Quick Answer
1 mile per gallon (US) (mpg) = 0.425144 kilometers per liter (km/L), and 1 kilometer per liter = 2.3521 mpg (us). Kilometers per Liter is the larger unit, so the same physical amount needs a bigger number when measured in mpg (us). Convert either way with the live tool below or the dedicated converter pages.
Key Facts
- 1 mile per gallon (US) (mpg) = 0.425144 km/L
- 1 kilometer per liter (km/L) = 2.3521 mpg
- Conversion is exact multiplication - no rounding in the factor
- Table below covers common values in both directions
- Dedicated converters: mpg→km/L and km/L→mpg pages with live tools
Frequently Asked Questions
Which is bigger, a mile per gallon (US) or a kilometer per liter?
One mile per gallon (US) equals 0.425144 km/L, and one kilometer per liter equals 2.3521 mpg. The unit with the larger factor is the physically bigger one.
How do I convert mpg (us) to kilometers per liter?
Multiply by the factor: value in km/L = value in mpg × 0.425144. Example: 5 mpg = 2.1257 km/L. Reverse: divide by 0.425144 (or multiply by 2.3521).
Why are mpg (us) and kilometers per liter different?
They are two different units measuring the same physical quantity. A mile per gallon (US) is defined as exactly 0.425144 km/L, and a kilometer per liter as exactly 2.3521 mpg. Because the units differ in size, the number you write down for the same amount depends on which unit you use - the conversion factor itself is exact, with no rounding.
Is there a quick way to convert without a calculator?
Memorize the 1-to factor: 1 mile per gallon (US) ≈ 0.425144 km/L. Then multiply. For 2 mpg that's ≈ 0.850287 km/L.