🖼️ Picture Frame Mat Calculator
Calculate exact mat border widths, opening sizes, and mat dimensions for any frame and artwork size
Standard framing
Medium weight
Museum/archival
Double mat show
| Frame Size | Artwork Size | Avg Border Width | Mat Opening |
|---|---|---|---|
| 5 x 7 in | 3.5 x 5 in | 0.75 in | 3.25 x 4.75 in |
| 8 x 10 in | 5 x 7 in | 1.5 in | 4.75 x 6.75 in |
| 11 x 14 in | 8 x 10 in | 1.5 in | 7.75 x 9.75 in |
| 16 x 20 in | 11 x 14 in | 2.5 in | 10.75 x 13.75 in |
| 18 x 24 in | 12 x 18 in | 3 in | 11.75 x 17.75 in |
| 20 x 24 in | 14 x 18 in | 3 in | 13.75 x 17.75 in |
| 24 x 30 in | 16 x 20 in | 4 in | 15.75 x 19.75 in |
| 30 x 40 in | 20 x 28 in | 5 in | 19.75 x 27.75 in |
| Frame Size Range | Recommended Border | Gallery/Museum | Notes |
|---|---|---|---|
| Up to 8 x 10 in | 1 – 1.5 in | 1.5 – 2 in | Wider looks professional |
| 11 x 14 in | 1.5 – 2 in | 2 – 2.5 in | Equal or bottom-weighted |
| 16 x 20 in | 2 – 2.5 in | 3 – 3.5 in | Bottom add 0.25–0.5 in |
| 20 x 24 in | 2.5 – 3 in | 3.5 – 4 in | Consider double mat |
| 24 x 30 in | 3 – 4 in | 4 – 5 in | Gallery style preferred |
| 30 x 40 in and larger | 4 – 5 in | 5 – 6 in | Bottom-weight always |
| Undercut Amount | Use Case | Effect on Opening | Typical Application |
|---|---|---|---|
| 1/16 in (0.0625) | Tight fit | Opens each side by 1/16 in | Small prints, photos |
| 1/8 in (0.125) | Standard | Opens each side by 1/8 in | Most artwork — default |
| 3/16 in (0.1875) | Canvas texture | Shows more artwork edge | Textured paper, pastels |
| 1/4 in (0.25) | Large art | Generous reveal | Prints 16x20 and larger |
| 0 (flush cut) | Edge-to-edge | No artwork hidden | Decorative mats only |
A picture frame mat is the border that separates the artwork from the frame. The process of placing these mats is called “matting“. In English, you use the term mount.
A photo, print or other image is laid under the mat and the cutout part surrounds it. This mat not only beautifies the image but also makes framing easy
Picture Frame Mat: What It Is and Why You Should Use It
Using a mat is not only about looks or design. It serves to raise the glass above the artwork so it does not press the image, which could damage it. When glass touches paper, condensation can happen or even mold can grow.
So, never put glass directly on the art. For any type of frame, you can use little spacers to stop the photograph from touching the glass.
For small pieces, a mat gives more force and helps tiny masterpieces get the wall space they deserve. With a frame, a painting or image gets more depth and more attention. The outside dimensions of the mat must be the same as the inside of the frame.
Even so, the window of the mat, where you see the art, must be only a bit smaller than the image itself.
The size of the mat depends on taste and balance, but it must be wide enough so that the paper does not look too narrow. Width between two and a half and four inches usually works well. Instead of choosing from ready sizes, you can order custom cuts so that the mat perfectly matches with the image.
Mats made from acid-free cardboard are ideal for protecting precious images for art shows, ceremonies or talks.
One reason to cut your own mats is the possibility to set the measures exactly as you want. If you buy a ready mat, you must choose which part of the photograph matches with it best. Stores offer very cheap big sheets, so you certainly can cut your own.
It is not just cardboard, but an important layer between the art and the frame. Good advice is to buy the materials, like mat-board and corner glues, but leave the cutting to professionals. Many frame stores cut the hole very cheaply if you bring the board.
Also, it is smart to wear protective gloves so you do not leave fingerprints on the mat.
Bright white borders that do not match the whiteness of the art can create too strong contrast and make the image look old or dark. One way to improve that is to paint the mat a different color. Also covering a plain mat with fabric is a good idea.
Custom mats give a much more polished impression than basic mats bought instore.
