Paper Size Converter: A4, Letter, Legal Dimensions in mm, cm, and Inches
Paper sizes vary around the world and it is easy to get confused. A4 and Letter look similar but are not interchangeable. A3 is double A4, but how big is that in inches? What is Legal size in millimeters?
Our Paper Size Converter gives you instant dimensions for all standard paper sizes — ISO A series (A0–A7), ISO B series, North American sizes (Letter, Legal, Tabloid, Executive), and common envelope formats — in millimeters, centimeters, and inches simultaneously.
The ISO A series follows a mathematically elegant progression:
ISO A Series vs North American Sizes
The ISO A series (used in Europe, Asia, Australia, and most of the world) is based on the DIN 476 standard with a consistent 1:√2 aspect ratio. This means folding any A-size sheet in half always produces the next smaller size.
North American sizes (Letter, Legal, Tabloid) have no such mathematical relationship. Letter (8.5×11") and A4 (8.27×11.69") are close but different enough to cause printing problems when mixing formats.
Practical Conversion Guide
Designing for print: Always check whether your target country uses A4 or Letter
PDF documents: Set your document size in the export settings, not just the printer settings
Margin conversion: When converting A4 layouts to Letter, reduce top/bottom margins to compensate for the shorter height
Poster printing: Use A series for international distribution; US printers often offer 11×17 (Tabloid) as the closest alternative to A3
Practical Examples
Printing an A4 document in the US
- 1.A4: 210×297mm (8.27×11.69")
- 2.Letter: 216×279mm (8.5×11")
- 3.Difference: A4 is 5mm narrower and 18mm taller
- 4.Solution: Scale to fit, or adjust bottom margin by 18mm
Choosing paper for a poster
- 1.A2: 420×594mm — medium poster, commonly available
- 2.A1: 594×841mm — large poster, print shops
- 3.A0: 841×1189mm — exhibition poster, specialist printing
Frequently Asked Questions
What is the size of A4 paper in inches?
A4 paper is 210 x 297 mm, which equals 8.27 x 11.69 inches. It is the standard paper size used in most of the world outside North America.
What is the difference between A4 and Letter size?
A4 is 210 x 297 mm (8.27 x 11.69 inches) and Letter is 216 x 279 mm (8.5 x 11 inches). A4 is 5mm narrower but 18mm taller than Letter. A4 is standard in Europe and Asia; Letter is standard in the USA and Canada.
What is the size of Letter paper in millimeters?
US Letter paper is 216 x 279 mm (8.5 x 11 inches). It is the standard paper size for offices, home printers, and business documents in the United States, Canada, and Mexico.
What does the A series paper sizing system mean?
The ISO 216 A series is based on a root-2 ratio (1:1.414). Each size is exactly half of the previous size when folded. A0 is 841 x 1189 mm and has an area of 1 square meter. Each subsequent size (A1, A2, A3, A4...) is half the area of the previous.
What is A3 paper size in inches?
A3 paper is 297 x 420 mm, which equals 11.69 x 16.54 inches. It is double the size of A4 and equivalent to two A4 sheets placed side by side. Used for drawings, diagrams, and tabloid-format newspapers.
What is Legal size paper?
Legal paper is 216 x 356 mm (8.5 x 14 inches). It is 3 inches (76mm) taller than Letter paper. Used in the USA for legal documents, contracts, and certain government forms.
What is Tabloid (Ledger) paper size?
Tabloid (also called Ledger) is 279 x 432 mm (11 x 17 inches). It is equivalent to two Letter sheets placed side by side. Used for newspapers, large spreadsheets, and technical drawings.
Why does printing from A4 to Letter sometimes cut off content?
A4 is taller but narrower than Letter. When printing an A4 document on Letter paper without scaling, the bottom 18mm may be cut off. Always select 'Fit to page' or 'Scale to paper size' in your print settings when converting between formats.