Fuel Consumption Converter
Convert between MPG (US), MPG (UK), L/100km, and km/L fuel efficiency units.
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How to use this calculator
- 1
Enter your fuel consumption value.
- 2
Select the unit you are converting from (e.g. MPG US).
- 3
Select the target unit (e.g. L/100km).
- 4
The result appears instantly. Note that higher MPG = lower L/100km (inverse relationship).
Frequently asked questions
How do I convert MPG to L/100km?
Divide 235.215 by the MPG value to get L/100km. For example, 30 MPG (US) = 235.215 ÷ 30 = 7.84 L/100km.
What is the difference between US MPG and UK MPG?
US MPG uses the US gallon (3.785 L), while UK MPG uses the imperial gallon (4.546 L). 30 US MPG = 36 UK MPG approximately — the same car appears more efficient in UK figures.
Is lower L/100km better or worse?
Lower L/100km is better — it means you use fewer litres to travel 100 km. A car using 5 L/100km is more fuel-efficient than one using 10 L/100km.
How do I convert km/L to L/100km?
Divide 100 by the km/L value. For example, 15 km/L = 100 ÷ 15 = 6.67 L/100km.
Fuel consumption unit conversion
MPG vs L/100km
MPG (miles per gallon) is used in the US and UK. L/100km (litres per 100 kilometres) is used in most other countries. The two are inversely related — a higher MPG means a lower L/100km. This inverse relationship means you cannot simply multiply or divide; you must use the formula 235.215 ÷ MPG (US) = L/100km.
Fuel efficiency reference points
A very efficient car: ~50 MPG US / 4.7 L/100km. Average car: ~28 MPG US / 8.4 L/100km. Large SUV/truck: ~18 MPG US / 13 L/100km. Hybrid vehicles: 45–60 MPG US. Electric vehicles are measured in MPGe (miles per gallon equivalent).
Why the US and UK MPG differ
The US gallon is 3.785 litres. The UK (imperial) gallon is 4.546 litres — about 20% larger. This means a car rated at 40 MPG in the US would be rated at approximately 48 MPG in the UK for the same fuel consumption. Always check which gallon is being used when comparing vehicle specs internationally.
Fuel consumption: how it works
Unit conversion matters across engineering, science, cooking, and everyday life. This tool applies internationally recognised conversion factors to deliver precise, instant results across all major unit systems — no manual lookup needed.
Who uses this tool?
Scientists, engineers, chefs, and international travellers use this tool daily to bridge the gap between different measurement systems. It eliminates the need to memorise conversion factors or hunt through reference tables.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →