ISO Paper Size Calculator
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ISO 216 paper dimensions — A, B, and C series in millimeters and inches.
ISO size lookup
Dimensions
210 × 297 mm
A4 — 0.062 m² area
- Inches
- 8.27 × 11.69 in
- Area
- 624 cm²
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ISO paper sizes
ISO 216 defines A, B, and C paper series used worldwide (except US Letter/Legal). Each size has a width-to-height ratio of √2 (≈1.414). Folding an A sheet in half along the short edge gives the next size down — A4 folded → A5.
A series is for general printing (A4 is standard office paper). B series is for posters and books. C series sizes fit A series envelopes — C4 holds a flat A4 sheet.
Example: A4 = 210 × 297 mm (8.27 × 11.69 in). A0 = 841 × 1189 mm — one square meter in area. A5 = half of A4 at 148 × 210 mm.
Common questions
How is A4 different from US Letter?
A4 is 210 × 297 mm. US Letter is 8.5 × 11 in (216 × 279 mm) — slightly wider and shorter. They are not interchangeable in most printers.
What is the B series for?
B sizes sit between A steps — B4 is between A4 and A3. Used for posters, envelopes, and print imposition.