Asphalt Calculator
Estimate how much asphalt you need for a driveway, path or road from its length, width and thickness. The calculator works out the volume, then multiplies by the asphalt density to give the weight in kilograms and tonnes. Enter dimensions in metres and adjust the density to match your mix.
Formula
Volume = Length × Width × Depth; Weight = Volume × Density
- Volume is length × width × thickness, all in metres, giving cubic metres of asphalt.
- Weight is volume × density. Compacted hot-mix asphalt is typically around 2300 kg/m³, but adjust the density for your specific mix.
- Thickness is entered in metres — for example 0.05 m for a 5 cm layer. Convert centimetres to metres before entering.
- Order a little extra (about 5–10%) to allow for compaction, uneven sub-base and waste.
Example: 20 m × 4 m driveway, 5 cm thick
Inputs
- Length: 20 m
- Width: 4 m
- Thickness: 0.05 m
- Asphalt Density: 2300 kg/m³
A 20 m by 4 m area at 0.05 m thick is 4 m³ of asphalt. At 2300 kg/m³ that is 9,200 kg, or about 9.2 tonnes.
Frequently asked questions
How much asphalt do I need?
Multiply length × width × thickness for the volume in cubic metres, then multiply by the density (about 2300 kg/m³) to get the weight in kilograms and tonnes.
What density should I use?
Compacted hot-mix asphalt is usually around 2300 kg/m³. Use the figure your supplier gives for your specific mix if it differs.
How do I enter the thickness?
Enter it in metres. A 5 cm layer is 0.05 m, and a 75 mm layer is 0.075 m.
Should I order extra?
Yes — add roughly 5–10% to allow for compaction, an uneven base, edges and waste so you don't run short.
Does this account for compaction?
It estimates the compacted weight from the density you enter. Loose, uncompacted asphalt occupies more volume, so always rely on the tonnage rather than loose volume when ordering.
Related calculators
Concrete Driveway Calculator Concrete Driveway Calculator is a construction estimator that helps you calculate material quantities needed for a construction or renovation task. The formula used is: Volume = Length × Width × Thickness; Cement bags ≈ Volume × 320 / 50 (M20 mix). Accepts imperial (feet, inches) or metric (metres, cm) units as labelled on each input. Gravel Calculator Gravel Calculator is a construction estimator that helps you calculate gravel values from your input data. The formula used is: Volume = Length × Width × Depth; Weight = Volume × 1680 kg/m³. Accepts imperial (feet, inches) or metric (metres, cm) units as labelled on each input. Paving Calculator Paving Calculator is a construction estimator that helps you calculate paving values from your input data. The formula used is: Area = Length × Width; Pavers = ceil(Area / Paver Area × (1 + Wastage/100)). Accepts imperial (feet, inches) or metric (metres, cm) units as labelled on each input.