Paper Size Calculator Online
Need to know the exact dimensions of a paper size? This free online calculator lets you compare A-series (A0–A10), US Letter, Legal, Tabloid and more — in millimetres, centimetres or inches. Select a format below and get the answer in one click.
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Standard Paper Sizes Explained
Paper sizes follow two main systems: the ISO 216 standard (used worldwide) and the North American system. ISO sizes — A0, A1, A2, A3, A4, A5 — each have an aspect ratio of 1.414, so folding an A3 sheet in half gives you two A4 sheets. North American formats (Letter, Legal, Tabloid) use different aspect ratios based on historical printing conventions. Use the calculator above to see the exact dimensions of any format in mm, cm or inches.
How to Use the Paper Size Calculator Online
Select the paper format from the dropdown (e.g. A4, Letter, Legal). The width and height appear immediately in all three unit systems: mm, cm and inches. You can switch units at any time — the calculator updates in real time directly in your browser, so no data leaves your device.
Common Paper Size Reference Table
A0: 841 x 1189 mm | A1: 594 x 841 mm | A2: 420 x 594 mm | A3: 297 x 420 mm | A4: 210 x 297 mm | A5: 148 x 210 mm | US Letter: 216 x 279 mm | US Legal: 216 x 356 mm | Tabloid: 279 x 432 mm. These dimensions follow ISO 216 and ANSI standards.
Frequently Asked Questions
What is the size of A4 paper in mm and inches?
A4 paper measures 210 x 297 mm (8.27 x 11.69 inches). It is the most widely used paper size in the world outside North America.
What is the difference between Letter and A4 paper?
US Letter is 216 x 279 mm (8.5 x 11 in), while A4 is 210 x 297 mm. Letter is slightly wider but shorter than A4.
How do I convert paper size from mm to inches?
Divide the mm value by 25.4 to get inches. For example, 210 mm / 25.4 = 8.27 inches. Our calculator does this automatically for every format.
What paper size is bigger, A3 or A4?
A3 is exactly twice the size of A4: 297 x 420 mm vs 210 x 297 mm. Each A-series size is half of the one above it.
Is this paper size calculator free to use online?
Yes, 100% free, no account needed. Just select your paper format and the dimensions appear instantly in your preferred unit.