I really like the look of the layered Window Frames and decided to make a list of all the measurements of the the layers  and leave it in the case that holds it.  As long as I remember to open the case and pull the list out I won't have to measure it again.  Here's a sample of what the layers look like.  

The smallest Window Frame ( will refer to as frame 1)  layers with a 1-1/8" sqaure
Frame 2 layers with a  2" sqaure
Frame 3  layers with a  2-1/2" square
Frame 4 layers with a  2-7/8" square
Frame 5  layers with a  3-3/8" square
Frame 6 layers with a  3-7/8" square

Hope this list will be useful to you and maybe even save you a minute or two looking for a ruler!  If you don't have the Window Frames framelits yet you can order them through my online store  and  remember you receive a FREE spool of the 3/8" Stitched Satin ribbon with every $40 purchase.    Sweet deal and another good reason to shop!