Driveway Calculator

Measure the driveway, pick the material, and the calculator works out the order. It shows the area, the net volume, the volume with waste, and the amount to order rounded up so you do not run short.

1. Enter the length and width of the driveway in feet.
2. Enter the depth in inches. 4 in suits cars, 5 to 6 in suits heavier vehicles.
3. Pick the material, concrete, asphalt, gravel or pavers.
4. Set the waste allowance. 10% is typical, and 5% suits a flat, even site.
5. Press Calculate, or press Enter. The amount to order appears first and large, with the area and the volume below.

The driveway formula is volume = length x width x depth, with the depth turned from inches into feet first. A 20 by 12 ft driveway at 4 in deep is 20 x 12 x (4 / 12) = 80 cubic feet. Divide by 27, because one cubic yard is 27 cubic feet, and the net volume is 80 / 27 = 2.96 cubic yards.

Then add the waste allowance. At 10%, the order volume is 2.96 x 1.10 = 3.26 cubic yards, and ready mix orders round up to the nearest half yard, so you order 3.5 cubic yards. Asphalt converts at 2.0 tons per cubic yard and gravel at 1.4 tons per cubic yard, each rounded up to the nearest half ton. Pavers skip the volume and count from the area at 4.5 pavers per square foot. Our concrete calculator prices slabs and footings the same way, and our asphalt calculator works out tons for any asphalt area.

A two car driveway is 20 ft long and 12 ft wide, 4 in deep, in concrete, with a 10% waste allowance. Here is exactly what the calculator does.

1. Area: 20 x 12 = 240 sq ft.
2. Volume: 240 x 4 / 12 = 80 cubic feet.
3. Cubic yards: 80 / 27 = 2.96 cu yd.
4. Waste: 2.96 x 1.10 = 3.26 cu yd to cover.
5. Order: 3.26 rounded up to the nearest half yard = 3.5 cu yd.
6. Bags: 88 cubic feet / 0.6 per 80 lb bag = 147 bags, if you mix by hand instead.

As a second check, a 20 by 10 ft single car driveway in asphalt at 3 in deep is 200 sq ft, 50 cubic feet, 1.85 cu yd, 2.04 cu yd with waste, and 4.5 tons to order. The same steps work for any size, so try your own numbers in the tool above.

Concrete is the most common driveway surface. It lasts 25 to 30 years, needs a 4 in slab for cars and 5 to 6 in for heavier vehicles, and costs about $130 to $180 per cubic yard for ready mix, before labor. A 24 by 24 ft driveway at 4 in needs 7.11 cu yd before waste, or 7.82 cu yd with a 10% allowance.

Asphalt costs less up front and goes down fast, but it needs sealing every few years and softens in heat. It runs about 2.0 tons per cubic yard. Gravel is the cheapest to lay and the easiest to repair, but it needs topping up and it migrates, so it suits rural drives and light use. It runs about 1.4 tons per cubic yard.

Pavers cost the most and last the longest, and a single damaged paver can be lifted and replaced without redoing the drive. At 4 by 8 in, they need 4.5 pavers per square foot, so a 10 by 10 ft area needs 495 pavers with a 10% allowance. The depth you enter sets the gravel base under them.

Always order more than the net volume. The ground is never perfectly flat, forms flex, spillage happens, and a short load mid pour means a cold joint, a weak seam where the new concrete meets concrete that already started to set. That is why the default waste allowance is 10%.

Use 5% only on a flat, well formed site with an even subgrade you have already checked. Use 10% for most driveways, and 15% for an uneven site, a curved edge, or a first time pour. Ready mix plants also set a minimum load, commonly 2 to 4 cubic yards, and charge a short load fee below it, so a very small driveway can cost more per yard than a big one.

For pavers the waste covers cutting at the edges and a few broken pieces. For gravel it covers compaction, because the base settles under the first rains and the first cars. Measure the site twice, and order the rounded up figure the calculator gives you.

The most common mistake is forgetting the depth conversion. Depth in inches must be divided by 12 before it multiplies the area. A 4 in slab is 0.333 ft, not 4 ft, and skipping that step gives a volume twelve times too big.

A second mistake is ordering the net volume with no waste. The pour always needs a little more than the math says, and running short mid pour costs far more than the extra half yard would have. Order the rounded up figure, and keep the waste allowance at 10% unless the site is truly flat.

A third mistake is pouring too thin for the traffic. A 4 in slab suits cars, but a driveway that carries a heavy truck, a boat or a camper needs 5 to 6 in, and a weak subgrade needs a thicker gravel base under it. Check the base, compact it, and confirm the thickness with your supplier before the truck arrives.