Quick answer: asphalt is ordered by the ton, and a common rule of thumb is 110 pounds per square yard for every inch of compacted thickness. A 12 × 50 ft driveway paved 2 inches thick needs about 7.3 tons; at 3 inches thick it needs about 11 tons. The rule comes from the Asphalt Institute, published in Asphalt magazine, and local agencies use slightly different numbers, so ask your paving contractor for the figure they use.
You can run the numbers in the Asphalt Calculator. Below is the math, the thickness rules that determine whether a driveway layer will hold together, and examples for typical driveway sizes.
The tonnage formula
Area (yd²) = length (ft) × width (ft) ÷ 9
Tons = area (yd²) × thickness (in) × 110 ÷ 2,000
There is a shortcut in square feet. Because 110 ÷ 9 ÷ 2,000 is about 0.00611:
Tons ≈ area (ft²) × thickness (in) × 0.00611
So each 100 square feet of pavement needs about 0.61 tons per inch of compacted thickness.
Worked example: a 12 × 50 ft driveway
- Area: 12 × 50 = 600 ft², which is 600 ÷ 9 = 66.7 yd².
- At 2 inches thick: 66.7 × 2 × 110 = 14,667 lb, or 7.3 tons.
- At 3 inches thick: 66.7 × 3 × 110 = 22,000 lb, or 11.0 tons.
Tons for common driveway sizes
| Driveway size | Area (yd²) | 2 in thick | 3 in thick |
|---|---|---|---|
| 10 × 20 ft | 22.2 | 2.4 tons | 3.7 tons |
| 12 × 24 ft | 32.0 | 3.5 tons | 5.3 tons |
| 12 × 50 ft | 66.7 | 7.3 tons | 11.0 tons |
| 16 × 40 ft | 71.1 | 7.8 tons | 11.7 tons |
At 2.5 inches, a 16 × 40 ft driveway comes to 9.8 tons.
Why the 110 lb number is only a rule of thumb
The spread rate depends on the mix. Asphalt magazine notes that the Illinois Department of Transportation uses 112 pounds per square yard per inch, and the Tennessee DOT mostly uses 106 for dense-graded mixes. Open-graded mixes have more air voids and weigh less per inch, with TDOT using 88 and INDOT using 100 in practice. Some specialty mixes weigh more.
For a homeowner this means two things: your contractor’s estimate may differ from yours by a few percent, and you should ask which spread rate they use and whether their quote includes a waste allowance.
Lift thickness: why you can’t just pave 1 inch
Thickness isn’t only a cost decision. It affects whether the pavement can be compacted properly. The Asphalt Institute recommends that for dense-graded mixes a layer (called a lift) be at least four times the nominal maximum aggregate size (NMAS) of the mix. Finer mixes can use a minimum of three times the NMAS.
For a typical ½-inch NMAS mix, that gives a minimum lift of 2 inches, or about 1½ inches for a finer gradation. Asphalt magazine adds that very thick lifts can also compact well, but that is a contractor decision, not a DIY one. The takeaway: a 1-inch skim coat over a poorly prepared surface is a short-lived repair, not a new driveway.
Loose versus compacted thickness
The rule of thumb above assumes compacted thickness. Crews lay hot mix thicker than the finished layer because it compresses under rolling. Asphalt magazine says to set the paver’s screed height at about 1.25 times the final compacted thickness for typical mixes (about 15% more than final for open-graded mixes). That is why a contractor says “2 inches” and lays about 2½ inches loose. Your order tonnage is based on the compacted figure.
What the order doesn’t include
Asphalt is only the top of a driveway. Underneath it you need a prepared, compacted base of stone, and it must be drained and graded correctly. Calculate stone for the base separately with the Crushed Stone Calculator or the Paver Base Calculator, and read our guide on how much gravel you need for base depths.
Estimating your own driveway
- Measure the paved area. Break a curved or flared driveway into rectangles, triangles and half-circles. The Square Footage Calculator helps.
- Convert to square yards. Divide square feet by 9, or use the Square Yard Calculator.
- Choose a compacted thickness. Ask your contractor, who will base it on traffic, soil and the mix.
- Multiply by 110 lb per yd² per inch and divide by 2,000 for tons.
- Ask what allowance is included. Edges, aprons and uneven base all use more than the geometric volume.
- Compare quotes in the same unit. Per ton, per square foot and per job are not directly comparable until you convert them.
Common mistakes
- Mixing up loose and compacted thickness. Use the compacted depth for the formula.
- Forgetting the base. The asphalt tonnage says nothing about the stone you need beneath it.
- Choosing a thickness too thin for the mix. If the mix needs a 2-inch lift and you specify 1 inch, you get poor compaction and early failure.
- Treating the tonnage as exact. The mix, the surface and the crew all move the number.
Frequently asked questions
How many tons of asphalt for a 20 × 20 driveway?
400 ft² is 44.4 yd². At 2 inches thick that is 44.4 × 2 × 110 ÷ 2,000 = 4.9 tons; at 3 inches it is 7.3 tons.
How thick should an asphalt driveway be?
It depends on traffic, the base and the mix. The Asphalt Institute rule is that a lift should be at least four times the largest aggregate size in the mix, which for a ½-inch mix means about 2 inches. Your local contractor and building rules decide the final design.
How much does a cubic yard of asphalt weigh?
By the 110 lb per yd² per inch rule, one square yard 36 inches deep is 3,960 lb, so a cubic yard of compacted asphalt weighs roughly 2 tons.
How many square feet does a ton of asphalt cover?
At 2 inches thick, one ton covers about 82 square feet (2,000 ÷ 110 ÷ 2 yd² × 9). At 3 inches, about 54 square feet.
Is cold patch the same?
No. Cold patch is a bagged repair material, not hot-mix paving, and it isn’t sold or estimated this way.
Sources
- Danny Gierhart, P.E. and Jason Wielinski, P.E., >Five handy rules of thumb for successful asphalt pavement construction, Asphalt magazine (Asphalt Institute), 2023: 110 lb/yd²/in spread rate, state variations, lift thickness versus NMAS, screed height factor.
- NIST, >Guide to the SI, Appendix B.8: unit conversions.
These are planning estimates. Your paving contractor’s mix design and quoted tonnage take priority.