MPG to km/L: converting to the unit most of Asia uses
What this conversion does
It converts US miles per gallon into kilometres per litre. Both are distance-per-volume units, so — unlike the L/100km conversions on this site — no reciprocal is involved: this is a straight multiplication, and both figures get better as they get bigger. km/L is the everyday economy unit in Japan, India, Brazil and much of Latin America.
Where the 0.4251 multiplier comes from
One US gallon is 3.785411784 litres and one mile is 1.609344 kilometres, so a car returning 1 MPG (US) travels 1.609344 km on 3.785411784 litres — which is 0.425144 km per litre. Multiply any US MPG figure by that and you have km/L. The same multiplier also connects MPG to L/100km, but there it appears in the denominator, which is why that conversion divides.
MPG (US) to km/L conversion table
US fuel economy figures with their kilometres-per-litre equivalent. Because this conversion is proportional, the gaps stay even: every extra 5 MPG is worth a steady 2.1 km/L.
| Miles per gallon (US) | Kilometres per litre |
|---|---|
| 10 mpg | 4.2514 km/L |
| 15 mpg | 6.3772 km/L |
| 20 mpg | 8.5029 km/L |
| 25 mpg | 10.6286 km/L |
| 30 mpg | 12.7543 km/L |
| 35 mpg | 14.8800 km/L |
| 40 mpg | 17.0057 km/L |
| 45 mpg | 19.1315 km/L |
| 50 mpg | 21.2572 km/L |
| 60 mpg | 25.5086 km/L |
Why km/L is common outside Europe
km/L keeps the "bigger is better" direction that drivers expect from a mileage figure while staying inside the metric system. Japan, India, Brazil and several other markets use it on window stickers and in owner manuals, so a car imported from those markets will quote km/L where an American listing quotes MPG. Because both units are distance-per-volume, a comparison is direct — no mental inversion needed.
Converting on the road
To go the other way, divide km/L by 0.4251, or roughly multiply by 2.35. A dashboard reading 15 km/L is about 35 MPG (US). If your car was imported and the trip computer is stuck in the wrong unit, this is the number you need to make sense of it.
Frequently asked questions
Is km/L the same as L/100km reversed?
Not quite — they are reciprocals of each other scaled by 100. km/L = 100 ÷ L/100km. So 8 L/100km is 12.5 km/L. Converting MPG to km/L directly, as this page does, avoids a two-step calculation and any rounding that creeps in along the way.
Which countries use km/L?
Japan, India, Brazil, Chile and several other Latin American and Asian markets quote fuel economy in kilometres per litre. It is also common in owner forums worldwide even where the official unit is different, because it reads intuitively as "distance per litre".
Why does 30 MPG become 12.75 km/L and not something rounder?
Because a US gallon is not a round number of litres and a mile is not a round number of kilometres. The exact multiplier is 1.609344 ÷ 3.785411784 = 0.4251437, so 30 MPG is 12.7543 km/L. The calculator keeps full precision and rounds only at display.
Does this work for diesel cars too?
Yes. The conversion is purely about units and says nothing about the fuel. Diesel contains more energy per litre, so a diesel car usually returns a better km/L figure than a petrol car of the same size, but the arithmetic between the units is identical.
What is a good km/L figure?
Around 20 km/L and above is excellent and typical of hybrids, 12–18 km/L covers most modern compact cars, 8–12 km/L is a larger petrol car or a small SUV, and below 8 km/L is a large or performance vehicle. Convert your own figure above to see where it lands on the MPG scale.