← Back

Base64 Encoder/Decoder Tool

Free online tool to instantly encode text to Base64 or decode Base64 back to readable text. All conversions happen securely in your browser - your data never leaves your device, ensuring complete privacy. Perfect for developers, system administrators, and anyone working with data transmission or storage.

Result:

Understanding Base64 Encoding

Base64 is a binary-to-text encoding scheme that transforms binary data into an ASCII string format. It's essential when you need to transmit or store binary data through text-only systems. Our tool provides:

  • Complete privacy - All processing happens in your browser
  • Universal compatibility - Works with all modern browsers and devices
  • Full UTF-8 support - Handles special characters and emojis
  • Smart validation - Detects invalid Base64 during decoding

How to Use This Tool

Encoding Text

  1. Select the "Encode to Base64" tab
  2. Enter your text (supports up to 10MB of data)
  3. Click "Encode" to convert
  4. Copy or download the Base64 result

Decoding Base64

  1. Select the "Decode from Base64" tab
  2. Paste your Base64 string
  3. Click "Decode" to reveal original content
  4. View, copy, or save the decoded text

Technical Details

Base64 works by converting every three bytes (24 bits) of binary data into four 6-bit Base64 digits. These digits are then mapped to ASCII characters (A-Z, a-z, 0-9, +, /) for safe transmission. When the input isn't divisible by 3, padding characters (=) are added to make the output length a multiple of 4.

Common Applications

Web Development

Embed images directly in HTML/CSS using data URIs to reduce server requests and improve loading speed.

Email Attachments

Encode files for safe transmission through email systems that only support text content.

API Integration

Include binary data in JSON payloads when working with web services and REST APIs.

Frequently Asked Questions

Is Base64 secure for sensitive data?

Base64 is not encryption - it's simply encoding. Anyone can easily decode Base64 data. For sensitive information, always use proper encryption methods before encoding.

Why does my Base64 string end with equals signs?

The = characters are padding to ensure the output length is a multiple of 4. They don't contain data but are required for proper Base64 formatting.

What's the difference between Base64 and Base64URL?

Base64URL replaces + and / with - and _ to make strings URL-safe. Use it when encoding data for URLs or filenames.

Expert Recommendations

  • For large files, compress data before Base64 encoding to minimize size increase
  • When using in URLs, always implement proper URL encoding
  • Test edge cases with special characters and long strings
  • Remember that encoded data is about 33% larger than original