How big do adult bettas get?

I've only seen the ones for sell, the descriptions I've read say 2-1/2 inches, does that include his tail?

 

Most of the places that I've read about bettas says they grow up to 3". It probably includes it's tail.
Tom

 

That's about right. That's how I knew Rusty was fully mature when I got him.

 

The biggest Betta I've personally seen was about 3.5" - an older Plakat, but I'd agree on 2.5 to 3" for most male Bettas.. probably about an inch less for females.. does this sound right to our more experienced Betta parents?

 

Yeah 2.5-3" sounds about right.