Paper Size Chart
Choose a standard paper size to see its dimensions in both millimetres and inches.
How to use the Paper Size Chart
- Pick a size from the list: A4, A5, A3, B5 or Letter (US), then press Calculate.
- The result gives the dimensions in millimetres with the inch equivalent beside them.
- To compare two sizes, change the list and press Calculate again.
Halving an A size gives you the next one
Every A size under ISO 216 sets its long side against its short side at one to the square root of two, about 1.414. Folding in half keeps that ratio, so A4 folded is A5 and A3 folded is A4, and scaling between them never distorts artwork.
A4 and Letter are close but not interchangeable
Letter is 5.9 mm wider than A4 and 17.6 mm shorter, and A4 has about 3 percent more area. An A4 layout printed on Letter can lose the foot of the page, which is what fit to page in the print dialog rescales around.
| Size | Millimetres | Inches |
|---|---|---|
| A3 | 297 x 420 | 11.69 x 16.54 |
| A4 | 210 x 297 | 8.27 x 11.69 |
| A5 | 148 x 210 | 5.83 x 8.27 |
| B5 | 176 x 250 | 6.93 x 9.84 |
| Letter | 215.9 x 279.4 | 8.5 x 11 |
Inches are the millimetre values divided by 25.4.
Frequently asked questions
Is A4 an international standard?
Yes, it is defined by ISO 216 and used in most of the world. Each A size is exactly half the previous one, which is why scaling between them never distorts the layout.
Why does the US use different sizes?
North America kept its own Letter and Legal formats rather than adopting ISO 216. Letter is slightly wider and shorter than A4, which is why documents often reflow when crossing between the two.
Which is bigger, A4 or Letter?
A4, by area, with roughly 3 percent more surface. Letter wins on width by 5.9 mm but gives up 17.6 mm of height.
Is the B5 here the same as a Japanese B5?
No. This page lists the ISO B5 at 176 x 250 mm, while the JIS B5 used for many Japanese and Korean books is 182 x 257 mm.