Frame & Mat Size
The window is cut smaller than the sheet, and the frame is ordered to the outside of the mat. Everyone gets this wrong the same way.
14.5 × 17.5 in
Mat opening 10.5 × 13.5 in
12 × 18 in — 3 in out across both dimensions, so the mat would need cutting to suit.
Mat covers 44% of the framed face.
For anything you care about, ask for conservation materials: acid-free board, reversible hinges rather than dry mounting, and UV-filtering glazing where daylight reaches it.
Frame and mat sizes: the arithmetic a framer uses
Framing has one piece of arithmetic in it and everybody gets it wrong the same way. The mat window is cut smaller than the artwork, not the same size, so the paper is held rather than balanced on an edge. A quarter inch of overlap on each side is the trade default. The frame is then ordered to the outside of the mat, which is also the size of the glass.
So an 11 × 14 inch print, matted with a 2 inch border, needs a mat opening of 10.5 × 13.5 inches and a 14.5 × 17.5 inch frame. This calculator does that both ways, and names the nearest ready-made size.
How wide should the mat be?
Wider than looks obvious. A narrow mat reads as a mistake; a generous one reads as intention. For a small print up to about 14 inches on the long side, 2 inches is comfortable. Up to 20 inches, use 2.5. Up to 30 inches, 3 inches. Above that, 3.5 to 4 inches and more if the work is delicate.
Never make the mat border the same width as the frame moulding — the two compete. Either mat generously in a narrow frame, or use a wide frame with a modest mat.
Weighted bottoms and why they exist
Traditional framing adds a little extra to the bottom border, usually a quarter to a half inch, sometimes more on large works. Hung above eye level, a mat with equal borders appears bottom-light; the extra depth corrects that optically. Prints, drawings and photographs all take it well. If the work will hang at or below eye level, equal borders are fine.
Working to a ready-made frame instead
If you have a frame and need to fit the work to it, invert the sum: mat border equals half the difference between the frame size and the artwork, plus the overlap. An 8 × 10 print in an 11 × 14 frame gives a border of about 1.6 inches on the short sides and 2.1 on the long sides — visibly uneven, which is why custom mats exist.
For anything you care about, ask for conservation materials: acid-free rag or alpha-cellulose mat board, hinged with reversible tape or corner pockets, never dry mounted, and UV-filtering glazing if the work will see daylight.
| Artwork | Mat border | Mat opening | Frame and glass |
|---|---|---|---|
| 5 × 7 in | 1.75 in | 4.5 × 6.5 in | 8 × 10 in |
| 8 × 10 in | 2 in | 7.5 × 9.5 in | 11.5 × 13.5 in |
| 11 × 14 in | 2 in | 10.5 × 13.5 in | 14.5 × 17.5 in |
| 12 × 16 in | 2.5 in | 11.5 × 15.5 in | 16.5 × 20.5 in |
| 16 × 20 in | 2.5 in | 15.5 × 19.5 in | 20.5 × 24.5 in |
| 18 × 24 in | 3 in | 17.5 × 23.5 in | 23.5 × 29.5 in |
| 24 × 36 in | 3 in | 23.5 × 35.5 in | 29.5 × 41.5 in |
Assumes a quarter inch of mat overlap on each side and equal borders. Add a weighted bottom for a traditional look.
Questions we are asked
- What size frame do I need for an 11 × 14 print with a mat?
- With a 2 inch mat border, order a 14.5 × 17.5 inch frame and a mat opening of 10.5 × 13.5 inches. A ready-made 16 × 20 frame also works with a wider mat.
- How do I calculate mat board size?
- Take the artwork size, subtract twice the overlap (usually a quarter inch per side) for the opening, then add twice the border width for the outside of the mat, which is the frame and glass size.
- How wide should a mat border be?
- About 2 inches for small prints, 2.5 to 3 inches up to 30 inches, and 3.5 to 4 inches on large works. Err generous; narrow mats look accidental.
- Should the bottom mat border be wider?
- Traditionally yes, by a quarter to a half inch, which corrects the optical illusion that makes equal borders look bottom-light when a work hangs above eye level.
- What is the difference between frame size and mat opening?
- The frame size is the outside of the mat and the size of the glass. The mat opening is the window, cut slightly smaller than the artwork so the paper is held behind it.
Beyond the FrameHave the work recorded
Its size, its framing and its condition, entered as they stand today.