Asphalt Calculator

Calculating how much asphalt you need

Asphalt is ordered by weight, but the area you want to cover is measured in length. The link between the two is volume. Multiply the width, length and depth of the finished layer, then convert that volume to weight with the density of compacted hot mix asphalt.

volume = width × length × depth

weight = volume × densityThe calculator uses 145 lb per cubic foot, which is about 2,323 kg per cubic metre.

cost = weight in tons × price per ton

Keep every dimension in the same unit before multiplying. Depth is usually quoted in inches or centimetres, so a 2 inch layer is 2 ÷ 12 of a foot. The calculator takes care of this: each field has its own unit menu, and you can mix feet, yards, inches, centimetres and metres.

Example (US units): a driveway 20 ft long and 10 ft wide, paved 2 inches deep. The volume is 20 × 10 × (2 ÷ 12) = 33.33 ft³, which is about 1.235 cubic yards. At 145 lb per cubic foot that is 4,833 lb, or 2.42 tons. With asphalt at $95 per ton the material costs 2.42 × 95 = $229.58.

Example (metric): a path 5 m long and 3 m wide with a 5 cm layer. The volume is 5 × 3 × 0.05 = 0.75 m³, which weighs about 0.75 × 2,323 = 1,742 kg, or 1.74 tonnes.

Tons, tonnes and the weight shown

Two different units both get called a ton, which is a common source of price mistakes. Choose the unit system that matches your supplier's price.

With US units the calculator reports short tons and pounds; with metric units it reports tonnes and kilograms. When the whole job weighs less than half a ton, it shows only pounds or kilograms, since a fraction of a ton is hard to read. The price you enter is per ton in the first case and per tonne in the second, and the cost is calculated from the unrounded weight.

Asphalt basics and common uses

Asphalt, often called blacktop, is a mixture of crushed stone, gravel and sand bound together with bitumen, a dark, sticky by-product of refining crude oil. The binder usually makes up only a small share of the mix by weight; the stone does most of the work of carrying loads.

For hot mix, the ingredients are heated at a plant, trucked to the site while still hot, spread and then compacted with rollers before the mix cools. Good results depend as much on the base beneath as on the asphalt itself: a firm, well-drained foundation of compacted gravel matters more than an extra half inch of surface. A gravel calculator can size that base layer, and the sand calculator helps with bedding material.

Typical rules of thumb are 2 to 3 inches of compacted asphalt for a residential driveway and a thicker build-up, often laid in two courses, for parking lots and roads that carry trucks. Local standards and the soil underneath decide the real specification, so confirm with a contractor or engineer.

• Roads, highways and runways
• Driveways and residential streets
• Parking lots, loading areas and bike paths
• Playgrounds, tennis courts and sports surfaces

Types of asphalt

• Hot mix asphalt (HMA): the standard for new surfaces, laid while hot. This is what the calculator models.
• Warm mix asphalt: made with additives that let it be mixed and laid at lower temperatures, which saves fuel and reduces fumes.
• Cold mix asphalt: can be used straight from the bag for pothole and patch repairs, but it is less durable.
• Porous (permeable) asphalt: an open-graded mix that lets water drain through to a stone bed below.
• Stone mastic asphalt: a stone-rich mix with extra binder, built for heavy traffic and resistance to rutting.
• Mastic asphalt: a poured, sand-rich mix used for waterproofing and for footways.

Densities differ a little from one mix to the next, so a supplier's own tons-per-yard figure may not match the standard value used here. Treat the result as a planning estimate and confirm quantities with your supplier. Concrete is a common alternative for the same surfaces; compare volumes with the concrete calculator.

Estimates only. Always check quantities and specifications with your supplier or contractor before ordering. See our disclaimer.