September 7, 2026
Working between US inches and metric centimeters for poster projects? Here are every standard size converted, with field notes from a decade of campaign work.
Working between US inches and metric centimeters for poster projects? Here are every standard size converted, with field notes from a decade of campaign work.
Standard poster size in cm depends on which standard you’re working with. The United States uses inch-based dimensions. Most of the rest of the world uses the ISO metric system, which measures in millimeters and centimeters.
If you’re producing posters for a US campaign, you’ll work in inches. If you’re working with a European design team, a metric-based print shop, or producing materials for international distribution, you need the cm conversions.
We run campaigns across US cities and work with clients who distribute globally. We deal with both measurement systems regularly. Here’s the full reference for standard poster sizes in centimeters.
The US poster industry works in inches. Here are all the standard US sizes converted to centimeters for international reference.
| Poster Name | US Size (inches) | Size in CM | Typical Use |
|---|---|---|---|
| Small Photo Poster | 8 x 10 in | 20.3 x 25.4 cm | Interior close-up, photo prints |
| Small Poster | 11 x 14 in | 27.9 x 35.6 cm | Bar walls, store windows |
| Tabloid / Small Campaign | 11 x 17 in | 27.9 x 43.2 cm | Interior campaigns, flyers |
| Medium Poster | 18 x 24 in | 45.7 x 61 cm | Concert venues, event promotion |
| Poster Board (Standard) | 22 x 28 in | 55.9 x 71.1 cm | School projects, retail signage |
| Standard Outdoor Poster | 24 x 36 in | 61 x 91.4 cm | Street campaigns, outdoor advertising |
| Movie One-Sheet (US) | 27 x 40 in | 68.6 x 101.6 cm | Theater lobbies, entertainment |
| Large Format | 36 x 48 in | 91.4 x 121.9 cm | Exhibition, academic conference |
| Transit / Two-Sheet | 40 x 60 in | 101.6 x 152.4 cm | Bus shelter, transit advertising |
Europe and most of the world outside the United States use the ISO 216 standard. This system defines paper and poster sizes in millimeters. When converted to centimeters, here are the key sizes.
| ISO Size | Dimensions (mm) | Dimensions (cm) | Closest US Equivalent |
|---|---|---|---|
| A0 | 841 x 1189 mm | 84.1 x 118.9 cm | 33.1 x 46.8 in (larger than 24×36) |
| A1 | 594 x 841 mm | 59.4 x 84.1 cm | 23.4 x 33.1 in (close to 24×36) |
| A2 | 420 x 594 mm | 42 x 59.4 cm | 16.5 x 23.4 in (close to 18×24) |
| A3 | 297 x 420 mm | 29.7 x 42 cm | 11.7 x 16.5 in (close to 11×17) |
| A4 | 210 x 297 mm | 21 x 29.7 cm | 8.3 x 11.7 in (letter size) |
The most commonly used European poster size is A1 at 59.4 x 84.1 cm. This is the closest metric equivalent to the US 24×36 inch (61 x 91.4 cm) format. A1 is slightly narrower and shorter than the US 24×36, but the difference is small enough that artwork can be adapted between the two with minor adjustments.
For US campaigns, the standard outdoor poster is 24×36 inches, which converts to exactly 61 centimeters wide by 91.4 centimeters tall.
61 x 91.4 cm is the dimension to give a metric-measurement print shop if you want a standard US outdoor poster. Some international print shops stock this exact roll width (61 cm is also sold as a standard roll in metric markets), so the cut is clean.
A 24×36 / 61 x 91.4 cm poster is about as tall as a seated adult person. Mounted at eye level on a wall in SoHo or along the Bowery in New York, it fills the visual field of a pedestrian walking past. That’s the practical size perception that makes it effective outdoors.
Quick Conversion: 1 inch = 2.54 centimeters. So 24 inches = 60.96 cm (round to 61 cm) and 36 inches = 91.44 cm (round to 91.4 cm). For a 24×36 poster, tell any metric-based printer: 61 cm x 91.4 cm.
The US poster industry uses inches because the US printing industry standardized on the imperial measurement system. Roll paper widths, press sheet sizes, and cutting machines in US print shops are calibrated in inches. Changing the system would require replacing billions of dollars in equipment.
Europe adopted the ISO metric system after World War II, aligning with the international scientific community’s move to metric measurements. The ISO 216 standard (A-series paper) was designed with elegant mathematical properties: each size is exactly half the area of the one above it, and all sizes have the same aspect ratio (1:√2 ≈ 1:1.414). This makes scaling and proportional design simpler.
The two systems aren’t compatible by design. The US 24×36 (61×91.4 cm) doesn’t map to any ISO size. A1 (59.4×84.1 cm) is the closest match, but it’s not identical. If you’re designing for both markets, you need separate file versions or must accept that one version will have small margins or slight cropping when printed in the other format.
The conversion factor is simple: 1 inch = 2.54 cm. Going the other way: 1 cm = 0.394 inches.
For common poster widths:
Most design applications let you set the canvas size in either inches or centimeters. In Adobe Illustrator, go to Document Setup and change the unit to centimeters if you’re working with a metric-based print shop. In Photoshop, go to Image Size and change the width/height units to centimeters before entering dimensions.
When working with a European print shop, always confirm the unit system before submitting artwork. A file built at “24×36” can be interpreted as 24×36 cm if the shop’s system defaults to metric, giving you a tiny print that’s less than half the intended size. Specify units explicitly in your print order.
When campaigns run across both US and European markets, our approach is to produce artwork at the larger format (US 24×36 at 61×91.4 cm) and then create a second version sized to A1 (59.4×84.1 cm) for European placements.
The difference between the two is small: about 1.6 cm (less than 5/8 of an inch) in width and about 7.3 cm (about 2.9 inches) in height. For most artwork, this difference can be absorbed by adjusting margins and background extension. Strong central imagery tends to adapt well. Edge-to-edge designs with important elements near the borders require more careful adjustment.
We always design at the US size first because our primary market is the United States. The A1 version is produced by scaling the US file slightly down and adjusting margins. This approach works for most campaign artwork with clean, centered compositions.
For clients who are distributing internationally from the start, we recommend designing at A1 (59.4×84.1 cm) and extending the US version to 24×36 by adding background at the top and edges. This is often less disruptive to the composition than shrinking the US version down to fit A1.
International Campaign Tip: Always produce separate print-ready files for US (24×36 in / 61×91.4 cm) and European (A1 / 59.4×84.1 cm) distribution. Do not simply submit the same file to both markets. The size difference, while small, can cause cropping issues at the print shop.
Different applications have their own standard dimensions in centimeters. Here’s a quick reference for the most common scenarios.
US 24×36 in = 61 x 91.4 cm. European equivalent: A1 at 59.4 x 84.1 cm.
27×40 in = 68.6 x 101.6 cm. There is no direct ISO equivalent. European productions often use A1 for lobby display in non-US markets.
US 18×24 in = 45.7 x 61 cm. European equivalent: A2 at 42 x 59.4 cm.
US 11×17 in = 27.9 x 43.2 cm. European equivalent: A3 at 29.7 x 42 cm.
US 22×28 in = 55.9 x 71.1 cm. No direct ISO equivalent exists.
The US standard poster size in cm is 61 x 91.4 cm (24×36 inches converted). The European standard is A1 at 59.4 x 84.1 cm. Both are commonly used for outdoor and advertising campaigns in their respective markets.
A1 is 59.4 cm wide by 84.1 cm tall (594 x 841 mm). It is the most common European poster format and the metric equivalent closest to the US 24×36 poster.
Multiply each dimension by 2.54. 18 inches x 2.54 = 45.72 cm. 24 inches x 2.54 = 60.96 cm. So 18×24 inches = 45.72 x 60.96 cm, commonly rounded to 45.7 x 61 cm.
The US movie one-sheet (27×40 inches) converts to 68.6 x 101.6 cm. There is no direct ISO A-series equivalent. European markets often use A1 (59.4×84.1 cm) for film display instead.
Not directly. A1 (59.4×84.1 cm) is smaller than 24×36 (61×91.4 cm). If you submit a 24×36 file for A1 printing, the shop will either scale it down (losing edge detail) or crop it. Create a separate A1-sized file with adjusted margins for European print runs.
The US standard poster board (22×28 inches) converts to 55.9 x 71.1 cm. This is not a standard metric size and has no direct ISO equivalent. European stationery retailers typically sell A1 foam core instead.
For more on this, explore our guerrilla marketing services.
Close but not identical. A2 is 42 x 59.4 cm. The US 18×24 converts to 45.7 x 61 cm. A2 is narrower and shorter. The proportions (aspect ratio) are also different: A2 is 1:√2, while US 18×24 is 3:4. They look similar on a wall but are not interchangeable without artwork adjustment.
Ready to Run Your Campaign?
Call us or email us. We’ll tell you exactly what we can do in your market and what it costs.
American Guerrilla Marketing — Los Angeles
Street-level campaigns in Los Angeles and nationwide. Wheatpasting, LED trucks, street teams, and more.
(646) 776-2770
Related Services
Explore similar advertising solutions offered by American Guerrilla Marketing.
September 7, 2026
September 7, 2026
September 7, 2026
September 7, 2026
September 7, 2026
