A4 Millimetres To Inches Converter
Instantly convert A4 and other paper sizes from millimetres to inches. Pick a standard size or enter your own dimensions for an accurate, instant result.
Convert Millimetres To Inches
Select a standard paper size or enter custom dimensions in millimetres to get an instant, accurate conversion to inches, using the exact rate of 1 inch = 25.4mm.
mm to Inches Converter
Fill in your dimensions to see the converted result
Choose a preset or select Custom to enter your own
Shorter edge of the sheet
Longer edge of the sheet
Converted Dimensions
Millimetres converted using 1in = 25.4mm
Standard Paper Sizes In mm & Inches
Common A-series and US paper sizes, with millimetre dimensions converted to inches for reference.
| Size | Millimetres | Inches | Common Use |
|---|---|---|---|
| A2 | 420 x 594mm | 16.54 x 23.39in | Posters |
| A3 | 297 x 420mm | 11.69 x 16.54in | Drawings, charts |
| A4 | 210 x 297mm | 8.27 x 11.69in | Letters, documents |
| A5 | 148 x 210mm | 5.83 x 8.27in | Notebooks, flyers |
| A6 | 105 x 148mm | 4.13 x 5.83in | Postcards |
| US Letter | 215.9 x 279.4mm | 8.50 x 11.00in | US/Canada documents |
| US Legal | 215.9 x 355.6mm | 8.50 x 14.00in | US legal documents |
mm To Inches FAQ
Everything you need to know about converting paper sizes between millimetres and inches.
A4 paper measures 210mm by 297mm, which converts to approximately 8.27 inches by 11.69 inches. It is the standard paper size used across the UK, Europe, and most of the world outside North America.
To convert millimetres to inches, divide the millimetre value by 25.4, since one inch is exactly 25.4 millimetres. For example, 210mm divided by 25.4 equals 8.27 inches.
A4 is 210mm x 297mm (8.27in x 11.69in) and is used almost everywhere outside North America. US Letter is 215.9mm x 279.4mm (8.5in x 11in) and is the standard size in the United States and Canada. A4 is slightly narrower and longer than Letter.
A4 belongs to the ISO 216 A-series, where each size has an aspect ratio of 1:1.41421 (the square root of 2). This means folding a sheet in half along its longer side produces a smaller sheet with the exact same proportions, which is why A4 folds neatly into A5, A3 into A4, and so on.