What is A1 size in cm?
A1 is 594 × 841 mm — that is 59.4 × 84.1 cm, or 23.39 × 33.11 inches. It is exactly half an A0 sheet and exactly twice an A2, and it covers half a square metre.
The full A-series size chart
Millimetres are the definition under ISO 216 and are exact; centimetres and inches are converted from them. Every size is exactly half the area of the one above it — fold an A3 in half and you have an A4, at the same proportions.
| Size | Millimetres | Centimetres | Inches | Area |
|---|---|---|---|---|
| A0 | 841 × 1189 mm | 84.1 × 118.9 cm | 33.11 × 46.81 in | 1 m² |
| A1 | 594 × 841 mm | 59.4 × 84.1 cm | 23.39 × 33.11 in | ½ m² |
| A2 | 420 × 594 mm | 42.0 × 59.4 cm | 16.54 × 23.39 in | ¼ m² |
| A3 | 297 × 420 mm | 29.7 × 42.0 cm | 11.69 × 16.54 in | ⅛ m² |
| A4 | 210 × 297 mm | 21.0 × 29.7 cm | 8.27 × 11.69 in | 1/16 m² |
| A5 | 148 × 210 mm | 14.8 × 21.0 cm | 5.83 × 8.27 in | 1/32 m² |
| A6 | 105 × 148 mm | 10.5 × 14.8 cm | 4.13 × 5.83 in | 1/64 m² |
| A7 | 74 × 105 mm | 7.4 × 10.5 cm | 2.91 × 4.13 in | 1/128 m² |
| A8 | 52 × 74 mm | 5.2 × 7.4 cm | 2.05 × 2.91 in | 1/256 m² |
A0 is exactly one square metre. That is where the series starts, and every size below it is the one above folded in half. It is also why the proportions never change: the ratio of every A size is 1 : √2.
How big is A1, really?
A1 is about the span of an adult's shoulders — 594 mm across — and a little under waist height when stood on its long edge. It is the size of a typical shop window poster or an event poster on an easel. A0, the next size up, is roughly a doorway's width laid flat, and it is what most people are picturing when they say “a big poster”.
What each A size is actually used for
| Size | Where you see it | Read from |
|---|---|---|
| A0 | Trade show graphics, engineering drawings, cinema-style posters | Across a room |
| A1 | Shop window posters, event posters, seating charts, exhibition boards | 3–5 m |
| A2 | Café menus on a wall, notice boards, real estate window cards | 2–3 m |
| A3 | Counter signage, table menus, school notices, certificates | 1–2 m |
| A4 | Letterhead, flyers, price lists, the standard office sheet | Arm's length |
| A5 | Flyers, event invitations, menus, product inserts | In the hand |
| A6 | Postcards, save-the-dates, loyalty cards | In the hand |
Will people be able to read it? The lettering rule
Most people asking what size A1 is are really asking whether it will be readable. The working rule is about 25 mm of capital letter height for every metre of viewing distance.
| Read from | Minimum cap height | Fits comfortably on |
|---|---|---|
| 1 m | 25 mm | A4, A3 |
| 3 m | 75 mm | A2, A1 |
| 5 m | 125 mm | A1, A0 |
| 10 m | 250 mm | A0 and larger, or a banner |
A headline that fails this rule on an A1 does not get fixed by printing it on A0 — it gets fixed by using fewer words.
Printing something at this size?
A1 is 594 × 841 mm, and our standard corflute sign is 600 × 900 mm — near enough the same size on the wall, but waterproof and rigid, so it works on a gate, a fence or a shop window where paper would not last a week.
If the sign needs to stand up by itself, a pull up banner at 800 × 2000 mm is usually what people mean when they ask for “a big poster for the entrance”. For something rigid and indoors, foam board sits on an easel. Past A0, a printed sheet stops being practical and fabric or vinyl banners are what scale.
Everything is printed in our own Melbourne factory and dispatched within 24 hours of proof approval. You can put your own wording on a ready-made design online for free, or send us print-ready artwork. We also offer custom sizing if none of the standard sizes fit.
Related: A5 size in cm · Is A3 bigger than A4? · Common poster sizes in Australia · A1 vs A2 vs A3
