Area times thickness times density, and only one of those is a fact
The tonnage arithmetic is trivial. Take the area in square feet, multiply by the compacted thickness in feet, and you have cubic feet. Multiply by the density in pounds per cubic foot and divide by 2,000 and you have tons. A 60 by 12 driveway at 3.5 inches total is 720 square feet times 0.2917 feet, or 210 cubic feet, and at 145 lb per cubic foot that is 15.2 tons before any allowance.
The density is the only part that is not arithmetic. Compacted hot mix asphalt is commonly taken somewhere near 145 to 150 lb per cubic foot, which works out to roughly 1.95 to 2.0 tons per cubic yard, but that is a range for dense-graded mixes and not a constant. Open-graded and porous mixes are lighter. Mixes with heavy aggregate are heavier. Because the tonnage scales directly with this number, a five percent error in density is a five percent error in what you order, so it is worth one phone call to the plant to get the figure for the specific mix.
Paving crews carry a shortcut version of the same relationship: at 145 lb per cubic foot, one square yard at one inch thick weighs about 109 lb, so roughly 110 lb per square yard per inch. It is a useful check on any quote. If someone quotes tonnage that is far off your square yards times inches times 110, one of you has the wrong thickness.
Compacted thickness, not the thickness that comes out of the paver
Asphalt is placed loose and rolled down. The lift leaves the screed noticeably thicker than it finishes, and the specified thickness is always the compacted one. This calculator takes compacted thickness, which is what you want, because the density figure is also the compacted density and the two go together. If you enter a loose thickness against a compacted density you will over-order.
Lifts also have practical thickness limits relative to the aggregate size in the mix — a coarse binder mix cannot be laid paper thin, and a fine surface mix laid too thick will not compact uniformly through its depth. Those limits come from the mix design and are worth asking about if your numbers are unusual in either direction.
Two courses, because one rarely does the job
| Layer | What it does | Notes |
|---|---|---|
| Compacted aggregate base | Carries the load and drains | Not asphalt, not in this tonnage, and the layer that decides whether the pavement survives |
| Binder or base course | Structural asphalt layer, coarser mix | Usually the thicker of the two asphalt lifts |
| Surface or wearing course | The finished, finer-textured top | Thinner, and what everything from tyres to snowplough blades acts on |
Enter the two asphalt lifts separately here and each is priced and reported on its own, because they are frequently different mixes at different prices and the plant will quote them separately. Set the binder to zero if you are laying a single-lift overlay over sound existing pavement.
Where the tonnage stops being the question
Asphalt fails from the bottom up far more often than from the top down. A pavement over a soft or poorly drained subgrade cracks and ruts regardless of how many tons went on it, and adding thickness to compensate for a bad base is the most expensive way to buy a short-lived driveway. If the existing surface is alligator-cracked across large areas, that is a base problem and an overlay will telegraph through it within a couple of seasons.
Thickness specifications, base depth, drainage, entrance geometry where a driveway meets a public road, and impervious-surface limits are all local decisions. Get them from your building department and, for anything touching a public road, the road authority. For the compacted stone under all of this, the gravel driveway calculator handles the aggregate quantity, and if the subgrade needs shaping first, the cut and fill calculator will tell you whether the dirt balances.
Questions people ask
How many tons of asphalt do I need per square foot?
At a compacted density near 145 lb per cubic foot, one square foot at one inch thick is about 12.1 lb, so 1,000 square feet at 2 inches is roughly 12.1 tons. The cleaner form of the same relationship is about 110 lb per square yard per inch, which is the version crews actually use. All of these scale directly with the density figure, so if your mix is lighter or heavier the whole answer shifts by the same proportion. Enter the density your plant gives you rather than accepting any default, including the one here.
How many tons is a cubic yard of asphalt?
Around 1.95 to 2.0 tons for typical dense-graded compacted hot mix, which comes from 145 to 150 lb per cubic foot times 27 cubic feet, divided by 2,000. That is why paving people treat a cubic yard and two tons as roughly interchangeable in conversation. Do not carry the approximation into an order of any size — a 2.5 percent difference on 40 tons is a ton of material, and open-graded or porous mixes sit meaningfully below the range entirely.
Should I get one thick lift or two thinner ones?
For anything structural, two lifts is the normal approach, and the reason is compaction rather than tradition. A binder or base course of coarser mix carries the load, and a finer surface course gives a tight, durable wearing surface. Each lift is compacted on its own, so you get uniform density through the full depth, which a single very thick lift does not reliably achieve. There are also practical minimum and maximum thicknesses tied to the aggregate size in each mix. What is right for your specific driveway is a question for the paving contractor and, where a specification applies, whoever wrote it.
Does the calculator include the gravel base?
No. It calculates asphalt tonnage only. The compacted aggregate base is a separate material bought by the ton or the cubic yard, and it is generally the layer that determines how long the pavement lasts. Skimping there and adding asphalt thickness instead is a poor trade. Work the base quantity out separately, on a subgrade that has been properly prepared and compacted, and treat the base and the asphalt as one design rather than two purchases.
Why is the waste allowance defaulted to 8 percent?
Because real thickness is never nominal. Subgrade and base surfaces have low spots that swallow mix, edges take more than the plan area suggests, the last of a load rarely places cleanly, and paving crews run slightly thick rather than risk running thin. Eight percent is a middle figure for a driveway on a decent base. On rough or irregular ground push it higher. On a machine-laid overlay over sound, uniform pavement you can pull it down. Running short mid-job is the outcome to avoid, because a partial load ordered late arrives cold and joints badly.