Base64 Decode
Decode a Base64 string back to readable text.
Runs in your browser FreeNo sign-in Works without JavaScript
How to use base64 decode
- Paste your text. Paste or type the text into the box on this page. Nothing is uploaded — the work happens on this page as you go.
- Set the options. Adjust the settings shown for base64 decode. The defaults suit most files, so you can usually leave them alone.
- Check and save the result. Run the tool and download the plain text result. Compare it against your original before you rely on it — conversions do not always carry every detail across.
Privacy
By default this page does the work itself and your file never leaves the device. If JavaScript is unavailable, the form posts to the server instead, where the file is processed in a temporary folder and deleted as soon as the result is written. The result link works once and expires.
Questions
What happens to my file?
By default nothing leaves your device — the tool runs in your browser. If JavaScript is unavailable the same page falls back to a server form, where the file is processed in a temporary folder and deleted the moment the result is written.
Will the plain text result match my Base64 file exactly?
Not always, and it is worth knowing why. It is encoding, not encryption, and offers no protection whatsoever. It also inflates the data by roughly a third. Check the result against your original before relying on it.
Is there a limit on how much text I can paste?
There is no fixed limit. Very large amounts may slow your browser down, since the work happens on your own device, but ordinary documents pasted whole are no trouble.
Does it work on a phone?
Yes. The interface is built mobile-first and works in current versions of Chrome, Safari, Firefox and Edge. Pasting long passages is simply more comfortable on a keyboard.
Working with Base64 and plain text
About Base64
An encoding that represents binary data using 64 printable characters, so files can travel through channels that only handle text, such as email or a data URI.
It is encoding, not encryption, and offers no protection whatsoever. It also inflates the data by roughly a third.
About plain text
Characters and line breaks with no formatting at all — the most portable and durable way to store writing.
Encoding still matters. A file saved as one character set and read as another produces the familiar run of replacement characters, particularly around accents and quotation marks.
Troubleshooting
- Nothing happens after choosing a file. Check the file really is B64 — a renamed extension fails here the same way it fails in other readers.
- The upload is refused. Files over 32 MB are rejected. Split the document first, or use one of the browser-side tools, which are limited only by your device memory.
- The result looks different from the original. Some conversions cannot carry every feature across formats. The page says what was dropped when that happens.