What Is A4 Paper Size?
A4 is part of the ISO 216 standard, which traces its origins to the DIN 476 standard developed in Germany in 1922. The goal was simple but ambitious: create a paper sizing system where every size maintains the same ratio, allowing documents to scale proportionally without distortion.
The system works through a simple principle. Start with A0, which has an area of one square meter. Fold it in half, and you get A1. Fold A1 in half, and you get A2. Continue this process, and you eventually arrive at A4 paper size — the format that has become the international default for business and personal documents.
Today, A4 is used in virtually every country except the United States, Canada, and a handful of others that still rely on North American paper standards. If you're sending a document internationally, you need to set the size of A4 paper to 210 by 297 millimeters.
So, what makes A4 so enduring? The answer lies in its versatility. It's large enough for formal documents but small enough for everyday printing. It fits standard filing systems and binders. And because every A-series size shares the same proportions, content designed for A4 can be scaled to A3 or A5 without awkward cropping.
SwifDoo PDF covers related cluster topics to explain all kinds of paper sizes. Check this list for more professional information:
- Legal Paper Size Guide: Dimensions, Uses, and How to Print
- Complete Guide for Long Bond Paper Size: Dimension, Types, Uses
- Statement Paper Size: The Size, Uses, How to Print [2025]
A4 Paper Dimensions
Now let's get precise. The size of A4 paper is consistent across all manufacturers and countries that use the ISO 216 standard. Here are the exact measurements in every commonly used unit.
A4 Paper Size in mm
- Width: 210 mm
- Height: 297 mm
This is the base measurement from which all other units derive. When you see A4 paper size in mm listed in printer settings or design software, 210 x 297 is the figure you'll encounter.
A4 Paper Size in cm
- Width: 21.0 cm
- Height: 29.7 cm
The A4 size in cm is simply the millimeter measurement divided by ten. This unit is commonly used in European countries for everyday descriptions — a standard sheet of A4 paper dimensions is 21 by 29.7 centimeters.
A4 Paper Size in inches
- Width: 8.27 inches
- Height: 11.69 inches
For users in countries that still think in imperial units, the A4 size in inches is 8.27 by 11.69 inches. This is slightly narrower and slightly longer than the US Letter size, which measures 8.5 by 11 inches. The difference is subtle but significant — a document formatted for one will not fit perfectly on the other without scaling.
A4 Paper Size in pixels
Digital designers need pixel dimensions, which depend on the resolution (DPI) of the output.
| Resolution | Width (pixels) | Height (pixels) |
|---|---|---|
| 72 DPI (web) | 595 | 842 |
| 150 DPI (standard print) |
1240 | 1754 |
| 300 DPI (high-quality print) |
2480 | 3508 |
Quick Reference
| Unit | Width | Height |
|---|---|---|
| Millimeters | 210 | 297 |
| Centimeters |
21.0 | 29.7 |
| Inches |
8.27 | 11.69 |
| Pixels (300 DPI) |
2480 | 3508 |
These A4 paper measurements are standardized globally. Whether you're in Tokyo, Berlin, or São Paulo, a sheet of A4 paper measures the same.
Common Uses of A4 Paper Size
The A4 paper size is so ubiquitous that it's easy to take for granted. Let's examine where it appears in daily life.
- Office Documents: Reports, memos, letters, and presentations are almost universally formatted for A4 outside North America.
- Business Printing: Letterheads, invoices, purchase orders, and marketing materials are commonly printed on A4.
- Academic and Educational Materials: Textbooks, research papers, exam papers, and lecture notes frequently use A4.
- Personal Documents: Resumes, cover letters, invitations, and personal records are often formatted for A4.
A4 vs Letter Paper Size
In this A4 vs letter comparison, you can see their differences. These two formats dominate their respective regions: A4 internationally, Letter in North America, and converting between them requires attention to detail.
Letter paper measures 8.5 by 11 inches (215.9 by 279.4 millimeters). A4 measures 8.27 by 11.69 inches (210 by 297 millimeters). This means a document formatted for Letter will have its right edge cropped when printed on A4, and a document formatted for A4 will have extra space at the bottom when printed on Letter.
The A4 paper size vs. Letter comparison is further complicated by scaling conventions. When printing Letter documents on A4 paper, most software suggests scaling to 94% to fit the width. When printing A4 documents on Letter paper, a scale of 97% is often recommended.
A4 vs A5 Paper Size
The A4 vs A5 comparison is more relevant for international users and anyone working with booklets, notebooks, or compact documents. A5 is exactly half the size of A4. Fold a sheet of A4 in half, and you get A5. This relationship is fundamental to the ISO 216 system.
- A4 is the standard for full-page documents: reports, letters, contracts, presentations, and academic papers. Its generous surface area accommodates detailed content without feeling cramped.
- A5 is ideal for compact formats: notebooks, journals, brochures, event programs, and pocket guides. Its smaller size makes it portable and easy to handle, while still providing enough space for readable text.
Letter vs A5 vs A4 Paper Size Comparison Table
For a visual overview, here's an A4 paper size chart comparing the major formats:
| Format | Width (mm) | Height (mm) | Region |
|---|---|---|---|
| A4 | 210 | 297 | International |
| Letter |
215.9 | 279.4 | North America |
| Legal |
215.9 | 355.6 | North America |
| A5 |
148 | 210 | International |
How to Resize and Print A4 Paper with SwifDoo PDF
SwifDoo PDF is a powerful desktop PDF solution built for users who need precise control over page dimensions, especially when printing on A4 paper.
The software includes a dedicated page resize tool that supports A4, A5, Letter, Legal, and custom dimensions. You can batch-process multiple PDFs at once, adjust content scaling to prevent cropping, and preview the result before sending it to your printer.
For anyone who regularly prints A4 documents or works with international paper standards, SwifDoo PDF eliminates the guesswork. Set your page size, confirm your margins, and print it. Now, follow the next steps to resize and print A4 paper with SwifDoo PDF.
How to Resize PDF Pages to A4 with SwifDoo PDF
Step 1: Download and install SwifDoo PDF and open your PDF in it.
Step 2: In the Page tab, click Page Setup.
Step 3: Choose A4 from the Standard Size drop-down menu and then choose the page range.
Step 4: Click OK to resize the page to A4.
How to Print A4 PDFs with SwifDoo PDF
Most printers outside North America default to A4. If you're in the US or Canada, you may need to load A4 paper into a dedicated tray or the manual feed slot.
Step 1: Open your PDF in SwifDoo PDF and press Ctrl+P.
Step 2: Choose your printer and choose A4 under the Paper Size and Orientation options.
Step 3: Set the page sizing and handling options and click Print. Ensure the page scaling option is set to Actual Size or 100% to prevent unwanted shrinking or expansion. If printing an A4 document on Letter paper, select "Shrink to Fit" and expect a 94% scale.
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READ MORE >Conclusion
What is A4 paper size? The size of A4 paper — 210 by 297 millimeters, or 8.27 by 11.69 inches — represents the global standard for business, education, and personal printing. This article covered the precise A4 dimensions in every unit, compared A4 to Letter, Legal, and A5, and explored its countless applications.
When you need to resize PDFs to A4, SwifDoo PDF provides the simplest solution. Its intuitive page management tools handle single documents and batch conversions with equal ease.
