What it does
Look up the size of any common paper in millimetres, centimetres, inches or pixels, see two sizes drawn side by side to the same scale, and read off the percent you need to print one on the other. It covers the A, B and C series, US Letter, Legal and Tabloid, photo prints and passport photo sizes.
Nothing is sent anywhere and it works offline. To make blank pages in a size you pick, use printable paper; to fit a picture to a size in pixels, use image resizer; and to rearrange the pages of a PDF, use organise PDF.
How to use it
- Choose “Size one” and “Size two”.
- Pick the unit, and the dpi if you need pixels.
- Read the scale lines under the picture, or browse the full table by group.
What each setting does
- Show in: millimetres, centimetres or inches.
- Pixels at (dpi): the pixel size of a page for a given print resolution. 300 dpi is normal for print.
- Fit: the scale that makes all of page one visible on page two.
- Fill: the scale that covers page two completely, cutting some off.
Worked example
A4 is 210 x 297 mm. To print an A4 page on Letter (215.9 x 279.4 mm), width allows 102.8% but height allows only 94.1%, so the whole page fits at 94.1%. At 300 dpi, A4 is 2480 x 3508 pixels.
FAQs
What makes A sizes special? Each size is half of the one before, with the same shape, so scaling between them is exact.
Which passport photo size should I use? It depends on the country and changes. Check the official source.
Are these sizes exact? ISO sizes are rounded to the millimetre, as in the standard.
Where the numbers come from
- ISO 216 (A and B series) and ISO 269 (C series) sizes, rounded to whole millimetres. US sizes are in inches (ANSI/ASME Y14.1). Photo and passport sizes follow common practice; they change, so check the official source for your country.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.