Do I need a new enclosure for my BP and if so, suggestions?

[Sauzo]

My big female is in a 40 long. She is about 4 to 4.5 feet long. I was reading that small males can stay in a 20 long, but that seems nuts to me.

Basically, the tank should be half as long as your snake. A 6 foot snake needs a 3 foot long tank. Most bps don't get that long and a 40g will be just fine.

I disagree with "A 6 foot snake needs a 3 foot long tank". General rule of thumb is minimum cage size is length+depth is equal to the snakes total length. The old rule of thumb was length multiplied by depth. I have Rosey, my 6.5-7' girl in a T10 which is 4x2 and I feel it's too small but I cant order a T25(72x30) cage until spring. I have my BP who is just a bit over 4' in a 4x2 and she uses every inch of that cage. The cage should be 3/4 the length of the snake.