Aspect Ratio Explained: What It Means for Picture Frames

Aspect Ratio Explained: What It Means for Picture Frames and Print Sizes

Aspect ratio is the relationship between width and height. It determines whether your image fits a standard frame size, how much you have to crop, and what the framed piece will read as on the wall.

Aspect ratio is the relationship between the width and height of a print or photograph. It's expressed as two numbers separated by a colon: 4:3, 3:2, 16:9. The ratio matters because the frame has to match the print, and the wrong ratio means either the print gets cropped or the frame is the wrong shape.

This guide explains the common aspect ratios for printed art and photography and how to pick a frame that fits.

How Aspect Ratio Affects Picture Frame Sizing

A 4x6 photograph has a 2:3 aspect ratio. A 5x7 has a 5:7 ratio. An 8x10 has a 4:5 ratio. The two numbers describe the proportional relationship; you can multiply both by the same number to get a different size with the same shape.

A 4:5 aspect ratio (like 8x10) at twice the size is 16x20. At three times the size, 24x30. The shape stays the same; only the absolute size changes.

The frame opening must match the aspect ratio of the print, or the print won't fit cleanly. An 8x10 print needs an 8x10 mat opening, not an 8.5x11 opening that would leave white space, not a 7.5x9.5 opening that would crop the print.

Common aspect ratios for prints

3:2 ratio. Common for digital photography from DSLR and mirrorless cameras. Print sizes: 4x6, 8x12, 12x18, 16x24, 24x36. Most modern photographs come in this ratio.

4:3 ratio. Common for older film cameras and some digital cameras. Print sizes: 6x8, 9x12, 12x16, 18x24. Less common in newer photography but still relevant for certain workflows.

4:5 ratio. Common for portrait photography and Instagram-friendly compositions. Print sizes: 4x5, 8x10, 11x14, 16x20. The classic studio portrait ratio.

5:7 ratio. Common for casual prints. Print sizes: 5x7, 10x14. Older but still around.

1:1 ratio (square). Common for Instagram and modern art. Print sizes: 8x8, 10x10, 12x12, 16x16, 20x20, 24x24.

Letter and legal ratios. Documents and certificates. 8.5x11 (close to 4:5), 8.5x14 (close to 1:1.65). Most diplomas and certificates fit these.

Panoramic ratios. Wide-format prints like landscape photography or architectural photography. 1:2, 1:2.5, or wider. Print sizes: 8x16, 10x20, 12x24, 16x32.

Picking the frame size for the print

The simplest approach: order a frame with an opening that exactly matches the print size. If you have a 16x20 print, order an 16x20 mat opening. The frame's outer dimensions are determined by the mat width plus the print size.

For a 16x20 print with a 3-inch mat width, the outer frame is 22x26.

For unusual sizes (10x14, 18x36, 12x36 panoramic), a made-to-size frame at the exact print dimensions plus mat width is the right call. Standard ready-made frames don't accommodate non-standard ratios.

What happens when the ratio is wrong

If you put a 4:5 print (8x10) into a 3:2 frame opening (8x12), the print does not fill the opening. Two inches of empty space on one dimension. The frame looks awkward.

If you put a 3:2 print (8x12) into a 4:5 opening (8x10), the print is too long for the opening. Either the print gets cropped (lose 2 inches of image) or the print sticks out beyond the mat.

Neither outcome is good. Match the aspect ratio at order time.

Resizing for a different ratio

If you have a print in one ratio and want a frame in a different ratio (say, you have a 4x6 photograph and you want to display it as a square in a 6x6 frame), you have two options.

Crop the print. A 4x6 cropped square loses 2 inches of width. The cropped print fits the 6x6 frame opening exactly. The decision is whether the cropped image still works artistically.

Re-print at the new size. Rather than cropping, re-print the photograph or art at the new size. A 4x6 can be re-printed as a 4x6 (same ratio, same size) or scaled to a different ratio with intentional cropping or extension. Many printing services offer this.

For valuable original art (signed prints, drawings, paintings), do not crop. Order a frame that matches the existing dimensions.

Why the configurator asks for exact print dimensions

When you order a size-matched frame, the configurator typically asks for the print's exact dimensions, not the standard ratio. The reason is that prints are not always at standard sizes. An 8x10 print is sometimes 7.875x9.875 or 8.125x10.125 depending on the printer. A 16x20 is sometimes slightly off.

Measure the print with a ruler before ordering. Use the actual dimensions for the frame opening. The mat width is a separate decision around that opening.

For prints with unusual sizes, the exact measurement at order time prevents the print from arriving and not fitting the frame.

Frequently asked questions

Why are some aspect ratios more common than others?

The ratios that dominate consumer printing reflect the cameras and printers that produced the prints. 3:2 is the digital DSLR standard. 4:5 is the studio-portrait standard. 5:7 is the historical film snapshot. 1:1 became popular with Instagram. The "common ratios" are not absolute; they reflect the supply chain that produced the prints.

Should I always pick the print size that matches a standard ratio?

For most prints, yes. Standard ratios mean standard frame sizes, which are cheaper and easier to find. For unusual ratios, non-standard-size frames work but cost slightly more.

What's the easiest way to measure a print's aspect ratio?

Measure the print's actual width and height. Divide the longer dimension by the shorter dimension. The result is the aspect ratio (1.5 means 3:2, 1.25 means 4:5, 1.4 means 5:7).

Can a square print go in a rectangular frame?

Only if the rectangular frame's mat opening is sized to the square print. The mat covers the rectangular space outside the square. Common for displaying a small square print in a larger frame with mat padding around it.

Are panoramic frames more expensive than standard frames?

Slightly. The wider profile uses more moulding material per linear foot. Panoramic frames at 12x36 typically cost 25 to 40 percent more than 12x36 standard-ratio frames.

What we ship

Our configurator handles any aspect ratio. Enter your print's exact dimensions and choose a mat width. The frame is built to those specifications. We don't restrict to "standard sizes" because the right size is the one that fits your art, not the one that fits a pre-cut frame.

For prints in unusual ratios (panoramic, ultra-portrait, oversized square), the framing is the same process. We just cut the moulding and mat to your specifications.

The goal is for the print to fit perfectly in the frame, with no awkward white space and no cropping required. Done right, the aspect ratio is invisible, the print just fits.