How do I convert MPG to L/100km?

Use the formula: L/100km = 235.214 ÷ MPG. For example, 30 MPG equals 235.214 ÷ 30 = 7.84 L/100km. The conversion is inverse because MPG measures distance per fuel while L/100km measures fuel per distance.

Is higher MPG or L/100km better?

Higher MPG is better (more miles per gallon = more efficient), but lower L/100km is better (less fuel consumed per 100 km = more efficient). They're inversely related: high MPG converts to low L/100km.

Why do UK and US MPG numbers differ?

UK uses Imperial gallons (4.546 liters) while US uses US gallons (3.785 liters). UK gallons are 20% larger, so the same car rated at 40 MPG (UK) only gets about 33 MPG (US). Always check which gallon measurement is used.

What is good fuel economy in L/100km?

Under 6 L/100km is excellent (equivalent to over 39 MPG), 6-8 L/100km is good (29-39 MPG), 8-10 L/100km is average (23-29 MPG), and over 10 L/100km is below average for modern cars.

Why do Europeans use L/100km instead of MPG?

L/100km is more intuitive for budgeting (easy to calculate fuel needed for a trip), directly measures consumption, and fits naturally with the metric system using kilometers and liters that are standard worldwide.

Fuel Economy Comparison: Understanding US MPG vs European L/100km

Two Different Ways to Measure

🇺🇸 MPG (US)

Miles Per Gallon

Measures:

Distance traveled per unit of fuel

Higher = Better

🇪🇺 L/100km (Europe)

Liters per 100 Kilometers

Measures:

Fuel consumed per distance

Lower = Better

Key Difference

MPG is inverse to L/100km. A high MPG (good) converts to a low L/100km (also good). This confuses many people at first!

Conversion Formulas

MPG → L/100km

L/100km = 235.214 ÷ MPG

Example: 30 MPG

235.214 ÷ 30 = 7.84 L/100km

L/100km → MPG

MPG = 235.214 ÷ L/100km

Example: 8 L/100km

235.214 ÷ 8 = 29.4 MPG

Comparison Chart

US MPG	EU L/100km	Rating
15 MPG	15.68 L/100km	Poor
20 MPG	11.76 L/100km	Below Average
25 MPG	9.41 L/100km	Average
30 MPG	7.84 L/100km	Good
35 MPG	6.72 L/100km	Very Good
40 MPG	5.88 L/100km	Excellent
50 MPG	4.7 L/100km	Outstanding
60 MPG	3.92 L/100km	Hybrid/EV

Real-World Examples

🚗 Compact Car

US: 32 MPG city / 42 MPG highway

Good fuel economy for commuting

EU: 7.3 L/100km city / 5.6 L/100km highway

Equivalent European rating

🚙 SUV

US: 22 MPG city / 28 MPG highway

Typical mid-size SUV

EU: 10.7 L/100km city / 8.4 L/100km highway

Higher fuel consumption

⚡ Hybrid

US: 50 MPG city / 47 MPG highway

Excellent hybrid efficiency

EU: 4.7 L/100km city / 5.0 L/100km highway

Low fuel consumption

Why Europeans Use L/100km

✓ More Intuitive for Budgeting

"This trip is 500km, my car uses 8L/100km, so I need 40 liters of fuel." Easy mental math for trip planning.

✓ Direct Consumption Measure

Shows how much fuel you're actually consuming, making it easier to calculate costs and environmental impact.

✓ Consistent with Metric System

Fits naturally with kilometers and liters, which are standard worldwide measurements.

Understanding UK MPG vs US MPG

⚠️ Important: UK and US Gallons Are Different!

• US Gallon: 3.785 liters

• UK (Imperial) Gallon: 4.546 liters (20% larger!)

This means a car rated at 40 MPG (UK) only gets about 33 MPG (US). Always check which gallon measurement is being used!

Practical Tips

For Americans in Europe

Rental cars showing 6-7 L/100km are getting excellent mileage (equivalent to 33-39 MPG). Under 5 L/100km is exceptional (over 47 MPG).

For Europeans in the US

Cars rated at 30+ MPG are considered efficient. Remember US gallon prices are per US gallon, about 20% cheaper per liter than UK prices appear.