Refuels & Fuel Efficiency
Questions about recording refuels and calculating fuel efficiency
refuel fuel mpg consumption partial efficiency
How does My Cars calculate fuel efficiency?
Fuel efficiency is calculated by dividing distance traveled by fuel consumed:
Example: 500 miles ÷ 20 gallons = 25 miles per gallon (MPG)
The app uses the fuel quantity from your current refuel (not the previous one) because this represents the actual fuel consumed during that distance.
What is a partial refuel?
A partial refuel is when you don’t fill up the tank completely. Mark your refuel as “partial” so the app knows to accumulate the fuel amounts until your next full tank.
Fuel efficiency will be calculated once the accumulated fuel exceeds your tank size threshold (set in refuel preferences).
What distance values can I enter for refuels?
You can choose between:
- Odometer reading: Total mileage on your car (e.g., 50,000 miles)
- Trip distance: Distance since your last refuel (e.g., 350 miles)
Switch between these modes in Preferences > Refuel settings.
Why is my fuel efficiency showing as 0 or incorrect?
Common reasons:
- Partial refuels: Efficiency isn’t calculated until you do a full tank
- Wrong distance mode: Check if you’re using odometer vs trip distance consistently
- First refuel: The app needs at least 2 refuels to calculate efficiency