Fuel Economy Converter
Convert km/L, L/100 km, US mpg and UK mpg correctly, including inverse units, and work out fuel for a trip.
Tool guide
What this tool does
Fuel Economy Converter translates mileage between distance-per-fuel and fuel-per-distance units used in India, Europe, the US and the UK. It handles the inverse L/100 km scale properly and estimates the fuel needed for any trip.
Car mileage is reported in opposite ways around the world. India and parts of Asia use kilometres per litre, Europe uses litres per 100 kilometres, and the US and UK use miles per gallon, but with different gallons. Comparing a European review with an Indian brochure needs more than a single multiplier, because L/100 km gets smaller as efficiency improves.
This converter uses km/L as its base. Linear units scale by exact factors: a US mpg is 1.609344 km per 3.785411784 L (about 0.4251 km/L), and a UK mpg uses the 4.54609 L imperial gallon (about 0.3540 km/L). Inverse units are converted with a reciprocal, for example L/100 km = 100 ÷ km/L. The trip panel turns any economy figure and distance into litres and gallons of fuel. All calculations run on your device.
How to use Fuel Economy Converter
- Enter the fuel economy figure in the Value field.
- Choose its unit in From, such as Miles per gallon (US).
- Choose the unit you want in To, such as Litres per 100 km, and read the Result.
- Swap the units to convert back, or change Decimal places.
- In Fuel needed for a trip, enter an economy figure and the trip distance in km.
- Convert several vehicles at once with Batch convert and export a CSV.
Tips for better results
- A handy shortcut: L/100 km ≈ 235.2 ÷ US mpg, or 282.5 ÷ UK mpg.
- For km/L to L/100 km, divide 100 by the km/L figure: 20 km/L is 5 L/100 km.
- Official test figures are usually better than real-world driving; compare like with like.
Common use cases
- Comparing car reviews from the US, UK, Europe and India.
- Estimating the fuel needed for a road trip before setting off.
- Converting your own mileage logs to the unit used in a forum or app.
- Checking manufacturer claims against your measured consumption.
Common mistakes to avoid
- Multiplying instead of dividing when going between km/L and L/100 km.
- Using US mpg figures as if they were UK mpg; UK mpg values are about 20% higher for the same car.
- Comparing L/100 km figures thinking higher is better; lower consumption is better.
Frequently asked questions
How do I convert mpg to L/100 km?
For US mpg, divide 235.215 by the mpg value; for UK mpg, divide 282.481 by it. So 30 US mpg is about 7.84 L/100 km.
How do I convert km/L to mpg?
Multiply km/L by about 2.352 for US mpg or 2.825 for UK mpg. A car that gives 18 km/L does about 42.3 US mpg.
Why are UK mpg figures higher than US ones?
An imperial gallon holds 4.546 L and a US gallon 3.785 L, so the same car travels further on a UK gallon.
What happens if I enter zero?
Zero distance per litre or zero litres per 100 km has no meaningful inverse, so the converted value is shown as a dash rather than an infinite number.
Feedback & suggestions
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