What size exercise ball should I get?

I want to get an exercise ball to take with me to the hospital. They have them there, but I would rather have my own. I'm 5'6" and I found a few online that are 75", 65", and 55".
TIA

<blockquote><b>Quoting Cute&Wicked:</b>" I want to get an exercise ball to take with me to the hospital. They have them there, but I would rather have my own. I'm 5'6" and I found a few online that are 75", 65", and 55". TIA"</blockquote>


Id probably go with the 65"

Quoting Cute&Wicked:" I want to get an exercise ball to take with me to the hospital. They have them there, but I would rather have my own. I'm 5'6" and I found a few online that are 75", 65", and 55". TIA"

I'm 5 even and I use the 55. . . You'd prob want rge 65. I think 75 would be too big.

Sorry about the post and run. Thanks a lot ladies  I was thinking the same thing too.