The two sources agree closely, so 1.30–1.45 tons/yd³ covers both — but treat it as a floor rather than a ceiling: saturated or compacted material runs heavier than either published range. We use 1.375 tons/yd³ as the display figure, drawn from:

Read more in our density methodology.

FAQ

How much gravel do I need for a driveway?
For a standard 4" compacted base, multiply the driveway's length and width in feet, divide by 3 (to get the volume in cubic feet at 4"), then divide by 27 for cubic yards. A 12 ft × 40 ft driveway at 4" needs about 5.9 cubic yards before waste — use the calculator above to add your waste factor and get a tonnage.
Why does gravel weight per cubic yard vary so much?
Density depends on the stone's size, shape, and how tightly it's packed. Clean, uniformly sized drainage stone has more air gaps and weighs less; dense-graded gravel with a mix of fines compacts tighter and weighs more. That's why we show a range, not just one number — always confirm the exact figure with your supplier for a large order.
Should I measure loose or compacted depth?
Compacted. If you spread gravel loose and don't compact it, plan on it settling 10-20% within the first few weeks of foot or vehicle traffic. Ordering based on the final, compacted depth you want — and letting the waste factor cover the settling — avoids running short later.
Is it cheaper to buy gravel in bags or bulk?
Bulk almost always wins past about 1 ton (roughly 27 bags at 0.5 cu ft each). Bagged gravel carries packaging and handling costs that can put it at 2-3x the price per ton of a bulk delivery. Bags make sense for small top-offs or projects without truck access.
How deep should gravel be for a walkway versus a driveway?
A walkway topping only needs about 2 inches since it's not bearing vehicle weight. A driveway needs a compacted base of 4 inches or more — sometimes 4-6 inches in freeze-thaw climates — because it has to resist rutting and heaving under repeated load.
What's a reasonable waste factor for gravel?
10% covers typical spillage and minor sub-base irregularities on a rectangular area. Bump it to 15% for irregular shapes, sloped sites, or a first-time sub-base that hasn't been graded — you're accounting for both cutting waste and the gravel needed to fill low spots.
How many truckloads of gravel will I need?
Divide your adjusted cubic yardage by the truck's capacity — most standard dump trucks carry about 10-14 cubic yards. The calculator above uses 12 cubic yards as a default and rounds up, since a partial truckload still requires a full trip.