Base64 Encoder/Decoder
Free online Base64 encoder and decoder, pure client-side — nothing leaves your browser.
Base64 is an encoding scheme that turns arbitrary binary data (text, images, files) into printable ASCII characters. It's commonly used to embed binary data in text-only contexts like URLs, JSON, or email attachments. It's just an encoding, not encryption — anyone can decode it back to the original with standard tools.
Your text is encoded/decoded only in your browser. Nothing is uploaded.
FAQ
- Why does Base64 output look longer than the input?
- Base64 encodes every 3 bytes of input as 4 printable characters, so the encoded output is roughly 33% larger than the original data.
- Is Base64 encryption?
- No. Base64 is just an encoding, not encryption — there's no key, and anyone can decode it back to the original with standard tools. Don't use it to protect sensitive data.
- Why does decoding fail?
- Usually because the input contains characters outside the Base64 alphabet, has an invalid length, or the decoded bytes aren't valid UTF-8 text.