Fuel Economy Calculator
Convert MPG (US/UK) to L/100km and km/L · Calculate real economy from trip data
Quick answer: 30 MPG (US) = 7.84 L/100km = 12.75 km/L = 36.0 MPG (UK). The US and UK gallon are different sizes — use the converter below for exact figures.
Fuel Economy Units by Country
| Country / Region | Standard unit | Note |
|---|---|---|
| 🇺🇸 USA | MPG (US gallons) | US gallon = 3.785 litres; cars show City/Hwy/Combined |
| 🇬🇧 UK | MPG (Imperial gallons) | Imperial gallon = 4.546 L; WLTP test cycle from 2018 |
| 🇪🇺 EU / Germany / France | L/100km | Lower is better; WLTP replaces old NEDC |
| 🇦🇺 Australia / NZ | L/100km | Metric since 1970s; ADR test cycle |
| 🇨🇦 Canada | L/100km | Also shows MPG on US-market vehicles |
| 🇯🇵 Japan | km/L (JC08 / WLTC) | Higher is better; WLTC from 2022 |
| 🇮🇳 India | km/L (ARAI) | ARAI certification required for all cars |
| 🇨🇳 China | L/100km (CLTC) | China Light-duty Vehicle Test Cycle since 2021 |
| 🇧🇷 Brazil | km/L (INMETRO) | Also uses km/L standard like Japan/India |
Frequently Asked Questions
Why is L/100km preferred in Europe?
Lower L/100km is always better — it is intuitive in the same way as cost per 100km. With MPG, a jump from 20 to 25 MPG saves twice as much fuel as a jump from 40 to 50 MPG, which is counterintuitive. Litres per 100km makes fuel savings directly proportional: going from 10 to 5 L/100km cuts fuel use in half.
What is the average fuel economy of a car?
Global averages vary significantly. US new car fleet average (CAFE standard) targets 49 MPG by 2026. EU WLTP average for new cars is around 5.5-6.5 L/100km. UK average is around 38-42 MPG (UK). Petrol cars worldwide average about 7-9 L/100km in real-world conditions.
How do electric vehicles fit into fuel economy?
EVs are rated in miles per kWh (US) or kWh per 100 miles (UK/EU), or Wh/km. A typical EV uses 15-25 kWh per 100 km. To compare with petrol: divide by roughly 10 to get an approximate L/100km equivalent for energy cost comparison purposes.