Paper sizes in cm and inches: A4, Letter, A5 and more
Two paper systems are in everyday use. Most of the world uses the A series (A4, A5 and so on), defined in millimeters. The US and Canada mostly use Letter, Legal and Tabloid, defined in inches. Here are the exact sizes in both units.
The A series
| Size | Millimeters | Inches |
|---|---|---|
| A3 | 297 × 420 mm | 11.69 × 16.54 in |
| A4 | 210 × 297 mm | 8.27 × 11.69 in |
| A5 | 148 × 210 mm | 5.83 × 8.27 in |
| A6 | 105 × 148 mm | 4.13 × 5.83 in |
Every A size is half of the one above it: fold an A4 sheet in half and you get A5. That only works because the sides have a ratio of 1 to √2 (about 1 : 1.414), which is the one shape that stays the same shape when halved. The series starts from A0, which is exactly one square meter.
US paper sizes
| Size | Inches | Millimeters |
|---|---|---|
| Letter | 8.5 × 11 in | 215.9 × 279.4 mm |
| Legal | 8.5 × 14 in | 215.9 × 355.6 mm |
| Tabloid / Ledger | 11 × 17 in | 279.4 × 431.8 mm |
| Half Letter | 5.5 × 8.5 in | 139.7 × 215.9 mm |
Letter is a little wider and shorter than A4: 6 mm wider and 18 mm shorter. That’s why a document laid out for one often loses its margins when printed on the other. If you share files internationally, check the page size in your print settings before printing.
Cards and photos
| Item | Millimeters | Inches |
|---|---|---|
| Bank card / ID card (ISO ID-1) | 85.60 × 53.98 mm | 3.37 × 2.13 in |
| Business card (US) | 88.9 × 50.8 mm | 3.5 × 2 in |
| Business card (most of Europe) | 85 × 55 mm | 3.35 × 2.17 in |
| Photo print 4×6 | 101.6 × 152.4 mm | 4 × 6 in |
| Photo print 5×7 | 127 × 177.8 mm | 5 × 7 in |
The bank-card size is the one this site uses for calibration, because nearly everyone has a card that size in their wallet.
Checking a size yourself
To check whether a sheet is A4 or Letter, measure the short side: 210 mm (8.27 in) means A4, 216 mm (8.5 in) means Letter. A full sheet won’t fit on most screens, but its short edge often will on a laptop — set the ruler to mm and line it up against the screen. To convert any other size, use the unit converter: inches × 25.4 gives millimeters.