August 11, 2026
Poster size in centimeters matters the moment you work with international print vendors, run campaigns in European markets, or operate any design workflow that uses metric units. The United States runs on inches for printing and marketing. Most of the world follows centimeters and millimeters, using the ISO A-series paper standard as the baseline for everything from flyers to large-format outdoor prints. Understanding how poster sizes convert between these systems prevents costly ordering errors, file setup mistakes, and the kind of spec confusion that causes a print run to arrive wrong.
At American Guerrilla Marketing, we run campaigns across 50+ US markets and support brands with international activations. Our domestic campaigns use inch specifications. Our international work requires metric precision. This guide covers every relevant conversion and explains how the US and ISO systems compare, where they diverge, and how to work accurately in both without errors.
Whether you are ordering prints from a Brooklyn vendor or a Berlin shop, getting the centimeter dimensions right from the start saves time, money, and reprints.
One inch equals exactly 2.54 centimeters. This is an internationally fixed standard. To convert any poster dimension from inches to centimeters, multiply by 2.54. To convert from centimeters to inches, divide by 2.54.
Common US poster sizes converted to centimeters:
For millimeters (which many European vendors prefer), multiply the centimeter values by 10. A 24 x 36 inch poster is 609.6 x 914.4 mm. An 18 x 24 is 457.2 x 609.6 mm.
The following table covers all standard US poster formats with their centimeter equivalents and primary use cases. Our team references this when coordinating between domestic print vendors and international partners for cross-market campaigns.
| US Size (Inches) | Width (cm) | Height (cm) | Primary Use |
|---|---|---|---|
| 8.5 x 11 | 21.59 | 27.94 | Counter cards, lobby inserts |
| 11 x 14 | 27.94 | 35.56 | Photo prints, framed retail display |
| 11 x 17 | 27.94 | 43.18 | High-volume street campaigns, tabloid |
| 12 x 18 | 30.48 | 45.72 | Small indoor posters, window displays |
| 18 x 24 | 45.72 | 60.96 | Medium campaign posters, outdoor signage |
| 24 x 36 | 60.96 | 91.44 | Standard street poster, event marketing |
| 27 x 40 | 68.58 | 101.60 | One-sheet, cinema lobbies |
| 36 x 48 | 91.44 | 121.92 | Large-format outdoor, construction walls |
| 48 x 72 | 121.92 | 182.88 | Extra-large format, premium outdoor placements |
The ISO A-series is the global standard paper sizing system used in every country except the United States, Canada, and a few others that maintain inch-based systems. The A-series is built on a mathematical foundation where each size is exactly half the area of the size above it, and every size shares the same aspect ratio of approximately 1:1.414 (square root of 2). This means you can fold an A1 in half and get two perfect A2 sheets. The system was designed for logical scaling and reprographics.
For poster and marketing applications, the key ISO sizes in centimeters:
| ISO Size | Width (mm) | Height (mm) | Width (cm) | Height (cm) | Approx. Inches |
|---|---|---|---|---|---|
| A4 | 210 | 297 | 21.0 | 29.7 | 8.27 x 11.69 |
| A3 | 297 | 420 | 29.7 | 42.0 | 11.69 x 16.54 |
| A2 | 420 | 594 | 42.0 | 59.4 | 16.54 x 23.39 |
| A1 | 594 | 841 | 59.4 | 84.1 | 23.39 x 33.11 |
| A0 | 841 | 1189 | 84.1 | 118.9 | 33.11 x 46.81 |
| 2A0 | 1189 | 1682 | 118.9 | 168.2 | 46.81 x 66.22 |
A4 is the global equivalent of the US Letter size (8.5 x 11 inches), though the two sizes are not identical. A4 is slightly taller and narrower than Letter. In marketing, A4 is used for flyers, counter cards, inserts, and small display prints. It is the most commonly printed poster format in Europe for indoor use.
A3 is twice the area of A4 and roughly equivalent to the US Tabloid (11 x 17 inches), though slightly wider and shorter. A3 posters are common in European retail environments, restaurant windows, and indoor campaign applications. At 29.7 x 42.0 cm, it is a versatile size for medium-priority information and secondary campaign materials.
A2 is the international approximate equivalent of the US 18 x 24 format. At 42.0 x 59.4 cm, it is used for retail window posters, transit advertising, and mid-size campaign materials. The US 18 x 24 (45.72 x 60.96 cm) is measurably larger – about 8.9 percent wider and 2.6 percent taller – so files do not transfer between these sizes without adjustment.
A1 is the international standard for campaign posters. At 59.4 x 84.1 cm, it is the metric equivalent of the US 24 x 36 format (60.96 x 91.44 cm). The US format is about 2.6 percent wider and 8.7 percent taller. For any brand running campaigns in both US and international markets, the A1 vs. 24 x 36 gap is the most practically important size mismatch to understand.
A0 is the largest standard single-sheet ISO size used in common production. At 84.1 x 118.9 cm, it is equivalent to four A2 sheets or two A1 sheets. A0 is used for trade show panels, large window graphics, exhibition displays, and high-visibility outdoor campaigns. The nearest US equivalent is the 36 x 48 format (91.44 x 121.92 cm), which is slightly larger in both dimensions.
No US standard poster size exactly matches any ISO size. This is a fundamental reality for any brand operating across both systems. The size gaps create specific problems when trying to use a file built for one system with a printer operating in the other.
US 11 x 17 inches = 27.94 x 43.18 cm. ISO A3 = 29.7 x 42.0 cm. The A3 is about 6.3 percent wider but 2.7 percent shorter than the US 11 x 17. A design built for 11 x 17 will have white borders on the sides when printed at A3, and content near the top may be trimmed slightly. Not a critical mismatch for most designs, but noticeable with full-bleed backgrounds.
US 18 x 24 inches = 45.72 x 60.96 cm. ISO A2 = 42.0 x 59.4 cm. The US format is 8.9 percent wider and 2.6 percent taller. An 18 x 24 design printed at A2 will be cropped on all edges. Significant enough to matter for any content positioned near the edges.
US 24 x 36 inches = 60.96 x 91.44 cm. ISO A1 = 59.4 x 84.1 cm. The US format is 2.6 percent wider and 8.7 percent taller. The height gap is substantial – nearly 7.3 cm of difference. A 24 x 36 design adapted to A1 will require content in the bottom portion to either be cropped or compressed.
US 36 x 48 inches = 91.44 x 121.92 cm. ISO A0 = 84.1 x 118.9 cm. The US format is 8.7 percent wider and 2.5 percent taller. The width difference is significant. An A0 design adapted to 36 x 48 will have narrow vertical borders on both sides unless the artwork is scaled up or extended.
When AGM coordinates international wheatpasting or poster campaigns, working with European vendors requires a clear process to prevent spec errors. Here is the workflow we follow.
Do not assume. Ask the vendor for the exact print dimensions in millimeters. Get the actual number, not just the ISO label. A vendor might say “A1” but their press has a slightly different actual printable area. If they say 594 x 841 mm, build to that exactly.
Do not try to adapt a US-size file by scaling. Build the file at the target metric dimensions from the start, or deliberately resize an existing design with full awareness of where content will shift. Set the document in your design software to the exact centimeter or millimeter dimensions before placing any elements.
Standard bleed for European print vendors is 3 mm per side (0.3 cm). Some require 5 mm. In US terms, 3 mm = 0.118 inches, which is close to but not the same as the US standard 0.125 inch bleed. Always confirm the specific bleed with the vendor before building the file.
Keep all critical text, logos, and key visual elements at least 5 mm (0.5 cm) from the trim edge. This is the safety margin that accounts for mechanical cutting variation. The safe zone applies inside the trim line – bleed extends outside it.
300 DPI is the global standard for high-quality print at normal viewing distances. For large-format prints viewed from greater than 1 meter, 150-200 DPI is acceptable. Color mode should be CMYK for offset and most large-format inkjet. Some wide-format presses accept RGB and convert internally – confirm with the vendor. File format is typically PDF/X-1a or PDF/X-4 for offset, high-quality PDF or TIFF for large-format inkjet.
Switching your design software from inches to metric is straightforward but requires doing it before placing elements, not after.
Go to File > Document Setup > Units and change to Millimeters or Centimeters. Set the artboard to the exact target size. For A1, set to 594 x 841 mm. Add bleed in the Document Setup panel (3 mm or confirm with vendor). Save the file in this configuration before beginning layout so all rulers and guides display in metric throughout.
Go to File > Document Setup and change Units from Inches to Millimeters. Set page dimensions to the exact metric target. Set bleed to 3 mm on all sides. If you are adapting an existing inch-based file, verify all element positions and sizes after switching units because the underlying measurements convert but may shift visually.
Canva allows custom document sizes in centimeters. Create a custom canvas and enter target dimensions in cm. For A1, use 59.4 x 84.1 cm. Set the export resolution to the highest available (Canva prints at 300 DPI when using print-quality export). Choose PDF Print as the export format for vendor use. Confirm whether the vendor needs CMYK color – Canva exports in RGB by default.
In the US, our wheatpasting and poster campaigns primarily use the 24 x 36 inch format (60.96 x 91.44 cm) because it maximizes visual impact at eye level while being manageable to apply in quantity. For high-volume wheat paste runs, we also deploy 11 x 17 (27.94 x 43.18 cm) when coverage volume is the priority over individual poster impact.
For international markets operating in the metric system, A1 (59.4 x 84.1 cm) is the direct equivalent. It fills the same visual role in a street campaign – large enough to stop attention, practical enough to apply in volume. The slight size difference from the US 24 x 36 format is not perceptible to a passerby; it only matters at the spec level.
Our guerrilla marketing services team coordinates size specs as part of every campaign brief. Whether the run is 500 or 5,000 posters, knowing the exact centimeter dimensions before going to press prevents the kind of vendor-side substitutions that change how artwork appears in the field.
DPI (dots per inch) is an inch-based measurement. When working in centimeters, the equivalent is DPC (dots per centimeter). 300 DPI equals approximately 118 DPC. Most international print vendors accept DPI specifications and handle the internal conversion, so you generally do not need to convert resolution specs when working with metric vendors. That said, confirm the vendor’s preferred specification before sending files. Some vendors who primarily use metric for all measurements prefer DPC to keep their entire workflow in metric units.
For large-format prints at A0 (84.1 x 118.9 cm) or larger, typical viewing distance increases and the required DPI decreases accordingly. At 2+ meter viewing distance, 100-150 DPI produces clean results. At close inspection distances (under 50 cm, as with a retail counter card), 300 DPI minimum is required to prevent pixelation.
Different countries have developed local poster standards for specific applications, particularly in transit advertising and outdoor media. These often differ from the core ISO A-series.
UK outdoor advertising uses imperial-derived sheet sizes alongside ISO formats. The 4-sheet outdoor format is 101.6 x 152.4 cm (40 x 60 inches). Bus shelter advertising uses the 6-sheet at 119.4 x 179.4 cm. For indoor retail and general campaign use, A1 (59.4 x 84.1 cm) is the standard. The UK is a metric country for print but retains some legacy imperial outdoor formats from its pre-metric advertising industry history.
Germany uses the DIN A-series, which is identical to ISO. The standard outdoor poster format is the Stadtplakat (city poster) at 59.4 x 84.0 cm, which is A1. Large outdoor formats use DIN A0 (84.1 x 118.9 cm) and above. Transit advertising in Germany uses standardized Citylight formats at 117.5 x 175 cm.
Both countries follow ISO A-series. Standard campaign poster use follows A1 (59.4 x 84.1 cm) for indoor and outdoor applications. Large-format outdoor uses A0 (84.1 x 118.9 cm) and custom wide-format sizes. The Australian market has minimal legacy non-metric poster formats compared to the UK.
When ordering large print runs across multiple vendors in different countries, the most efficient approach is to build a master file in the larger of the two formats (typically the US inch size) and create explicit metric variants for international vendors rather than asking vendors to adapt files on their end.
The master-to-metric adaptation process should be documented in the print brief: “Original US file at 24 x 36 inches (60.96 x 91.44 cm). International variant resized to A1 (59.4 x 84.1 cm) with design adapted to maintain headline and primary visual at full bleed. Bottom secondary content zone reduced proportionally.” This level of documentation prevents the vendor from making independent adaptation decisions that may not match your intent.
Our street team deployments and experiential marketing activations often involve coordinating materials across multiple cities and markets simultaneously. Standardizing on metric centimeter specs for international vendors – documented in the same brief as the US inch specs – keeps the production side clean regardless of which printer handles which market.
In the US, the standard poster size is 24 x 36 inches, which equals 60.96 x 91.44 centimeters. Internationally, the nearest equivalent is A1 at 59.4 x 84.1 centimeters. The two formats are close but not identical – the US standard is slightly larger in both dimensions.
A1 is 59.4 x 84.1 centimeters (594 x 841 millimeters), or approximately 23.4 x 33.1 inches. It is the most common standard poster size in European and international markets and the closest equivalent to the US 24 x 36 format.
A2 is 42.0 x 59.4 centimeters (420 x 594 millimeters), or approximately 16.5 x 23.4 inches. It is roughly equivalent to a US 16 x 24, slightly smaller than the US 18 x 24 format.
Multiply each dimension by 2.54. A 24 x 36 inch poster is 60.96 x 91.44 centimeters. For European vendors who work in millimeters, that is 609.6 x 914.4 mm. Ask your vendor whether they can print to this exact size or whether they need you to adjust to A1 (594 x 841 mm).
A0 is 84.1 x 118.9 centimeters (841 x 1189 millimeters), or approximately 33.1 x 46.8 inches. It is the largest standard ISO paper size used in common production, used for large-format displays, trade show graphics, and high-visibility outdoor posters.
No. US inch-based poster sizes do not align exactly with ISO A-series metric sizes. The differences range from 2 to 10 percent per dimension. Artwork built for a US size must be deliberately resized or cropped to fit an ISO size, and vice versa. Never assume files are interchangeable between systems.
Most European print vendors require 3 mm bleed on all sides, which equals 0.3 cm. Some require 5 mm (0.5 cm). Always confirm with your specific vendor before setting up files. Keep all critical content at least 5 mm from the trim edge to account for mechanical cutting variation.
Campaign Architect — American Guerrilla Marketing
In the US, the standard poster size is 24 x 36 inches, which equals 60.96 x 91.44 centimeters. Internationally, the nearest equivalent is A1 at 59.4 x 84.1 centimeters. The two formats are close but not identical – the US standard is slightly larger in both dimensions.
A1 is 59.4 x 84.1 centimeters (594 x 841 millimeters), or approximately 23.4 x 33.1 inches. It is the most common standard poster size in European and international markets and the closest equivalent to the US 24 x 36 format.
A2 is 42.0 x 59.4 centimeters (420 x 594 millimeters), or approximately 16.5 x 23.4 inches. It is roughly equivalent to a US 16 x 24, slightly smaller than the US 18 x 24 format.
Multiply each dimension by 2.54. A 24 x 36 inch poster is 60.96 x 91.44 centimeters. For European vendors who work in millimeters, that is 609.6 x 914.4 mm. Ask your vendor whether they can print to this exact size or whether they need you to adjust to A1 (594 x 841 mm).
A0 is 84.1 x 118.9 centimeters (841 x 1189 millimeters), or approximately 33.1 x 46.8 inches. It is the largest single-sheet ISO paper size and is used for large-format displays, trade show graphics, and high-visibility outdoor posters.
No. US inch-based poster sizes do not align exactly with ISO A-series metric sizes. The differences range from 2 to 10 percent per dimension. Artwork built for a US size must be deliberately resized or cropped to fit an ISO size, and vice versa.
Most European print vendors require 3 mm bleed on all sides, which equals 0.3 cm. Some require 5 mm (0.5 cm). Always confirm with your specific vendor before setting up files. Keep all critical content at least 5 mm from the trim edge.
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American Guerrilla Marketing — Los Angeles
Street-level campaigns in Los Angeles and nationwide. Wheatpasting, LED trucks, street teams, and more.
(646) 776-2770
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