A common challenge in picture framing is how to make art fit a ready made picture frame. Ready made frames are appealing because they are cheap. But because ready made frames are already assembled they are only available in the most popular standard sizes like 8″x10″, 11″x14″ and 16″x20″. So what do you do when the art you want to frame doesn’t match one of these sizes?

This is where a mat can be your friend. By using a window mat you can adjust the size of your presentation to fit a standard size frame. Here’s how it works.

Let’s say you art is 19″ x 22″ and you want to use a ready made frame. Using a mat, you could squeeze it into a 20″ x 24″ but that would result in one inch wide mat borders, which are too narrow and would look amateurish. These days having wider borders is preferred, so a better option would be to go with a 24″x30″ for your 19″x22″ art.

To determine the measurements of the mat, take the narrow dimension of the art and subtract it from the narrow dimension of the frame. In this case, subtract 19″ from 24″. The difference is 5″. Now acknowledge the fact that there must be two mat borders on each dimension. So, for example, the width dimension of the mat will have a border on either side of the window. So take the 5″ and divide it in half. 5 ÷ 2 = 2-½”. Your mat will have 2-½” borders on either side of the window.

Next take the long dimension of the art and subtract it from the long dimension of the frame. In this case, subtract 22″ from 30″. The difference is 8″. Then divide it in half. 8 ÷ 2 = 4″. Your mat will have 4″ borders on either side of the window on the long dimension.

Now you have all the measurements of your mat: the overall size plus the sizes of the borders on each side of your mat’s window. But there’s one more thing you should know before you begin cutting.

Make your mat borders slightly wider. This is necessary because otherwise the window will be the same size as the art, and there will be no overlap of the mat onto the edges to support the art. To get the necessary overlap, add 1/4″ to each of your four mat borders. In our example, add  ¼” + 2-½” = 2-¾ for the borders on the short dimension. And  4″ ¼” + 4″ = 4-¼” for the borders on the long dimension.

Here’s the bottom line. If you cut a mat with an overall size of 24″x30″, and you cut borders on the narrow dimension of 2-¾” and borders on the long dimension of 4-¼”, you will be able to frame a 22″x24″ in a ready made 24″x30″ frame.

That’s how to make art fit a ready made picture frame.