Private fill-up history · no account

Real-World MPG & Fuel Log

Track full or partial fills, see distance-weighted MPG and L/100km, and learn what every mile actually costs. Entries stay in this browser unless you export them.

Add a Fill-Up

Uncheck for a partial fill. It will be included when the tank is next filled.

Your first full fill establishes the odometer baseline.

Last Tank
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MPG
Weighted Average
—
MPG
Average Cost
—
¢ per mile
Tracked Distance
—
miles between full fills

Fill-Up History

0 entries
No fills yet. Add a full fill to start your baseline.

How to Calculate Gas Mileage Correctly

  1. Fill to a repeatable full point and record the odometer.
  2. At the next full fill, record the new odometer and gallons added.
  3. Divide distance driven by the fuel added at the ending fill.
MPG = Miles Between Full Fills ÷ Gallons Added
L/100km = Liters Added ÷ Kilometers Driven × 100

A partial fill is not a problem if it is logged: this tool adds the partial fuel and the ending full fill, then divides the complete full-to-full distance by that total. The first fill has no economy result because it establishes the baseline.

Why the Average Is Distance-Weighted

Do not take the ordinary average of individual MPG numbers. Combine total distance and total fuel, then divide once. That prevents a short tank from affecting the average as much as a long tank.

What Changes Real-World Economy?

Short trips, temperature, traffic, speed, idling, tire pressure, load, fuel blend, modifications, and measurement consistency can all move a tank result. Look for a trend across several fills rather than diagnosing a vehicle from one number.

Privacy and Backups

The log is stored in local browser storage and is not uploaded by TunerBench. Browser-data cleanup removes it, and it does not automatically move to another device. Export CSV periodically for a durable backup.

Need the step-by-step version? Read How to Calculate Gas Mileage Accurately.

Frequently Asked Questions

How do I calculate real-world MPG?

Use two full fills. Subtract the first odometer from the second and divide that distance by the gallons added at the second fill.

Can I calculate MPG with partial fill-ups?

Yes. Start and end at full, and add all fuel purchased between those endpoints. The tracker does that accumulation automatically.

Why is the first tank blank?

The first full fill supplies the starting odometer. Economy becomes calculable at the next full fill.

Does TunerBench upload my fill-up history?

No. Entries stay in this browser's local storage. Export a CSV before clearing browser data or moving devices.