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Base64 Decoder

Paste a Base64 string and read the original text instantly, even when the padding is missing.

Processed locally in your browser

Options
0 chars · 0 lines
The result will appear here.

What is Base64 Decoder?

Base64 turns bytes into printable characters. Decoding reverses that: every 4 Base64 characters become 3 bytes, which are then read as text.

This decoder is forgiving: it ignores spaces and line breaks, accepts both the standard (+ /) and URL-safe (- _) alphabets, understands data: URL prefixes and tolerates missing "=" padding.

How does it work?

  1. Paste the Base64 string in the input box; decoding happens as you type.
  2. Pick the text encoding (UTF-8 by default) if the source used something else, such as ISO-8859-1.
  3. Copy or download the decoded text. If the bytes are binary (an image, a ZIP) you will see a warning: use the Base64 File Decoder instead.

Common use cases

  • Reading the contents of a Base64 value found in a config file, log line or API response.
  • Inspecting the "user:password" part of an HTTP Basic Authorization header while debugging.
  • Decoding email or MIME snippets copied from raw message source.
  • Checking a value before you paste it into a JWT or JSON tool.

Examples

Try this input in the tool above:

Input
SGVsbG8gd29ybGQ=
Output
Hello world

Privacy

Base64 Decoder runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

A successful decode does not tell you whether the content is trustworthy. Binary payloads cannot be shown correctly as text.

Frequently asked questions

Why do I get an "Invalid Base64" error?

The input contains characters outside the Base64 alphabet, or its length is impossible (a remainder of 1 character). Check for stray quotes, truncated copy-paste or a different encoding such as hex.

Can it decode Base64URL used in JWTs?

Yes. The "-" and "_" characters are accepted automatically. To inspect a whole token, use the JWT Decoder.

The output looks like garbage. What now?

The data is probably binary (an image, archive or encrypted blob) or uses another text encoding. Try another encoding in Options or decode to a file.

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