Gravel Calculator
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Result
Gravel needed
- In cubic yards
- 5.19 cubic yards
- Estimated cost
- $327
- Area covered
- 400 sq ft
- Density used
- 1.4 tons per cubic yard
- Aggregate is sold by weight, not volume. Suppliers quote per ton, so the tonnage figure is the one to order against — the cubic yards are for working out whether it will fit on site.
Recommended depth by application
| Application | Depth | Note |
|---|---|---|
| Garden path, foot traffic | 2–3 in | Pea gravel or #57 over fabric |
| Driveway surface course | 4 in | Over a compacted base layer |
| Driveway base course | 4–6 in | Crusher run, compacted in lifts |
| Drainage / French drain | 6–12 in | Clean washed stone, no fines |
| Paver or slab base | 4–6 in | Crusher run, then bedding sand |
Tonnage by stone type
The same volume ordered in each aggregate, since density decides the bill.
| Stone | Tons / yd³ | Tons needed |
|---|---|---|
| Crushed stone (#57, 3/4") | 1.4 | 7.26 |
| Pea gravel | 1.35 | 7 |
| Crusher run / road base | 1.5 | 7.78 |
| Sand | 1.35 | 7 |
| River rock | 1.4 | 7.26 |
How much gravel do I need?
To calculate gravel, multiply the area in square feet by the depth in feet, divide by 27 for cubic yards, then multiply by the stone's density to get tons. Crushed stone runs about 1.4 tons per cubic yard, so a 400 square foot driveway at 4 inches needs roughly 6.9 tons.
tons = ((area_sqft × depth_in ÷ 12) ÷ 27) × density_tons_per_yard- area
- Surface area in square feet
- depth
- Finished depth in inches, divided by 12 to reach feet
- 27
- Cubic feet in a cubic yard
- density
- Tons per cubic yard — 1.35 to 1.5 depending on the stone
Gravel starts as a volume calculation and ends as a weight one, because that is how aggregate is sold. Work out the cubic yards from area and depth, then multiply by density: crushed stone is about 1.4 tons per cubic yard, crusher run nearer 1.5 because the fines pack between the stones, and pea gravel about 1.35. Two adjustments separate a correct order from a short one. Compaction comes first: crusher run and other base materials lose up to 20% of their loose volume when tamped, so reaching a 4-inch finished depth means ordering closer to 4.8 inches of loose material. Clean washed stone with no fines barely compacts at all, which is why it is used for drainage and why no allowance is added for it here. Waste comes second and is smaller — five percent covers spreading past the edges and settling into a soft subgrade.
- Measure the area's length and width in feet.
- Multiply them for the area in square feet.
- Divide the finished depth in inches by twelve.
- Multiply area by depth, then divide by 27 for cubic yards.
- Add a compaction allowance if the layer will be tamped.
- Multiply by the stone's tons per cubic yard to get the order weight.
Worked example: A 40 ft by 10 ft driveway surface in #57 crushed stone, 4 inches deep
A 40 ft by 10 ft driveway surface in #57 crushed stone, 4 inches deep
The area is 40 × 10 = 400 square feet. Four inches is 0.3333 feet, so the volume is 400 × 0.3333 = 133.3 cubic feet, or 4.94 cubic yards. Clean #57 stone does not compact meaningfully, so no compaction allowance applies; adding 5% for spread and settling brings it to 5.19 cubic yards. At 1.4 tons per cubic yard that is 7.26 tons, and at $45 delivered that is about $327. Ordering the same job in crusher run instead changes two things: density rises to 1.5 tons per yard and a 20% compaction allowance applies, taking it to 6.22 cubic yards and 9.33 tons. That is 29% more material for the same finished depth, which is exactly the mistake that leaves a base course an inch shallow after tamping.
What each gravel input means
- Stone type
- What you are ordering. Density varies by type, and this is what converts cubic yards into the tons the supplier actually bills.
- Area shape
- A driveway or path is rectangular; a fire pit surround or pad may be circular.
- Length
- The run of the driveway or path, in feet.
- Width
- In feet. A single-car driveway is usually 10–12 ft; a garden path 3–4 ft.
- Diameter
- For a circular area, the full width across in feet.
- Depth
- Finished depth in inches. A gravel driveway wants 4 inches of surface stone over a 4-inch base; a path 2–3 inches.
- Order extra for compaction
- Base material loses up to 20% of its loose volume when tamped. Leave this on for any layer you intend to compact, or the finished depth comes up short.
- Waste allowance
- Loose fill spreads beyond the edges and settles into the subgrade. Five percent is typical.
- Price per ton
- Delivered price per ton, for the cost estimate. Aggregate is billed by weight, not volume.
What this gravel does not account for
- Densities vary by quarry and by moisture content. The figures here are conventional trade averages — ask your supplier for theirs, since you are billed by weight.
- Compaction only applies to material with fines in it. Clean washed stone used for drainage barely compacts, and adding an allowance would over-order.
- An existing surface is not deducted. Topping up a worn driveway needs only the missing depth, not the full build-up.
- A gravel driveway needs a base course under the surface course. Ordering only the surface depth gives a driveway that ruts in a season.
- Geotextile fabric under the stone is strongly recommended on soft ground and is not costed here. Without it, gravel migrates into the subgrade and the depth disappears.
- Delivery is usually by the full truckload. A supplier may have a minimum tonnage, and part-loads often carry a surcharge.
Frequently asked questions
How many tons of gravel are in a cubic yard?
About 1.4 tons for #57 crushed stone, 1.5 for crusher run, and 1.35 for pea gravel and sand. The variation comes from how tightly the particles pack, and it matters because aggregate is billed by weight.
How deep should gravel be for a driveway?
Four inches of surface stone over a four to six inch compacted base. Under three inches the gravel ruts and scatters under vehicle weight, and a surface course laid straight on soil will disappear into it.
How much gravel do I need for a 40x10 driveway?
About 7.3 tons of #57 crushed stone at 4 inches deep, including a 5% allowance. That is 400 square feet, which works out to 4.94 cubic yards before waste and 5.19 after.
Does gravel need to be compacted?
Base material does — crusher run loses up to 20% of its loose volume when tamped, so you must order extra to reach the finished depth. Clean washed stone used for drainage is not compacted at all.
What is the difference between crusher run and #57 stone?
Crusher run contains fines that pack between the stones, so it compacts into a solid base. #57 is washed to remove fines, so it drains freely and stays loose — which makes it a surface or drainage stone.
Is gravel sold by the ton or the yard?
By the ton, almost everywhere. Cubic yards are useful for checking whether a delivery will fit on site, but the invoice is by weight, which is why density matters to the order.
Sources and review
Last reviewed .