Loading Calculator...
Please wait a moment
Please wait a moment
Compare A4 and US Letter paper dimensions with detailed size analysis
Width Difference:
Letter is 6 mm (0.23 in) wider
Height Difference:
A4 is 18 mm (0.69 in) taller
Area Difference:
A4 is 3.5% larger
Aspect Ratio:
A4: 1:√2, Letter: 1:1.294
A4 is part of the ISO 216 international standard, which is used in nearly every country except the United States and Canada. The A series is based on a √2 aspect ratio, meaning when you fold an A4 sheet in half, you get A5 with the same proportions. This makes it ideal for scaling documents.
Letter size (8.5 × 11 inches) is the standard in North America. It originated from traditional paper manufacturing processes and doesn't follow the same mathematical proportions as the ISO standard. However, it's deeply embedded in US business and education systems.
When printing A4 documents on Letter paper (or vice versa), you may experience margins being cut off or extra white space. Most modern printers and PDF software offer "fit to page" options to handle these conversions automatically.
A4 is slightly larger overall with 3.5% more area. Letter is wider (8.5 vs 8.27 inches), but A4 is taller (11.69 vs 11 inches). A4 has 62,370 mm² compared to Letter's 60,264 mm².
Yes, but you'll need to scale the document. Most PDF readers and printers have a "fit to page" or "shrink to fit" option. The document will be reduced to about 94% to fit properly on Letter paper, or you may have small margins cut off if printed at 100%.
The ISO 216 standard (A4) was adopted by most countries for its mathematical precision and scalability. The US and Canada continued using traditional sizes like Letter that were already established in their manufacturing and business practices.
A4 has an aspect ratio of 1:√2 (1:1.414), which means folding it in half preserves the proportions. Letter has a ratio of 1:1.294, which doesn't maintain proportions when halved. This makes A4 better for scaling and reproduction.
For documents that might be printed on either size, use margins of at least 1 inch (25mm) on all sides. This ensures your content remains visible regardless of which paper size is used and accounts for potential scaling.
A4 is used in Europe, Asia, Africa, Australia, and South America (most of the world). Letter is primarily used in the United States, Canada, and parts of Mexico. Some countries use both depending on the context.