Asphalt Calculator

This is an estimate, not professional advice. Check your inputs and verify the result against your plans and local building code before you build or order. See terms and disclaimer.

How this calculator works

Enter your dimensions and the result updates instantly. A waste allowance is included so you order slightly over rather than running short mid-pour, and ready-mix is rounded up to the nearest quarter yard, which is how it is sold.

Worked example

A 40 ft × 25 ft driveway at 3 inches compacted, HMA at 145 lb/ft³, with a 10% waste allowance. Inputs: Length 40 ft, Width 25 ft, Compacted thickness 3 in, Mix density 145 lb/ft³, Waste allowance 10 %. Result: 19.94 tons.

Asphalt for common paving sizes

Calculated for 3 inches compacted HMA at 145 lb/ft³ with a 10% waste allowance. Tap a size to load it above.

Method & assumptions

Hot mix asphalt is bought by weight, in US tons. We work out the compacted volume of your pavement (area times the finished thickness in feet), multiply by the mix density to get pounds, then divide by 2,000 to convert to tons. Standard dense-graded hot mix asphalt (HMA) weighs about 145 lb/ft³ once compacted; stone matrix asphalt (SMA) is closer to 150, and cold mix around 140, so the density is adjustable.

Tonnage is based on the compacted volume on purpose: compaction removes air voids and reduces volume, but it does not change the weight of material you ordered. That is why we do not inflate the tonnage by the compaction factor. The factor is used for one thing only, the loose lay thickness: to finish at 3 inches compacted you spread roughly 3.8 inches of loose mix behind the paver screed, using a loose to compacted ratio of about 1.25 to 1.35 (Asphalt Institute MS-22). We round truck loads up, because a tandem dump hauls a fixed load of about 18 to 20 tons.

Add a waste allowance of 5 to 10 percent for grade variation, edge spillage and handling, and more for curves or irregular shapes. Match the thickness to the use: 2 inches is a typical overlay, 3 inches suits residential driveways, and 4 inches or more is common for parking lots and light traffic over a compacted aggregate base. For volume in cubic yards, see the related square footage and paver calculators when you are scoping the area first.

Pro tips and common mistakes

• Order by the ton, not the yard. Asphalt plants sell and bill hot mix by weight. Use the tons figure for your order and treat cubic yards as a sanity check on volume, not the quantity you ask for.
• Lay it thicker than the finished depth. Hot mix compacts down. To hit 3 inches finished you spread close to 3.8 inches loose behind the screed. The loose lay thickness output handles that for you so the crew sets the screed right.
• Confirm the density with your supplier. Mix designs vary from about 140 to 150 lb/ft³. A 5 lb/ft³ difference moves a driveway order by a few percent, so ask the plant for the unit weight of the specific mix you are buying.
• Compact while it is hot. Asphalt only reaches its density in a narrow temperature window. Have the roller ready before the truck arrives; mix that cools below roughly 175 to 185 °F will not compact to spec and will ravel early.
• Build the base first. Asphalt is only as good as what is under it. Pave over 4 to 8 inches of compacted aggregate base, not soft soil. A failing base telegraphs straight through the surface as ruts and cracks.
• Mind the minimum order. Many plants have a minimum load or charge a small-load fee. For a tiny patch, cold mix in bags can be cheaper than firing up a hot mix delivery, even though it is less durable.

Frequently asked questions

References

• Asphalt concrete (Wikipedia)
• Asphalt Institute: mix design (MS-22)
• FHWA: hot mix asphalt pavement (U.S. DOT)

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