Convert Between Units of Frequency
Fuel efficiency describes how far a vehicle travels per unit of fuel, or how much fuel it uses per distance. Common units include miles per gallon (mpg), liters per 100 kilometers (L/100 km), and kilometers per liter (km/L). Converting fuel efficiency is helpful when comparing vehicles, trip estimates, and manufacturer specifications across regions that use different conventions.
About Frequency Conversions
Helpful context and notes for converting Frequency units.
The biggest confusion is that mpg and L/100 km move in opposite directions: higher mpg is better, lower L/100 km is better. Another common trap is gallon type. US gallons and imperial gallons are different sizes, so mpg (US) is not the same as mpg (UK/imperial). Real-world fuel efficiency also depends on driving conditions, speed, temperature, and load, so conversions should be used for comparison, not as a promise.
Practical tip: convert fuel efficiency into the form you naturally think in, then sanity-check the direction. If you switch from mpg to L/100 km, a good vehicle might show 6–9 L/100 km, while larger vehicles may be 10–15 L/100 km or higher. If you see L/100 km increasing when you expect improvement, you may have inverted the relationship or mixed US vs imperial gallons.
Frequently Asked Questions
Fun Fact
In computing, a 'jiffy' can be 0.01 seconds – basically the time between hitting 'print' and regretting your life choices.
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