Fuel Economy Converter

Convert between distance-per-fuel and fuel-per-distance economy measures. Enter your own values below to see fuel economy and check the method behind it.

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Your inputs

Change the example values to match your situation.

Your result

Let’s work it out.

Fill in your inputs and select Calculate.
Your result and breakdown will appear here.

How this calculator works

Convert through kilometres per litre. Litres per 100 km is reciprocal: 100 ÷ km/litre.

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What is Fuel Economy Converter?

Fuel Economy Converter helps you convert between distance-per-fuel and fuel-per-distance economy measures.

The main result is fuel economy. The formula, example and assumptions below explain how to interpret it.

How to use Fuel Economy Converter

Use the example to get familiar with the form, then enter your own figures. Any rates in the example are illustrative. Check the field labels and units before calculating.

  1. Gather fuel economy, from unit and to unit. Use values from the same situation or reporting period.
  2. Replace the example fuel economy with your own value, then complete the other fields. Check the displayed units and each selected option.
  3. Select Calculate and read fuel economy. Change one input and calculate again to compare a second scenario. Reset restores the original example.
  • Enter fuel economy, at least 0.000001. Decimals are accepted.
  • Choose from unit from km/litre, litres/100 km, US mpg and Imperial mpg.
  • Choose to unit from km/litre, litres/100 km, US mpg and Imperial mpg.

Fuel Economy Converter: a worked example

With the inputs below, the result is 6.666667 litres/100 km (fuel economy). Follow the example, then replace these illustrative values with your own.

Example inputs and output
Input or outputExample value
Fuel economy15
From unitkm/litre
To unitlitres/100 km
Fuel economy6.666667 litres/100 km

Understanding the Fuel Economy result

The main output is fuel economy, expressed in litres/100 km. It applies to the inputs and operation you selected.

Displayed results use a readable number of decimal places. When checking a result by hand, keep extra precision until the last step. To compare scenarios, change one input at a time and keep the others fixed.

Fuel Economy Converter: assumptions and common mistakes

A useful estimate starts with the right inputs. Check the following assumptions and limits before applying the result to your situation.

  • Select the correct unit system. US and imperial gallons differ, local land units vary, and exchange rates need a dated source.

For wider guidance, visit NIST measurement units. The formula and scope of this specific tool are stated on this page.

Fuel Economy Converter FAQs

What does Fuel Economy Converter calculate?

Fuel Economy Converter helps you convert between distance-per-fuel and fuel-per-distance economy measures. Its main output is fuel economy in litres/100 km.

What inputs do I need for Fuel Economy Converter?

You need fuel economy, from unit and to unit. Use the field labels and units to match your figures to the formula.

Which formula does Fuel Economy Converter use?

Convert through kilometres per litre. Litres per 100 km is reciprocal: 100 ÷ km/litre.

What is a worked example for Fuel Economy Converter?

Example inputs: Fuel economy: 15; From unit: km/litre; To unit: litres/100 km. The result is 6.666667 litres/100 km (fuel economy).

How should I enter fuel economy?

Enter fuel economy, at least 0.000001. Decimals are accepted.

How do I choose from unit?

Choose from unit from km/litre, litres/100 km, US mpg and Imperial mpg. The example uses km/litre; replace it if your circumstances differ.

How should I read fuel economy?

The main output is fuel economy, expressed in litres/100 km. It applies to the inputs and operation you selected.

Why might my Fuel Economy Converter result differ from my records?

Select the correct unit system. US and imperial gallons differ, local land units vary, and exchange rates need a dated source. Differences in entered values, units or rounding can also change the comparison.

Can I compare two scenarios in Fuel Economy Converter?

Yes. Note your first fuel economy, change fuel economy or another input, and select Calculate again. Editing a field clears the old result so it is not mistaken for a new calculation.

Is Fuel Economy Converter free, and where are my inputs calculated?

This calculator is free to use without signing in. Its formula runs in your browser; calculator inputs are not sent to a calculation API. The inputs reset to the example values when you reset the form or start a fresh page.