What size gas tank do I have?

[tcestes]

I'm having the all too common problem with my fuel gauge not reading correctly. Can someone tell me what size gas tank I have? I've got a 2001 Grand Prix GT with the 3800 series engine.

[Toofastgs]

Just shy of 18g

[Sabrewings]

GM says 17 gallons, plus whatever the fill neck can hold.