The asphalt tonnage formula
tons = length (ft) × width (ft) × thickness (in) ÷ 12 × 145 ÷ 2,000
Step by step for a 20 × 50 ft driveway at 3 inches compacted:
- Area: 20 × 50 = 1,000 square feet
- Volume: 1,000 × 3 ÷ 12 = 250 cubic feet (9.26 cubic yards)
- Weight: 250 × 145 = 36,250 lb
- Tons: 36,250 ÷ 2,000 = 18.1 tons
The 145 lb per cubic foot is a typical density for compacted hot mix asphalt. Mixes vary, roughly 140 to 150 lb per cubic foot, so ask the plant for the density of the mix you are buying.
The square yard shortcut
Paving contractors often work in square yards with a rule of thumb of about 110 lb per square yard per inch of compacted asphalt:
tons = square yards × thickness (in) × 110 ÷ 2,000
The same driveway is 1,000 ÷ 9 = 111.1 square yards. 111.1 × 3 × 110 ÷ 2,000 = 18.3 tons. The two methods land within about 1 percent of each other; the 110 rule is slightly more generous.
Cubic yards to tons of asphalt
One cubic yard of compacted asphalt at 145 lb per cubic foot weighs 27 × 145 = 3,915 lb, or about 1.96 tons. So:
| Cubic yards | Tons, about |
|---|---|
| 1 | 1.96 |
| 2 | 3.92 |
| 5 | 9.79 |
| 10 | 19.58 |
| 20 | 39.15 |
For other materials, use the cubic yards to tons converter.
Driveway tonnage chart
Tons of compacted asphalt, no waste added:
| Area | 2 in | 3 in | 4 in |
|---|---|---|---|
| 10 × 20 ft (200 sq ft) | 2.4 | 3.6 | 4.8 |
| 12 × 24 ft (288 sq ft) | 3.5 | 5.2 | 7.0 |
| 20 × 20 ft (400 sq ft) | 4.8 | 7.3 | 9.7 |
| 10 × 50 ft (500 sq ft) | 6.0 | 9.1 | 12.1 |
| 20 × 50 ft (1,000 sq ft) | 12.1 | 18.1 | 24.2 |
| 24 × 60 ft (1,440 sq ft) | 17.4 | 26.1 | 34.8 |
Compacted vs loose thickness
Hot asphalt is spread loose and then rolled down, so it is laid thicker than its finished thickness. A common rule of thumb is about 1¼ inches loose for every inch compacted. The calculator wants the compacted (finished) thickness, because the 145 lb per cubic foot figure is for compacted asphalt. Your paver sets the loose depth to hit it.
What goes under the asphalt
Asphalt sits on a compacted aggregate base, which is a separate layer and a separate order. Its thickness depends on soil and traffic; residential bases are commonly several inches of crushed stone. To work out the base in cubic yards and tons, use the cubic yard calculator with Gravel selected as the material, or the cubic yards to tons converter.
Patching and odd shapes
- Patches and potholes: measure the cut-out area and the depth after cleaning it out. Small jobs are often done with bagged cold patch, which lists its coverage on the bag.
- Curves and turnarounds: add a Circle section for a round turnaround, or a Triangle for a flared apron at the street.
- Several areas: add a section for each and the calculator totals the tons.
Ordering
Asphalt plants sell by the ton and many have a minimum. Order a little over the calculated figure (the calculator adds 5 percent by default) to cover uneven base and edges. Hot mix has to be placed while it is hot, so a short load cannot simply be topped up later the way bulk stone can.
Tonnage here is based on a typical compacted density of 145 lb per cubic foot. The plant's mix density and your contractor's specified thickness are the numbers to use for the final order.
Questions people ask
- How do I calculate tons of asphalt?
- Square feet × thickness in inches ÷ 12 × 145 ÷ 2,000. A 20 × 50 ft driveway at 3 inches: 1,000 × 3 ÷ 12 × 145 ÷ 2,000 = 18.1 tons.
- How many tons of asphalt are in a cubic yard?
- About 1.96 tons for compacted hot mix at 145 lb per cubic foot (145 × 27 = 3,915 lb). Many people round it to 2 tons per cubic yard.
- How do I convert square yards to tons of asphalt?
- Square yards × thickness in inches × 110 ÷ 2,000. The 110 is the common rule of thumb for pounds of compacted asphalt per square yard per inch.
- How thick should an asphalt driveway be?
- Residential driveways are commonly 2 to 3 inches of compacted asphalt over a compacted aggregate base. Heavier traffic and poor soil call for more. Your paving contractor will specify it for your site.
- Is asphalt sold by the ton or the yard?
- Hot mix plants usually sell asphalt by the ton, which is why the calculator shows tons and takes a price per ton.