Add the requested inputs
Use the labelled fields in the workspace above. If example values are provided, try them first or replace them with your own.
Travel & transport · Free online tool
Fuel economy converter
Convert between UK MPG, US MPG, litres per 100 km and kilometres per litre.
3 guest runs per rolling 24 hours10 with a free accountPrivate inputsMobile-friendly
Fuel economy converter workspace
Runs locally in your browser
Result
Litres per 100 km—
Kilometres per litre—
MPG (UK)—
MPG (US)—
Conversion summary
Use it with confidence
How to use the fuel economy converter.
Calculate and review
Use the main action when needed. UK MPG converts through 282.481 ÷ MPG, US MPG through 235.215 ÷ MPG, and km/L as 100 ÷ km/L to litres per 100 km.
Try a worked example
45 UK MPG is about 6.28 L/100 km and 37.5 US MPG.
Check the assumptions
Manufacturer and real-world figures differ with driving conditions; use a comparable measurement standard when comparing vehicles.
A clearer answer
How do I convert MPG to L/100 km?
Enter a value and choose the source unit. The tool converts between UK MPG, US MPG, litres per 100 km and kilometres per litre.
See the useful decision, not only one number.
It keeps the gallon standard explicit—UK MPG uses the imperial gallon—so you do not accidentally mix measurement systems.
Worked example: 45 UK MPG
45 UK MPG is about 6.28 L/100 km, 15.93 km/L and 37.5 US MPG.
Method: UK MPG → L/100 km: 282.481 ÷ MPG. US MPG → L/100 km: 235.215 ÷ MPG. km/L → L/100 km: 100 ÷ km/L.
Common mistakes to avoid.
- Using the US gallon for a UK MPG figure
- Comparing manufacturer figures measured on different standards
- Treating a best-case figure as real-world economy
- Ignoring the difference between imperial and US gallons
Use the result with the right assumptions.
Real fuel economy depends on driving conditions, load, weather and style. Use the same measurement standard when comparing vehicles or routes.
Helpful answers
Fuel economy converter FAQs.
Is the fuel economy converter free?
Yes. Guests receive 3 runs per rolling 24 hours, verified free accounts receive 10, and Premium subscribers receive unlimited normal use.
Does UtilHub upload or save my inputs?
No. This tool runs in your browser and UtilHub does not receive or store the values you enter. Your browser or device may still retain normal local history or form data.
How does this fuel economy converter work?
UK MPG converts through 282.481 ÷ MPG, US MPG through 235.215 ÷ MPG, and km/L as 100 ÷ km/L to litres per 100 km.
What should I check before using the result?
Manufacturer and real-world figures differ with driving conditions; use a comparable measurement standard when comparing vehicles.
Why is UK MPG different from US MPG?
UK MPG uses the imperial gallon of about 4.546 litres, while the US gallon is about 3.785 litres. The same distance figure therefore produces different litres per 100 km.
Which unit should I use in the UK?
UK vehicles and official figures normally use miles per imperial gallon or litres per 100 km. The converter shows all four so you can compare consistently.