How the asphalt calculator works
Asphalt plants sell hot-mix by weight. Work out the compacted volume, then multiply by the density of the mix.
volume (cu ft) = length × width × (thickness in ÷ 12) × (1 + waste %)
tons = volume × density (lb per cu ft) ÷ 2,000
A typical compacted hot-mix weighs around 145 lb per cubic foot (about 2,320 kg/m³). Mixes vary with the stone and the amount of compaction, so treat this as a planning figure. A handy rule of thumb that follows from it: about 6 tons of asphalt per 1,000 sq ft for each inch of compacted thickness.
Worked example
A driveway 50 ft long and 12 ft wide covers 600 sq ft. At 3 inches compacted, that is 150 cu ft, or 157.5 cu ft with 5 percent extra (5.83 cubic yards). At 145 lb per cu ft it weighs 22,838 lb, which is 11.42 US tons. In metric the area is 55.7 m², the volume 4.46 m³ and the weight 10.36 tonnes.
Tons of asphalt per 1,000 sq ft
| Compacted thickness | Tons per 1,000 sq ft (no waste) |
|---|---|
| 1 in | 6.04 |
| 2 in | 12.08 |
| 3 in | 18.13 |
| 4 in | 24.17 |
Based on 145 lb per cu ft. Thickness always means compacted thickness. Loose asphalt from the paver is thicker and is rolled down to the finished depth.
Typical residential thickness
| Use | Typical compacted asphalt | Typical aggregate base |
|---|---|---|
| Walkway or light-use path | about 2 in | about 4 in |
| Car driveway | 2 to 3 in | 4 to 8 in |
| Driveway with occasional heavy vehicles | 3 to 4 in | 8 in or more |
These are common rules of thumb. Soft or wet soil needs a thicker base; ask your contractor what your site needs. The asphalt thickness guide goes into more detail, and the gravel calculator works out the base stone.
Why add extra?
Edges are rarely perfectly straight, the base is never perfectly flat, and some mix stays in the truck or is lost at the margins. A few percent covers this. Larger jobs with a well-graded base need less; small patch jobs need proportionally more.
Common estimating mistakes
- Using loose thickness. Quantities are based on the finished, compacted thickness.
- Forgetting the apron and flares. Add the area where the driveway widens at the street and any turnaround or parking pad.
- Mixing up tons. A US ton is 2,000 lb. A metric tonne is 1,000 kg, or about 1.1 US tons. The calculator shows tonnes when you switch to metric.
- Ignoring the base. The asphalt tonnage is only part of the job. Base stone, excavation and haul-away are often a large share of the cost.
Tips before you order or hire
- Compare quotes on the same basis: area, compacted thickness, base depth and tons.
- Drainage matters as much as thickness. Water standing on or under asphalt shortens its life, so the surface should shed water away from the house.
- Hot-mix needs warm weather. Many plants in cold regions shut down for winter, so late fall is a good time to plan a spring job.
- Check local rules for driveway permits, curb cuts and drainage before work starts.
Safety
Hot-mix arrives at high temperature and can cause serious burns. Keep children and pets away from the work area, and let professionals operate rollers and pavers. For small repairs with bagged cold patch, follow the bag directions.
Frequently asked questions
How many tons of asphalt do I need for a driveway?
Multiply length × width × compacted thickness in feet to get cubic feet, then multiply by about 145 lb and divide by 2,000. A 50 × 12 ft driveway at 3 inches needs about 11.42 tons with 5 percent extra.
How much does a cubic yard of asphalt weigh?
At 145 lb per cubic foot, a cubic yard of compacted asphalt weighs about 3,915 lb, or just under 2 US tons.
How many square feet does a ton of asphalt cover?
At 2 inches compacted and 145 lb per cubic foot, one ton covers about 83 sq ft. At 3 inches it covers about 55 sq ft.
Is this for hot-mix or cold patch?
Hot-mix asphalt bought by the ton. For bagged cold patch, follow the coverage on the bag.