Paper Size Chart
ISO A, B and C paper sizes — dimensions in mm and inches, A0 to A10.
The Paper Size Chart gives the exact dimensions of every ISO 216 size — A0 through A10, plus the B series (posters, books) and C series (envelopes) — in millimeters and inches, computed from the elegant rule that defines them.
ISO paper is built on one idea: the ratio √2:1, so folding a sheet in half always produces the next size with the same proportion. A0 is exactly 1 m², A1 is half of it, and A4 — the world's printing default at 210 × 297 mm — is A3 folded once.
Select any series and number for an instant dimension card, and scan the full table below to compare sizes at a glance. US Letter (215.9 × 279.4 mm) is the notable non-ISO exception. Everything runs locally.
Dimensions
A4 = 211 × 298 mm
8.3 × 11.7 in · 0.063 m²
| Size | mm | inches |
|---|---|---|
| A0 | 841 × 1189 | 33.1 × 46.8 |
| A1 | 841 × 595 | 33.1 × 23.4 |
| A2 | 421 × 595 | 16.6 × 23.4 |
| A3 | 421 × 298 | 16.6 × 11.7 |
| A4 | 211 × 298 | 8.3 × 11.7 |
| A5 | 211 × 149 | 8.3 × 5.9 |
| A6 | 106 × 149 | 4.2 × 5.9 |
| A7 | 106 × 75 | 4.2 × 3.0 |
| A8 | 53 × 75 | 2.1 × 3.0 |
| A9 | 53 × 38 | 2.1 × 1.5 |
| A10 | 27 × 38 | 1.1 × 1.5 |
ISO paper follows the √2 ratio: every size is half of the previous one, so A4 is half of A3. A4 (210 × 297 mm) is the world's most printed size; US Letter (215.9 × 279.4 mm) is the main exception.
How to use the Paper Size Chart
- Pick the series: A (standard), B (posters/books) or C (envelopes).
- Choose a size number from 0 to 10.
- Read the dimensions in mm and inches.
- Scan the full table for comparisons.
- Use the sizes for print, layout and envelope selection.
Frequently asked questions
Why is A4 half of A3?
ISO paper keeps a √2:1 ratio, so cutting a sheet in half along its long side produces the next smaller size with identical proportions. A3 (297 × 420) folds to exactly A4 (210 × 297).
What are the B and C series for?
B series sits between A sizes — B5 fits between A4 and A5 — used for posters, books and passports. C series is sized for envelopes: a C4 envelope fits an A4 sheet unfolded.
How does US Letter compare to A4?
Letter is 215.9 × 279.4 mm — slightly wider and shorter than A4 (210 × 297). The two are close enough that printers handle both, but layouts designed for one do not map perfectly to the other.
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