Paper Size in Inches
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Width × Height
Instantly convert A4 and all ISO 216 A-series paper sizes to inches, mm, and cm
Convert paper size A4 to inches and explore all A-series dimensions. Includes a custom mm to inches converter and a full ISO 216 reference table for 2026.
Professional paper dimension reference for designers, printers, students, and offices
Get exact paper size A4 to inches conversions based on the ISO 216 international standard. A4 measures precisely 8.268 × 11.693 inches (210 × 297 mm), and every figure in this tool is derived directly from that standard without rounding errors.
Select any paper size from A0 to A10 to instantly view its dimensions in inches, millimetres, and centimetres. Whether you need A3 for presentations or A6 for postcards, all ISO 216 sizes are covered in one place.
Essential for graphic designers, print shops, architects, students, and office workers who need to switch between metric and imperial paper dimensions. Perfect for setting up documents in Word, Photoshop, Illustrator, or any design software in 2026.
Select a standard paper size or enter a custom mm value below
A4 is the world's most widely used paper size, defined by the ISO 216 international standard. It measures exactly 210 × 297 millimetres, which converts to 8.268 × 11.693 inches. The standard was first described by German scientist Georg Christoph Lichtenberg in 1786, then formalised by the German Institute for Standardisation in 1922 as DIN 476, before becoming the global ISO 216 standard used in over 160 countries today.
The defining feature of ISO 216 paper sizes is their √2 aspect ratio (approximately 1:1.4142). This means when you fold an A4 sheet in half along its longest edge, you get a perfect A5 sheet. Double an A4 and you get A3. This mathematical relationship — used in area and dimension standards worldwide — ensures consistent scaling across all print and copy equipment.
One inch is defined as exactly 25.4 mm under the international inch standard since 1959.
A4 paper is often confused with the American US Letter size (8.5 × 11 inches / 215.9 × 279.4 mm). While they look similar, A4 is slightly narrower and taller than US Letter. A4 has more vertical length (11.693 in vs 11 in) but less width (8.268 in vs 8.5 in). This matters when printing documents designed for one region on paper from another — margins may shift, and content can be clipped if not adjusted.
A4: 210 × 297 mm | 8.268 × 11.693 inches | 21.0 × 29.7 cm
US Letter: 215.9 × 279.4 mm | 8.5 × 11 inches | 21.59 × 27.94 cm
Difference: A4 is 0.23 in narrower and 0.69 in taller than US Letter.
Each size is exactly half the area of the size above it. A4 (highlighted in red) is the most widely used size globally.
This reference table lists all ISO 216 A-series paper sizes from A0 to A10, showing exact dimensions in inches, millimetres, and centimetres. A4 to inches is the most commonly searched conversion, but all sizes follow the same formula: divide millimetres by 25.4 to get inches.
| Paper Size | Inches (W × H) | Millimetres (W × H) | Centimetres (W × H) | Common Use |
|---|---|---|---|---|
| A0 | 33.110 × 46.811 in | 841 × 1189 mm | 84.1 × 118.9 cm | Technical drawings, large posters |
| A1 | 23.386 × 33.110 in | 594 × 841 mm | 59.4 × 84.1 cm | Posters, flip charts |
| A2 | 16.535 × 23.386 in | 420 × 594 mm | 42.0 × 59.4 cm | Art prints, wall calendars |
| A3 | 11.693 × 16.535 in | 297 × 420 mm | 29.7 × 42.0 cm | Spreadsheets, presentations |
| A4 ★ | 8.268 × 11.693 in | 210 × 297 mm | 21.0 × 29.7 cm | Standard documents, letters |
| A5 | 5.827 × 8.268 in | 148 × 210 mm | 14.8 × 21.0 cm | Notebooks, booklets |
| A6 | 4.134 × 5.827 in | 105 × 148 mm | 10.5 × 14.8 cm | Postcards, index cards |
| A7 | 2.913 × 4.134 in | 74 × 105 mm | 7.4 × 10.5 cm | Small notebooks, cards |
| A8 | 2.047 × 2.913 in | 52 × 74 mm | 5.2 × 7.4 cm | Business cards, tickets |
| A9 | 1.457 × 2.047 in | 37 × 52 mm | 3.7 × 5.2 cm | Labels, stickers |
| A10 | 1.024 × 1.457 in | 26 × 37 mm | 2.6 × 3.7 cm | Stamps, tiny labels |
ISO 216 defines the international A, B, and C series paper sizes. The A series is the most widely used, with A4 as the global standard for documents. It is used in over 160 countries including all of Europe, Australia, and most of Asia. The United States and Canada are the main exceptions, using Letter and Legal sizes instead.
Every ISO 216 A-series sheet has a width-to-height ratio of 1:√2 (approximately 1:1.4142). This means that folding any A-series sheet in half always produces the next smaller A-series size with identical proportions — a fundamental property that makes scaling between sizes completely consistent and predictable.
When setting up an A4 document in design or word processing software, use 8.27 × 11.69 inches (rounded) or 210 × 297 mm for maximum precision. At 96 DPI (screen), A4 is 794 × 1123 pixels. At 300 DPI (print), it is 2480 × 3508 pixels — the standard for high-quality print production in 2026.
A4 and US Letter are the world's two dominant paper standards. A4 is taller and narrower; Letter is shorter and wider. When sharing documents internationally, it is good practice to use PDF format with embedded margins, as this prevents layout shifts when the file is printed on a different paper size in another country.
You may see A4 described as 8.27 × 11.69 inches in some sources and 8.268 × 11.693 in others. Both are correct — the first is rounded to two decimal places for everyday use, while the second is the more precise figure. For professional design and print work, always use the full-precision value: 8.268 × 11.693 inches.
Explore the full ISO 216 standard covering A, B, and C series paper sizes. Learn how each series is used — A for general documents, B for posters and books, C for envelopes — and how they work together in 2026.
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