Free Fuel Log Calculator — MPG, L/100km & Cost per Mile
Log fill-ups and get real consumption: L/100km and MPG between full tanks, cost per mile or km, and monthly fuel spend. All private, in your browser.
How to use this tool
- 1
Fill the tank and log it: date, odometer, volume, total price.
- 2
Mark partial fills as partial — they fold into the next full tank.
- 3
From the second full fill-up, consumption computes automatically.
- 4
Watch L/100km / MPG trends and monthly spend as the log grows.
Frequently asked questions
▸How is fuel consumption calculated?
Fill-to-fill: the distance between two full fill-ups divided by the volume added at the later fill (partial fills fold into the next full one). That's the standard method that smooths out tank-level guesswork.
▸Does it work in metric and imperial?
Yes — each vehicle picks its units (km/L or mi/gal) and the log computes both L/100km and US MPG for every interval, plus cost per distance in your currency.
▸Why does my first fill-up show no MPG?
Consumption needs two full fill-ups — the first one establishes the baseline odometer. From the second full tank on, every interval computes.