How Big Is 28×40? | Print Size, Pixels & Conversions

28×40 inches is a common print and poster size measuring 28 inches by 40 inches (about 71.1 cm by 101.6 cm), with a total area of 1,120 square inches and a 7:10 aspect ratio.

A 28×40 print is large — big enough to serve as a statement wall piece or a professional presentation poster. It’s part of the Common US Press Sheet series, not an ISO A-series size, so you’ll mostly encounter it in American print shops and frame catalogs. The most common mistake? Confusing it with 27×40 inches, which is the standard movie poster size. They look similar but are not interchangeable. This quick guide covers the exact dimensions, the pixel count you need for sharp output, and how to avoid print-order mix-ups. If you’re ready to shop, see our roundup of the best 28×40 frames that fit this exact size.

Exact Dimensions of 28×40

Here are the precise measurements for the 28×40 format, whether you’re ordering a print or checking frame compatibility.

• Inches: 28 in × 40 in
• Centimeters: 71.12 cm × 101.6 cm
• Area: 1,120 square inches (about 7,225.79 cm²)
• Aspect ratio: 7:10 (roughly 1:1.43)
• Diagonal: about 48.83 inches (about 124.02 cm)
• Perimeter: 136 inches (about 345.44 cm)

What Kind of Paper or Print Uses 28×40?

28×40 is classified as a Common US Press Sheet size. Print shops and commercial printers use it for large-format projects like posters, architectural renderings, presentation boards, and art prints. It is not a standard ISO A-series size — those are defined by ISO 216 and follow a different dimension logic. If you’re ordering a custom poster or a large frame in the U.S., 28×40 is one of the sizes you’ll see listed. The nearby 27×40 size is the movie-poster standard, so double-check which one your project actually requires before submitting a design or buying a frame.

What Pixel Size Do You Need?

To print a 28×40 image at professional quality (300 DPI), your digital file must be large enough. Print vendors typically use 300 DPI as the target for sharp, gallery-grade output.

• Minimum image size at 300 DPI: 8,400 pixels wide × 12,000 pixels tall (because 28 × 300 = 8,400 and 40 × 300 = 12,000).
• Formula: Pixels ÷ desired DPI = print size in inches. So if you have a file, divide its width and height by 300 to see if it reaches 28×40.

Note that different print vendors have different art specs. One may require CMYK color mode with a 0.125-inch bleed on all sides, while another accepts RGB with Adobe RGB (1998) as a color profile. Always confirm your printer’s exact specification sheet before finalizing the file.

Common Mistakes to Avoid

A few easy mix-ups can ruin a print order or a frame purchase:

• Confusing 28×40 with 27×40: 27×40 is the standard movie-poster size. A 27×40 poster will not fit a 28×40 frame, and vice versa.
• Assuming it’s an ISO A-series size: It’s not. 28×40 is a U.S. press sheet standard; ISO A-series sizes follow different proportions (like A0, A1, etc.).
• Using insufficient pixel dimensions: An image that’s 2,000 × 3,000 pixels cannot print sharply at 28×40. You need 8,400 × 12,000 pixels for 300 DPI output.
• Trusting one printer’s color rules for all: Some require CMYK; others accept RGB. Always check the printer’s art-spec sheet.

FAQs

How big is 28×40 compared to a movie poster?

A standard movie poster is 27×40 inches, slightly narrower by one inch. While 28×40 and 27×40 look close, they are not interchangeable for frames or print jobs — always verify which size your project specifies before ordering.

Can a 28×40 poster fit in a 27×40 frame?

No. The 28×40 poster is one inch wider than a 27×40 poster, so it will not seat properly in a 27×40 frame. For a clean fit, choose a frame labeled specifically for 28×40 prints or one that lists adjustable dimensions covering this size.

Is 28×40 a standard size at print shops?

Yes, 28×40 is a recognized size in the Common US Press Sheet series, so many U.S. commercial print shops and online print services offer it as a custom or standard option. However, it is not an ISO A-series size, so shops outside the U.S. may not carry it as a stock item.