Base64 Decoder

Decode Base64 back to text or download it as a file.

Encoding Runs in your browser
Base64
Decoded

Nothing decoded yet

Paste a Base64 value. Both alphabets are accepted, padding is optional, and non-text results can be downloaded as a file.

Runs entirely in your browser. Your data isn't uploaded — this page makes no network request with anything you type, which you can verify in your browser's network tab. How this works.

What is the Base64 Decoder?

Decoding Base64 is the everyday half of the job: reading a Kubernetes Secret, inspecting a token segment, recovering a file that was pasted into a config, or checking what an integration partner actually sent.

This decoder accepts both alphabets, tolerates missing padding and stray whitespace, and can hand the result back either as UTF-8 text or as a file download when the bytes are not text at all.

How to use it

  1. Paste the Base64 string.
  2. Press Decode (or Ctrl/Cmd + Enter).
  3. If the bytes are not valid UTF-8, switch to the hex view or use Download to save the original file.

Example

A Kubernetes Secret value decoded.

Input
cG9zdGdyZXM6Ly9hcHBAZGItaG9zdDo1NDMyL2FwcGRi
Result
postgres://app@db-host:5432/appdb

Features

  • Accepts standard and URL-safe alphabets automatically
  • Tolerates missing padding, newlines and surrounding whitespace
  • Text, hex and byte-size views of the decoded output
  • Download decoded binary as a file, with content-type sniffing
  • Clear errors that name the invalid character and its position

Frequently asked questions

Why do I get "invalid character" errors?
Something non-Base64 is in the string — often a URL-encoded %3D instead of =, a quotation mark copied with the value, or a line-wrapped value that picked up a stray character. The error names the character and position.
Why is the decoded text garbled?
The bytes probably are not UTF-8 text — they may be a compressed or binary payload, or text in another encoding. Use the hex view to check for a file signature, then download it.
Can I decode a JWT here?
You can decode an individual segment, but the JWT Decoder is the better tool: it splits the three parts, decodes both JSON objects and checks the standard claims.
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