Photo Mat Size Calculator
Calculate the correct mat board size, window opening, border widths, and double-mat reveal for any photo, print, or artwork. Get a clean framing plan before you cut, order, or visit a framer.
Build your photo mat cutting plan
Measure the artwork and the usable inner opening at the back of the frame. The calculator will show the outer mat board, cut window, visible borders, and double-mat reveal.
Use a second mat board underneath the top mat when you want a thin accent border around the window.
An 11 ร 14 in mat for your 8 ร 10 in artwork
The window will overlap the artwork around every edge and leave balanced borders inside the frame.
Visible mat borders
Layout is schematic
The preview shows proportion and position only. Confirm physical measurements before cutting a board.
Lower mat opening
The lower mat uses the same outer board size. Its opening is larger than the top opening so the selected reveal remains visible on all four sides.
Photo mat checklist
- Confirm the artwork dimensions and orientation.
- Measure the usable inner opening at the back of the frame.
- Check that the top-mat window is smaller than the artwork by the chosen overlap.
- Verify the displayed borders are positive and visually balanced.
- Decide whether you want a single mat or a double-mat accent reveal.
Plans stay only in this browser. Load one to compare a different frame or border layout.
No saved photo mat plans yet.
Quick answer: how do you calculate a photo mat size?
The outer size of a photo mat should match the usable inner dimensions of your frame. The opening in the top mat should be slightly smaller than the artwork so the board overlaps the print on every side. Once you know the frame size and the window size, the remaining space becomes the mat border. This Photo Mat Size Calculator handles those measurements in one place and turns them into a clear cutting plan.
Start with accurate artwork dimensions, then measure the frame from the back where the glass, mat, and backing sit. That inner measurement is more important than the outside dimensions printed on a retail frame package. An artwork may fit visually in a frame but still need a different mat-board size because the moulding takes away usable space.
The calculator uses your selected overlap to reduce the window size. It then calculates the visible top, bottom, left, and right borders. You can keep the layout centered or make the bottom border a little larger for a traditional presentation. When you enable a double mat, it also calculates the lower opening needed to leave a consistent reveal around the top window.
Measure the artwork, frame, and mat opening correctly
Measure the visible image area you want the mat to frame. For a printed photograph with a white paper margin, decide first whether the mat should cover that margin or show it. Use the dimension that matches your intended visible result. Then measure the inside opening of the frame at the back. This is often called the rabbet or rebate area, and it determines how large the mat board can be.
The opening should normally be smaller than the artwork. That small difference is called overlap. It keeps the artwork from slipping through the cut window and avoids tiny gaps from appearing if the print shifts. A very small overlap may suit a precisely mounted print, while a larger overlap can give more tolerance for a home-cut mat. Choose an amount that suits your artwork and how you will mount it.
A standard centered layout divides the remaining horizontal and vertical border space equally. A bottom-weighted layout keeps the left and right borders even but shifts extra space to the lower edge. This can look especially balanced on portrait photographs, certificates, and vertical art. The calculator shows the exact visible borders, so you do not need to rely on guesswork or mental arithmetic.
Single mat vs. double mat: what changes?
A single mat uses one board with one window. It is clean, simple, and suitable for most framed photos. A double mat places a second board behind the top mat. The lower board has a slightly larger opening, so a narrow color reveal appears around the artwork. The reveal can pull out a color from the image, match the frame, or create a subtle layered look.
Both boards normally share the same outer dimensions because both must fit into the same frame. What changes is the window cut. The lower opening is wider and taller than the top opening by twice the reveal measurement. For example, a 0.25-inch reveal adds 0.50 inch to both the width and height of the lower opening. This tool states both openings clearly when double-mat mode is on.
Before choosing a double mat, check the depth of your frame. Two mat boards, glazing, artwork, backing, and mounting materials need enough space inside the frame. A local framer can help if you are unsure whether the moulding depth is sufficient.
Use framing measurements with other home-planning tools
Framing is usually part of a wider room-layout decision. After choosing the frame and mat size, use the TV Mounting Height Calculator to check a comfortable viewing height when the artwork will sit near a television wall. It helps you avoid placing either piece so high that the arrangement feels disconnected from the room.
For fashion illustrations, measurement charts, or a framed outfit print, the Dress Size Measurements Calculator can help you create an accurate reference layout before you print and frame it. And for kitchen prints, recipe art, or a menu board, the Air Fryer Calculator is a practical companion when you are designing useful decor for an everyday cooking space.
These tools solve different problems, but they share the same habit: measure first, choose proportions intentionally, and keep a copyable plan before you commit to a purchase or installation.
Common photo matting mistakes to avoid
Using the outside frame size
Measure the inside space at the back of the frame. The outside dimensions do not tell you whether the board will fit.
Cutting the window too large
Leave a small overlap so the mat holds the artwork and does not reveal a distracting edge gap.
Ignoring border balance
Even borders feel clean, while a slightly larger lower border can create a more classic visual balance.
Forgetting the cutting plan
Copy the outer board, opening, and border sizes before ordering materials or handing the project to a framer.
Photo Mat Size Calculator FAQs
How do I calculate the right photo mat size?
Start with the usable inside dimensions of the frame, because that is the outer size of the mat board. Then make the window slightly smaller than the artwork so the mat overlaps and holds the edges. The remaining space between the window and the outside of the mat becomes the visible borders. This calculator works out the mat board size, window cut size, and border widths from those measurements.
Should the mat opening be smaller than the photo?
Usually, yes. A small overlap lets the mat hold the photo or artwork in place and avoids a visible gap around the edges. The exact amount depends on the artwork and mounting method. This calculator lets you choose the overlap instead of assuming one fixed rule.
Do I measure the outer frame or the inner frame opening?
Measure the usable inner space at the back of the frame, sometimes called the rabbet or rebate area. The outside dimensions of the frame do not tell you how large the mat board can be. A mat cut to the outer frame size may not fit inside the frame.
What is a bottom-weighted mat?
A bottom-weighted mat uses a slightly wider lower border than the top border. It is a common presentation choice for photographs, prints, and artwork because it can make the framed piece feel visually balanced. The calculator offers centered, slightly bottom-weighted, and classic bottom-weighted layouts.
How does a double mat work?
A double mat uses a top mat over a second mat. The lower mat is cut with a slightly larger window, leaving a narrow colored reveal around the top-mat opening. Both boards normally use the same outer size, while the lower opening is wider by twice the reveal amount.
Can I use centimeters, millimeters, or inches?
Yes. Choose inches, centimeters, or millimeters before entering your artwork and frame dimensions. The calculator converts all measurements internally, so the layout stays consistent when you switch units.
What happens if the artwork or window is too large for my frame?
The calculator shows an alert instead of presenting a misleading cutting plan. Use a larger frame, reduce the overlap carefully, or choose a different artwork size. A mat needs positive border space on every side to be usable.
Is this photo mat size calculator a substitute for a professional framer?
No. It is a planning tool. A professional framer can check mounting, glazing, conservation materials, irregular artwork, moulding depth, and cutting tolerances. Use the results as a clear starting specification when ordering a mat or discussing a custom frame.
This tool is for educational purposes only. Always verify important results with a qualified professional.
