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.
Frequently Asked Questions
Base64 converts binary data into an ASCII text representation. It is commonly used to embed images in HTML/CSS, transmit binary data over text-only protocols like email (MIME), and store binary values in JSON or XML payloads.
No. Base64 is an encoding scheme, not encryption. Anyone can decode a Base64 string back to the original data. If you need to protect sensitive information, use proper encryption before encoding.
The tool handles inputs up to 50 MB directly in your browser. For larger files, consider using a command-line tool like the built-in base64 command on macOS and Linux.