toolkit

Base64 Encoder

Runs in browser

Convert text to Base64 format

How to Use

Enter text to encode or Base64 to decode. Toggle tabs to switch modes.

You will see:

  • Instant Conversion
  • Copy-ready Output
  • Error Validation
  • Safe Local Processing
Base64 Output

No output yet

Enter text and click Encode

About Base64 Encoding

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It's essential for transmitting binary data over text-based protocols like HTTP, email, and JSON.

Key Features

  • Bidirectional: Seamlessly switch between encoding and decoding without reloading.
  • Real-time Validation: Checks for valid Base64 characters before processing.
  • Privacy Focused: All conversion happens locally in your browser. No data is sent to any server.
  • Deep Linking: Share specific strings via URL for quick references.

What is Base64?

Base64 encoding converts binary data (bytes) into a set of 64 printable ASCII characters:

A-Z (26) + a-z (26) + 0-9 (10) + +/ (2) = 64 characters

Plus = for padding

How Base64 Works

  1. Take 3 bytes (24 bits) of binary data
  2. Split into 4 groups of 6 bits each
  3. Convert each 6-bit group to a Base64 character (0-63 → A-Za-z0-9+/)
  4. If input isn't divisible by 3, pad with = characters
Input:  "Hi"  → 01001000 01101001 (2 bytes)
Padded: 01001000 01101001 00000000 (3 bytes)
Groups: 010010 000110 100100 000000
Base64: S      G      k      =
Result: "SGk="

Common Use Cases

Data URLs

Embed images directly in HTML/CSS using data:image/png;base64,... format.

API Authentication

HTTP Basic Auth encodes credentials as Base64(username:password) in the Authorization header.

Email Attachments

MIME encodes binary attachments as Base64 for transmission in text-based email protocols.

JWT Tokens

JSON Web Tokens use Base64URL encoding (URL-safe variant) for the header and payload sections.

Base64 in Code

JavaScript

// Encode
btoa("Hello World") // "SGVsbG8gV29ybGQ="

// Decode
atob("SGVsbG8gV29ybGQ=") // "Hello World"

// For Unicode (use TextEncoder)
btoa(unescape(encodeURIComponent("Héllo")))

Python

import base64

# Encode
base64.b64encode(b"Hello").decode() # "SGVsbG8="

# Decode
base64.b64decode("SGVsbG8=").decode() # "Hello"

Important Notes

  • Not encryption: Base64 is encoding, not encryption. Anyone can decode it.
  • Size increase: Base64 output is ~33% larger than the input.
  • URL safety: Standard Base64 uses + and / which are URL-unsafe. Use Base64URL variant for URLs.
  • Unicode: JavaScript's btoa() only works with Latin1. Use TextEncoder for Unicode.

💡 Pro Tips

  • Use Base64URL (- and _) for URLs and filenames
  • Don't use Base64 for large files — it increases size by 33%
  • Base64 padding (=) is optional in many implementations
  • This tool processes everything locally in your browser

Further Reading