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Fuel Consumption Calculator

Convert fuel efficiency between mpg (US & UK), L/100km, and km/L. Calculate trip cost from distance and fuel price.

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mpgL/100kmfuel efficiencytrip cost
Fuel efficiency converter
Miles per gallon (US)
mpg (US)
Miles per gallon (UK)
mpg (UK)
Litres per 100 km
L/100km
Kilometres per litre
km/L
Quick examples
Trip fuel cost calculator
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Enter distance, consumption, and price

What is Fuel Consumption?

Fuel consumption (also called fuel efficiency or fuel economy) measures how much fuel a vehicle uses over a given distance. In Europe and most of the world, it is expressed as litres per 100 kilometres (L/100km) —lower is better. In the US and UK, miles per gallon (mpg) is used —higher is better. Kilometres per litre (km/L) is common in Japan and parts of Asia.

How to Use Fuel Consumption

  1. Type a fuel efficiency value into any field (mpg US, mpg UK, L/100km, or km/L).
  2. All other units update instantly.
  3. Use the Trip Cost section to estimate the fuel cost for a journey: enter distance (km), consumption (L/100km), and fuel price per litre.
  4. The consumption field in the trip section auto-fills from the converter above.

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Understanding Fuel Efficiency Units ▾
Example
Input 30 US mpg
Output 7.84 L/100km / 12.75 km/L / 36.05 UK mpg
Common Use Cases
  • Comparing fuel efficiency of cars across different markets
  • Estimating trip fuel cost before a journey
  • Converting an EU car spec (L/100km) to US mpg
  • Fleet management and logistics cost planning
Frequently Asked Questions
How do I convert mpg to L/100km?

For US mpg: L/100km = 235.215 ÷ mpg. For UK mpg: L/100km = 282.481 ÷ mpg. For example, 30 US mpg = 235.215 ÷ 30 = 7.84 L/100km.

What is the difference between US mpg and UK mpg?

The US gallon is 3.785 litres; the UK (imperial) gallon is 4.546 litres. So 30 UK mpg is more fuel-efficient than 30 US mpg. 30 UK mpg ≠25 US mpg.

How do I calculate trip fuel cost?

Fuel cost = (distance ÷ 100) × L/100km × price per litre. For example: 200 km ÷ 100 × 7 L/100km × $1.50/L = $21.00.

What is km/L?

Kilometres per litre (km/L) is the inverse of L/100km and is common in parts of Asia and Latin America. Higher km/L = more fuel efficient.