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Base64 Encoding and Decoding: A Complete Guide

Understand Base64 encoding, when and why to use it, and common applications in web development and data transfer.

2025-01-124 min

What is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It uses 64 printable characters to represent binary data.

Why Use Base64?

Base64 encoding is useful when you need to:

  • Embed images in HTML/CSS: Data URIs use Base64
  • Transmit binary data over text protocols: Email attachments, JSON payloads
  • Store binary data in text formats: Configuration files, databases
  • Encode authentication credentials: HTTP Basic Authentication
  • How Base64 Works

    Base64 encoding works by:

  • Dividing binary data into 6-bit groups
  • Mapping each group to one of 64 characters (A-Z, a-z, 0-9, +, /)
  • Padding with '=' if needed
  • This increases data size by approximately 33%.

    Common Use Cases

    Data URIs

    <img src="data:image/png;base64,iVBORw0KGgo..." />

    API Authentication

    Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=

    JSON with Binary Data

    {
      "file": "SGVsbG8gV29ybGQh",
      "type": "text/plain"
    }

    Our Base64 Tool Features

  • Encode text to Base64
  • Decode Base64 to text
  • Support for file encoding
  • URL-safe Base64 option
  • Real-time conversion