Free Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text. Everything runs in your browser.
The Base64 Encoder / Decoder converts text to Base64 and back, entirely in your browser. It is the go-to for handling headers, embedded data, and any string that needs safe text encoding.
What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of 64 ASCII characters. It's designed to transport or store binary data in environments that only reliably support text. The encoding uses A-Z, a-z, 0-9, and two punctuation characters (+ and /) to represent binary data as readable text strings. The "=" character serves as padding when the input length is not divisible by three bytes. Base64 is not encryption and provides no security; it's purely an encoding method to ensure binary data remains intact when transmitted through systems that might otherwise interpret certain byte values as control characters. It's defined in RFC 4648 and is widely supported across programming languages and platforms, making it a universal standard for text-based data transmission.
While Base64 encoding increases data size by about 33%, it's invaluable for transmitting binary data through text-only protocols. It's widely used in email attachments (MIME), embedding images directly in HTML or CSS files, encoding JSON Web Tokens (JWT), and storing binary data in XML or JSON formats where binary characters might cause parsing issues. In email, Base64 ensures that attachments with binary content like images or documents arrive intact without being corrupted by mail servers that expect text. In web development, it allows embedding small images directly in HTML, reducing HTTP requests. For JWT authentication, tokens contain Base64Url-encoded JSON payloads that carry user claims and session data securely between client and server without requiring database lookups for each request.
Our Base64 encoder/decoder runs entirely in your browser—no data ever leaves your device. This makes it fast, secure, and privacy-focused. You can encode text to Base64 or decode Base64 back to its original form instantly. The tool handles any text input and produces clean, readable output with a one-click copy feature for convenience. The conversion uses JavaScript's built-in atob() and btoa() functions, which implement the standard Base64 algorithm precisely. When encoding, the tool properly handles Unicode text by first converting it to UTF-8 bytes before applying Base64, ensuring international characters are preserved correctly. This local processing means you can confidently encode sensitive information like API keys or personal data without worrying about it being intercepted or logged anywhere.
How to use this Base64 Tool
- Select "Encode" to convert text to Base64 or "Decode" to convert Base64 back to text.
- Type or paste your text/encoded content into the input field.
- Click or select to see the result instantly in the output area.
- Click on the result to copy it to your clipboard with one tap.
- Switch between encode and decode modes at any time to test both transformations.
FAQ
What is Base64 encoding?
Base64 is a way to represent binary data as ASCII text using 64 characters. It's commonly used for embedding images in HTML, encoding emails, and transmitting data in URLs.
Does Base64 encoding upload my text to a server?
No. All encoding/decoding happens entirely in your browser using JavaScript. Nothing is uploaded or stored.
Is this Base64 tool free?
Yes, completely free with no limits.
Can I both encode and decode Base64?
Yes. You can encode plain text into Base64 and decode Base64 back into plain text, both in the same tool.