Paper sizes A0 to A4 explained
Every A size is the one above it folded in half. That single idea explains the whole system, and it is why artwork scales so neatly from a flyer to a wall poster.
The sizes in full.
| Size | Millimetres | Inches, approx | Typical job |
|---|---|---|---|
| A0 | 841 x 1189 | 33.1 x 46.8 | Conference posters, large plans, shop displays |
| A1 | 594 x 841 | 23.4 x 33.1 | Window posters, display boards, presentations |
| A2 | 420 x 594 | 16.5 x 23.4 | Noticeboards, menus on a wall, small posters |
| A3 | 297 x 420 | 11.7 x 16.5 | Table-top signs, counter cards, charts |
| A4 | 210 x 297 | 8.3 x 11.7 | Letters and leaflets; handy for scaled-down test prints |
How the system works.
Start with A0, which has an area of one square metre. Cut it across the long side and you get two A1 sheets. Cut one of those and you get two A2 sheets, and so on. Each step halves the area, and the shape never changes. This works because the long side is always about 1.414 times the short side, the square root of two.
A few things follow from that:
- Four A2 posters take up the same area as one A0.
- A size number going down means the sheet is getting bigger. A1 is larger than A2.
- Doubling the width and height of a sheet moves it up two sizes, not one. A3 doubled in each direction is A1.
That last point trips people up. An A1 poster looks twice as tall as an A3 and has four times the area.
Scaling artwork from one size to another.
Because the proportions match, you can scale a design between A sizes with no cropping and no redesign. Use this chart if you are enlarging from A4.
| Target size | Scale in each direction |
|---|---|
| A3 | 141% |
| A2 | 200% |
| A1 | 283% |
| A0 | 400% |
Each single step up is 141%. Each single step down is about 71%. Remember that this applies to pictures as well. A photo that was sharp on an A4 flyer has had its pixels spread four times wider at A0, so it may need replacing with a larger version.
What about sizes that are not A sizes?
Photographers tend to work in inches, because of camera and frame formats, and those sizes have a different shape. Our page on inch and metric print sizes sets the two systems side by side. Beyond A0, simply give us the width and height you need.
Ordering by A size.
When you send a file, state the finished size and whether it is portrait or landscape. If the print runs to the edge, add bleed around the sheet as our bleed guide explains. Sizes for posters at A3 and A2, and large format prints up to A0, are all on our price list.
Standard sizes on the wall.
Your questions.
Is A0 the biggest paper size?
It is the largest common one in everyday use. Oversized formats exist, but for a print larger than A0 it is simpler to quote the actual dimensions.
Why do some countries use different sizes?
North America uses its own system, including Letter and Tabloid, based on inches. Those sizes do not share the A series proportions, so a US file may need adjusting.
Can I print A4 artwork at A0?
Yes, if the file holds up. Vector artwork will scale cleanly, but photos may look soft, so send it to us to check first.