Base64 Encoder & Decoder Online
Encode text, files, and binary data to Base64 or decode Base64 strings back to their original form. Fast, private, and entirely browser-based.
How Base64 Encoding Works
Base64 encoding takes every three bytes of input and maps them to four characters from a 64-character alphabet (A-Z, a-z, 0-9, +, /). If the input length is not divisible by three, padding characters (=) are appended. The result is roughly 33% larger than the original but safe for transmission through any text-based channel.
Base64 Variants
The standard Base64 alphabet uses + and / as the last two characters, with = for padding. URL-safe Base64 replaces these with - and _ to avoid conflicts in URLs and filenames. This tool supports both variants and auto-detects which one was used when decoding.