How to calculate MPG during a partial fill

[TheIVJackal]

I was running on E and was starting to get nervous about driving so I put in two gallons of gas instead of filling up. Now, how do I calculate my MPG after I fill up? Thanks!
- Aaron

How-To: When you do a partial-fill (meaning you didn't fill the tank, e.g. you only put in a few gallons) keep the odometer running and when you finally do fill up, add the gallons from the partial-fill to the full tank. If you put in two gallons then later fill with 10, add those two gallons to the fill-up to get a total of 12 and use that in your MPG calculator.

[jakobnev]

Just add the two gallons to whatever you put in later to fill the tank. (??)

[Gealii]

dont reset your trip and make note of how many gal you added than add the gal to youro fill up

[TheIVJackal]

But wouldn't that assume that I used two gallons by the time I fill-up? I was thinking more of finding out how much gas each mile uses and using that in some sort of equation?

[roosterk0031]

It all works out, just add your part fill to next full fill, even if 5 of them, you'll get a high tank, but average mpg will work out, kind of like 3 tank MPG. You could put in th 2 gallons and tip OD and reset trip and it would all average out, but give crazy high tank MPG.

[mcrews]

get a scangaugeII.

[euromodder]

Originally Posted by TheIVJackal

But wouldn't that assume that I used two gallons by the time I fill-up?

NO.

What you already used up, you'll need to add again when topping up.
What's left in the tank, you won't need to add again

Keep the miles counter running until you fill up completely, and add the previous 2 gal to the volume you tanked - done.

[TheIVJackal]

Alright, it's starting to click in my head. So just to be clear, if the next time I fill up I pump 10 gallons, I want to add the previous two gallons to that correct? I'll have a total of 12 gallons that I will use to determine MPG for that tank right? I use the total OD mileage. Thanks!

[Gealii]

yes just make sure you dont reset your trip untill you fill completely

[TheIVJackal]

Excellent, thanks!