The first step in mat cutting is to cut your 32x40 mat board into smaller mat sizes to match the frame sizes you intend to use. Cutting windows for your picture is described separately. Pay attention to how you lay out your cutting pattern so you can maximize the number of smaller mats you can get from one large mat board. Cutting one way on a 32x40 board gives 16, 8x10 mat boards, but cutting the other way gives only 15, 8x10 mat boards, resulting in 6.25% wastage. You should draw the pictures and verify this for your self.

When cutting 11x14 inch mats, you can get six 11x14 and six 5x7 mats from one 32x40 inch board.

Make sure your measurements are exact. Mat boards may by slightly larger than 32x40 in which case you may have to trim one of the ends.

Make sure your boards and mats are square. Don't use a T-square to make square lines. They are too often in error. It is best to measure from one known straight and square side on the top and bottom and then draw a line connecting the marks to make a cutting line.

To guide your cut, use a metal ruler at least as long as the line you want to cut. That is, you need to have a metal ruler at least 40 inches long. A shorter one is also good when working with smaller mats and shorter cuts. Buy the widest ruler you can because it will be easier to hold down. A good cheap compromise is a metal yard stick. Yes, it is only 36 inches, but it only costs a few dollars compared to $20 or $30 for a good metal ruler.

A wood ruler is not good since your knife will cut into the wood.

Any standard utility knife with sharp blades is OK for cutting the outside edges of the mats. Special tools are available but they are very expensive compared to a utility knife.

A special mat cutting tool is needed to cut the mat windows since they are cut at a 45 degree angle called bevel cuts. The outside edge of the mats are standard 90 degree cuts.

To make you cut with the utility knife, stand directly behind the line to be cut and pull the knife toward you. You will not be able to cut through the board in one pass so don't try. The first pass is critical so make sure you knife stays on the metal edge. You might want to tape your metal edge down so it doesn't move. Make a light first cut, just enough to cut a small groove in the board which will guide you knife on future cuts. Continue making cuts until your knife goes through the board. It may take a few as four or as many as ten passes. Don't force it. Extra force will cause you to pull away from your line and ruin your mat board. Patience is key here as well as throughout the entire matting process.