Base64 Encoder/Decoder

Encode and decode Base64 strings instantly

About This Tool

Our Base64 Encoder/Decoder provides instant, free conversion between binary data and Base64 text format. Whether you're working with API authentication, data URIs, email attachments, or need to embed binary data in JSON, this tool offers fast, secure Base64 encoding and decoding directly in your browser with no server uploads required.

What is Base64?

Base64 is a binary-to-text encoding scheme that converts binary data into an ASCII string format using 64 printable characters (A-Z, a-z, 0-9, +, /). Each Base64 character represents exactly 6 bits of data, meaning 4 Base64 characters encode 3 bytes of original data. The padding character (=) is used when the input length isn't divisible by 3, ensuring the output length is always a multiple of 4. This encoding method was originally designed for MIME email encoding but has become essential for modern web development, allowing binary data to be safely transmitted through text-based protocols.

Key Features

  • Instant Encoding and Decoding: Convert Base64 strings in real-time with immediate visual feedback and error detection for invalid input
  • Full UTF-8 Support: Properly handles international characters, emoji, and special symbols without data loss or corruption
  • Client-Side Processing: All conversions happen locally in your browser, ensuring your sensitive data never leaves your computer
  • Copy to Clipboard: One-click copying of results for seamless integration into your development workflow
  • Unlimited Usage: No file size restrictions, no rate limits, and completely free for both personal and commercial use
  • Error Handling: Clear error messages when decoding invalid Base64 strings help you quickly identify and fix issues
  • Statistics Display: View input/output length and size change percentage to understand encoding overhead

Common Use Cases

Base64 encoding is used across countless web development and software engineering scenarios. Understanding when and how to use Base64 can significantly improve your application's data handling capabilities and ensure compatibility across different systems.

  • Data URIs: Embed images, fonts, and files directly in HTML, CSS, or SVG to reduce HTTP requests and improve page load times
  • Email Attachments: MIME encoding for email attachments ensures binary files are transmitted correctly through mail servers
  • API Authentication: HTTP Basic Authentication encodes credentials in Base64 format within the Authorization header
  • JSON Data Transfer: Embed binary data like images or PDFs in JSON payloads for REST API responses and database storage
  • URL Parameters: Safely pass binary data through URL query strings without breaking URL parsing or causing encoding issues
  • Configuration Files: Store binary configuration data or certificates in text-based config files like YAML or JSON

How to Use

Using our Base64 encoder/decoder is straightforward and intuitive. Simply follow these steps to convert your data between formats quickly and accurately.

  1. Select "Encode" mode to convert text to Base64, or "Decode" mode to convert Base64 back to text
  2. Paste or type your input data into the left text area (plain text for encoding, Base64 string for decoding)
  3. Click the conversion button to instantly see your results in the right panel with statistics
  4. Use the "Copy Output" button to quickly copy the result to your clipboard for immediate use
  5. Click "Clear All" to reset both input and output fields and start a new conversion

Benefits and Best Practices

Base64 encoding ensures data integrity during transmission across systems that may modify or corrupt non-ASCII characters. It's platform-independent and universally supported across programming languages and systems. However, Base64 increases data size by approximately 33%, so it's important to consider this overhead for large files. Remember that Base64 is not encryption - it's merely encoding for transport. Encoded data can be easily decoded by anyone, so never rely on Base64 alone for security. Always use proper encryption (like AES or RSA) for sensitive data before Base64 encoding for transmission.

Technical Details

Our tool uses the browser's native btoa() and atob() functions for encoding and decoding, ensuring maximum performance and standards compliance. Base64 encoding follows RFC 4648 specification. The character set consists of uppercase A-Z, lowercase a-z, digits 0-9, plus (+), and forward slash (/), with equals (=) for padding. This tool works in all modern browsers including Chrome, Firefox, Safari, and Edge without requiring any plugins or extensions. All processing is done using JavaScript in your browser for optimal privacy and security.