Yep, it is 7/8" I was putting some squares on point which were a strange finished size of 2.125" So I guessed that a square cut in half of 2.75" would work. It was short just like yours. 3" square cut in half worked perfectly. I usually round up to an inch and then trim. I have never made anything with an 1/8" inch but I am once again making Bibles bags for our missionaries going to the Philippines later this fall again.