The right mat size for a 16×20 frame depends on your artwork’s dimensions, with an 11 x 14 print using a 10.5 x 13.5 inch opening.
Matching a mat to a 16×20 frame goes wrong when the opening is too large (print slips through) or underlaps the art (raw edge shows). Neither is fixable after cutting. The process comes down to measuring your artwork first, then working backward to the opening size. Whether framing a family photo, certificate, or poster, the math stays the same. A mat creates visual breathing room and keeps art from touching glass—both depend on getting the opening dimensions right.
Measuring Your Artwork Before Anything Else
Start with the actual piece, not the frame size. Measure the artwork’s exact height and width in inches. Prints labeled “11 x 14” can vary by a fraction of an inch depending on the printer, so a quick measurement prevents a frustrating mismatch. For a 16×20 frame, the most common setup pairs it with an 11 x 14 print. The mat’s outside edge matches the frame’s inside edge at 16×20, while the opening is cut to fit the print. Using a ready-made mat avoids the cost and hassle of custom cutting.
The Standard Opening Size for an 11 x 14 Print
A standard ready-made mat for a 16×20 frame with an 11 x 14 print uses a 10.5 x 13.5 inch opening. That half-inch difference is deliberate—the extra quarter-inch on each side lets the mat overlap the print’s edges so the art stays put without tape or adhesive touching the image. This overlap also creates even borders: roughly 2.5-inch side borders and 3-inch top and bottom borders. The slight extra weight at the bottom is a classic framing choice that keeps the piece visually grounded.
Cutting a Mat for a 16 x 20 Artwork
If your artwork is itself 16 x 20 and you want a mat around it, the frame must be larger, like a 20 x 24, since a same-size frame leaves no room for mat borders. When cutting a mat for artwork slightly smaller than the frame, the opening must overlap the art edges. Standard practice cuts the opening 0.25 to 0.5 inches smaller than the artwork on each dimension, with at least 1/8 inch overlap per edge to keep the art secure and prevent raw edges from peeking through. For example, an 8 x 10 artwork gets a mat opening around 7.75 x 9.75 inches.
Avoiding the Measurement Mistakes That Ruin Frames
Frame sizes are measured from the back inside edge, called the rabbet—the lip the glass, mat, and backing sit against. The rabbet must accommodate the combined thickness of everything going into the frame; if too shallow, the backing won’t close properly. Check rabbet depth against your materials:
- Standard single mat: roughly 1/8 inch thick, plus glass and backing board
- Glass adds about 1/16 to 1/8 inch depending on type
- Backing board adds roughly 1/8 inch
- Total stack for a single mat setup: about 1/4 to 3/8 inch
Most commercial frames accommodate a single mat with standard glass. Double matting or thick canvas prints push the stack higher and may require a deeper rabbet. Another frequent slip: measuring the mat’s outside dimension instead of the opening. The outside edge must match the frame’s inside rabbet, while the opening must match the art. Mixing these leads to a mat that rattles or covers part of the image. If you’d rather not calculate and cut, pre-sized options solve the problem—ready-made mats for 16×20 frames with 11 x 14 openings are widely available, and the best 16×20 frame with mat options we’ve tested pair both so the sizing work is done.
| Artwork Size | Mat Opening | Border Width |
|---|---|---|
| 11 x 14 print | 10.5 x 13.5 inches | 2.5″ sides, 3″ top/bottom |
| Artwork slightly smaller than 16×20 | 0.25–0.5″ smaller than art | Depends on art size |
| 16 x 20 artwork | Needs larger frame (e.g., 20 x 24) | Depends on frame choice |
When measuring your art, note whether you want a wider bottom border—many framers add an extra half-inch to visually offset the frame’s weight. This is purely aesthetic, so match it to the room and piece rather than a hard rule.
Matboard Plus’s sizing guidance reinforces the core principle: the opening must always be smaller than the art. Their framing reference documents the overlap requirement that keeps mats from looking like a mistake. Matboard Plus’s mat opening size guide covers standard formulas for common print sizes.
FAQs
Can I use a 16×20 frame without a mat?
Yes. A 16 x 20 artwork fits directly in a 16 x 20 frame with no mat. The art sits against the glass, which works fine for posters and casual displays, though glass contact can cause sticking over time with certain prints or photos.
What size mat do I need for an 8×10 photo in a 16×20 frame?
An 8 x 10 photo needs a mat with a 7.5 x 9.5 inch opening (0.5 inches smaller than the art) and an outside edge cut to 16 x 20. This creates borders of roughly 3.75 inches on the sides and 5 inches top and bottom.
Should the mat opening overlap the artwork?
Yes, the mat opening should overlap the artwork by at least 1/8 inch on each edge. Without this, the art can shift, slide, or show a raw edge. Standard practice cuts the opening 0.25 to 0.5 inches smaller than the artwork dimensions.
References & Sources
- Matboard Plus. “Mat Size vs. Opening Size.” Explains the overlap requirement and standard opening formulas.
