Base64 Decoder
Decode Base64 strings (standard or URL-safe) to readable text — all client-side.
What it does
Base64 is a way of encoding arbitrary bytes using only 64 safe characters (A-Z, a-z, 0-9, +, /). It's used to embed binary in text — data URLs, email attachments, JWT segments, HTTP Basic auth.
Decoding Base64 is mostly trivial, but online tools often upload your input to do it, which is embarrassing for something that every browser can do natively. convert2 does it in JavaScript on your machine.
How to use it
- Paste the Base64 string into the left pane.
- The decoded text appears on the right.
- Standard and URL-safe variants both work —
-/_instead of+//. - Missing padding (
=) is tolerated and added back before decoding.
Example
Y29udmVydDIuYXBwIOKAlCBwYXN0ZSBvbiB0aGUgbGVmdCwgYmVhdXR5IG9uIHRoZSByaWdodC4=convert2.app — paste on the left, beauty on the right.Why convert2
- Local. Base64 often carries credentials (HTTP Basic auth) or token segments — keep them in your browser.
- URL-safe aware. Both
+/and-_variants supported automatically. - Padding-tolerant. Missing
=padding gets reconstructed. - UTF-8 safe. Non-ASCII text (Turkish, Japanese, emoji) decodes correctly.
Common use cases
- Reading the header or payload of a JWT by hand (before reaching for the JWT decoder).
- Decoding HTTP Basic auth from an
Authorization: Basicheader. - Inspecting data URLs (
data:image/png;base64,...). - Reading base64-encoded secrets stored in Kubernetes
Secretobjects.
Base64 Decoder specifics
- Input character set:
A-Z a-z 0-9 + / - _ =(whitespace is stripped). - Decodes to UTF-8 text. Binary output (PNG, PDF, etc.) is shown as its UTF-8 interpretation — which will be garbled for true binary.
- For encoding (the other direction), use your browser's console:
btoa("your text"). - For encoding of non-ASCII text, use
btoa(unescape(encodeURIComponent(text))).
Frequently asked questions
Does it handle URL-safe Base64?
Yes. Both standard Base64 and URL-safe variants (with - and _ instead of + and /) are supported automatically.
Is it safe for sensitive data?
Yes. All decoding runs in your browser. Nothing is uploaded.
What if my Base64 is binary data like a PNG?
The decode still works but the output is binary, displayed as UTF-8 text which will look garbled. For binary, save the decoded bytes to a file via a tool that supports it.
What about encoding?
convert2 currently focuses on decoding. For encoding, use your browser's devtools console: btoa('your text').