Asphalt Calculator
Enter your paving area dimensions and we work out the asphalt tonnage, volume (m³ and yd³), and total cost based on the standard hot-mix density.
Total cost
£487.62
- Area (m²)
- 40
- Volume with wastage (m³)
- 2.1
- Volume with wastage (yd³)
- 2.75
- Mass (metric tonnes)
- 4.88
- Mass (US short tons)
- 5.38
Volume = length × width × thickness. Mass = volume × 2,322 kg/m³ (Asphalt Institute MS-22 density for compacted hot-mix asphalt, equivalent to 145 lb/ft³). Cost = mass × price per tonne. Wastage is applied to volume before the mass and cost calculations.
How to use this calculator
Enter the length and width of the area you are paving in metres. Set the compacted thickness in millimetres — 40–60 mm is typical for a residential driveway, 75–100 mm for a car park, and 150 mm or more for a road base. Add a wastage allowance — 5% is the contractor default, raise it to 10% for irregular shapes or first-time DIY work. Price per tonne is the supplier’s delivered HMA rate; in the UK that is usually £80–£140, in the US roughly $80–$130.
How the calculation works
Volume in cubic metres = length × width × (thickness in mm ÷ 1000). The neat volume is multiplied by (1 + wastage%) to give the order quantity. Mass = volume × 2,322 kg/m³, the Asphalt Institute MS-22 density for compacted hot-mix asphalt (equivalent to 145 lb/ft³). One metric tonne = 1,000 kg; one US short ton = 907.185 kg. Cost = mass in tonnes × price per tonne.
Worked example
A 10 m × 4 m driveway laid 50 mm thick with 5% wastage at £100/tonne: area 40 m²; neat volume 40 × 0.050 = 2.0 m³; with wastage 2.0 × 1.05 = 2.1 m³ (≈ 2.75 yd³). Mass = 2.1 × 2,322 = 4,876 kg = 4.876 tonnes (≈ 5.38 US tons). Cost = 4.876 × £100 ≈ £487.62. Cross-check using the field rule of thumb "110 lb of HMA per square yard per inch of thickness": 40 m² ≈ 47.84 yd², 50 mm ≈ 1.97 in, so 47.84 × 1.97 × 110 ≈ 10,366 lb ≈ 4.70 tonnes — within rounding of the precise figure once wastage is removed.
Frequently asked questions
How thick should my asphalt driveway be?
For a residential driveway carrying cars and the occasional delivery van, 40–60 mm of compacted hot-mix on top of a well-prepared sub-base is the usual spec. Frequent heavy loads (vans, caravans, skips) push the recommended thickness toward 75 mm. A car park or commercial yard wants 75–100 mm, and an actual road base is 150 mm or more, often in two lifts. Going thinner than 40 mm risks cracking and rutting within a season.
What density does this calculator use for asphalt?
It uses 2,322 kg/m³, which is the standard Asphalt Institute MS-22 figure for compacted dense-graded hot-mix asphalt (equivalent to 145 lb/ft³). Open-graded and porous mixes are lighter (around 1,900–2,100 kg/m³). Mass quantities here are for compacted in-place asphalt, which is what your supplier quotes and what is paid for on a tonnage basis.
Should I order in tonnes or cubic metres?
Asphalt is almost always sold by mass (tonnes in the UK and Europe, US short tons in North America), because the supplier weighs the truck at the plant. Volume figures are useful for visualising the pour and ordering haulage, but the invoice will be in tonnes. The calculator shows both so you can sanity-check the order against your tape measure.
How much wastage should I allow?
5% is the contractor default for a clean rectangular driveway. Raise it to 7–10% for awkward shapes, sloping ground, or hand-laid work where some loss to wheelbarrows and edges is inevitable. Running short mid-pour means another delivery charge and a cold joint where the new asphalt meets the old, which is the most common point of failure in DIY paving — over-order by 5% rather than under-order by 0%.
How does the calculator convert between m³ and yd³?
1 yard = 0.9144 m exactly (NIST definition), so 1 yd³ = 0.9144³ ≈ 0.7646 m³, and 1 m³ ≈ 1.308 yd³. Both figures are shown so US and UK users can cross-check against quotes given in either unit.
Does the price include delivery and laying?
No — "price per tonne" is the supplier’s rate for the asphalt itself, delivered to site. Labour to lay and compact it is usually quoted separately, either by the square metre or as a fixed price for the job. Plant hire for a roller, edging restraints and any sub-base preparation are also extras. Use this calculator to size the asphalt order, then get a separate quote for the laying labour.