How to Calculate Fuel Efficiency
What is Fuel Efficiency?
Fuel efficiency measures how far a vehicle travels per unit of fuel. The UK and US use MPG (miles per gallon), while most of the world uses L/100km (litres per 100 kilometres). Confusingly, a higher MPG is better, but a lower L/100km is better.
Step-by-Step Guide
- 1UK MPG to L/100km: divide 282.5 by the MPG figure
- 2US MPG to L/100km: divide 235.2 by the MPG figure
- 3Note: UK and US gallons differ — 1 UK gallon = 4.546L, 1 US gallon = 3.785L
- 4km/L to L/100km: divide 100 by the km/L figure
Worked Examples
Frequently Asked Questions
What is Fuel Efficiency?
Fuel efficiency measures how far a vehicle travels per unit of fuel. The UK and US use MPG (miles per gallon), while most of the world uses L/100km (litres per 100 kilometres)
How accurate is the Fuel Efficiency calculator?
The calculator uses the standard published formula for fuel efficiency. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Fuel Efficiency calculator use?
This calculator works with inches, kilometres, miles, litres. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Fuel Efficiency calculator use?
The core formula is: Note: UK and US gallons differ — 1 UK gallon = 4.546L, 1 US gallon = 3.785L. Each step in the calculation is shown so you can verify the result manually.
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