Asphalt Calculator
The volume and tonnage of asphalt for a driveway, path or car park from its area and compacted depth, with waste and cost.
Result…
How it's calculated
Volume = area × compacted depth Weight = volume × density × (1 + waste %) Imperial: tons = ft³ × lb/ft³ ÷ 2000 Cost = weight × price per tonne (or ton)
Works out how much asphalt (blacktop, tarmac or hot mix) to order for a driveway, path or car park from its area and compacted depth. The volume times the compacted density gives the weight, which is how plants sell it: tonnes in metric countries and US tons (2,000 lb) in the United States. The default density is the widely used estimating rule of 110 lb per square yard per inch of depth, which is 146.7 lb/ft³ or about 2.35 t/m³; real mixes vary, so use your supplier's figure when you have it. Add the base course and each layer separately if they differ.
Your numbers, step by step
About the Asphalt calculator
This asphalt calculator works out how much asphalt, also called blacktop, tarmac or hot mix, to order for a driveway, path or car park. Enter the length and width, or the area, and the compacted depth, and it multiplies them into a volume and then into a weight at the density you set. The default density is the common estimating rule of 110 lb per square yard per inch of depth, which Asphalt magazine's rules of thumb give as the typical spread rate. That is 146.7 lb/ft³, or about 2.35 t/m³. Real mixes vary, so replace it with your supplier's figure when you have one. Add a waste allowance and a price per tonne or per US ton for the cost. Results come in metric and imperial, with each step shown. For a concrete drive instead, use the concrete calculator.
How to use it
- Choose metric or imperial units, then enter the “Length” and “Width”, or switch “I know the” to “Area”.
- Enter the “Compacted depth”, the finished thickness after rolling.
- Check the “Asphalt density” against your supplier's mix, or keep the default estimating figure.
- Set the “Extra for waste” for edges and uneven ground.
- Add a “Price per tonne” or “Price per ton” for the cost, then read the tonnage, volume and spread rate.
Worked example
A drive 20 × 4 m is 80 m². At a compacted depth of 50 mm the volume is 80 × 0.05 = 4 m³, which at 2.35 t/m³ weighs 9.4 t. With 5% extra that is 9.4 × 1.05 = 9.87 t (about 10.88 US tons). At 100 per tonne the asphalt costs 987. The spread rate is 2.35 × 50 = 117.5 kg/m².
Updated
Questions people ask
How many tons of asphalt do I need for a driveway?
Multiply the area by the compacted depth to get the volume, then by the density. In imperial, square feet × depth in inches ÷ 12 gives cubic feet; multiply by about 146.7 lb/ft³ and divide by 2,000 for US tons.
How much does a cubic metre of asphalt weigh?
Compacted asphalt is roughly 2.35 tonnes per cubic metre by the common 110 lb per square yard per inch rule, but it depends on the mix and how well it is rolled. Your asphalt plant can give the density of the mix you are buying.
What is the 110 pounds per square yard per inch rule?
It is an estimating rule: each square yard of pavement 1 inch thick takes about 110 lb of asphalt. A 2 inch layer is about 220 lb per square yard, which is how the spread rate in this calculator is worked out.
Should I enter the loose or the compacted depth?
Enter the compacted depth, the finished thickness after rolling. Asphalt is spread thicker and rolled down, and tonnage worked from the finished depth at compacted density already allows for that.
How thick should an asphalt driveway be?
It depends on the ground, the base underneath and the traffic, and local practice differs. This calculator does not choose a thickness: ask your contractor or an engineer, then use their depth for each layer.