Understanding Standard Paper Dimensions
Whether you are designing a digital poster, setting up a print document, or buying frames, knowing the exact physical dimensions of your paper is crucial. Our Free Paper Size Calculator helps you translate industry standards into practical measurements.
The ISO A-Series (International Standard)
Used by almost every country in the world (except the US and Canada), the ISO 216 standard is based on a mathematical aspect ratio of 1 to the square root of 2. This means that every time you fold a piece of A-series paper in half, you get the exact dimensions of the next smaller size.
- A0: Exactly one square meter in area.
- A4: The global standard for office documents and letters.
- A5: Commonly used for notebooks and flyers.
North American Standards (US Standard)
The United States, Canada, and parts of Latin America use a different sizing system based on traditional inch measurements.
- US Letter (8.5" × 11"): The standard size for everyday printing and office use.
- US Legal (8.5" × 14"): Used frequently for contracts and legal documents.
- Tabloid (11" × 17"): Often used for small posters and newsletters.
Frequently Asked Questions (FAQ)
What is the difference between A4 and US Letter?
While they are used for the exact same purposes, they are not the same size. A4 is slightly taller and narrower, measuring 8.27 × 11.69 inches (210 × 297 mm). US Letter is slightly wider and shorter, measuring 8.5 × 11 inches (215.9 × 279.4 mm). If you print a US Letter document on A4 paper, you may notice wider margins at the top and bottom.
How do I calculate paper size in pixels?
Physical paper sizes (like inches or millimeters) do not inherently have "pixels." Pixel dimensions depend entirely on the resolution, or DPI (Dots Per Inch), at which you intend to print or display the document. The industry standard for high-quality printing is 300 DPI. To find the pixel size, you multiply the inch dimensions by the DPI. (e.g., US Letter width: 8.5 inches × 300 DPI = 2550 pixels).
What is the ISO B-Series used for?
The ISO B-Series was created to provide a wider range of sizes that fall exactly between the A-Series sizes. It is very commonly used in the printing industry for books, passports, and envelopes.