Base64 Encoder / Decoder

Base64 represents binary data using 64 printable ASCII characters: A-Z, a-z, 0-9, plus "+" and "/". Three input bytes become four output characters, so any file, image, or text can travel through channels that only accept plain text. Common uses include embedding images in CSS data URIs, packing credentials into HTTP headers, and serializing binary data inside JSON.

No. Base64 is encoding, not encryption. Anyone can decode a base64 string back to the original bytes instantly with no key required. Never use it to protect passwords, API keys, or anything sensitive. If you need confidentiality, use a real encryption scheme like AES-GCM.

Standard base64 uses "+" and "/" as its 63rd and 64th characters. Those symbols must be percent-encoded inside URLs and break many file systems. URL-safe base64 (RFC 4648 section 5) replaces "+" with "-" and "/" with "_", so the output works directly in URLs, filenames, and JSON Web Tokens without any extra escaping. This decoder accepts both alphabets regardless of which mode you select.

Base64 packs every 3 input bytes into 4 output characters. Padded Base64 has a length that is a multiple of 4. One leftover byte adds two "=" characters, while two leftover bytes add one. Unpadded Base64 omits those characters. This tool accepts both forms, but another decoder or protocol may require canonical padding.

Yes. The encoder converts your text to UTF-8 bytes first, then encodes those bytes. An accented letter like "e" with an acute accent becomes 2 bytes; a typical emoji becomes 4 bytes. All of those bytes encode fine. The older browser function btoa() skips the UTF-8 step and crashes on anything outside Latin-1, which is why this tool uses TextEncoder before encoding.