How Base64 Encoding Works
Base64 encoding converts binary data (or text) into a sequence of ASCII characters using 64 printable characters: A–Z, a–z, 0–9, + and /. Every 3 bytes of input produce 4 Base64 characters, resulting in approximately 33% size overhead.
It is commonly used to embed binary data in JSON/XML, encode credentials in HTTP Basic Auth headers, and transmit email attachments. The decoder reverses this process exactly.
Frequently Asked Questions
No. Base64 is encoding, not encryption. It can be decoded by anyone without a key. Do not use Base64 to protect sensitive data — use proper encryption instead.
Yes. The encoder handles UTF-8 text including accented characters, CJK characters and emoji.
No. All encoding and decoding happens entirely in your browser using the native btoa()/atob() JavaScript functions.
There is no explicit limit, but very large inputs (multi-megabyte) may slow down the browser tab.
This tool encodes text. For binary file encoding, use a dedicated file conversion tool.
Related Tools
All generated data is entirely fictional and not suitable for use as real personal information.