Paper Size Reference

About the Paper Size Reference

The Paper Size Reference lists dimensions for all standard paper sizes in the ISO A series, B series, and common US/North American formats. View dimensions in millimeters, inches, or typographic points.

The ISO 216 standard defines A-series paper sizes, where A0 is exactly 1 square meter in area and each successive size (A1, A2, A3, A4, ...) is half the previous one. The aspect ratio is always 1:√2, which means folding a sheet in half produces the next smaller size with the same proportions. This elegant system is used worldwide except in the US and Canada.

US paper sizes (Letter, Legal, Tabloid, Ledger) evolved from traditional printing practices and have no mathematical relationship to each other. This reference covers both systems so you can quickly compare and convert between them.

When This Page Helps

Designers, printers, and office workers frequently need exact paper dimensions. This reference eliminates searching through multiple charts and shows all sizes with mm, inch, and point measurements.

How to Use the Inputs

1. Select the paper size series (A, B, or US).
2. Choose the specific paper size from the list.
3. View dimensions in millimeters, inches, and points.
4. Compare sizes across series using the output display.
5. Use point dimensions for desktop publishing and design software.

Example Calculation

Tips & Best Practices

• A4 (210 × 297 mm) is the global standard for documents; US Letter (8.5 × 11 in) is used mainly in North America.
• When printing US-formatted PDFs on A4, scale to 97% to fit, or vice versa.
• B-series sizes are geometric means between A sizes and used for books, posters, and envelopes.
• The ISO C-series (not shown) defines envelope sizes designed to hold A-series sheets.
• Points (pt) are critical in design: 1 pt = 1/72 inch. A4 is 595 × 842 pt.

The ISO 216 Standard

ISO 216 was adopted in 1975 and is based on the German DIN 476 standard from 1922. The mathematical elegance of the 1:√2 aspect ratio means that any A-series sheet folded in half produces the next smaller size with identical proportions, making scaling straightforward.

US Paper Sizes

US Letter (8.5 × 11 in) and Legal (8.5 × 14 in) have no mathematical basis. They evolved from traditional papermaking practices. ANSI/ASME Y14.1 defines engineering drawing sizes (A through E), which are different from consumer paper sizes.

Practical Considerations

When creating documents for international distribution, design for A4 with margins that also work on Letter paper. Most printers can handle both sizes. For printing, always check the margin requirements — most printers have a 5–10 mm non-printable border.

Frequently Asked Questions

• What is the most common paper size?

  Globally, A4 (210 × 297 mm) is the most common paper size. In the United States and Canada, Letter size (8.5 × 11 inches or 216 × 279 mm) is the standard.

• What is the difference between A4 and US Letter?

  A4 is 210 × 297 mm (8.27 × 11.69 in). US Letter is 216 × 279 mm (8.5 × 11 in). Letter is wider but shorter than A4. This can cause formatting issues when sharing documents internationally.

• How does the A-series sizing work?

  A0 is 841 × 1189 mm (exactly 1 m²). Each subsequent size (A1, A2, A3, etc.) is created by cutting the previous size in half parallel to the short side. The aspect ratio of 1:√2 is maintained throughout.

• What is B-series paper used for?

  B-series sizes fall between A-series sizes. B5 is between A4 and A5, for example. They are commonly used for books, passports, posters, and specialty printing where A-series sizes are too big or too small.

• What are typographic points?

  A point (pt) is 1/72 of an inch (0.3528 mm). Design software like Adobe InDesign and Illustrator use points as the native unit. A4 in points is 595 × 842 pt.

• What is Tabloid/Ledger size?

  Tabloid and Ledger are the same sheet: 11 × 17 inches (279 × 432 mm). Tabloid refers to portrait orientation; Ledger refers to landscape. It's exactly two Letter sheets side by side.