Fuel Economy Calculator
Fill in the values and the answer updates as you type.
How the Fuel Economy Calculator works
Consumption (L/100 km) = fuel used ÷ distance × 100. US mpg = 235.215 ÷ L/100 km and UK mpg = 282.481 ÷ L/100 km, because the US and UK gallons differ in size. Fill the tank to the same level each time for the most accurate reading. Example: with the default values, 36 L over 450 km is 8.0 L/100 km, or 29.4 US mpg.
Inputs and results
The Fuel Economy Calculator takes 2 inputs and gives 4 results.
What you enter
- Distance driven (km) — starts at 450.
- Fuel used (L) — starts at 36.
What you get
- Consumption (L/100 km)
- Efficiency (km/L)
- Efficiency (US mpg)
- Efficiency (UK mpg)
Example: Fuel Economy Calculator with the starting values
With distance driven 450 km and fuel used 36 L, the calculator returns:
| Consumption (L/100 km) | 8 |
|---|---|
| Efficiency (km/L) | 12.5 |
| Efficiency (US mpg) | 29.4 |
| Efficiency (UK mpg) | 35.3 |
Change any value above and the results update straight away.
Fuel Economy Calculator FAQ
How do I use the Fuel Economy Calculator?
Enter distance driven and fuel used in the fields, then read consumption (l/100 km), efficiency (km/l), efficiency (us mpg) and efficiency (uk mpg) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Fuel Economy Calculator calculate?
Fuel consumption in L/100 km, km/L, and miles per gallon. It returns consumption (l/100 km), efficiency (km/l), efficiency (us mpg) and efficiency (uk mpg) from the 2 values you provide.
What values does the Fuel Economy Calculator start with?
It opens with distance driven 450 km and fuel used 36 L so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Fuel Economy Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Fuel Economy Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.