How to use Base64 Codec
- Paste text to encode, or select Decode and paste a standard Base64 value.
- Run the operation. Encoding uses UTF-8, including Chinese characters and emoji.
- Compare the result with the expected text before copying it into another system.
Worked examples
Use the inputs below to compare the selected mode with a known result. Loading an example replaces the current input.
Encode an ASCII word
Input
Hello
Expected result
SGVsbG8=
There is no newline after Hello. Adding one changes the encoded output.
Decode Chinese text
Input
5L2g5aW9
Expected result
你好
The result is UTF-8 text, not one character per byte.
Detect non-text bytes
Input
/w==
Expected result
Cannot decode this as UTF-8 text.
This is valid Base64 for the byte FF, but that byte alone is not a valid UTF-8 text sequence.
What this tool does and does not do
This is a text codec using the standard + and / alphabet. It accepts omitted padding when the remaining length is valid and ignores whitespace during decoding. URL-safe - and _ characters, arbitrary binary data and whole Data URLs are not accepted as UTF-8 Base64 text.
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Common questions
Is Base64 encryption?
No. Anyone with the encoded string can decode it. Do not use it to hide passwords or tokens.
Why does a valid Base64 string fail here?
Its decoded bytes may be an image, a compressed file or text in another encoding. This decoder deliberately reports invalid UTF-8 instead of replacing bytes silently.
Can I decode a JWT?
A JWT has multiple dot-separated Base64url segments and a signature. This tool is not a JWT parser or signature verifier.