Asphalt Driveway Calculator

Most home driveways are asphalt over a stone base: the soil is dug out and compacted, a crushed stone base is compacted on top, and hot mix is paved and rolled over it. Full-depth asphalt skips the stone and uses a thicker asphalt section instead. An overlay adds a new layer on an existing driveway that is still sound underneath.

These minimums from the Colorado Asphalt Pavement Association suit cars, light trucks, and the occasional delivery truck. Many contractors build thicker, and where the ground freezes deep or drains poorly, more base helps. Your ZIP in the planner adds a frost reminder.

The calculator does not guess a national price, because paving prices swing with oil prices, the season, and how far you are from a plant. Instead it builds the cost from your numbers: tons of hot mix times the price per ton, base stone by the yard, and an installed price per square foot from a local quote. All the defaults are examples for you to replace.

The useful part is the quote check. Type in the price you were quoted and it shows the price per square foot and per ton of asphalt, and how much of it is the asphalt itself. The rest is labor, equipment, dig-out, base work, trucking, and profit. When two quotes are far apart, check that both name the same compacted thickness and base depth.

Measure the length along the center and the width in a few places, and use the average. Add the apron at the street, any turnaround, and parking pads as extra areas, or trace the whole thing on the satellite map. Typical widths are about 10 to 12 ft for one car and 16 to 20 ft for two.

A new driveway over base means digging out the asphalt and base thickness: 7 inches for the common minimum, more on poor soil. Soil swells about 25 percent when it is dug, so the pile is bigger than the hole. On a 500 sq ft driveway that is roughly 13.5 cubic yards of loose dirt, which is a dumpster or a haul-away, not a few pickup loads. If you are paving over an old gravel driveway, much of the base may already be there; untick the dig-out to leave it out.

The Colorado Asphalt Pavement Association puts it plainly: there is no such thing as leftover asphalt. A crew at the door with a truck of “extra” hot mix and a cash price is a well-known scam. Get more than one written quote from contractors you can check, and make sure each one lists the dimensions, the compacted thickness of every layer, the materials, drainage, start and finish dates, and a written warranty.

Thickness is where quotes quietly differ. Going from 2 to 3 inches is 50 percent more asphalt, so two quotes for “a new driveway” can be for very different amounts of material. Put the quote total into the calculator and it shows the price per square foot and per ton, so you can compare them on the same terms.

• New asphalt can be driven on soon after it is placed, but it is best to wait a few days, and keep heavy trucks (like a moving truck) off a fresh driveway.
• Do not seal it until it is several months old, then seal every 2 to 5 years.
• The surface should slope at least 1/4 inch per foot so water runs off.
• Fix potholes and wide cracks early with cold patch. The asphalt calculator counts the bags.

• Accepting a quote that does not state the compacted thickness of the asphalt and the base.
• Paving over soft soil or topsoil instead of a compacted stone base.
• Building it flat. Without at least 1/4 inch per foot of slope, water sits and gets into the base.
• Forgetting the dig-out. Seven inches of soil from a two-car driveway fills a dumpster quickly.
• Hiring a door-to-door crew with leftover asphalt.