Base64 Decoder
Decode any Base64 string back to readable text — everything runs in your browser, nothing is uploaded.
What Is Base64 Decoding?
Base64 decoding is the reverse of Base64 encoding — it converts a Base64-encoded string back to its original text or binary form. Every four Base64 characters are converted back to three bytes of data. This tool handles the decoding entirely in your browser, supporting full UTF-8 character sets including accented characters, emoji, and non-Latin scripts.
How to Decode Base64 Online
Paste your Base64 string into the input panel on the left. The tool decodes it in real time as you type or paste. The decoded plain text appears in the right panel. If the Base64 string is invalid or contains non-Base64 characters, the tool will show an error message explaining the issue. Click "Copy Output" to copy the decoded text to your clipboard.
Common Things You Might Decode
Developers frequently decode JWT (JSON Web Token) payloads to inspect claims, API responses that return Base64-encoded data, email headers and attachments encoded in MIME format, configuration values stored as Base64 in environment variables, and authentication tokens from HTTP Basic Auth headers. If you're working with an API that returns Base64 data, paste the encoded string here to quickly see its contents.