Asphalt Calculator
Work out how many tonnes of asphalt (tarmac or blacktop) you need for a driveway, path, car park or road patch. Enter the area and compacted thickness, and optionally a price per tonne to estimate the material cost.
Calculate asphalt
Asphalt tonnage formula
Tonnes
Tonnes = L × W × thickness (m) × density (t/m³) × (1 + waste%)Asphalt is sold by weight but laid by thickness, so the calculator converts the compacted volume into weight. Use the compacted (finished) thickness; the plant delivers loose material that the roller compacts by about 20–25%, which the density already accounts for.
Imperial version
US tons = L × W (ft) × thickness (in) ÷ 12 × 145 lb/ft³ ÷ 2,000A quick rule: one US ton of hot mix covers about 83 ft² at 2 in thick.
Asphalt thickness guide
| Use | Base / binder course | Surface course |
|---|---|---|
| Footpath | 40–60 mm | 20–25 mm |
| Residential driveway | 40–50 mm (1½–2 in) | 20–30 mm (1 in) |
| Light car park | 60 mm | 30 mm |
| Commercial / HGV areas | 100 mm+ | 40 mm |
All of these sit on a well-compacted granular sub-base, typically 150 mm (6 in) for driveways. Work the sub-base out with the Gravel Calculator.
Worked example: 12 m × 3.5 m driveway, 6 cm thick
- Volume = 12 × 3.5 × 0.06 = 2.52 m³
- Tonnes = 2.52 × 2.32 = 5.85 t
- +5% waste = 6.14 tonnes
Frequently asked questions
How many tonnes of asphalt do I need?
Multiply area × compacted thickness × 2.32 t/m³. A 40 m² driveway at 6 cm needs 40 × 0.06 × 2.32 = 5.6 tonnes before waste.
How much does a cubic metre of asphalt weigh?
Compacted hot mix asphalt weighs about 2.3–2.4 tonnes per cubic metre, or roughly 145 lb per cubic foot.
How much area does a ton of asphalt cover?
One US ton covers about 83 ft² at 2 in thick, or about 55 ft² at 3 in. One tonne covers about 7.2 m² at 6 cm.
Related calculators
Results are estimates. Mix density varies by product; confirm with your asphalt plant.