Asphalt Calculator

Estimate the tonnage of asphalt for a driveway or path.

Asphalt needed

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Volume

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With 10% extra

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Area

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Depth

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Use the compacted depth and your supplier’s mix density. Order a little extra for compaction and waste.

From area to tonnage

Asphalt is sold by weight, but jobs are measured by area and depth. Bridging the two takes one extra step: turn the area and depth into a volume, then multiply by the mix density.

weight = area × depth × density

Density is the figure that varies most, so use your supplier’s number for the specific mix. The calculator also adds a 10% allowance for compaction and waste.

Worked example

A 50 m² area laid 5 cm deep is 2.5 m³ of asphalt. At a typical compacted density of 2.4 t/m³, that is about 6 tonnes.

Ordering for a clean lay

Running short part-way through a pour leaves a cold joint, so it is better to over-order slightly than to stop. A solid, well-compacted sub-base matters as much as the asphalt itself, and the compacted depth is what governs durability.

On-site notes

Compacted depth. Order to the finished thickness, not loose.
Confirm density. Ask the supplier for the mix figure.
Add a margin. A 5–10% cushion avoids a short load.

Frequently asked questions

How is the tonnage worked out?

Area times depth gives the volume, and volume times density gives the weight. Asphalt is ordered by weight, so the density of the mix is the key conversion.

What density should I use?

Compacted hot-mix asphalt is often around 2.3–2.4 t/m³ (about 145 lb/ft³), but it varies with the mix. Ask your supplier for the figure for the product you are buying.

Should I order extra?

Yes — allow a margin for compaction, uneven sub-base and waste. A 5–10% cushion is sensible, and laying slightly thick is usually better than running short mid-job.

Is depth measured compacted or loose?

Use the finished, compacted depth. Loose asphalt compacts down noticeably, so ordering to the laid thickness already accounts for that with the compacted density.