Gas Mileage Calculator
Enter the distance driven and the fuel used to get your fuel economy in miles per gallon and litres per 100 km. Add a fuel price for trip cost.
How to calculate gas mileage
- Enter the distance driven in miles or kilometres.
- Enter the fuel used in gallons or litres.
- Read your MPG, L/100km and km/L, plus cost per mile if you add a price.
Examples
US fuel economy
300 miles on 12 gallons
25 MPG (9.41 L/100km)
Trip fuel cost
300 miles, 12 gallons at $3.50
$42.00 total, $0.14 per mile
Frequently asked questions
How is MPG calculated?
Divide the miles driven by the gallons of fuel used. Driving 300 miles on 12 gallons gives 300 / 12 = 25 miles per gallon.
How do I convert MPG to L/100km?
They are inverse measures. This tool converts your miles and gallons to litres and kilometres, then divides litres by kilometres and multiplies by 100.
Can I use metric units?
Yes. Enter kilometres and litres instead of miles and gallons. The tool reports MPG, L/100km and km/L either way, using 1 mile = 1.609344 km.
How is fuel cost per mile worked out?
Total fuel cost equals the fuel used times the price you enter. Cost per mile is that total divided by the miles driven, so a $42 fill over 300 miles is $0.14 per mile.
Why is my real-world MPG lower than the sticker?
City driving, cold starts, idling, cargo, terrain and speed all lower economy. Measuring your own fill-ups, as this tool does, gives a truer figure than the rated number.
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