What Are the Measurements of an A1 Poster? Full Guide

An A1 poster is 594mm wide by 841mm tall, or 59.4 x 84.1 cm, or 23.4 x 33.1 inches. Here’s the full breakdown of A1 dimensions and how they compare to US standard sizes.

An A1 poster is 594mm wide by 841mm tall, or 59.4 x 84.1 cm, or 23.4 x 33.1 inches. Here’s the full breakdown of A1 dimensions and how they compare to US standard sizes.

What are the measurements of an A1 poster? The precise answer: 594 millimeters wide by 841 millimeters tall. In centimeters: 59.4 x 84.1. In inches: approximately 23.4 x 33.1.

A1 is part of the ISO 216 standard, the metric paper size system used in Europe, Australia, most of Asia, and most of Latin America. It’s the standard that replaced the patchwork of regional paper sizes in most of the world outside the United States.

We work primarily in US markets where dimensions are measured in inches. But we deal with A1 when working with European design studios, international clients, and campaigns that need to run in both US and European markets. Here’s everything you need to know about A1 poster measurements.

A1 Poster Measurements: All Three Unit Systems

A1 is defined in the metric system and expressed in millimeters in the ISO 216 standard. Here are the measurements in all three commonly used unit systems.

A1 Poster Measurements at a Glance:
Millimeters: 594 mm wide x 841 mm tall
Centimeters: 59.4 cm x 84.1 cm
Inches: 23.39 in x 33.11 in (commonly rounded to 23.4 x 33.1 in)

How A1 Relates to the ISO 216 Paper Size System

A1 is part of the ISO 216 A-series, a mathematically elegant system where each size is exactly half the area of the size above it. Every size in the A-series has the same aspect ratio: 1:√2, approximately 1:1.414.

Here’s how A1 fits into the full A-series hierarchy:

The key property: A1 is exactly half the area of A0, and exactly double the area of A2. This makes scaling between sizes exact and predictable. An A1 poster contains the same content as two A2 posters placed side by side.

The A0 sheet has an area of exactly 1 square meter (10,000 square centimeters). A1 is 4,999 square centimeters, approximately 0.5 square meters. The mathematical precision of the ISO system makes it attractive for standardization across countries and industries.

A1 vs. US 24×36: How They Compare

The US standard outdoor poster is 24×36 inches (61×91.4 cm). A1 is 23.4×33.1 inches (59.4×84.1 cm). The two are close but not identical.

The US 24×36 is about 11 percent larger in area than A1. The US format is also slightly wider relative to its height (2:3 ratio versus A1’s 1:√2 ratio). This difference is small but real. You can’t simply print a 24×36 file on an A1 sheet without some content being cut off, or an A1 file on a 24×36 sheet without small white margins appearing at the sides and top/bottom.

For most campaigns, artwork adapts between the two with minor adjustment. The key points to watch are: critical content near the top or bottom edge (more height in the US format), and any background patterns that extend to the sides (US format is wider). Keep important content at least 0.5 inches inside the trim edge and the adjustment between the two formats becomes straightforward.

For US Campaigns: Use 24×36 inch files. For European campaigns: use A1 (594x841mm) files. Don’t submit the same file to both markets without adjustment. The size and aspect ratio differences will cause cropping or margin issues in print.

Designing for A1 Poster Measurements

If you’re designing a poster specifically for A1 format, here’s the technical setup for the most common design applications.

Adobe Illustrator

File > New Document. Set the artboard to 594mm x 841mm. Add a bleed of 3mm on all sides. This extends the artboard to 600mm x 847mm for printing. Set color mode to CMYK for commercial printing.

Adobe Photoshop

File > New. Width: 594mm. Height: 841mm. Resolution: 150 pixels/cm (equivalent to approximately 380 DPI, which is more than sufficient). Color mode: CMYK. Add 3mm bleed by making the canvas 600mm x 847mm and centering the design with 3mm margins.

Adobe InDesign

File > New Document. Width: 594mm. Height: 841mm. Bleed: 3mm on all sides. Slug (optional): 5mm. This sets up a document with proper bleed for professional print production.

Canva

Create Design > Custom Size. Enter 594mm x 841mm. Canva works in px by default; switch to mm in the unit selector. For a print-quality Canva file, download as PDF (print) which preserves dimensions and resolution.

A1 Poster Measurements in Pixels

Digital design files work in pixels. Here’s how A1 poster measurements translate to pixel counts at different resolutions.

For outdoor viewing (pedestrians at 10 to 20 feet), 150 DPI at full size is the professional minimum for an A1 poster. For close-viewing gallery or retail applications, 300 DPI produces a visually perfect print. For very large outdoor placements where viewers are 30 or more feet away, 72 DPI can be sufficient.

When to Use A1 vs. US 24×36

The choice between A1 and US 24×36 comes down to where the poster is being printed and displayed.

Use A1 when:

• You’re printing with a European or metric-based print shop
• The poster will be displayed in European markets (UK, Germany, France, Australia, etc.)
• You’re working with a European design studio that works in ISO sizes
• The display hardware (frames, display cases) is built to A1 dimensions
• The client requires ISO standard documentation for regulatory or institutional purposes

Use US 24×36 when:

• You’re printing with a US print shop
• The poster runs on US outdoor walls, construction boards, or US venues
• You’re ordering from a US-based online print service
• Standard US frames (24×36) will be used for display
• The campaign is entirely within US territory

Frequently Asked Questions