How to use the Gas Mileage Calculator
Enter the starting odometer, ending odometer, fuel added and price per gallon and the result appears straight away. Everything runs in your browser, so nothing you type is uploaded.
The formula
US: mpg = (end − start) ÷ gallons. Metric: L/100 km = litres ÷ (end − start) × 100
Examples
- 350 miles on 12.5 gallons
Distance: 350 miles Gas mileage: 28 mpg Fuel cost: $43.75 Cost per mile: $0.13
- 412 miles on 11.2 gallons at 3.89
Distance: 412 miles Gas mileage: 36.79 mpg Fuel cost: $43.57 Cost per mile: $0.11
- 280 miles on 14 gallons (a truck)
Distance: 280 miles Gas mileage: 20 mpg Fuel cost: $49.00 Cost per mile: $0.18
Limitations and assumptions
Accurate only if the tank is filled to the same level at both readings.
Frequently asked questions
How do I calculate MPG?
Miles driven ÷ gallons used. Fill the tank each time for accuracy.
What is a good MPG?
Many modern cars manage 25 to 35 mpg; trucks and SUVs are lower.
How accurate is it?
Pump shut-off varies, so average several fill-ups.
How do I find fuel cost per mile?
Divide the price per gallon by your mpg.