Asphalt Calculator
Estimate asphalt volume and tonnes from paved dimensions and a chosen compacted density.
How the result changes
Only paved length changes; all other inputs stay at your current values. The line illustrates the formula across the shown range. This is not a forecast of real-world outcomes.
About this calculation
An asphalt order starts with the compacted space the finished layer must occupy. This calculator connects the paved footprint, layer depth, and chosen mixture density so that a square-metre measurement becomes a volume and estimated mass. Calculate asphalt when building or resurfacing a driveway.
Formula
volume = length × width × compacted depth; tonnes = volume × density ÷ 1,000
Worked example
With Paved length: 20 m, Paved width: 3 m, Compacted depth: 5 cm, Compacted density: 2400 kg/m³, compacted volume is 3 m³.
Inputs and units
Enter the finished paved length and width in metres, then the planned compacted depth in centimetres. Density is a bulk property of the particular asphalt mix after compaction; request the value used by the plant or contractor when accuracy matters.
- Paved length (m): Measure the run of the finished asphalt surface, rather than the excavation footprint.
- Paved width (m): Include the full width to be paved, including any shoulder specified in the plan.
- Compacted depth (cm): Use the compacted layer thickness; loose placement thickness is a different quantity.
- Compacted density (kg/m³): Use a supplier or mix-design density; 2,400 is only an illustrative starting value.
Calculation and worked example
Multiplying length by width gives paved area. Convert centimetres of depth to metres by dividing by 100, multiply by area for cubic metres, then multiply by kilograms per cubic metre and divide by 1,000 for metric tonnes In compact notation, volume = length × width × compacted depth; tonnes = volume × density ÷ 1,000.
A 20 m by 3 m driveway at 5 cm compacted depth occupies 20 × 3 × 0.05 = 3 m³. At an assumed 2,400 kg/m³, that is 7,200 kg, or 7.2 metric tonnes before any purchasing allowance.
How to use the answer
The volume describes the compacted layer, while the mass is an estimate of material needed to fill it at the chosen density. If the plant quotes tonnes, compare that mass with its minimum load and delivery conditions; do not call the cubic-metre number tonnes.
Measure separate rectangular sections and add their masses when a driveway changes width. A thicker patch can be calculated separately from the standard section, which avoids pretending the entire area has the same depth.
Assumptions and checks
The formula assumes a level rectangular footprint and uniform finished thickness. It does not include a base course, excavation, irregular edges, waste, or a compaction factor for loose material; discuss those separately with the installer.
A common error is entering 5 centimetres as 5 metres, making the order one hundred times too large. Another is using the loose aggregate density for a compacted asphalt layer; the chosen density directly scales the tonnage.
As a check, one square metre at a 1 cm compacted depth is 0.01 m³. Multiply that benchmark by the paved square metres and by the actual number of centimetres before applying density.
Common questions
What does the compacted volume result represent?
It is the metric-tonne estimate for the finished asphalt layer at your entered dimensions and density, with one tonne equal to 1,000 kilograms.
What should I check before relying on this result?
Confirm the measured surface, compacted thickness, and mix density with the project specification. Ask the supplier how it handles edge losses and order rounding.
Inputs
- Paved length (m)
- Paved width (m)
- Compacted depth (cm)
- Compacted density (kg/m³)