The Gravel Calculator converts an area and a depth into the volume and weight of gravel required, in cubic yards, cubic feet, cubic metres and US tons. Fourteen gravel types are built in, each with its own bulk density, so pea gravel and dense-graded base return different tonnages for identical dimensions. Compaction and waste allowances are applied on top, because gravel is delivered loose and loses volume when it is rolled.
Calculate gravel volume and weight
Gravel is ordered by weight in most of the United States and by volume in most of the rest of the world, so the calculation has to produce both. Volume comes from area multiplied by depth.
Weight comes from that volume multiplied by the bulk density of the specific gravel type, which ranges from 825 kg/m³ for lava rock to 2,002 kg/m³ for dense-graded aggregate.
Enter the area directly if you already know it, or let the calculator work it out from a rectangle, circle or triangle. Depth goes in inches or centimetres. Everything else, unit conversion, density lookup, tonnage, happens from there.
The area and depth do not need to share a unit. A driveway measured 40 ft by 12 ft with a 4-inch depth is a normal way to describe the job, and the calculator handles it without asking you to convert anything first.
Select a gravel type and density
Bulk density is the number that turns volume into an order. It varies by more than two to one across common gravel types, which means the same 200 square feet at 3 inches can be anything from 1.3 to 3.1 tons depending on what you are buying.
| Gravel type | Size | Density (lb/yd³) | Common use |
|---|---|---|---|
| Pea gravel | 1/8-3/8 in | 2,565 | Walkways, decorative beds, playgrounds |
| River rock | 1-2 in | 2,835 | Landscaping, drainage, decorative |
| Crushed stone #57 | 1/2-3/4 in | 2,431 | Driveways, drainage, concrete mix |
| Crushed stone #411 | 0-3/4 in | 2,835 | Base layer, compactable, driveways |
| Dense graded (DGA/QP) | 0-3/4 in | 3,374 | Road base, high-compaction areas |
| Bank run gravel | 0-3 in | 3,240 | Fill, base material, general purpose |
| Decomposed granite | 0-1/4 in | 2,781 | Pathways, compacts well, natural look |
| Lava rock | 1/2-3 in | 1,391 | Decorative, lightweight mulch |
| Marble chips | 3/8-3/4 in | 2,565 | Decorative, white and coloured accents |
| Riprap | 6-24 in | 2,700 | Erosion control, shoreline protection |
Bulk densities vary by supplier, moisture content and compaction. Confirm the actual density on the delivery ticket before ordering.
The distinction that matters most is whether the gravel contains fines. Crushed stone #57 is washed and uniformly sized, so it drains freely but never locks together, it stays loose underfoot forever. Dense-graded aggregate contains everything from 3/4-inch stone down to rock dust, and that dust is what lets it compact into a hard surface. Using #57 where you needed DGA produces a driveway that ruts in a season.
Apply the gravel volume formula
Four steps, and the only one people get wrong is the first.
1. Depth in feet = depth in inches ÷ 12
2. Volume (ft³) = area (ft²) × depth (ft)
3. Volume (yd³) = volume (ft³) ÷ 27
4. Weight (lb) = volume (yd³) × density (lb/yd³)Depth is almost always specified in inches and area almost always in square feet, so mixing them without converting is the standard error. Multiplying 200 ft² by 3 without dividing by 12 first gives 600, twelve times the real answer, and an order that arrives as six truckloads instead of half of one.
For metric, the same path runs through metres and cubic metres: depth in centimetres divided by 100, area in square metres, and density in kilograms per cubic metre.
Estimate pea gravel for a 20 × 10 patio
A patio area of 20 ft by 10 ft, covered 3 inches deep in pea gravel, needs 1.85 cubic yards weighing about 4,745 lb before any allowance is added. 1. Find the area. 20 ft × 10 ft = 200 ft²
2. Convert the depth to feet. 3 in ÷ 12 = 0.25 ft
3. Find the volume in cubic feet. 200 ft² × 0.25 ft = 50 ft³
4. Convert to cubic yards. 50 ft³ ÷ 27 = 1.85 yd³
5. Convert to weight. 1.85 yd³ × 2,565 lb/yd³ = 4,745 lb, or 2.37 US tons
Decorative pea gravel is not compacted, so only a waste allowance applies here. At 10 percent the order becomes 2.04 cubic yards, or 2.6 tons.
Swap pea gravel for dense-graded aggregate on the same patio and the weight jumps to 6,242 lb, because DGA is 31 percent denser. Same hole, same volume, materially different truck.
Add compaction and waste to the order
Gravel arrives loose and loses volume when it is compacted. Ordering the geometric volume leaves you short on every project that involves a plate compactor or a roller, which is most of them. This is the single most common reason a gravel order runs out.
Two separate allowances, applied one after the other:
Compaction covers the volume lost when loose gravel is rolled to its final density. Base layers under pavers, driveways and paths typically lose 15 to 25 percent. Decorative gravel that is simply raked level loses nothing, so the allowance is zero.
Waste and overrun covers spillage, rake loss, edges, and the material that disappears into a soft subgrade. Five to fifteen percent depending on how contained the area is.
Order volume = geometric volume × (1 + compaction%) × (1 + waste%)A 4-inch compacted driveway base calculated at 5 cubic yards becomes 5 × 1.20 × 1.10 = 6.6 cubic yards ordered. That is a third more than the raw geometry, and it is the correct number.
The calculator defaults to 15 percent compaction and 10 percent waste, shows both the geometric and the order volume side by side, and leaves both fields editable. Nothing is hidden inside a single figure.
Choose gravel depth by application
Depth is set by load, not by appearance. Too shallow and the surface fails under traffic; too deep wastes material and, on a decorative bed, makes walking unpleasant.
- Decorative beds and borders: 2 inches. Enough for coverage, shallow enough to stay put.
- Walking paths: 2 to 3 inches over a compacted subgrade.
- Driveway surface layer: 3 to 4 inches over an established base.
- Driveway base, new construction: 6 to 8 inches total, placed in 3 to 4 inch lifts and compacted between each.
- Paver and slab base: 4 to 6 inches of dense-graded, compacted, depending on soil.
- French drain fill: trench depth, using washed #57 so water moves freely.
- Playground safety surfacing: 9 to 12 inches of rounded pea gravel. Follow the fall-height guidance for the equipment rather than a general figure.
Anything deeper than about 4 inches should go in lifts. Gravel placed in one thick layer compacts only at the surface and stays loose underneath, which is why a driveway can look finished and still develop ruts.
Buy gravel by the ton or by the yard
Quarries sell by the ton. Landscape suppliers often sell by the yard. Converting between them needs the density, which is exactly what the calculator has already looked up, so it reports both and you can compare quotes directly. For most common gravels, one cubic yard weighs between 1.2 and 1.7 US tons.
Pea gravel is about 1.28 tons per yard; dense-graded aggregate is about 1.69. A price quoted per ton and a price quoted per yard are not comparable until that conversion is done, and the gap is large enough to change which supplier is cheaper.
Bagged gravel exists but is expensive per unit volume, and a cubic yard is 27 one-cubic-foot bags. Above roughly a quarter of a yard, bulk delivery is cheaper even after the delivery fee. Most suppliers set a minimum load of one to three yards, and some charge the same for one yard as for three, worth asking, because it sometimes makes sense to take the extra.
Frequently asked questions
How much gravel do I need for a driveway?
A driveway needs its area multiplied by total depth, then compaction and waste added. A 40 ft by 12 ft driveway at 6 inches of base plus 2 inches of surface works out at 480 ft² × 0.667 ft = 320 ft³, which is 11.85 cubic yards geometric, or about 15.6 cubic yards ordered with 20 percent compaction and 10 percent waste.
How many tons of gravel are in a cubic yard?
Between 1.2 and 1.7 US tons for most gravel types. Pea gravel runs about 1.28 tons per cubic yard, crushed stone #57 about 1.22, and dense-graded aggregate about 1.69. Multiply cubic yards by the density in pounds per cubic yard, then divide by 2,000 to get US tons.
How deep should gravel be for a driveway?
Six to eight inches total for a new driveway, placed in 3 to 4 inch lifts and compacted between each. Use dense-graded aggregate for the base layers and a decorative or angular stone for the top 2 to 3 inches. On soft or clay soil, add a geotextile fabric beneath the base and increase the depth.
What is the difference between crushed stone and pea gravel?
Crushed stone is mechanically broken, so it has sharp angular faces that lock together under compaction. Pea gravel is naturally rounded by water and never locks, it shifts underfoot and migrates out of unedged areas. Use crushed stone for anything load-bearing and pea gravel where appearance and comfort matter more than stability.
Does gravel compact, and how much extra should I order?
Yes. Loose gravel loses 15 to 25 percent of its volume when compacted, so ordering the geometric volume leaves you short. Add 15 to 25 percent for compaction on any base layer, plus 5 to 15 percent for waste and spillage. Decorative gravel that is only raked level needs the waste allowance but no compaction allowance.
How much area does a ton of gravel cover?
At 2 inches deep, one ton of typical gravel covers about 100 square feet. At 3 inches it covers roughly 65 square feet, and at 4 inches about 50. The exact figure depends on density, so a ton of lava rock covers nearly twice the area of a ton of dense-graded aggregate.
Can I put new gravel over old gravel?
Yes, and it is the usual way to refresh a driveway. Rake the existing surface level, remove any vegetation, and add 2 to 3 inches of new material. If the old surface has deep ruts or a soft subgrade, those need fixing first, new gravel over a failing base fails in the same places within a year.
Do I need landscape fabric under gravel?
Under a decorative bed or a path, fabric is worth it: it stops the gravel sinking into soil and slows weed growth. Under a load-bearing driveway base, use a woven geotextile rather than standard landscape fabric, and only on soft or clay soils where it separates the base from the subgrade. It does not change how much gravel you need.
Summary
The Gravel Calculator turns an area and a depth into cubic yards and tons, using the bulk density of the specific gravel type selected. Volume in cubic feet divided by 27 gives cubic yards; multiplied by density it gives weight.
Density varies by more than two to one across common types, so the type matters as much as the dimensions. Add 15 to 25 percent for compaction on any base layer and 5 to 15 percent for waste, because gravel is delivered loose and always loses volume when rolled. Match depth to the load the surface will carry, place anything over 4 inches in lifts, and convert quotes to a common unit before comparing suppliers.