Paper Size Converter
NewReference dimensions for A-series (A0-A7), B-series (B0-B7), and US/ANSI paper sizes (Letter, Legal, Tabloid), shown in millimeters, centimeters, or inches.
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Frequently Asked Questions
How are A-series sizes related to each other?
Each size is exactly half the area of the one before it when folded along its longer side — A0 is 1 square meter, A1 is half of A0, A2 is half of A1, and so on, all while maintaining the same 1:√2 aspect ratio at every step.
Why is US Letter a different shape than A4?
US Letter (8.5" × 11") uses a different historical standard than the ISO 216 A-series used almost everywhere else in the world, so it has a slightly different aspect ratio than A4 — this is why documents formatted for one don't scale perfectly onto the other.
What's the difference between B-series and A-series?
B-series sizes are also ISO 216 standard but sit between consecutive A-series sizes in area, used less commonly than A-series but still seen in some poster, passport, and envelope formats.
Where is ANSI paper sizing used?
ANSI sizes (ANSI A through ANSI E) are the US engineering-drawing equivalent of the ISO series, with ANSI A matching Letter size and each subsequent size roughly doubling in area, commonly used for technical and architectural drawings in the US.