Web Development & APIs
Transmit binary payloads, inline images as data URIs, and construct HTTP Basic Auth headers.
Encoding
Source text
Base64 result
Base64 Encode & Decode
A fast and secure tool to encode text into Base64 format and decode Base64 back to plain text.
Supports multiple character encodings: UTF-8, Windows-1251, KOI8-R, IBM866, ISO-8859-5, Windows-1252, ASCII, UTF-16.
How Base64 works
The principle of transforming binary data into transmission-safe ASCII text.
1. Split into bytes
Every 3 bytes of raw input data (24 bits) are combined into a continuous bit stream.
2. Divide into 6-bit groups
The 24-bit stream is partitioned into 4 groups of 6 bits each. A 6-bit number ranges from 0 to 63.
3. Character substitution
Each 6-bit index is mapped to a character from the Base64 alphabet (A-Z, a-z, 0-9, +, /). Padding = is appended if bytes are missing.
Encoding example: 'Cat' in UTF-8
The 3 letters 'Cat' correspond to bytes 43, 61, 74 (24 bits total). Split into four 6-bit groups, they produce the Base64 string: Q2F0.
About the tool
A practical utility for web development, data transmission, and debugging.
Network Protocols
Encode attachments and headers for email formats (MIME) and messaging protocols.
Debugging & Security
Quickly inspect token payloads, webhooks, and serialized data structures.