Shape Based pricing Template-Contact your local PO
Here ya go Fran, and some other folks who have been having to just put up with being overcharged for the past 15 months.
I found This page at the USPS
To help determine mailpiece size, use Notice 3-S, First-Class Mail Shape-Based Pricing Template. Contact your local Post Office to obtain one.
I will call my local PO tomorrow, and get the details (cost, availability, whatever) I had talked to my Post Master some time back about them being available to the public, and he was not aware that they were, but we both thought it would be a good idea if they were available. I'm sure if he doesn't have the details, that he will certainly get them for me. I have some of the most wonderful local PO folks. They are really on the ball, and aim to please.