Base64 Encoder & Decoder
Encode and decode UTF-8 text without uploads.
Workspace
Result
Your result will appear here.
What does this tool do?
Base64 represents bytes using text characters. It is used to transport data in APIs and formats that expect text. This tool locally converts UTF-8 text to standard Base64 and recovers UTF-8 text from Base64. It is reversible encoding, not encryption: it does not hide information or protect secrets.
How to use it
- Select Encode for UTF-8 text or Decode for a Base64 string.
- Paste content for the selected mode, without data URL prefixes.
- Select Convert and review the output. If decoding fails, check the alphabet, padding and whether the bytes represent valid UTF-8 text.
- Select Copy result. Switching modes preserves input but clears the previous output and errors.
Input and output examples
Input
Hola, café ☕Output
SG9sYSwgY2Fmw6kg4piVInput
SG9sYSwgY2Fmw6kg4piVOutput
Hola, café ☕Important limitations
- Works with UTF-8 text, not files or binary downloads. Valid Base64 representing invalid UTF-8 bytes produces an error.
- Uses the standard Base64 alphabet with + and /. Base64url with - and _, and headers such as data:text/plain;base64, are not accepted directly.
- Decoding ignores whitespace and line breaks; empty input, invalid characters and malformed padding are rejected. Encoding empty input produces empty output.
- Base64 usually increases size compared with the original bytes. Large inputs can consume memory and temporarily block the tab.
Common mistakes
- Confusing encoding with encryption or sharing secrets because they are in Base64.
- Pasting a full data URL, a Base64url string or unencoded text in Decode mode.
- Expecting a file or image when decoding binary bytes.
- Switching modes and converting again without checking that input matches the new mode.
Frequently asked questions
Does Base64 protect passwords or tokens?
No. Anyone can reverse the encoding without a key. It does not replace encryption or access controls.
Are accented characters and emoji supported?
Yes. Encoding converts text to UTF-8 bytes; decoding requires the bytes to form valid UTF-8 text.
Why does an apparently valid Base64 string fail?
It may have invalid characters or padding, use Base64url or contain bytes that are not UTF-8 text. The tool reports an error rather than producing a binary download.
Is content sent to a server?
It is not sent to a conversion service. Processing happens in the browser without saving inputs in persistent storage. Switching languages on the same tool transfers them temporarily in memory.