What is the difference between A4 and Letter paper size?

A4 and Letter are standard document sizes. A4 is international (ISO 216) measuring 210 x 297 mm (8.27 x 11.69 inches). US Letter is the North American standard measuring 215.9 x 279.4 mm (8.5 x 11.0 inches). Letter is wider, while A4 is taller.

How does DPI affect converting paper size to pixels?

Pixels depend on resolution (DPI - Dots Per Inch). To find pixel dimensions, multiply physical inches by the DPI value. For example, at 300 DPI (high-res printing), an 8.5 x 11-inch Letter sheet converts to 2550 x 3300 pixels.

How do you scale an A4 document to print on A3 paper?

Because the ISO 216 ratio is 1:sqrt(2) (1:1.4142), scaling up from one size to the next larger size (like A4 to A3) requires scaling by exactly 141.4%. Scaling down (A3 to A4) requires scaling by 70.7%.

Paper Size Converter (A4, Letter, etc.)

Convert and compare standard paper systems (ISO A/B/C, North American, ANSI, ARCH, JIS) to inches, mm, cm, points, and pixels dynamically at any DPI resolution.

Select Standard System

Select Primary Paper Size

Width

Height

Input Unit

Orientation

Resolution for Pixels (DPI / PPI)

Compare Against (Dotted Overlay)

Selected Size

Comparison Size

Dimensions & Details

Unit	Width	Height
Inches (in)	0.00	0.00
Millimeters (mm)	0.00	0.00
Centimeters (cm)	0.00	0.00
PostScript Points (pt)	0.00	0.00
Picas (pc)	0.00	0.00
Pixels (px)	0.00	0.00

Area Comparison

Print Scaling Cheat Sheet

When printing a document designed for the selected size onto a target paper size, configure your printer's scaling percentage to match the recommendations below to prevent clipped margins or excessive white borders:

Target Size	Layout Mode	Required Scale Factor	Print Output Result

Folding & Subdivision Guide

About Paper Size Converter (A4, Letter, etc.)

This online Paper Size Converter (A4, Letter, etc.) is a simple, lightweight utility designed to help you quickly convert files and data between different formats. Whether you are a developer, designer, or content creator, this tool runs instantly inside your web browser without requiring any software installation, email signups, or accounts.

How to Use

Using this tool is straightforward. Simply input your data into the corresponding fields above, and the calculations or file processing will update automatically in real time. We built it with simplicity in mind so you can get your results with just a single click.

100% Secure & Private

We respect your privacy. Almost all calculations and operations on Apex Tools Hub are performed entirely on the client side using JavaScript. This means your text, images, files, or financial details are never sent to our servers or stored anywhere. Everything stays safe on your own device.

Frequently Asked Questions

Are my files or inputs stored on the server?

No. We do not upload or store any data from our tools. All processing is executed locally in your browser, guaranteeing complete data privacy.

Is this tool free?

Yes. All utilities on Apex Tools Hub are completely free to use. There are no daily limits, hidden costs, or paid features.

Can I use this tool offline?

Yes. Once you load this page in your browser, the tool operates using local JavaScript code, allowing you to use it even without an active internet connection.

Conclusion: Achieving Flawless Document Layouts

Standardized paper sizing is key for maintaining high-quality document layouts. By converting dimensions accurately and matching layouts to the correct paper system, you can avoid printing errors and format clipping. Use this converter to check dimensions, calculate print scaling requirements, and verify layout specifications. Consult with your local printing partner to establish custom bleed tolerances for commercial printing runs.