Base64 Encoder/Decoder
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It is widely used in web development, data transmission, and email.
What is Base64?
Base64 encoding converts binary data into a text string using 64 printable ASCII characters. Each Base64 digit represents 6 bits of binary data.
How It Works
Encoding:
- Groups bytes into 6-bit sequences
- Maps each 6-bit value to a Base64 character
- Adds padding (
=) if needed
Decoding:
- Converts Base64 characters back to 6-bit sequences
- Reconstructs the original binary data
Common Uses
- Email attachments - Encoding files for email transmission
- Data URIs - Embedding images in HTML/CSS
- Authentication - HTTP Basic Auth headers
- APIs - Transmitting binary data over JSON
- Cookies - Storing encoded session data
Formula
Base64 uses this character set (64 characters):
A-Z (0-25), a-z (26-51), 0-9 (52-61), +, / (62-63)
Examples
| Input | Output |
|---|---|
| Hello | SGVsbG8= |
| Test123 | VGVzdDEyMw== |
| A | QQ== |
Tips
- Every 3 bytes encode to 4 Base64 characters
- Output length is always a multiple of 4
- Padding with
=indicates incomplete final chunk - Base64 URL-safe variant uses
-and_instead of+and/