UTF-8 Base64 encoder and decoder
Convert UTF-8 text to standard Base64 or Base64url and back. Validate padding and decoded text locally. Encoding is not encryption.
Converted text
The output updates as you type. Encoding does not hide information.
Inputs are processed in this tab. No text, paths or results are sent to our server or saved in an account. Privacy details.
From input to a useful answer.
- 01
Choose encoding or decoding and the intended alphabet.
- 02
Paste UTF-8 text or an encoded text value.
- 03
Review the output and byte count before copying it.
Base64 represents data without hiding it
Base64 expresses bytes with a restricted text alphabet. This tool first converts input text into UTF-8 bytes, then encodes them. Anyone holding the encoded value can decode it without a password. It is useful for representation and interoperability, not concealing secrets.
The byte count measures UTF-8 data, which can differ from the number of visible characters. An accented letter can occupy multiple bytes. Check bytes when a receiving protocol specifies a byte limit rather than assuming each visible character occupies one.
Choose standard Base64 or Base64url
Standard output uses letters, digits, plus and slash, with equals-sign padding when needed. Base64url replaces plus and slash with minus and underscore. This tool omits trailing padding in Base64url output; choose the form expected by the receiving application.
Maple is five UTF-8 bytes. It becomes TWFwbGU= in standard Base64 or TWFwbGU in URL-safe output. This expands representation rather than compressing it: padded output uses four characters for each three-byte group, including a final padded group for leftover bytes.
Decode valid UTF-8 text
The decoder ignores whitespace, checks the chosen alphabet and padding, and rejects non-canonical pad bits. Missing padding is accepted where the length permits and reconstructed for decoding. Another decoder may accept unusual input that this tool rejects.
Decoded bytes must form valid UTF-8 text. An image or archive can be valid Base64 and still fall outside this text tool’s scope. Input is limited to 200,000 characters. The tool does not upload a file, execute decoded contents or infer a different character encoding.
References
RFC 4648 — Base64 and Base64url ↗MDN — TextEncoder and UTF-8 ↗MDN — TextDecoder ↗A few useful answers
Is Base64 encryption?
No. It is reversible encoding without a secret key and provides no confidentiality by itself.
Why is valid Base64 rejected after decoding?
Its bytes may be binary data or text in another encoding. This tool requires valid UTF-8 text.
Can I omit the equals signs?
The decoder accepts omitted padding when the length is valid. A receiving protocol may require padding, so follow its documentation.