Find paper dimensions, compare international formats and convert paper sizes between millimeters, centimeters, inches and pixels. Explore ISO A-series and B-series sizes as well as common North American formats such as Letter, Legal and Tabloid.
Popular Paper Sizes
These are some of the most frequently used paper formats for documents, printing, design and office work.
| Paper size | Millimeters | Centimeters | Inches |
|---|---|---|---|
| A5 | 148 × 210 mm | 14.8 × 21.0 cm | 5.83 × 8.27 in |
| A4 | 210 × 297 mm | 21.0 × 29.7 cm | 8.27 × 11.69 in |
| A3 | 297 × 420 mm | 29.7 × 42.0 cm | 11.69 × 16.54 in |
| US Letter | 215.9 × 279.4 mm | 21.59 × 27.94 cm | 8.5 × 11 in |
| US Legal | 215.9 × 355.6 mm | 21.59 × 35.56 cm | 8.5 × 14 in |
| Tabloid / Ledger | 279.4 × 431.8 mm | 27.94 × 43.18 cm | 11 × 17 in |
Calculate Print Size from Image Pixels
Enter an image’s width, height and PPI to find its maximum print size in inches, centimeters and millimeters. You can also calculate the pixels required for A4, A3, Letter and other print formats.
International and North American Paper Standards
Most countries use the ISO 216 paper size system. Its best-known format is A4, measuring 210 × 297 millimeters. The A-series maintains the same proportions as each sheet is divided into the next smaller size, making it easy to enlarge or reduce documents between formats.
The United States and parts of North America commonly use formats such as Letter, Legal, Tabloid and Ledger instead. US Letter is slightly wider and shorter than A4, so documents designed for one format may need adjustments before being printed on the other.
Paper Sizes for Digital Design and Printing
A physical paper format does not have one fixed pixel size. The required pixel dimensions depend on the selected resolution. For example, A4 requires approximately 2481 × 3508 pixels at 300 PPI, but only about 1241 × 1754 pixels at 150 PPI.
Use Paper Sizes in Pixels when you start with a paper format. Use the Print Size Calculator when you already know the dimensions of your image.
Frequently Asked Questions
What is the most common paper size?
A4 is the standard office and document size in most countries using ISO 216. US Letter is the most common equivalent in the United States and parts of North America.
Is A4 the same size as US Letter?
No. A4 measures 210 × 297 millimeters, while US Letter measures 8.5 × 11 inches, or 215.9 × 279.4 millimeters. Letter is slightly wider and A4 is slightly taller.
Why do A-series paper sizes keep the same proportions?
A-series formats use an aspect ratio of 1 to the square root of 2. This allows a sheet to be divided in half while keeping the same proportions.
How many pixels does A4 need?
At 300 PPI, an A4 page requires approximately 2481 × 3508 pixels. The required dimensions change when a different print resolution is selected.