When people say a tort is 6", are they referring to the length of the plastron or carapace or nose to tail or what? Finally gonna get Gomez and Morticia's stats this weekend.
Ignore the bit about Jackson ratio in the above link. The pictures show you how to measure the length of your tort... basically a straight line front to back of shell length.
I put a piece of paper on the floor against the skirting board. Pop the tort on the paper (do it when he's cold, or he will walk off!) so he is hard against the skirting board and then use a book at the other end so I can mark the length on the paper with a pencil.