Gravel Driveway Calculator
Enter the length and width of the driveway and the depth of each layer of stone. You get the cubic yards and the tons of base, middle and surface stone, ready to read out to the quarry as three lines.
How much gravel do I need for a driveway?
Multiply length by width by the depth of each layer in feet, add 20 % for compaction, divide by 27 for cubic yards, then multiply each layer by the density of its stone for tons. A 12 ft x 50 ft driveway with 4 in of base, 3 in of middle stone and 2 in of surface stone takes 20 cubic yards, or about 28 tons.
Gravel for your driveway
600 sq ft in 3 layers, 9 in in total: 20 cu yd, about 28 tons of stone.
- Base layer
- 8.89 cu yd12 tons at 1.35 t per cu yd
- Middle layer
- 6.67 cu yd9.33 tons at 1.4 t per cu yd
- Surface layer
- 4.44 cu yd6.67 tons at 1.5 t per cu yd
- Total weight
- 28 tonswith 20 % for compaction
The numbers above are the worked example for a 12 ft x 50 ft driveway in three layers of 4, 3 and 2 in with a compaction allowance. Allow this page to run scripts in your browser to use your own dimensions, or follow the formula further down the page and do it by hand.
How the gravel driveway calculator works, step by step
A gravel driveway is not one deep layer of one stone. It is a coarse base that carries the load, an intermediate stone that locks into it, and a dense surface that the tires actually touch. Each layer is a different product with a different weight per cubic yard, so the calculator works each one out on its own and then adds them up. The general gravel calculator does one layer at a time; this page does the whole driveway at once.
total = base + middle + surface
Worked example: a 12 ft x 50 ft driveway in three layers
- Area: 12 x 50 = 600 sq ft
- Base, 4 in: 600 x 4 / 12 x 1.2 = 240 cu ft = 8.89 cu yd, x 1.35 = 12 tons
- Middle, 3 in: 600 x 3 / 12 x 1.2 = 180 cu ft = 6.67 cu yd, x 1.40 = 9.33 tons
- Surface, 2 in: 600 x 2 / 12 x 1.2 = 120 cu ft = 4.44 cu yd, x 1.50 = 6.67 tons
- Total: 20 cu yd and 28 tons
A quick check: 9 in of stone is 0.75 ft, 600 x 0.75 = 450 cu ft, times 1.2 is 540 cu ft, and 540 / 27 is 20 cubic yards. The full derivation, with where each density comes from, is in how much gravel for a driveway.
Gravel for common driveway sizes
The two presets in the calculator are the sizes people ask about most. A 12 ft wide, 50 ft long driveway at 4 in of surface stone is a top-up or a light build on firm ground. A 12 ft x 100 ft driveway at 6 in, split into 4 in of base and 2 in of surface, is a typical new build on reasonable soil.
| Driveway | Layers | Cubic yards | Tons |
|---|---|---|---|
| 12 x 50 ft | 4 in surface stone at 1.5 t | 8.89 | 13.33 |
| 12 x 50 ft | 4 in base, 3 in middle, 2 in surface | 20 | 28 |
| 12 x 100 ft | 4 in base, 2 in surface | 26.67 | 37.33 |
To scale any of these, remember that every 100 ft of a 12 ft wide driveway is 1,200 sq ft, and every inch of compacted stone over that area is 4.44 cu yd once the 20 % allowance is in.
| Compacted depth | Cubic yards | Tons |
|---|---|---|
| 2 in | 8.89 | 12.44 |
| 3 in | 13.33 | 18.67 |
| 4 in | 17.78 | 24.89 |
| 6 in | 26.67 | 37.33 |
| 8 in | 35.56 | 49.78 |
| 12 in | 53.33 | 74.67 |
What goes in each layer
Base
The base is the structure. It is the largest stone in the build, often a No. 3 or No. 2 clean stone, and its job is to spread the weight of a vehicle over soft ground. On firm, well-drained soil 4 in is enough. On clay, fill or anywhere that stays wet, the base gets thicker, and a woven geotextile between the soil and the stone stops the two from mixing and the base from sinking out of sight in the first wet spring.
Middle
The intermediate layer is a mid-size stone such as No. 57. It fills the voids at the top of the base so the surface stone has something to lock into instead of falling between the large stones. On a short or lightly used driveway it is often left out, and the base goes straight under the surface stone, which is what the 12 x 100 ft preset does.
Surface
The top layer is a dense-graded aggregate such as crusher run, which carries stone dust with it. The fines fill the gaps and the layer compacts into a hard, drivable crust. It is the heaviest stone per cubic yard of the three, which is why the default density is higher, and the layer that needs topping up every few years as traffic pushes it to the edges.
The densities in the calculator, 1.35, 1.4 and 1.5 tons per cubic yard, are planning values. Every quarry measures its own stone and prints the figure on the product sheet or the scale ticket. Ask for it and type it into the density fields: a 0.1 change on a 20 cu yd order moves the weight by 2 tons.
Compaction: why the calculator adds 20 %
Stone arrives loose and is rolled or plate-compacted into place, and it loses volume as it locks together. If you order exactly the finished volume, you will run short on the last stretch of the driveway. The 20 % allowance is a planning figure for clean and dense-graded stone. Some road specifications place loose stone at a third more than the finished depth, so on a driveway where every inch of compacted thickness matters, order towards the high end and keep the surplus for the first top-up.
Untick the compaction box when you are pricing a layer that will not be compacted, such as decorative surface stone raked over a finished base.
From tons to truckloads
Quarries sell by weight and deliver by the truckload. A tandem dump truck typically carries 10 to 15 tons, so the 28 tons of the three-layer example is two loads, and the 37 tons of the 12 x 100 ft preset is three. Order each layer as its own line, and have the base delivered first: it has to be spread and compacted before the next stone goes on top. A truck can only dump where it can reach without sinking, so plan the drop points before the first load arrives.
Cases the simple formula does not cover
Curves, turnarounds and parking pads
Split the driveway into rectangles, work out each one separately and add the results. A curved driveway can be measured along its centerline for the length, which is close enough for ordering stone. A turnaround or a parking pad is just another rectangle at the same layer depths.
A crown and a ditch
A driveway that sheds water has a crown, higher in the middle than at the edges. The crown adds very little stone, but it is shaped in the surface layer, so a crowned driveway needs the full surface depth along the edges, not just in the middle.
Resurfacing an existing driveway
If the base is sound and you are only restoring the top, set the base and middle depths to 0 and enter 2 to 3 in of surface stone. Measure the thinnest areas first: the stone you need is the missing depth, not a full new layer.
Frequently asked questions
How much gravel do I need for a 12 x 50 driveway?
In three layers of 4, 3 and 2 in with a 20 % compaction allowance, 20 cubic yards, or about 28 tons. As a single 4 in layer of surface stone, 8.89 cubic yards, or about 13.3 tons at 1.5 tons per cubic yard.
How many tons of gravel for a 100 foot driveway?
A 12 ft x 100 ft driveway at 6 in, built as 4 in of base and 2 in of surface stone, takes 26.67 cubic yards, or about 37.3 tons. Each inch of compacted stone over that driveway adds 4.44 cubic yards, which is about 6.2 tons at 1.4 tons per cubic yard.
How deep should a gravel driveway be?
A new driveway is commonly built 6 to 9 in deep in two or three layers, with 4 in of base on firm ground and more on clay or wet soil. The surface layer itself is 2 to 4 in. Soft or frost-prone ground calls for a thicker base and a geotextile under it.
How many cubic yards are in a ton of gravel?
At 1.4 tons per cubic yard, one ton is about 0.71 cubic yards, or 19.3 cubic feet. Heavier, dense-graded stone at 1.5 tons per cubic yard gives 0.67 cubic yards per ton. The density of your stone decides the conversion, so ask the quarry for its figure.
Do I need landscape fabric under a gravel driveway?
A woven geotextile between the soil and the base is worth it on clay, fill or wet ground, because it stops the base from mixing into the soil. On firm, well-drained ground many driveways are built without it. Use a woven driveway fabric, not the thin non-woven sheet sold for flower beds.
Source
The volume arithmetic on this page is the definition of a cubic foot and a cubic yard, so there is no coverage rate to go out of date. The three densities are planning values for stone as delivered, not published constants: bulk density is a property of each quarry's rock, measured by the supplier, and the fields are editable so you can enter the figure on your quote. The sources behind the planning values and the compaction range are set out in the three-layer driveway example.