Base64 & URL Encoder/Decoder

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that converts binary data into an ASCII string format by translating it into a radix-64 representation. It uses a set of 64 characters (A-Z, a-z, 0-9, +, /) to represent binary data in a text-safe format. Base64 encoding is commonly used to encode binary data (like images, files, or binary streams) for transmission over media that are designed to handle text, such as JSON, XML, or email.

What is URL Encoding?

URL encoding (also known as percent encoding) is a mechanism for encoding information in a URL by replacing unsafe ASCII characters with a "%" followed by two hexadecimal digits. URLs can only be sent over the Internet using the ASCII character set, so special characters like spaces, symbols, and non-ASCII characters must be encoded. For example, a space becomes "%20" and an ampersand becomes "%26". This ensures that URLs are properly formatted and can be safely transmitted across the internet.

How to Use This Tool

1. Base64 Text: Enter plain text and click "Encode" to convert it to Base64, or paste a Base64 string and click "Decode" to convert it back to plain text
2. URL Encoding: Enter a URL or text and click "Encode URL" to percent-encode special characters, or paste an encoded URL and click "Decode URL" to convert it back
3. File to Base64: Upload any file by clicking "Choose File" or dragging and dropping it. The tool will convert it to Base64 automatically
4. Toggle "Include Data URI prefix" to add the proper MIME type prefix for embedding in HTML/CSS
5. Use "Copy Output" to copy the result to your clipboard, or "Download Result" to save it as a text file
6. View statistics about encoding size changes and performance metrics

Common Use Cases

• Embedding Images in HTML/CSS: Convert images to Base64 data URIs to embed them directly in your stylesheets or HTML, eliminating additional HTTP requests
• Sending Binary Data in JSON/XML: Encode files or binary data as Base64 strings to include them in JSON API responses or XML documents
• Email Attachments: MIME (Multipurpose Internet Mail Extensions) uses Base64 encoding for email attachments
• Authentication Tokens: JWT (JSON Web Tokens) use Base64URL encoding for token components
• URL Parameters: Encode special characters in URL query parameters to ensure they're transmitted correctly
• Form Submissions: URL encode form data when submitting via GET requests or application/x-www-form-urlencoded POST requests
• Data Storage: Store binary data in text-only databases or configuration files
• File Uploads: Transmit file data through text-based protocols or APIs

Understanding Base64

Base64 encoding converts binary data into a text format using 64 printable ASCII characters. Here's how it works:

• Character Set: Uses A-Z (26 chars), a-z (26 chars), 0-9 (10 chars), plus (+), and slash (/)
• Padding: Uses equals signs (=) for padding when necessary
• Size Overhead: Base64-encoded data is approximately 33% larger than the original binary data
• Groups of 3: Every 3 bytes of binary data becomes 4 characters of Base64 text
• UTF-8 Support: This tool properly handles UTF-8 characters including emojis and international characters

Features

• Three Modes: Base64 text encoding/decoding, URL encoding/decoding, and file-to-Base64 conversion
• UTF-8 Support: Properly handles international characters, emojis, and special symbols
• File Upload: Drag & drop or click to upload any file type for Base64 conversion
• Image Preview: Automatically displays a preview for uploaded image files
• Data URI Generation: Optional MIME type prefix for direct HTML/CSS embedding
• Copy & Download: One-click copying to clipboard or downloading results as text files
• Statistics Display: View size changes, character counts, and performance metrics
• Error Handling: Clear error messages for invalid input or file reading issues
• Sample Data: Load example data to test each mode
• Client-side Processing: All encoding happens in your browser - your data stays private

Frequently Asked Questions

Is Base64 encoding the same as encryption?

No! Base64 is encoding, not encryption. It's easily reversible and provides no security. Anyone can decode Base64 strings back to their original form. Base64 is designed for data representation, not data security. Never use Base64 alone to protect sensitive information - use proper encryption instead.

Why is Base64-encoded data larger than the original?

Base64 encoding increases data size by approximately 33% because it converts every 3 bytes of binary data into 4 characters of text. This overhead is the trade-off for being able to safely transmit binary data through text-only channels. The padding and character set restrictions are necessary to ensure the encoded data can be transmitted and stored without corruption.

When should I use Base64 encoding?

Use Base64 when you need to: (1) Embed binary data in text formats like JSON or XML, (2) Include images directly in CSS or HTML to reduce HTTP requests (for small images), (3) Transmit binary data through systems that only handle text, or (4) Store binary data in text-only databases. However, avoid Base64 for large files over HTTP as it increases size and processing time.

Is my data secure when using this tool?

Yes! All encoding and decoding happens entirely in your browser using JavaScript. Your files and text never leave your computer and are never sent to any server. This makes it safe to use with sensitive files, but remember that Base64 itself is not encryption - it's just encoding that can be easily reversed.

What's the difference between Base64 and URL encoding?

Base64 encoding converts binary data to ASCII text using a specific 64-character alphabet, primarily for data representation. URL encoding (percent encoding) converts special characters in URLs to %XX format (like space to %20), ensuring URLs are safe for transmission. Use Base64 for encoding binary data or files, and use URL encoding for encoding text that will appear in URLs or form submissions.

What are the file size limits?

There's no hard limit since all processing happens in your browser, but files larger than 5MB may take longer to process and could slow down your browser. Very large files (50MB+) might cause performance issues or browser memory errors. For very large files, consider using server-side encoding tools instead.

What is a Data URI?

A Data URI is a way to embed data directly into HTML or CSS using the format: data:[MIME-type];base64,[encoded-data]. For example: data:image/png;base64,iVBORw0KG.... This allows you to include images, fonts, or other files directly in your code without separate file requests. Check the "Include Data URI prefix" option to generate properly formatted data URIs.

Does this work offline?

Once the page is loaded, all encoding and decoding functionality works offline. The tool doesn't require an internet connection to process your data since everything runs locally in your browser.

Are there keyboard shortcuts available?

Yes! Use Tab to navigate between buttons and text areas, Enter to activate focused buttons, and Escape while focused on text areas to quickly clear content.