How to use the asphalt calculator
- Choose Metric or Imperial.
- Enter the area to pave. Use the square footage calculator first for irregular shapes.
- Enter the compacted thickness.
- Enter the density your supplier quotes, in kg/m³, to get the tonnage.
- Set a waste allowance.
How the calculation works
Volume = area × thickness × (1 + waste). If you enter a density, weight = volume × density. Metric tonnes = kg ÷ 1,000; US short tons = kg ÷ 907.18474 (one short ton is 2,000 lb).
Worked examples
Driveway. 50 m² at 50 mm: 2.5 m³; with 5% waste, 2.63 m³. With a supplier density entered, the calculator shows the tonnes to order.
US path. 500 ft² at 2 in: 83.3 ft³, about 3.09 yd³ before waste.
How to interpret the results
Plants sell hot mix by the tonne. Round up to the plant’s minimum order and confirm the delivery quantity with your contractor, who knows how their crew compacts the mix.
Tips and common mistakes
- Use the compacted thickness, not the loose thickness spread by the paver.
- Mix units carefully: 2 inches is 0.167 ft.
- Check the base before paving; asphalt won’t fix a soft base.
- Plan drainage with a fall away from buildings.
Planning the paving job
Asphalt is laid hot and has to be spread and compacted before it cools, so the order quantity matters more than with many materials: too little means a cold joint, too much means paying for waste. Measure the area carefully, split irregular driveways into rectangles and triangles, and confirm the finished thickness with your contractor. Ask the plant how they quote density and whether their tonnage includes any allowance. For small jobs, check the minimum load; a short load can cost almost as much as a full one.
Converting between units
One metric tonne is 1,000 kg and one US short ton is 2,000 lb, or 907.18 kg, so a quantity in short tons is about 10% larger than the same weight in tonnes. The calculator shows both so you can compare quotes from suppliers who use different units. Volumes convert exactly: one cubic yard is 0.7646 m³.
Related calculators
Use the square footage calculator to measure an irregular driveway, the volume calculator for the aggregate base layer below the asphalt, and the project materials list to keep the base, asphalt and edging together. If you are replacing an old surface, the cut and fill calculator helps you plan how much old material and soil will be removed.
Assumptions and limitations
The surface is treated as a single layer of even thickness. Multi-layer pavements need one calculation per layer.