You're Designing a Document and Need to Ensure It Prints Correctly on Different Paper Sizes
You created a template in US Letter size (8.5 × 11 inches), but your European clients need it in A4 (210 × 297 mm). Your printer defaults to A4, but you're trying to print on US Letter stock. An international business needs a single design that works across multiple paper standards. Converting paper sizes accurately ensures your designs print correctly without cropping, stretching, or wasting paper. Our paper size converter shows exact dimensions and helps you choose the right format.
What This Calculator Does
This paper size converter displays all major paper sizes and their exact dimensions in both inches and millimeters: A series (A0–A10), B series, US Letter, Legal, Tabloid, and specialty sizes. Select any two sizes to compare their dimensions side by side. Understand how sizes relate to each other and what adjustments your designs need to fit different formats. This is essential for designers, business professionals, and anyone creating documents for international use.
How to Use This Calculator
The converter displays a comprehensive chart of major paper sizes with dimensions. Select two sizes to compare directly. The converter shows length, width, and area for each format in both metric and imperial units. Use this to verify your document design will fit your intended paper stock, or to choose the best size for your project. Many professionals keep this chart bookmarked for instant reference when designing or printing documents.
The converter helps identify which paper size works for your project. If you're printing an A4 design on US Letter (which is slightly narrower), content might crop on the sides. If you're printing a US Letter design on A4 (which is slightly taller), you might have extra white space. Understanding these differences prevents printing surprises.
The Math Behind the Conversion
Paper sizing systems are mathematically elegant. The ISO 216 A-series paper standard (used worldwide except North America) is based on simple geometry. Each size has an aspect ratio of 1:√2 (approximately 1:1.414). When you fold an A-size paper in half along its length, you get the next smaller A-size.
Here are the base dimensions:
US standards (approximately):
Key conversion facts:
Worked example: You designed a document for A4 (210 × 297 mm) and need to print it on US Letter (216 × 279 mm):
To print A4 content on US Letter without cropping, you'd need to scale it down to 93.9% of its original size, or redesign with narrower margins.
Our paper size converter handles all of this instantly-but now you know the math behind it.
Graphic Design and Document Layout
Graphic designers working internationally constantly convert between paper sizes. A business card designed for A4-based specifications might need to fit on US Letter for an American client. A designer creating a poster uses A-series sizes in Europe but needs to know equivalents in US standards. A magazine designed for A4 might need adaptation for US Letter. Understanding dimensions and aspect ratios helps designers avoid costly reprinting errors.
International Business and Publishing
Publishers working across regions encounter multiple paper standards. A book designed in Europe (often A-format) might be republished in America (US standards). Business documents created in the US need European equivalents for international distribution. Packaging designers need to know how their designs scale across different paper sizes. Accurate size knowledge ensures documents print correctly everywhere.
Printing and Finishing Professionals
Printers, finishers, and binderies constantly work with multiple paper standards. A client provides a design in one size; the press runs a different format. Understanding conversions prevents waste and ensures correct output. Stationery suppliers stock multiple sizes; recommending the right format saves clients money and shipping issues.
Common Conversion Reference
Here are the most common paper sizes:
International A-Series (ISO 216):
US Standards:
B-Series (larger formats, less common):
Quick fact: US Letter is 0.5 inches wider and 0.7 inches shorter than A4. For document compatibility, A4 is the safer choice internationally.
Frequently Asked Questions
What's the difference between A4 and US Letter?
A4 (210 × 297 mm / 8.3 × 11.7") is the international standard used everywhere except North America. US Letter (216 × 279 mm / 8.5 × 11") is the North American standard. They look similar but differ in aspect ratio and dimensions. A4 is slightly narrower and taller. The 0.5" width difference can cause cropping in some designs.
Why does North America use different paper sizes?
Historical reasons. Standardization occurred independently in different regions before globalization. The US developed its own system (Letter, Legal, Tabloid) based on practical printing needs. Now everyone else uses ISO 216 (A-series). Changing US standards would be impractical, so both systems coexist.
Can I print A4 documents on US Letter paper?
Not directly without adjustments. A4 content will crop or need scaling. If you scale to fit, margins shrink. Some printers have A4 or Letter settings; choosing the right one helps. Many modern printers detect the paper size automatically. For professional documents, match the design's intended size to your paper.
What paper size should I use for international documents?
A4 is the safest choice. It's recognized everywhere. If your audience is international, design for A4. If you're US-based and your audience is primarily domestic, Letter is fine. For truly global documents, create in A4 but test printing on Letter to ensure nothing critical crops.
What's the difference between A-series and B-series paper?
A-series (A4, A5, etc.) is the standard for normal documents. B-series (B4, B5, etc.) is intermediate between A-series sizes and is used for envelopes and specialty items. For normal business, use A-series. B-series is less common and less necessary to understand.
How do I choose the right paper size for my project?
Consider your use case: business letters (A4 internationally, Letter in US), marketing materials (often A4 or smaller specialty sizes), posters (large formats like A1 or A2), forms (typically A4 or Letter), and envelopes (specialized sizes). Check standards in your intended market. International projects default to A4.
Related Calculators
Pair the paper size converter with related tools for comprehensive document and design work. The Length Converter helps you understand millimeters and inches if you need to work with precise margins or dimensions. The Area Converter translates paper area (useful for understanding coverage, quantity, or relative sizes). The Weight Converter helps if you're comparing paper weight specifications (basis weight varies by region). For design and layout work, use these tools alongside the paper size converter.