Quick answer: tons = length × width × depth (ft) × 145 ÷ 2,000. A 12 × 40 ft driveway at 3 inches compacted needs 120 ft³ ≈ 8.7 tons. Enter the compacted depth — loose mix shrinks about 20–25% under the roller.
Tonnage by area and depth
| Area | 2 in | 3 in | 4 in |
|---|---|---|---|
| 100 ft² | 1.2 tons | 1.8 | 2.4 |
| 200 ft² | 2.4 tons | 3.6 | 4.8 |
| 400 ft² | 4.8 tons | 7.3 | 9.7 |
| 480 ft² (12 × 40 ft) | 5.8 tons | 8.7 | 11.6 |
| 600 ft² | 7.3 tons | 10.9 | 14.5 |
| 1,000 ft² | 12.1 tons | 18.1 | 24.2 |
| 2,000 ft² | 24.2 tons | 36.3 | 48.3 |
The handy shortcut buried in that table: about 0.006 tons per square foot per inch of compacted depth. Multiply area × inches × 0.006 and you have your tonnage close enough for planning.
Layers: the part underneath matters more
| Application | Asphalt (compacted) | Aggregate base |
|---|---|---|
| Footpath / walkway | 1.5–2 in | 4 in |
| Residential driveway | 2–3 in | 4–8 in |
| Driveway (soft/clay soil) | 3 in | 8–12 in |
| Parking lot (cars) | 3 in | 6–8 in |
| Commercial / truck traffic | 4–6 in | 8–12 in |
| Overlay on sound asphalt | 1.5–2 in | Existing |
Almost every asphalt failure — alligator cracking, edge crumbling, potholes — begins in the base rather than the surface. A well-compacted aggregate base spreads load and drains water away from the subgrade; asphalt laid straight onto soft ground will crack no matter how thick you make it. Budget for the base first. The gravel volume calculator sizes that layer.
Common mistakes & pro tips
- Quoting loose depth instead of compacted. Hot mix loses 20–25% of its loose height under a roller. Always specify compacted thickness.
- Skimping on the base. Two extra inches of aggregate costs far less than resurfacing in three years.
- Paving in the cold. Hot mix needs to be laid and compacted while hot. Most contractors will not pave below about 50 °F because the mix stiffens before it is rolled.
- Forgetting the edges. Unsupported asphalt edges crumble. Either taper them or back them with compacted material.
- Pro tip — order slightly over. Asphalt cannot be delivered in small top-ups; a truck comes or it does not. Running 5% long is cheaper than a second delivery.
- Pro tip — check the density basis. Hot mix runs 140–150 lb/ft³ depending on the mix design. This calculator uses 145; ask your supplier for their figure on large jobs.
Frequently asked questions
How do I calculate asphalt tonnage?
Multiply length × width × compacted depth in feet for cubic feet, then multiply by 145 lb per cubic foot and divide by 2,000. A 12 × 40 ft driveway at 3 inches compacted is 120 ft³ × 145 = 17,400 lb, or about 8.7 tons of hot mix.
How many tons of asphalt per square foot?
Roughly 0.006 tons per square foot per inch of compacted depth. So a 2-inch layer is about 0.012 tons per square foot, and 3 inches about 0.018. For a 500 square foot driveway at 3 inches that is around 9 tons.
How thick should an asphalt driveway be?
For residential driveways, 2 to 3 inches of compacted asphalt over a 4 to 8 inch compacted aggregate base. Commercial and truck-bearing areas need 4 inches or more of asphalt on a deeper base. The base matters as much as the asphalt — most driveway failures start underneath.
How much does a ton of asphalt cover?
About 80 square feet at 2 inches compacted, or roughly 55 square feet at 3 inches. A ton of hot mix is around 13.8 cubic feet at 145 lb per cubic foot, so coverage falls as depth rises in the usual way.
Does asphalt shrink when compacted?
Yes, substantially. Loose hot mix compacts roughly 20 to 25 percent under a roller, so a 4-inch loose lift finishes near 3 inches. Order tonnage against the compacted depth you want — reputable suppliers quote on compacted figures, but confirm which basis a quote uses.