A1 Poster Size Explained: Dimensions, Uses, and the Best U.S. Alternative
If you have searched for A1 poster printing in the United States, you may have noticed something confusing: many American print shops do not offer true A1 sizing.
That does not mean your artwork cannot be printed correctly. In most cases, A1 poster designs can be resized or adapted to a common U.S. poster size such as 24×36 inches.
This guide explains what A1 poster size means, how it compares to 24×36 posters, and what to do if you need large poster printing in the United States.
What Size Is an A1 Poster?
A1 is part of the international ISO paper size system. It is commonly used in Europe and many other countries for posters, signs, drawings, and large printed graphics.
A1 Size in Inches
23.4" × 33.1"
A1 Size in Millimeters
594 × 841 mm
A1 Size in Centimeters
59.4 × 84.1 cm
A1 Aspect Ratio
1 : 1.414
A1 Poster Size Compared to 24×36
The closest common U.S. poster size to A1 is 24×36 inches. It is larger than A1 in both dimensions, and many artists, designers, and businesses use it as the American alternative.
A1 Poster
- 23.4" × 33.1"
- Aspect ratio 1 : 1.414
- International ISO paper size
- Common outside the U.S.
- Used for posters, signs, art, and technical prints
24×36 Poster
- 24" × 36"
- Aspect ratio 1 : 1.5
- Common U.S. poster size
- Easier to frame in America
- Popular for art prints, event posters, and convention displays
The One Thing Most A1 Guides Get Wrong: Shape
A1 and 24×36 are often called "basically the same," but they are not the same shape, and that matters more than the size difference.
Every ISO size, including A1, uses a 1 : 1.414 aspect ratio (the square root of 2). That ratio is what lets you fold any ISO sheet in half and get the next size down. A 24×36 poster uses a 1 : 1.5 ratio instead. In plain terms, 24×36 is proportionally taller and narrower than A1.
So when people say 24×36 is "slightly larger," that is true for the overall area — but it understates the shape change. If you drop A1 artwork straight onto a 24×36 canvas, the proportions will not line up, and you will end up with either extra space or trimmed edges. It is not a dealbreaker; it just means your file needs a deliberate adjustment rather than a straight scale. If you want to understand exactly how ratios affect cropping and white space, our guide to print aspect ratios breaks it down.
Can You Print A1 Posters in the United States?
Yes, but many U.S. printers do not stock true ISO paper sizes like A1. American poster printing is based on inch sizes such as 11×17, 18×24, and 24×36.
If your file is designed at A1 size, the most practical U.S. alternative is 24×36 poster printing. Because of the ratio difference above, the artwork will usually need slight resizing, cropping, or an extra margin, depending on the design.
Best U.S. Alternative to A1 Poster Printing
For most customers, 24×36 is the best alternative to A1. It gives you a large, impressive poster size without requiring a specialty international paper format.
24×36 works especially well for:
- Art prints
- Convention posters
- Retail signage
- Event posters
- Photography prints
- Theatrical and film-style posters
- Booth displays
Quick Recommendation
If your artwork is A1 size and you are printing in the U.S., choose 24×36 posters unless you specifically need exact A1 dimensions.
For most posters, art prints, and displays, the practical advantages of 24×36 outweigh the small difference in size and shape.
How to Resize A1 Artwork for 24×36 Printing
Because A1 (1 : 1.414) and 24×36 (1 : 1.5) are different shapes, your file needs an adjustment before printing. You have three clean ways to handle it:
Option 1: Scale to Fit
The full A1 design is scaled to fit inside the 24×36 poster. Nothing is cropped, but the ratio difference leaves a thin band of white space on two edges.
Option 2: Crop Slightly
The artwork fills the full 24×36 area, with a small amount trimmed from the top and bottom to match the taller proportion.
Option 3: Add Background
The design is extended with background color, texture, or bleed so the final print fills the full size cleanly with no cropping.
Tips Before Printing an A1 File
- Keep text and logos away from the edges. This gives the printer more room to adjust the file for the ratio difference.
- Use a high-resolution file. 300 DPI at full size is ideal for large poster printing.
- Include bleed when possible. Bleed helps prevent unwanted white edges after trimming.
- Check the final proof carefully. Make sure no important artwork, signatures, or text sits too close to the trim area.
Is A1 a Good Size for Art Prints?
A1 is a great size for large art prints, especially when the artwork is meant to be displayed as a statement piece. In the U.S., though, 24×36 is often a better selling size because frames are easier to find.
For artists selling prints online, at conventions, or in retail shops, standard U.S. sizes make life easier for customers. A buyer is more likely to purchase a print when they know they can frame it without ordering a custom frame.
Need Large Poster Printing?
Printkeg offers professional poster printing for artists, events, shops, and conventions. While we do not currently offer true A1 sizing, our 24×36 posters are a practical U.S. alternative for many A1 poster designs.
Popular large poster sizes include 24×36, 18×24, 13×19, and 11×17.
Every order is reviewed by a real human before printing to help catch common file issues like sizing, bleed, and resolution problems.
Frequently Asked Questions About A1 Poster Size
What size is an A1 poster in inches?
A1 poster size is 23.4 inches by 33.1 inches.
What size is an A1 poster in millimeters?
A1 size is 594 × 841 millimeters.
Is A1 the same as 24×36?
No. A1 is 23.4" × 33.1" with a 1 : 1.414 aspect ratio, while 24×36 is larger and uses a 1 : 1.5 ratio. 24×36 is the closest common U.S. poster size, but it is proportionally taller and narrower than A1.
Can I print an A1 file as 24×36?
Yes. Because the two sizes have different aspect ratios, the file usually needs slight resizing, cropping, or added background area to fit 24×36 correctly.
What is the best U.S. alternative to A1?
24×36 inches is the best U.S. alternative to A1 poster size.
Is A1 good for artist alley posters?
A1 is large and eye-catching, but 24×36 is often more practical for U.S. artists because it is easier to print, ship, and frame.
The Bottom Line
A1 poster size is a popular international format measuring 23.4" × 33.1" at a 1 : 1.414 aspect ratio. If you are printing in the United States, 24×36 posters are the closest and most practical alternative — just remember they are a slightly different shape, so your file may need a small adjustment.
For artists, photographers, event organizers, and shops, 24×36 gives you a large professional poster size that is easier to produce, easier to frame, and easier for customers to understand.
