Fuel Level Indicator

I wait until miles to empty is 0 miles unless it's a long ways to a gas station I want to use. I have about 1.8 gallons left at that point.

Edit: Fuzzy reminded me that since I have a Gen III, my run till 0 miles method isn't a good idea for a Gen II because Gen IIs have a fuel bladder which makes gas gauge readings unreliable, particularly at low fuel levels.

 

the bars (pips) are not linear and don't relate to much of anything. divide your miles by your average fuel economy gives a better sense of how much fuel has been used and fill up at two bars or more to be safe.

 

As already mentioned, the bars are not sufficiently linear or consistent to reliably assigned a gallon value. This is true in nearly all cars, not just Prius.

The Gen II has a fuel bladder, which adds considerable uncertainly and inconsistency beyond the norm of other cars. While some owners have often gone more than fifty miles beyond the flashing pip, others have run out of fuel very shortly after it began flashing, and a few have even run dry with one or two solid bars remaining. That is why the Gen II gas gauge is often called a 'Guess Gauge'.

Here are JimboPalmer's Gen II rules, the last sentence based on direct experience:

You have a Gen III, which does not have the fuel bladder. We Gen III owners have been consistently able to push well beyond the points where numerous Gen II owners have reported being stranded.

 

Deleted duplicate post