Security & Crypto
Base64 Encode Decode
Encode text to Base64 or decode Base64 to text, including Unicode.
Results appear here.
What the result means
Base64 rewrites bytes as a limited ASCII alphabet so they can live inside formats that dislike raw control characters. Encoding here starts from UTF-8. A character that occupies more than one byte is not forced through a single-byte call, which is what breaks a direct btoa on Unicode. Decoding reverses the alphabet, then requires the bytes to be valid UTF-8, so a random blob fails instead of showing replacement characters. Equals signs are padding and belong at the end. The alphabet uses plus and slash. It is not the minus-and-underscore form some URLs use, and it is not a cipher. Anyone who can read the result can reverse it without a key. The conversion stays in this browser.
Related tools
Questions
Is Base64 encryption?
No. Base64 is not encryption, only a way to write bytes with a limited alphabet. There is no key, and anyone can reverse the result. Do not use it to hide a password, a token, or a message.
Why did decode fail?
The text was not valid standard Base64, or the decoded bytes were not UTF-8. A missing character, a hyphen from the URL-safe alphabet, or a damaged ending will be rejected. The page does not invent a replacement or drop the bad bytes.
Does this accept URL-safe Base64?
No. Encoding writes plus, slash, and equals padding, and decoding expects that same alphabet. Minus and underscore belong to a different convention, so change them back to plus and slash before you decode here.