Proper Mat Size for Matting an Image

Written by Mark Rogers

Framing sounds simple on paper, but it’s trickier than you may think. Determining the proper mat size and mat opening for a print or photograph is one of the more confusing issues facing novice framers.

First, be sure you understand the two different measurements associated with a frame mat. There is the overall size of the mat, which is about the size of the inside of the frame. Then, there is the mat window measurement, which refers to the size of the opening in the mat through which we see the image.

Measure the Dimensions

To determine the general overall dimensions of the mat, measure the glazing size (size of the glass or acrylic) of the intended frame. If the glass fits inside the frame without too much wiggle room, then it’s a good template for cutting the mat to its overall size.

As for the size of the window in the mat, one simple general rule is that the opening should not be the same size as the print or photo. Cutting a mat to the exact dimensions of the outer border of a picture or photograph is almost impossible and it is nearly impossible to get them lined up perfectly.

Off-the-shelf, pre-cut picture frames usually have mat boards with openings that are half an inch smaller than the intended picture size. For example, a 16x20-inch frame including a mat purchased for use with 11x14 prints or photographs will have an actual window opening somewhere in the neighborhood of 10 1/2 x 13 1/2 inches.

This results in the mat overlaps each side of the print by 1/4 inch. A quarter of an inch does not sound like much on its own, but it adds up since every mat has four sides.

How to Determine Mat Size for a Picture?

One of the most common questions from DIY framers is how large should the mat border be? While we can make suggestions, the answer is: However big you’d like! As a general guideline, the mat should be at least 1.5 times the size of the frame to keep the frame from overpowering the artwork. Adjusting the size of the visible mat will dramatically change the appearance of your art, so it’s important to have an understanding of the desired final look.

Best Practice for Frame Mat Size

Many professional framers, including Frame Destination, recommend a mat border of 2 to 4 inches (unless you have a specific look in mind that calls for a wider or narrower mat). This provides the “traditional” framed look with a mat border that is equal on all sides and doesn’t overwhelm the art.

If your art is smaller, you may want to opt for a border that is closer to 2 inches to avoid overwhelming the artwork. Larger framed pieces can support wider mat borders while still retaining that classic framed look.

Frame Destination can custom cut a mat to any size, so you're not restricted to a standard frame size.

It’s also important to consider the color of the mat you’ve chosen. You can display a large amount of a neutral color mat board without it overwhelming and distracting from the art, but if you’ve opted for a bright, rich or bold colored mat, you may want to consider a narrower border.

More Mat = More Impact

When putting together a framed photo or piece of art, there are three major components that will affect the look and feel of the final piece:

  • The art
  • The frame
  • The mat

In traditional framing practices, the mat plays a supporting role. But in some applications it can become a much larger part of your framed art. Large mat borders can give your art a “gallery” look and can help draw attention to your art if it’s displayed on a large wall.

Opting for a weighted mat (where one or more sides has a wider mat border) is another popular option. Taking weighting to an extreme is a popular modern look that pairs well with black and white photography. There are many mat board styles to give your art the perfect look.

Using bright or bold colored mats is another way to add impact to your art, particularly for black and white photos. Mat board is available in just about every color of the rainbow — including green, blue, purple, orange, red and yellow — so you’re not limited to earth tones or neutrals when framing.

Adding Depth Without Size

If you want to add depth, character or color to your mat without overwhelming the art or opting for a large mat border, consider layered mats. In a layered mat situation, two or three mats (often of different colors) are framed. You see the most of the top layer and smaller amounts of each of the lower layers.

This technique allows you to add some depth to your framing, or introduce a pop of color. For just a little color touch, opt for a neutral or subtle top mat, then select a bold or bright color for the second layer. This technique is ideal when you want to call out a color featured prominently in the art, but don’t want a full-color border. To highlight more than one color, opt for a triple mat with a neutral top and colorful second and third mats. Or you can achieve a modern look by layering white-black-white mats.

For depth without color, opt for mat layers that are the same color or have slight shade variations within the same color palette. This will give you the tiered look without adding more color.

Layered mats can be as large as you’d like, so you can use this technique with large borders or with the traditional 2- to 4-inch mat border.

At the end of the day, how big your frame border is depends on personal preference and your desired look. When you order a mat board from Frame Destination, you can play with the sizes to see how your art will look with its new mat. You can even upload your image for a preview, and change all of the colors of the mat and frame to see all your options before you buy.

Matting Techniques

float mounting

Although allowing the mat to overlap the image is the most common matting technique, sometimes using a mat opening that is larger than the image, known as “float mounting,” works best. This matting technique prevents any masking (or covering) of any part of the framed image. It is especially useful when you want the ability to view the artist’s signature or print data.

There are several ways to accomplish this look, including using different overlap measurements on different edges of the work. Usually the side and top border measurements are between ¼ to ½  inch and the bottom is expanded to reveal between ¼ and 1 inch of the border. In most cases, the bottom dimensions of a mat are equal to the top and sides, but the presence of a signature changes all that. Getting it right requires a little math along with some good measuring skills. Beyond that, another common mistake is to forget to double the border size when calculating the opening.

For example, if the signature is shorter than ½  an inch, you can use ¼- or 3/8-inch top and side borders with a slightly larger ½- inch bottom border. If the signature has a height of 3/4 inch, you can use ½-inch top and side borders. In this case, the mat opening will be 1 inch larger than the image width, and 1¼ inches larger than the image height.

Sometimes drawing out a sketch prior to making any cuts helps better visualize your goals. Beyond that, never forget that the adage “measure twice, cut once” doesn’t just apply to carpentry.

Frame Destination carries several varieties of mats, including 100% cotton, acid-free and lignin-free mats with solid color throughout, plus mats that trap and neutralize pollutants and acid by-products. All mats from our shop feature larger windows than most store-bought mats, meaning more of the image showing through in a framed piece.

All artwork less than 20 inches on each side has mat windows cut ¼ inch smaller, which allows for an overlap of just 1/8 inch for each side. Openings for images 20 inches and larger on both sides are cut ½ inch smaller. The slightly enlarged window opening still allows for sufficient coverage or overlap of any paper border around the image, thereby supporting the image, and negating concerns that the substrate the image is mounted against will show up in the completed framed item.

In Praise of Mats

Mats are an integral part of framing. Practically, mats help keep the framed image flat, and provide a buffer layer between the art or photo and the frame glazing. Aesthetically, mats help accent the framed item, presenting your art at its best and creating a unique look. Depending on the mat’s composition, it can even help preserve your artwork.

In other words, getting matting right isn’t always a piece of cake, but it’s always worth it.

Updated June 25, 2021

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95 thoughts on “Proper Mat Size for Matting an Image”

  • Audrey Riccobono
    Audrey Riccobono October 8, 2021 at 3:08 pm

    The area of the piece I want to frame is 25"x 29" that leaves a 3" border that I would like to cover with a white mat. I think the actual size of the frame I need is 28"x32". Are my measurements correct? I need help in determining the exact size of the frame I need to hang a canvas map that measures 28x32. Please advise.

    • Heather

      Good afternoon Audrey,
      We measure from the inside out, and we recommend choosing your frame you prefer, then clicking on customize and going through the frame content options, including mat size.
      This is the easiest way for choosing a custom frame with the size mat that you prefer.
      For any other framing questions, please reach out to us by email at [email protected] or by phone at 972-479-1188.

      Thank you and have a great day!

  • Liz Clark h

    I have an old stitchery piece done by my lgreat-great grandmother. It was originally framed in a tray, which has not outlasted the lovely cross-stitch. I want to reframe it as wall art. The sitching extends 10"x14"wide on cloth 10"x16" wide. I would like a double or triple mat in black and pink tones, to contrast the beige background and bring out the main colors used in the piece.
    What would you suggest? Re frame size, I am at a loss, except I prefer white or black. XThanks

    • Heather

      Hi Liz! We have many frames with mats to choose from! I would suggest choosing the frame you want first, then go to customize and go through the options for frame contents and sizing.
      Give us a call or email if you have any other questions.
      Thank you and have a great day!

  • Bryan P.

    Hi, I have a piece of artwork I want to frame including a mat, but it has the very unusual dimensions of 25" x 39" and the frame that I bought for it has the equally unusual dimensions of 27" x 41" - what size matboard would be needed for this? Thanks ~ Bryan.

  • Craig A Michel
    Craig A Michel May 22, 2021 at 7:18 am

    If I have a 12"x24" print, what size matting and frame should I go with?

    Thank You So Much!


    • Heather

      Good afternoon Craig! We recommend choosing the frame profile you prefer, then going to customize frame and choosing your content and putting in the size of your artwork. From there you can also customize the mat borders.
      Let us know if you have any questions!
      Have a wonderful day!

  • Annette M.

    I bought a 8.5 by 11 size frame for a 7 by 9 size school certificate.....what size photo matt do I need please?

    • Joely Rogers
      Joely Rogers May 6, 2021 at 6:44 am

      Hi Annette, you'll need to know the frame opening size before you can order the correct size mat. I mention this because it could be 8.5" x 11", but most likely it's cut slightly larger to hold an 8.5" x 11". The easiest way to find out is by measuring the glass or piece of cardboard that came inside of the frame. Whatever that size is will be the outside dimension of your mat board. The inside dimension is opening that you will view your certificate through. The opening is cut slightly smaller so that what you put in it won't fall out. So, for example, with a 7" X 9" certificate and frame opening 8.5" x 11", on our website the dimension would look like this: Artwork Size: 7" x 9"
      Mat Window Opening: 6 3/4" x 8 3/4" Mat Outside: 8 1/2" x 11". This is a link to our mat board types - If you need further assistance please call customer service at (972)479-1188.

  • TD

    This is exactly why I never frame anything. I just have a collection of photos and art that sit in boxes never to be viewed. It's just too darn confusing to figure out the right sizes and it never looks good after I'm finished. I have a great animation cel that is 10.5" x 20" and it's crazy to try and figure out the proper matte size for it nevertheless a proper frame to follow that up with.

  • Cheryl F

    I have a 12x12 acrylic painting on paper that I would like to mat, what size mat should I buy?

    • Heather

      Hi Cheryl,
      Choosing a mat is very easy on our website! You can go to our mats, then specify the particular mat type and there you can see all of the types and colors we offer!
      Let us know by email or give us a call if you would like help or would like us to send you some free samples.

      Thanks and have a lovely evening!

  • Wanda Swanson

    I have a 12 x 12 frame. I Have a nine and three-quarter by nine and three-quarter picture. What size Mat do I need? Thank you

    • Heather

      Good afternoon Wanda!
      The size of the mat depends on how large you want your frame, or how big you want your borders. You can select the type of mat you want, then go to 'specify mat' and put in the artwork size and then select the outside mat size (frame size) or select how big you want the borders to be.


  • Amanda

    I have an 18 x18 frame and a photo that I need to size to fit that frame with the correct matting size as well, I am having the hardest time figuring this out! would I want to print a 14x14 or 16x16? My other problem is that the photo is perfect for a 4x6 or 8x12 ( not a square photo) so I am just lost to say the least! any recommendations? Thanks so much!

    • Heather

      Good afternoon Amanda!
      We measure from the inside out, so you can either have a mat or artwork at 18x18. Its would be up to your personal preference how large you wanted your mat borders to be or if you wanted a mat at all.


  • Steve S.

    Hi! I am trying to get a very exact width of mat visible between the art "window" and edge of the frame. Do I need to account for the width of the frame? For example, let's say I want 2-1/4" of mat visible and I'm using the Nielsen 93 metal frame. It looks like the frame part that covers the mat is 7/16" wide, from the profile drawing of that frame. So does that mean I would really want to order a mat that is 2-11/16" wide, so that the true "reveal" of the mat is 2-1/4"?

    • Heather

      Hi Steve,
      Our frames can have a overlap up to 1/4" of the artwork. Its important to add a small amount to your width and height of our artwork size if you want all of your artwork to be visible.
      Please give us a call if you have any questions.

      Thank you!


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