---
title: 'A1 Size: 59.4 × 84.1 cm (23.39 × 33.11 in) | Half of A0, Two A2 Sheets, and A1 vs 24 × 36 Posters'
url: https://joelin.cc/en/p/9611
source: https://joelin.cc/en/p/9611
lang: en
pubDate: '2026-10-19'
date_modified: '2026-10-19'
description: 'A1 paper is 59.4 × 84.1 cm (594 × 841 mm), about 23.39 × 33.11 in: half of A0, 7016 × 9933 px at 300 DPI, and slightly smaller than a 24 × 36 in poster.'
author: joe
ai_role: ai_only
translation_of: /p/9611
---

# A1 Size: 59.4 × 84.1 cm (23.39 × 33.11 in) | Half of A0, Two A2 Sheets, and A1 vs 24 × 36 Posters

A1 paper is 59.4 × 84.1 cm, or about 23.39 × 33.11 inches.

People who look up the A1 size usually have something that will hang on a wall and be seen from a distance: a film poster, the key visual for an event, or a print for an exhibition booth. Here are the answers first:

## A1 size quick reference

| Unit | A1 size |
| --- | --- |
| Centimeters | 59.4 × 84.1 cm |
| Millimeters | 594 × 841 mm |
| Inches | about 23.39 × 33.11 in |

One sentence is all you need to remember: A1 is A0 folded in half once. Put the other way, two A2 sheets together also make A1. A2 is 42 × 59.4 cm, so two side by side make 84 × 59.4 cm; turn that sideways and you are back at A1's 59.4 × 84.1 cm.

![A1 is 59.4 × 84.1 cm (594 × 841 mm), equal to A0 folded in half once and to two A2 sheets put together. At 300 DPI for print it is 7016 × 9933 px.](https://image.joelin.cc/cdn-cgi/imagedelivery/0xu8EsaSar9n3zUKY5d7xw/joelin/2026-08/a1-size-guide-v2/hero)

## Where A1 sits in the A series: the folding logic

The whole A-series family follows one rule: each step is a fold in half (or a doubling), and the aspect ratio is fixed at 1 : √2, so the shape stays the same after folding.

| Size | cm | Relationship to A1 |
| --- | --- | --- |
| A0 | 84.1 × 118.9 | Twice A1 (the sheet A1 comes from) |
| A1 | 59.4 × 84.1 | Reference size |
| A2 | 42 × 59.4 | A1 folded in half |
| A3 | 29.7 × 42 | A1 folded in half twice |

The same move works in both directions: A1 folded is A2, and A2 folded is A3; double A1 and you get [A0](/en/p/9614). A common approach in large-format design is to proof at A3 and output at A1, which works because folding never distorts the shape. The layout scales up four times proportionally, and type sizes and margins keep the same proportions without any rearranging. The other sizes in the series have their own guides: [A2 Size](/en/p/9612), [A3 Paper Size](/en/p/9609) and [A4 Paper Size](/en/p/9607).

## A1 vs US sizes: 24 × 36 and 22 × 34 inches

The United States has no A1. The closest inch-based sizes are the 24 × 36 in poster (ARCH D in architectural drawing sizes) and 22 × 34 in (ANSI D, used for engineering drawings).

| Size | cm | Inches | Compared with A1 |
| --- | --- | --- | --- |
| A1 (ISO) | 59.4 × 84.1 | about 23.39 × 33.11 | Reference size |
| ARCH D poster | 61 × 91.4 | 24 × 36 | 1.6 cm wider, 7.3 cm longer |
| ANSI D | 55.9 × 86.4 | 22 × 34 | 3.5 cm narrower, 2.3 cm longer |

A 24 × 36 in poster is larger than A1 in both directions, so an A1 print in a 24 × 36 frame needs a mat or leaves a gap, and a 24 × 36 file printed on A1 has to be scaled down. The 24 × 36 poster also has a ratio of 1 : 1.5 rather than A1's 1 : 1.41, so scaling one onto the other leaves white space on two sides. Check whether the file is set up as 594 × 841 mm or as an inch size before you order a print or a frame.

## What A1 is used for

- Film and theater posters: where A sizes are the norm, the single-sheet posters in cinema lobbies and display cases are often in the A1 size range. The US theatrical one-sheet is larger, at 27 × 40 in.
- Event posters and street notices: when a headline has to be readable at a glance from three to five meters away, A2 is too small and A1 is just right.
- Exhibition prints and booth visuals: side walls and standing signs at exhibition booths are often built from A1 modules.
- Large product posters and in-store POP displays: for a retail chain's seasonal campaign visuals, A1 is a common standard size.
- Entry-level academic and competition posters: smaller poster sessions sometimes specify A1, while large conferences usually ask for A0.

## How many pixels do you need to print A1?

The conversion formula is: millimeters ÷ 25.4 × DPI.

| Resolution | Pixels (594 × 841 mm) | Typical use |
| --- | --- | --- |
| 600 DPI | 14031 × 19866 px | Almost never needed for large-format output; only a few fine reproductions ask for it |
| 300 DPI | 7016 × 9933 px | Exhibition visuals and quality posters viewed up close |
| 150 DPI | 3508 × 4967 px | Posters and event signs viewed from a distance on a wall |
| 72 DPI | 1684 × 2384 px | Screen previews only; not recommended for print |

A1 covers a large area, and a 300 DPI file can easily run to several hundred megabytes, so even uploading it to a print shop takes a while. The deciding factor is viewing distance, not "the higher the better." Use 300 DPI for anything people will walk up to and examine. For something hanging on a wall or standing beside a walkway and seen from three meters away, 150 DPI looks almost identical.

### How the A1 pixel numbers are calculated

Every pixel figure for A1 comes from the same steps: divide millimeters by 25.4 to get inches, multiply by the DPI, then round to a whole pixel. At 300 DPI, the width is 594 ÷ 25.4 × 300 = 7015.7, which becomes 7016, and the height is 841 ÷ 25.4 × 300 = 9933.1, which becomes 9933. The same formula gives 14031 × 19866 px at 600 DPI, more than 270 million pixels in total, far larger than ordinary software or print shops need.

Because the A series is designed in metric units, its inch values always have decimals, so different software and websites sometimes disagree by one pixel, depending on whether the decimal is truncated or rounded. A one-pixel difference has no visible effect on a print.

### Use 300 DPI for print; for screens, only the pixel count matters

When you send a file to a printer or print shop, 300 DPI is the baseline used across the printing industry, which for A1 is 7016 × 9933 px. But because A1 prints usually hang on a wall and are seen from a distance, large-format print shops often accept 150 DPI, or 3508 × 4967 px. Asking the shop before you send the file is the surest way to know. At A1 size, 600 DPI has almost no practical use.

If the file will only be viewed on a screen (in a presentation, on a web page or on a phone), the DPI number does not affect sharpness, because screens only care about the total pixel count. The traditional convention is the 72 DPI set, 1684 × 2384 px, which is enough for previews and thumbnails.

## Where to print A1

This is where A1 feels most different from the smaller sizes. Office printers and self-service copiers usually top out at A3 or 11 × 17 in, so A1 is completely outside their range. You have three options: a wide-format printer at a copy shop (fastest, often same-day), a dedicated large-format print shop (the widest choice of materials), or a commercial printer (worth it only in volume; for a single sheet it is actually more expensive).

This is also the size at which the material starts to matter. Ordinary poster paper is the cheapest but creases easily. Photo paper gives saturated color and suits image-heavy designs. Synthetic paper is waterproof and tear-resistant, worth the extra cost outdoors or for posters that will be put up repeatedly. Canvas is used for exhibition backdrops that need to hang for a long time. Before sending the file, ask the shop about the bleed and color mode it needs. That is much cheaper than printing an A1 sheet twice.

## A1 in one sentence

A1 is the largest sheet most people deal with in everyday life. The next size up, [A0](/en/p/9614), belongs to the professional world of engineering drawings and large signage. Going down, A1 folded is [A2](/en/p/9612), folded again is [A3](/en/p/9609), and only after four folds do you get back to the hand-held [A5](/en/p/9447). The whole family is one sheet of paper cut in half again and again, and its shape never changes.

## Frequently asked questions

### How many centimeters is A1?

59.4 × 84.1 cm, or 594 × 841 mm, which is about 23.39 × 33.11 inches. It is the size of an A0 sheet folded in half once.

### How much bigger is A1 than A2?

A1 has twice the area of A2. Two A2 sheets (42 × 59.4 cm) side by side make one A1 sheet; in the other direction, A1 folded in half is A2.

### How big is A1 compared with everyday things?

Where A sizes are the norm, it is close to a single-sheet poster hanging in a cinema (the US one-sheet, 27 × 40 in, is larger), and it is about the size an adult can hold with both arms spread. A0 folded once is A1, and A1 has to be folded twice more to get down to A3.

### Is A1 the same as a 24 × 36 inch poster?

No. A 24 × 36 in poster is 61 × 91.4 cm, larger than A1 in both directions and with a different aspect ratio. The closest US engineering size, 22 × 34 in (ANSI D), is narrower and slightly longer than A1.

### How many pixels do you need to print A1?

7016 × 9933 px at 300 DPI for print and 3508 × 4967 px at 150 DPI. Use 300 DPI for exhibition visuals viewed up close; 150 DPI is usually enough for posters viewed from a distance on a wall.

### Can I print A1 on an office printer or self-service copier?

No. These machines usually go up to A3 or 11 × 17 in at most. A1 needs a large-format print shop, a wide-format printer at a copy shop, or a commercial printer.

### How many pixels is A1 at 600 DPI or 72 DPI?

14031 × 19866 px at 600 DPI and 1684 × 2384 px at 72 DPI, both calculated as millimeters ÷ 25.4 × DPI and rounded. An A1 file at 600 DPI has more than 270 million pixels and is almost never needed in practice. 72 DPI is only suitable for screen previews; for print, use at least the 150 DPI set, 3508 × 4967 px.

Keywords: A1 size, A1 paper size, A1 size in cm, A1 size in inches, A1 dimensions, A1 poster, A1 vs 24 × 36, A1 in pixels

Sources: The original Chinese article was first published on August 18, 2026, and last updated on October 19, 2026. A-series dimensions are fixed by the ISO 216 international standard; the US comparison sizes (the 24 × 36 in ARCH D poster, ANSI D 22 × 34 in and the 27 × 40 in theatrical one-sheet) were added for English-language readers. Taiwan-specific printing advice in the Chinese original has been replaced with general advice.