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Fuel Economy Calculator

Calculate fuel economy in MPG and L/100km from distance driven and fuel used. Works with miles/gallons or km/litres.

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How to use

  1. Select your distance unit (km or miles) and fuel unit (litres or US gallons).
  2. Enter the distance you drove and the amount of fuel used.
  3. Click Calculate Fuel Economy to see both L/100km and MPG results.

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Frequently Asked Questions

Is this fuel economy calculator free?
Yes, completely free with no signup and no usage limits.
Does my data leave my device?
No. All calculations run in JavaScript inside your browser. Nothing is sent to any server.
Does it work on mobile?
Yes. The calculator is mobile-first and works on iPhone Safari and Android Chrome.
What is a good fuel economy?
For petrol cars, under 7 L/100km (over 33 MPG) is considered efficient. Hybrid vehicles typically achieve 4–6 L/100km. The higher the MPG or the lower the L/100km, the more fuel-efficient your car.
Why are L/100km and MPG inversely related?
L/100km measures how much fuel you use per distance (lower is better), while MPG measures how far you go per unit of fuel (higher is better). To convert: MPG = 235.214 ÷ L/100km.

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