I get asked by a lot of the women in my classes how to use a paper trimmer. Many try what seems to be strange strategies to get the correct measurements. There are a lot of different types of cutters. Each has its' pros and cons. Each is slightly different but they generally operate under the same principle. Here is a little demo of how to use the measurements on your cutter to your paper to the exact size required.
For my photo mat for this layout I needed 3 1/2' x 2 1/2'. You will see in the photo below I have lined the edge of my paper up with the 31/2' measurement on the side. That is 3 1/2' from the cutting blade, from the plastic ruler which is running in line with the main part of the cutter.
I could go ahead and cut that piece of paper all the way to the bottom but I would rather have 2 pieces of paper (the piece I need and the left over piece) instead of 3 pieces (the piece I need and the 2 pieces cut from my original sheet).
To do this you need to locate the mark on your blade housing (the knob on your cutter which you slide up or down to cut) which indicates where the blade cuts.
See the line on the plastic dome? That is the line on my cutter which indicates where the blade cuts to.
So if you remember, I needed a piece 3 1/2' x 2 1/2'? My paper is already poking out and lining up with the 3 1/2' mark on the arm of my cutter so I take my blade marker down to 2 1/2'. I then cut to the top of the paper. Now I need to turn my paper around and line up the cut at 90 degrees to the plastic ruler which houses the cutting blade.
I hope that helps you with your measuring. Please leave a comment and ask any questions you may have regarding the use of your cutter.