Understanding Base64 Encoding and Decoding

What is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters. It converts binary data into a format that can be safely transmitted over text-based protocols.

Why Use Base64?

Base64 is commonly used for:

• Embedding binary data (images) in HTML/CSS
• Encoding data in JWT tokens
• Transmitting binary data over email (MIME)
• Storing binary data in JSON
• HTTP Basic Authentication headers

How Base64 Works

Base64 takes groups of 3 bytes (24 bits) and encodes them as 4 ASCII characters from a 64-character alphabet (A-Z, a-z, 0-9, +, /). The = sign is used for padding. If bits and bytes are new territory, our guide on how to read binary builds that foundation.

Base64 vs Encryption

IMPORTANT: Base64 is NOT encryption! It is easily reversible and provides no security. Never use it to secure sensitive data. For the full explanation of why — and what to reach for instead — see is Base64 encryption?

Using Base64 in JavaScript

Encoding: btoa('Hello, World!') Decoding: atob('SGVsbG8sIFdvcmxkIQ==')

Try Our Base64 Tools

• Base64 Encoder — Encode text or files
• Base64 Decoder — Decode Base64 strings

Weighing Base64 against other ways to write bytes as text? Base64 vs hex vs binary covers when each one fits.