Base64 Encoder / Decoder Details
Base64 Encoder and Decoder converts text into Base64 or turns a Base64 string back into readable text, picking the direction from what you paste in.
Use it to unpack an Authorization header, read a value embedded in a config file, or encode text for transport.
Step by step
Short version: give it input, run it, take the output. Details below.
- Paste the text or the Base64 string into the box.
- Run the tool: input that matches the Base64 alphabet is decoded, anything else is encoded.
- Copy the result or download it as a .txt file.
Limits and processing behaviour
Behaviour in detail:
- Direction is automatic: input made only of A-Z, a-z, 0-9, plus, slash and equals is treated as Base64 to decode.
- Encoding is UTF-8 safe, so accented characters and emoji survive the round trip.
- Everything runs in the browser; the text is never sent to a server.
- A malformed Base64 string surfaces the browser's own error in the output panel.
Is this the right tool
For moving between text and Base64 this page is enough. For percent escapes in a URL, the URL Encoder and Decoder is the right tool.
The tool works with text only; it does not accept file uploads or build Base64 data URIs. Base64 is an encoding, not encryption — anyone can decode it.
Small things that help
- Basic auth values decode to "user:password", split by the colon.
- Trailing equals signs are padding; leave them in place.
- Encoded text is roughly a third larger than the original, which matters for size budgets.
Privacy and data handling
The work happens locally and your data stays on the device. The single outgoing request is the usage counter, and your text is not part of it. Advertising and measurement cookies operate at page level, never inside the tool.