ARAI vs WLTP vs EPA: why one car has three mileage numbers
A car's mileage is not a single number. India quotes an ARAI figure in km/l, Europe quotes a WLTP figure in l/100 km, and the US quotes an EPA figure in miles per gallon. They come from different laboratory tests and use different units, so one car can have three that look unrelated.
Last updated 4 November 2026.
In short: the test decides the number first and the unit second. Convert units freely, but only compare figures that came from the same test. A tool for the unit part is the fuel economy converter.
The three standards
| Standard | Where | Test | Usual unit |
|---|---|---|---|
| ARAI | India | Run by the Automotive Research Association of India as part of certification. The Modified Indian Driving Cycle is described as equivalent to the European NEDC. | km/l |
| WLTP | Europe (and many other markets) | The Worldwide Harmonised Light Vehicles Test Procedure: a 1,800-second laboratory cycle of about 23.25 km at an average of 46.5 km/h, with four speed phases up to motorway speed. It replaced NEDC, which ran about 1,180 seconds and 11 km at roughly 34 km/h. | l/100 km |
| EPA | United States | The Environmental Protection Agency's label figures. The combined number weights the city result 55% and the highway result 45%. | mpg (US gallons) |
Why the same car gets different numbers
- Different cycles: each test sets a different speed profile, acceleration and duration. A slow, gentle cycle flatters a car; a faster, more dynamic one asks more of the engine. That is why WLTP figures tend to be higher than NEDC-style ones for the same car.
- Different cars: the "same" model is often a different car in each market, with other engines, gearboxes, tyres and weight. Our Honda Civic example below shows this clearly.
- Different units: mpg counts distance per fuel, l/100 km counts fuel per distance, and a US gallon is smaller than a UK one. The same economy can look like two or three different numbers.
- Real life: none of the tests include your traffic, your load or your weather. All three are best read as a way to rank cars against each other, not a promise.
How to convert
Work through l/100 km. km/l = 100 ÷ l/100 km, mpg US = 235.215 ÷ l/100 km and mpg UK = 282.481 ÷ l/100 km. Going the other way, divide the same constants by the mpg figure. Remember that a lower l/100 km is better but a higher km/l or mpg is better.
| l/100 km | km/l | mpg US | mpg UK |
|---|---|---|---|
| 3.5 | 28.6 | 67 | 81 |
| 4 | 25 | 59 | 71 |
| 5 | 20 | 47 | 56 |
| 6 | 16.7 | 39 | 47 |
| 7 | 14.3 | 34 | 40 |
| 8 | 12.5 | 29 | 35 |
| 10 | 10 | 24 | 28 |
| 12 | 8.3 | 20 | 24 |
For any other figure use the fuel economy converter, or the ready-made pages such as 30 mpg to l/100 km.
A worked example: the Honda Civic
The Honda Civic is in our database with a European WLTP figure and US EPA figures (model years 2025–2026). Converted to the same units:
| Standard | Version in our data | Quoted | l/100 km | km/l | mpg US | mpg UK |
|---|---|---|---|---|---|---|
| WLTP (European data, 2025 registrations) | 2.0 litre petrol, 141 hp (105 kW) | 5.2 l/100 km | 5.2 | 19.2 | 45 | 54 |
| EPA (US data, 2.0 litre petrol) | 2.0 litre 4-cylinder, regular fuel | 34–36 mpg | 6.5–6.9 | 14.5–15.3 | 34–36 | 41–43 |
| EPA (US data, hybrid) | hybrid, regular fuel | 48–49 mpg | 4.8–4.9 | 20.4–20.8 | 48–49 | 58–59 |
Do not read this as "WLTP says more than EPA" or the reverse. The rows are different versions: the European entry is the 2.0-litre engine registered in Europe in 2025, and the US entries are the 2.0-litre petrol and the hybrid sold there. Our data does not say the powertrains are identical, and the tests differ as well. That is the point of the guide: two honest numbers for "the same car" that cannot be compared directly.
Our data has no ARAI-labelled figure for any model, so there is no ARAI row. For India models we hold manufacturer figures in the spec sheets without a recorded test standard, and the India mileage list says so on the page.
Where to use this on CarSpecHub
- Best mileage cars in India, ranked in km/l with petrol, diesel and hybrid sections.
- Most fuel-efficient cars in South Africa, ranked in l/100 km.
- Most fuel-efficient cars, SUVs and trucks.
Every row on those lists shows which source its figure comes from, so you can see which standard you are looking at.
Sources
- Worldwide Harmonised Light Vehicles Test Procedure (WLTP): cycle duration, distance and speeds, with the NEDC comparison.
- EPA: text version of the gasoline label: the combined figure and its city/highway weighting.
- ARAI, AIS 040: describes the urban and extra-urban cycle parts used in Indian type-approval testing.
- Civic figures: European Environment Agency 2025 provisional data and FuelEconomy.gov, as in our database.
Frequently asked questions
Is ARAI mileage the real mileage?
No. ARAI figures come from a laboratory test run for certification, on a fixed cycle, so they describe a car in controlled conditions rather than your commute. Real-world mileage depends on traffic, load, air conditioning, tyres and driving style, and is usually worse than any test figure.
Is WLTP economy higher or lower than NEDC?
For the same car, WLTP usually gives a higher consumption figure (a worse l/100 km) than the older NEDC, because the WLTP cycle is longer, faster and more dynamic: 1,800 seconds and about 23.25 km at an average of 46.5 km/h, against about 1,180 seconds and 11 km at roughly 34 km/h for NEDC. India's ARAI test cycle is described as equivalent to NEDC, so the same direction of difference is plausible, but we have no model on this site with both an ARAI and a WLTP figure to show it.
How many mpg is 20 km/l?
20 km/l is 5 l/100 km, which is 47 mpg in US gallons or 56.5 mpg in UK gallons.
Why does the US use mpg and Europe l/100 km?
They measure opposite things. Miles per gallon is distance per unit of fuel, so a bigger number is better. Litres per 100 km is fuel per unit of distance, so a smaller number is better. The US also uses a smaller gallon (3.785 litres) than the UK (4.546 litres), so the same car has a different mpg figure in each.
Which of the three should I trust when comparing cars?
Compare cars only within one standard. A car's ARAI figure against another car's ARAI figure is meaningful; its ARAI figure against a WLTP or EPA figure is not. Our economy lists keep one source per model for that reason and show the source on every row.