Fuel Economy Converter
Convert between MPG (US), MPG (UK), L/100km and km/L with inverse relationship handling.
How to Use the Fuel Economy Converter
Convert between MPG (US), MPG (Imperial/UK), liters per 100 kilometers and kilometers per liter.
- Select the "From" unit — choose the fuel economy measure you want to convert from.
- Enter a value — type any number into the input field. The result updates in real time.
- Select the "To" unit — choose the target unit.
- Swap if needed — click the swap button to reverse the conversion direction.
- Copy the result — click Copy to send the value to your clipboard.
Note that the conversion between MPG/km/L and L/100km is inverse (not linear), so higher MPG = lower L/100km.
Frequently Asked Questions
How do I convert MPG to L/100km?
Divide 235.215 by the MPG (US) value. For example, 30 MPG (US) = 235.215 ÷ 30 = 7.84 L/100km. This is an inverse relationship: higher MPG means lower L/100km.
What is the difference between US and UK MPG?
US MPG uses the US gallon (3.785 liters), while UK MPG uses the Imperial gallon (4.546 liters). The same car will have a higher UK MPG number. To convert: UK MPG × 0.833 = US MPG (approximately).
Why is the MPG to L/100km conversion not linear?
MPG measures distance per fuel (higher = better), while L/100km measures fuel per distance (lower = better). They are inversely proportional. Going from 10 to 20 MPG saves more fuel than going from 30 to 40 MPG.
What is good fuel economy?
In the US, the average new car gets about 28 MPG (US) combined. Above 30 MPG is considered good, above 40 MPG is excellent. In metric, under 7 L/100km is good and under 5 L/100km is excellent.
How do I convert km/L to MPG?
Multiply km/L by 2.352 to get MPG (US) or by 2.825 to get MPG (Imperial/UK). For example, 15 km/L × 2.352 = 35.28 MPG (US).
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