Online Tool Store
Fuel Log
Record fuel purchases, trip distances, and efficiency so you can monitor spending, mileage, and vehicle performance over time.
This works right here on your device — nothing gets sent out.
Log a fill-up
Uncheck "Full tank" for partial fill-ups — fuel economy is only calculated between full-to-full fill-ups, the method fuel-tracking apps use for accuracy.
Total Spent
$0.00
—
Total Distance
0 mi
Between first and last odometer reading
Total Fuel
0 gal
0 fill-ups logged
Average Economy
—
Full-to-full fill-ups only
Fill-up History
| Date | Odometer | Distance | Fuel | Cost | Economy | Full? | Notes | Action |
|---|
How the fuel log works
- Pick your units — miles & gallons, or kilometers & liters — at the top of the log.
- Each time you fill up, enter the date, current odometer reading, fuel amount, and price per gallon or liter.
- Leave "Full tank" checked for a complete fill-up, or uncheck it for a partial top-off.
- Click "Log fill-up" to add the entry. Totals, cost per distance, and average fuel economy update automatically.
- Use "Download CSV" to save your log, or "Copy fuel log summary" to paste it elsewhere.
Fuel economy is only calculated between fill-ups marked "Full tank," using the distance covered divided by all the fuel added since the previous full tank — the standard full-to-full method used by dedicated fuel-tracking apps.
FAQ
How is fuel economy (mpg / km per liter) calculated?
The log uses the "full-to-full" method that dedicated fuel-tracking apps use for accuracy: it only measures economy between two fill-ups marked "Full tank," dividing the distance covered by all the fuel added in between (including any partial top-offs). This avoids the distortion a single partial fill-up would cause if it were measured on its own.
Why do I need to mark a fill-up as "Full tank"?
Fuel economy can only be measured accurately between two points where the tank was completely full, since that is the only way to know exactly how much fuel was actually burned over a given distance. Partial fill-ups are still logged and included in the fuel total for that stretch, they just cannot be an economy measurement endpoint on their own.
Can I track fuel economy in miles per gallon or km per liter?
Yes. Switch units at the top of the log between miles & gallons (mpg), kilometers & liters (km/L), or kilometers & liters (L/100km). Entries already logged automatically convert and redisplay in the newly selected units.
Is my fuel log data saved or uploaded anywhere?
No. Fuel Log runs entirely in your browser — nothing is sent to a server. Use "Download CSV" to save your log to your own device before closing the tab, since entries are not persisted between visits.
Can I export my fuel log?
Yes. Use "Download CSV" to export the full history (date, odometer, fuel amount, price, cost, full-tank status, and notes) as a spreadsheet-ready file, or "Copy fuel log summary" to paste a plain-text summary anywhere.
How we compare
| Feature | Online Tool Store | Fuelly | Drivvo |
|---|---|---|---|
| Works instantly in a browser, no install | ✓ | Mobile app or account required | Mobile app required |
| Full-to-full fuel economy calculation | ✓ | ✓ | ✓ |
| Cost-per-distance and total-spend tracking | ✓ | ✓ | ✓ |
| Switch mpg / km/L / L per 100km on existing entries | ✓ | Limited unit switching | ✓ |
| Free, no sign-up, nothing leaves your browser | ✓ | Free tier, account required for sync | Free tier, account required for sync |
Fuelly and Drivvo track fleet-wide history across devices via an account, which is worth it for tracking many vehicles long-term. Fuel Log gives an instant, private, no-sign-up log for a single vehicle or trip — export the CSV any time to keep the data yourself.