2012 Mazda 3 Mile Gauge Question

[updawg]

I recently purchased a Mazda 3 back in May and am a first time Mazda owner. I love my car thus far but I have one question about my car that is kind of annoying. The miles remaining estimator seems to use 12 gallons in its estimations instead of the full 14.5. For example, it would tell me that I have 30 miles remaining. I would then fill my tank and every single time it would be just shy of 12 gallons. Why is this? Is this expected? Where are the other 2.5 gallons? That is roughly 100 miles of travel lost, not that I would ever run my tank that low, but it still seems like a lot of gas unaccounted for. Any help in this matter would be appreciated.

 

[cymx5]

Every car manufacturer does this. It's to prevent the driver from getting comfortable draining the entire tank. The fuel in the tank doubles as a coolant for the fuel pump, so if you run the tank dry every time, you're actually causing additional wear and tear on the fuel pump.