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Convert between MPG and L/100km for car efficiency.
⛽ L/100km is inverse to mpg (lower = better): L/100km = 235.215 ÷ US mpg. km/L is linear: 1 km/L ≈ 2.35215 US mpg. UK mpg × 0.83267 = US mpg (1 UK gallon = 1.20095 US gallons). Enter a value greater than 0 (0 or negative is undefined). Values are approximate.
This tool converts between fuel economy units: MPG (miles per gallon, US and UK) and L/100km (liters per 100 km). These are the two main systems for measuring vehicle fuel efficiency.
MPG and L/100km work in opposite directions. Higher MPG is better (more miles per gallon); lower L/100km is better (less fuel for the same distance). This is why the conversion isn't a simple multiplier — it's a reciprocal.
The US gallon (3.785 liters) is smaller than the UK imperial gallon (4.546 liters), so a UK MPG number is about 20% higher for the same efficiency. Always check which gallon a source uses before comparing.
The Fuel Economy Converter converts fuel economy converterfrom one unit to another using the exact internationally defined conversion factors. Type a value, choose your source and target units, and the converted result is shown instantly — no waiting, no page reload.
Manual conversion is error-prone because it means memorizing ratios (how many feet in a meter, how many pints in a liter). This tool removes that friction: the conversion factor is built in, and the math is done to full precision with no rounding until the final displayed number.
Common uses: people reach for this tool when they need to look up a mpg to l 100km converter, liters per 100km to mpg us, km per liter to mpg, or fuel consumption unit converter.
Browser-based tools like this one have a few real advantages over installed software or manual methods:
The Fuel Economy Converter is based on the following formula:
L/100km = 235.214583 ÷ MPG (US) MPG (US) = 235.214583 ÷ (L/100km) L/100km = 282.481 ÷ MPG (UK) 1 MPG (UK) = 1.201 MPG (US)
Variables: MPG = miles per US gallon (1 US gal = 3.785411784 L) MPG (UK) = miles per imperial gallon (1 imp gal = 4.54609 L) L/100km = liters of fuel consumed per 100 kilometers
MPG measures distance per fuel (higher is better) while L/100km measures fuel per distance (lower is better), so the relationship is an inverse. The constant 235.214583 comes from 100 × 3.785411784 ÷ 1.609344; the UK version uses the larger imperial gallon, giving 282.481.
Worked example: A car rated at 30 MPG (US): L/100km = 235.214583 ÷ 30 = 7.84 L/100km Reverse: 235.214583 ÷ 7.84 ≈ 30 MPG A UK rating of 40 MPG (UK) = 40 × 1.201 ≈ 48.0 MPG (US)
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