A 20 x 20 print fits a 20 x 20 frame with no mat; adding a mat means buying a larger square frame, usually 24 x 24 or bigger.
Buy the wrong frame and you eat return shipping on a heavy box, or you trim the print to force a fit. The gap between the two answers comes down to one question: mat or no mat. A 20 x 20 print is a square format, which narrows your options to square frames — and square frames get thin on the ground fast once you pass 20 inches.
20 x 20 Print, No Mat: Buy a 20 x 20 Frame
Without a mat, the frame size and the artwork size are the same number. A 20 x 20 print drops straight into a 20 x 20 frame, and the frame’s inside edge holds the paper right at its border.
This is the cheapest, fastest route and the one most people should take for a poster-style print with a full-bleed image. Two things to check before you order:
- Print size vs. paper size. A print sold as “20 x 20” usually means the paper is 20 x 20. If the seller describes an image area of 20 x 20 printed on larger paper with a white border, that border has to go somewhere — either behind the frame lip or trimmed off.
- Frame lip width. The frame’s inside edge overlaps the print slightly to hold it against the glass. A thick lip trims a little more of your visible image than a thin one.
Also confirm the frame arrives with glass or acrylic plus a backing board. A frame listed as “frame only” leaves you sourcing both.
20 x 20 Print With a Mat: Buy the Mat’s Outer Size
With a mat, the frame must be larger than the print — the frame size equals the mat’s OUTER dimensions, not the artwork’s. That is the single rule that trips up most buyers.
The mat is a board with a window cut in it, and that window is deliberately smaller than the print. Framing guides note the opening is typically cut about 1/4 inch smaller on each side, so the mat’s inner edge overlaps the paper and keeps it from falling through. That overlap also hides the print’s edges and any handling marks.
The math runs in two steps. First, the opening equals the artwork size minus the overlap — so a 20 x 20 print gets an opening of roughly 19 1/2 x 19 1/2 inches. Second, the outer mat size equals the opening plus the border width on all four sides. A 2-inch border turns that 19 1/2-inch opening into an outer size near 23 1/2 x 23 1/2 inches.
Since frames come in standard sizes, a 2-inch border on a 20 x 20 print lands you at a 24 x 24 frame, where the mat picks up the small difference. A 1-inch border points toward a 22 x 22 frame. Wider borders push you to 26 x 26 or larger. Decide the border width you like first, then let it tell you the frame size.
| Presentation | Frame Size To Buy | What It Costs You |
|---|---|---|
| No mat, full-bleed print | 20 x 20 | Cheapest option; frame lip covers a sliver of the image edge |
| Narrow mat border (about 1 inch) | 22 x 22 | Modest size jump; still a common stock size |
| Standard mat border (about 2 inches) | 24 x 24 | Widely stocked; roughly 4 inches more wall space each way |
| Wide mat border (3 inches and up) | 26 x 26 or larger | Fewer ready-made options; custom cuts get expensive |
| Mat opening for a 20 x 20 print | About 19 1/2 x 19 1/2 | Not a frame size — this is the window the mat gets cut to |
| Pre-cut mat listed as “for 20 x 20” | Check its outer dimensions | Listings quote opening size, not the frame you’ll need |
| Framed print sold as “20 x 20” | Read the finished-size note | Sellers differ; some mean the artwork, some the frame |
Why the Two Numbers Keep Getting Confused
Print size and frame size only match when there’s no mat. The moment a mat enters the assembly, the frame has to swallow three layers — mat, glass, and backing — and each one adds bulk the frame must be built to hold.
That’s where the rabbet comes in. The rabbet is the recessed lip on the back of the frame that the whole stack sits inside. Its depth and inside dimensions need to be slightly larger than the mat, glass, and backing combined, or the package won’t seat and the frame won’t close flat. A frame with a shallow rabbet can’t take a mat, glass, and foam board no matter how correct its outer size looks.
Two other mistakes show up constantly. Cutting the mat opening to exactly 20 x 20 lets the print slip through the window — it has to be slightly smaller. And reading a pre-cut mat’s label as a frame size sends you shopping for the wrong outer dimensions; mat listings quote the opening.
If a white square frame is what you’re after, this roundup of tested 20 x 20 white picture frames covers the no-mat option in the size you need.
Measuring Before You Order
Confirm the frame’s listed size refers to the outer edge, then check the inside dimensions against your stack. Dick Blick’s framing guide and Logan Graphic’s mat measuring guide both walk through the opening-versus-outer-size math if you want to verify your numbers against a second source.
For a 20 x 20 print, the decision comes down to this: no mat means a 20 x 20 frame, and a mat means a bigger square frame sized to the mat’s outer edge. Measure the print, pick your border width, and buy the frame that matches the outer mat — not the artwork.
FAQs
Can I put a 20 x 20 print in a 24 x 24 frame without a mat?
Yes, if the frame has a mat or a filler board to bridge the extra inches. A 20 x 20 print in a 24 x 24 frame with no mat leaves a visible gap on every side, and the print won’t stay centered on its own. Order a mat or backing cut to the frame’s inside size.
Does a mat opening have to be smaller than the print?
Yes. Framing references put the overlap at roughly 1/4 inch per side, so a 20 x 20 print gets an opening near 19 1/2 x 19 1/2 inches. Cutting the opening to the full print size lets the paper drop through the window, and the mat can’t hold it flat.
How do I check a frame’s rabbet depth before buying?
Look for the frame’s inside dimensions and rabbet depth in the specs. The assembly — mat, glass, and backing — needs to fit inside that recess with a little room to spare. If the frame’s numbers don’t list a rabbet depth, ask the seller before ordering.
References & Sources
- Dick Blick. “Frame Guide.” Explains how frame, mat, and artwork sizes relate.
- Logan Graphic Products. “Measuring Mats.” Details mat opening overlap and outer mat sizing.
- Nations Photo Lab. “Framed Prints.” Covers framed print sizing for artwork dimensions.
