Base64 decoder
Turn Base64 back into the file, image or text it came from.
- Runs in your browser — your text is never sent anywhere
- No sign-up, no quotas, free to use as often as you like
How it works
Base64 turns up embedded in data URIs, API payloads, email attachments and configuration files. Decoding it usually means finding out what it actually is, which is why this shows images rather than just handing back bytes.
Data URIs are handled
A string beginning “data:image/png;base64,” carries its own type, and the prefix is stripped automatically. Plain Base64 with no prefix is fine too.
The type is detected when it is not declared
Without a prefix, the first few bytes are checked against the signatures of common formats — PNG, JPEG, GIF, PDF and ZIP all identify themselves this way. When the content turns out to be valid UTF-8 text it is shown as text instead.
Images are previewed
When the result is an image, it is displayed so you can confirm it is what you expected before downloading. Everything else is offered as a download with a sensible extension.
Why this matters for security
Base64 payloads regularly contain credentials, tokens and private documents. Decoding one on a remote server means handing it over. This runs in the page, so nothing is transmitted.
Base64 decoder — questions
Can it decode data URIs?
Yes. The data: prefix is recognised and stripped automatically.
What if my Base64 has no type information?
The first bytes are checked against common file signatures, and valid UTF-8 is shown as text.
Why does it say the Base64 is invalid?
Usually a truncated copy or stray characters. Check that the whole string was copied.
Is my data uploaded?
No. Decoding happens entirely in your browser.