Base64 Encoder & Decoder - Free Online Tool

Convert text to Base64 encoding or decode Base64 strings back to plain text with our free online tool.

📚 Complete Base64 Guide

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It’s commonly used when you need to transmit binary data over media that only supports text.

Common Use Cases

• Email attachments - MIME encoding uses Base64
• Data URLs - Embedding images directly in HTML/CSS
• API authentication - Basic auth headers use Base64
• Storing binary data - In JSON or XML documents
• JWT tokens - JSON Web Tokens use Base64URL encoding

How Base64 Works

Base64 converts every 3 bytes of binary data into 4 ASCII characters. This means Base64-encoded data is approximately 33% larger than the original.

// JavaScript example
const encoded = btoa('Hello World');  // "SGVsbG8gV29ybGQ="
const decoded = atob('SGVsbG8gV29ybGQ=');  // "Hello World"

# Python example
import base64
encoded = base64.b64encode(b'Hello World').decode()  # "SGVsbG8gV29ybGQ="
decoded = base64.b64decode('SGVsbG8gV29ybGQ=').decode()  # "Hello World"

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