Asphalt Calculator (Metric)
Enter your length and width in metres and depth in centimetres to get the cubic metres and tonnes of asphalt you need for a driveway or paved area.
What your result means
Order asphalt by the tonne, since that's how suppliers price it. The cubic metres are there for reference and for figuring base material. Whatever the tonnage reads, bump it up 5 to 10% on your order to cover what the roller compacts out.
How to use this calculator
- Measure the length and width of your driveway or paved area in metres.
- Decide on depth. Residential driveways typically use 5 cm; commercial uses 8 cm.
- Enter all three values above.
- Results show cubic metres and tonnes of asphalt needed.
- Order tonnes since asphalt suppliers price by weight.
The formula
Multiply length by width by depth (converting centimetres to metres) for cubic metres. Compacted hot-mix asphalt is about 2,323 kg per cubic metre, so multiply the volume by 2.323 for tonnes.
Worked example
Paving a 6 by 4 m area 8 cm deep gives 1.92 m³, about 4.46 tonnes of hot mix. Order roughly 4.8 tonnes to cover compaction.
Asphalt tonnage by driveway size (at 8 cm depth)
| Area | Depth | Approx. tonnes |
|---|---|---|
| 20 m² (1-car) | 5 cm | 2.3 |
| 40 m² (2-car) | 8 cm | 7.4 |
| 50 m² (long drive) | 8 cm | 9.3 |
| 75 m² | 8 cm | 13.9 |
| 100 m² | 8 cm | 18.6 |
Tips & gotchas
- Add 5 to 10% for compaction. Hot-mix squeezes down about 8% under the roller.
- The density used here is 2,323 kg per cubic metre, standard for compacted hot-mix asphalt.
- Cold patch is lighter and less dense, so save it for small repairs, not a full driveway.
- Get your quote per tonne, not per square metre.
- Lay it on a dry day above 10 °C or it won't bond and compact right.
Frequently asked questions
How many tonnes of asphalt do I need for a 100 m² driveway?
At 8 cm deep, around 18.6 tonnes. Run your exact dimensions through the calculator for a tighter number.
What thickness should my driveway be?
5 cm for cars, 8 cm for trucks or commercial traffic, always over a properly prepared base.
How much does asphalt cost?
Hot-mix material is commonly priced per tonne; installation labour adds a per-square-metre rate on top. Get local quotes.
Can I install asphalt myself?
Not really. Hot-mix has to stay above about 120 °C while you place it, which takes pro equipment.
What is the difference between asphalt and blacktop?
None. Blacktop is just the everyday name for asphalt pavement.
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