Gallons per 100 miles
 

Would it be possible to add an option to view everything as Gallons/100 miles instead of MPG? I've noticed that fueleconomy.gov has started to offer that option and it would be nice if Fuelly would do the same.

Gallons/100 miles is beneficial in a number of ways. Primarily, changes to the value are linear. When working in MPG, a five MPG increase doesn't equate to the same savings regardless of where you start from. In other words, going from 10MPG to 15MPG is a 50% increase, whereas going from 20MPG to 25MPG is only a 25% increase.

When working in Gallons/100 miles, on the other hand, a 1 point change does equate to the same savings irregardless of where you start from. Using the same example as before, if you use 10 gallons to go 100 miles (same as 10MPG, coincidently) and decrease your score to a 6.666 (which is the same as 15MPG), your score changes by 3.333 points. If you go from 20MPG to 25MPG, you score will go from 5.000 to 4.000, a change of just a single point.

From this example, you can see how Gallons/100 miles does a better job of showing the relative savings from increasing your fuel economy.

What I would like from Fuelly is an option that would let me view everybody's milage this way. That way, people who are more accustomed to seeing MPG could still view my vehicles that way, if they wished, and I could view theirs in Gal/100 Miles. All the raw data is the same, and would just require the inverse calculation (times 100) from what you are currently doing.

Thanks for making such a great and useful tool. I look forward to seeing how it evolves.

Yeah, not a bad idea. I've read that paper about gallons/10,000 miles to further make the differences clear on lower MPG cars. We'll see if we can fit in these other kinds of metrics.

Thanks for the quick reply. I do hope you can add this as an option at some point in the future.

This is one of the reasons we include Avg L/100km (Liters per 100 kilometers) in the stats even for people tracking with MPG. But I realize numbers related to liters aren't as meaningful as numbers related to gallons for those of us in the US. But much of the world is already comparing fuel economy with that type of metric.