How is the average mpg calculated?

So how exactly is the average mpg calculated? Is it based on since the last time you did a trip reset? Or an average of the last 5 miles? 25 miles? Etc.

 

If you are asking about the truck computer calculator....it it based off the last time you do a reset of the MPG calculator. How you do a reset may depend on the generation of your truck. Generally, you bring up the MPG display and keep holding the button to reset it.

 

Thanks @frichco228 . Yea that's what I was referring to. Just wasn't sure on that calculation.

 

on mine at least there is a Average MPG per tank, I think it resets itself after you fill up, and just an average MPG that you have to manually reset yourself

 

In my 2019, it automagically resets when I fill up. There is also a mpg for my last trip that shows up when I turn the truck off.