Base64 Tool

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It encodes data using 64 printable characters (A-Z, a-z, 0-9, +, /) making it safe for transmission over text-based protocols.

How It Works

Base64 encoding converts binary data (8-bit bytes) into groups of 6 bits, then maps each 6-bit group to one of 64 printable characters:

• Input: Binary data split into 24-bit groups (3 bytes)
• Process: Each 24-bit group split into four 6-bit groups
• Output: Each 6-bit group mapped to a Base64 character
• Padding: '=' characters added if input isn't divisible by 3
• Example: "Hello" → "SGVsbG8=" (5 bytes → 8 characters)

Common Use Cases

Base64 encoding is widely used in modern computing:

• Email (MIME): Encoding attachments for safe transmission
• Data URLs: Embedding images directly in HTML/CSS
• Basic Authentication: HTTP Basic Auth encodes credentials
• JSON/XML: Embedding binary data in text formats
• Cryptography: Encoding keys, certificates, and encrypted data
• URL Parameters: Safely passing binary data in URLs

Standard vs URL-Safe Base64

There are two main Base64 variants:

• Standard (RFC 4648): Uses +, /, and = characters
• URL-Safe (RFC 4648 §5): Uses -, _, and no padding

URL-safe Base64 replaces + with - and / with _ to prevent issues when encoding data for URLs, where + and / have special meanings.

Size Overhead

Base64 encoding increases data size by approximately 33%:

• Every 3 bytes of input → 4 bytes of output
• 1000 bytes of binary → ~1333 bytes of Base64
• Padding characters may add 1-2 extra bytes

Encoding Process Example

Let's encode "Hi!" step by step:

Security Note

Important: Base64 is an encoding method, not encryption. It does not provide any security or privacy. Anyone can decode Base64 data instantly. Never use Base64 alone to protect sensitive information!