Base64 Decoder — Free Online Tool
Decode Base64 strings back into readable text with Unicode support.
About Base64 Decoder
The Base64 Decoder converts Base64-encoded strings back into their original, readable text directly in your browser. It is perfect for inspecting JWT segments, data URIs, encoded API responses, and any other Base64 content you need to read quickly.
The tool decodes bytes as UTF-8 so international characters and emoji are restored accurately, and it shows a clear message when the input is not valid Base64. All processing is local, keeping your data private at every step.
How to Use Base64 Decoder
- Paste the Base64 string you want to decode into the input box.
- Click 'Decode' to convert it back into readable text.
- Review the decoded text in the output box.
- Use 'Copy Result' to copy the decoded text to your clipboard.
Key Features
Decode Base64 strings back into readable text instantly
Full Unicode and emoji support via UTF-8 decoding
Clear, friendly errors for invalid Base64 input
100% client-side - nothing is uploaded to a server
One-click copy of the decoded result
Frequently Asked Questions
What does a Base64 decoder do?
A Base64 decoder takes a Base64-encoded string and reconstructs the original text or data it represents. It is the reverse of Base64 encoding and is handy for inspecting tokens, data URIs, and API payloads.
Does it support Unicode text?
Yes. The decoder interprets the decoded bytes as UTF-8, so emoji, accented letters, and non-Latin scripts are restored correctly to their original form.
Why do I get an invalid Base64 error?
The error appears when the input contains characters that are not valid Base64 or has incorrect padding. Remove stray spaces or line breaks and make sure you pasted the complete string.
Is my data uploaded anywhere?
No. Decoding happens entirely in your browser, so your Base64 string and the decoded result never leave your device.