π Paper Size Converter
A0 to A10 plus US Letter, Legal, and Tabloid in mm, cm, and inches.
Dimensions
A-Series Sizes (mm)
| Size | mm | inches | Use |
|---|---|---|---|
| A0 | 841 Γ 1189 | 33.1 Γ 46.8 | Posters |
| A1 | 594 Γ 841 | 23.4 Γ 33.1 | Flip charts |
| A2 | 420 Γ 594 | 16.5 Γ 23.4 | Posters |
| A3 | 297 Γ 420 | 11.7 Γ 16.5 | Drawings |
| A4 | 210 Γ 297 | 8.3 Γ 11.7 | Standard document |
| A5 | 148 Γ 210 | 5.8 Γ 8.3 | Booklets |
| A6 | 105 Γ 148 | 4.1 Γ 5.8 | Postcards |
How to Use This Paper Size Converter
Pick any international A-series size or US size from the dropdown to see its exact dimensions in millimeters, centimeters, and inches, plus its area and aspect ratio. Designers use it for print layouts, offices use it to buy the right paper, and travelers use it to understand why US printers reject A4.
Select a paper size from the dropdown.
Read dimensions in mm, cm, and inches, plus area.
Use the comparison notes to pick the right size for printing or buying.
The A-Series: Elegant by Design
The ISO 216 A-series starts with A0, defined as exactly one square meter with a β2 aspect ratio (841 Γ 1189 mm). Each smaller size is half the previous one, cut across the long side, so the aspect ratio never changes. That is why A4 scaled to A3 fits perfectly with no wasted margin, and why the series feels so coherent: it is pure geometry, designed in 1922 and now used everywhere except North America.
US sizes are historical accidents by comparison. Letter (8.5 Γ 11 in) and Legal (8.5 Γ 14 in) date to early American papermaking, and Tabloid (11 Γ 17 in) is simply two Letter sheets side by side. Their aspect ratios differ from each other and from A4, which is why cross-Atlantic document exchange always involves slight scaling.
A4 vs US Letter
Printing an A4 document on Letter paper (or vice versa) at 100 percent scale clips about 6 mm somewhere. The safe fix is "fit to page" scaling, which shrinks everything by roughly 3 percent. For critical layouts, redesign at the target size instead.
Worked Example
You need a poster twice the area of A3. A3 is 297 Γ 420 mm; doubling the area means going one size up to A2 (420 Γ 594 mm), because each A step doubles or halves the area. For a US equivalent of A4, the closest is Letter, but expect the 6 mm height difference when exchanging files.
Buying and Printing Tips
Check your printer's supported sizes before buying specialty paper; many US printers cannot feed A4 properly. For presentations, A3 folded makes an A4 booklet with no trimming. And when a print shop asks for "bleed," add 3 mm on each side beyond the sizes shown here.
Frequently Asked Questions
What is A4 paper size in inches?
8.27 Γ 11.69 inches (210 Γ 297 mm). It is the standard document size in most of the world, slightly narrower and taller than US Letter.
What is the difference between A4 and US Letter?
A4 is 210 Γ 297 mm; US Letter is 215.9 Γ 279.4 mm (8.5 Γ 11 in). A4 is narrower and taller. Printing one on the other at 100 percent clips about 6 mm.
What paper size is legal?
US Legal is 8.5 Γ 14 inches (215.9 Γ 355.6 mm), the same width as Letter but 3 inches longer. It is common for contracts and legal documents in the US.
How does the A-series scaling work?
Each size is half the area of the previous one: A0 halved is A1, halved again is A2, and so on. The β2 aspect ratio never changes, so scaling between sizes needs no cropping.
What is tabloid paper size?
11 Γ 17 inches (279 Γ 432 mm), exactly two US Letter sheets side by side. It is called A3-equivalent in casual use, though true A3 is 297 Γ 420 mm.