Bitumen Calculator
Enter the length, width and thickness, the mix density and the bitumen content to get the bitumen, aggregate and total asphalt mix in tonnes or US tons. It handles bitumen content by weight of total mix or by weight of aggregate, which change the answer by several percent, and shows each step of the calculation.
Cost estimate (optional)
Quantities
Bitumen
—
Aggregate
—
Total mix
—
Estimated cost
—
How it was calculated
| Step | Formula | Working |
|---|
An estimate for planning and ordering. The bitumen content, density and thickness for your job come from its mix design and specification, and actual plant quantities depend on compaction, the base and the laying method.
Runs in your browser. Nothing uploaded.
How to use the bitumen calculator
- Enter the area and thickness. Length, width and compacted thickness, each with its own unit.
- Enter the mix. Compacted density, bitumen content and its basis, and a wastage allowance.
- Add prices under Cost estimate if you want one: a single price per tonne of mix, or bitumen and aggregate priced separately.
- Read the quantities. Bitumen, aggregate and total mix, with the formula and working for each step underneath.
How to calculate bitumen quantity for a road
- Volume = length × width × compacted thickness
- Mix weight = volume × compacted mix density
- Mix with wastage = mix weight × (1 + wastage ÷ 100)
- Bitumen = mix with wastage × bitumen content ÷ 100
- Aggregate = mix with wastage − bitumen
Everything is converted to metres and kilograms first, so the units you type in don’t have to match.
Worked example
The calculator opens with this example. A road 100 m long and 7.5 m wide gets a 50 mm course of mix at 2,350 kg/m³, with 5.5% bitumen by weight of mix and 5% wastage.
- Volume: 100 × 7.5 × 0.05 = 37.5 m³
- Mix: 37.5 × 2,350 = 88,125 kg
- With 5% wastage: 88,125 × 1.05 = 92,531 kg, or 92.53 t
- Bitumen: 92,531 × 0.055 = 5,089 kg, or 5.09 t
- Aggregate: 92,531 − 5,089 = 87,442 kg, or 87.44 t
By weight of mix, or by weight of aggregate?
This is the setting most bitumen calculators leave out, and it changes the answer.
Bitumen content is normally stated by weight of total mix. IRC:105-2019 asks for the binder percentage “by weight of total mixture”, and the Asphalt Institute’s binder content is defined the same way. Some specifications and older mix designs state it by weight of aggregate instead, and then the same number means less bitumen:
- By weight of mix: bitumen share = P ÷ 100
- By weight of aggregate: bitumen share = P ÷ (100 + P)
Take a road 1 km long and 3.5 m wide at 50 mm, with no wastage. That’s 411,250 kg of mix. At 5.5% by weight of mix, it needs 22,619 kg of bitumen. At 5.5% by weight of aggregate, it needs 21,440 kg. The difference is 1,179 kg, because reading an aggregate-based figure as mix-based overstates bitumen by 5.5%. Check which basis your specification uses before you order.
Typical bitumen content
These are the minimum bitumen contents in IRC:105-2019, Table 3.8, by weight of total mix. They assume aggregate with a bulk specific gravity of 2.7. The actual content for a job comes from a Marshall mix design.
| Mix | Layer thickness | Max. aggregate size | VG grade bitumen | Polymer modified |
|---|---|---|---|---|
| DBM Grading 2 (base course) | 50–100 mm | 26.5 mm | 4.5% | – |
| BC Grading 1 (binder course) | 50–75 mm | 19 mm | 5.2% | 5.4% |
| BC Grading 2 (wearing course) | 40–50 mm | 13.2 mm | 5.4% | 5.6% |
Most dense paving mixes land somewhere between 3.5% and 7.5%. The calculator notes when your figure is outside that, and never stops you using it.
Asphalt mix density
Use the compacted density from your mix design. Dense hot mix is usually about 2,300 to 2,400 kg/m³. Loose mix in a truck weighs less per cubic metre, so a loose figure applied to a compacted layer underestimates the tonnage.
| kg/m³ | t/m³ | lb/ft³ |
|---|---|---|
| 2,300 | 2.30 | 143.58 |
| 2,350 | 2.35 | 146.71 |
| 2,400 | 2.40 | 149.83 |
If a density is outside 2,200 to 2,450 kg/m³, the calculator asks you to check it. If it is far outside anything realistic, as when you type 2350 but leave the unit on t/m³, it stops and tells you which unit it read.
Units
- Length: metres, kilometres, feet or yards. Width: metres, feet or yards.
- Thickness: millimetres, centimetres or inches.
- Density: kg/m³, t/m³ or lb/ft³.
- Results: metric tonnes and kilograms, or US tons (2,000 lb) and pounds.
The factors are exact: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 lb = 0.45359237 kg, and 1 US ton = 907.18474 kg. Bitumen is also shown in litres, at an assumed density of 1,020 kg/m³, so a tonne is about 980 litres. Bitumen is sold by weight, so treat litres as a guide.
Wastage and cost
Wastage is added to the mix weight before it’s split, so bitumen and aggregate both include it. There’s no single standard figure. The default 5% is a planning allowance; use your own experience or contract figure, or set it to 0 to see the net quantity.
For cost, you can price the whole mix at one rate per tonne, which is how plant-supplied asphalt is usually bought. Or you can price bitumen and aggregate separately, which is closer to how a mixing plant’s own costs work. Prices follow the result units: per tonne in metric, per US ton in US units.
Prime coat and tack coat
This calculator is for bitumen in a mix. Prime and tack coats are sprayed, so their quantity is simply area × spray rate. The rate, in kg/m² or L/m², comes from your specification and depends on the surface and the binder.
What it doesn’t cover
- Roofing. Modified bitumen roofing is sold by the roll, not by density.
- Recycled asphalt (RAP) and the bitumen it already contains.
- Irregular areas. Split them into rectangles and add the results.
Frequently asked questions
How do you calculate bitumen quantity for a road?
Multiply length by width by compacted thickness to get the volume, multiply by the mix density to get the mix weight, add wastage, then multiply by the bitumen content. For a 100 m by 7.5 m road at 50 mm thick, that is 37.5 m³, and at 2,350 kg/m³ it is 88,125 kg of mix. With 5% wastage the mix is 92,531 kg, and at 5.5% bitumen that is 5,089 kg of bitumen and 87,442 kg of aggregate.
What bitumen content should I use?
The one in your mix design. As a guide, IRC:105-2019 sets minimum bitumen contents by weight of total mix of 4.5% for DBM Grading 2, 5.2% for BC Grading 1 and 5.4% for BC Grading 2 with VG grade bitumen, and 5.4% and 5.6% for the two BC gradings with polymer modified bitumen. Those are minimums; the actual figure comes from a Marshall mix design.
Is bitumen content by weight of mix or by weight of aggregate?
Usually by weight of total mix, which is how IRC:105-2019 and the Asphalt Institute state it, but some specifications use weight of aggregate. It matters: 5.5% by weight of aggregate is 5.213% of the mix, so using the wrong basis overstates bitumen by 5.5%. On a 1 km by 3.5 m road at 50 mm, that is 22,619 kg of bitumen instead of 21,440 kg, a difference of 1,179 kg. The calculator has a setting for each.
What density should I use for asphalt?
The compacted density from your mix design. Dense hot mix is usually about 2,300 to 2,400 kg/m³, which is 143.58 to 149.83 lb/ft³. Loose mix in a truck is lighter, so using a loose figure for a compacted layer underestimates the tonnage. The calculator warns you if the density is outside 2,200 to 2,450 kg/m³.
How much wastage should I allow?
There is no single standard figure. The default here is 5%, a planning allowance for handling losses, uneven base levels and compaction. Use your own site experience or your contract's allowance, and set it to 0 to see the net quantity.
How many litres is a tonne of bitumen?
About 980 litres at a density of 1,020 kg/m³, which is typical for paving grade bitumen. The calculator shows litres at that assumed density as a guide. Bitumen is sold and specified by weight, and its density varies with grade and temperature, so use your supplier's figure when litres matter.
Last updated: September 16, 2026