Base64 Decode
Convert a Base64 string back into readable text.
About the Base64 Decoder
This tool reverses Base64 encoding: paste a Base64 string and it reconstructs the original text. Base64 is everywhere - in data URIs, JSON Web Tokens, email attachments and API responses - so being able to read it back quickly is handy when you are debugging or inspecting a payload. Decoding is UTF-8 aware, so multi-byte characters come back intact.
How to use it
- Paste the Base64 string into the input box.
- The decoded text appears immediately below.
- Copy the readable result wherever you need it.
A frequent use is peeking at the payload of a JWT, whose middle segment is Base64URL-encoded JSON. If decoding fails, the input usually contains stray spaces, line breaks or characters that are not valid Base64 - trim those and try again. Because the work happens locally in your browser, the string you paste is never uploaded, which matters when it might contain tokens or other sensitive data.
Frequently asked questions
Why does my Base64 string fail to decode?
Invalid Base64 usually contains characters outside A-Z, a-z, 0-9, +, / and =, or has incorrect padding. Remove stray spaces, quotes or line breaks and make sure the length is a multiple of four.
Can I decode the payload of a JWT here?
Yes, you can decode each Base64URL segment to read the header and payload JSON. Note that this does not verify the token's signature, so do not trust the contents without separate validation.
Does it handle Unicode text correctly?
Yes. The decoded bytes are interpreted as UTF-8, so emoji and accented characters are restored exactly as they were before encoding.
Is the string I paste sent to a server?
No. All decoding runs in your browser, so sensitive values like tokens never leave your device.