Example: Miles driven: 342 mi · Gallons used: 11.8 gal → Fuel economy: 29 mpg.
L/100km: 8.1
Miles per tank (15 gal): 435
Frequently asked questions
How do I calculate gas mileage? Enter your numbers above and the result updates instantly. For example: Miles driven: 342 mi · Gallons used: 11.8 gal → Fuel economy: 29 mpg.
Is this Gas Mileage Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for gas mileage. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.