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Base64 Decoder

Decode standard Base64 into readable UTF-8 text. Check invalid input, binary-file limitations and when to use the separate JWT decoder for Base64url tokens.

Read text that has been represented as standard Base64. The decoder interprets the decoded bytes as UTF-8 and reports an error for invalid input or invalid UTF-8. Base64 is a representation of bytes, not a security boundary or a way to decrypt protected content.

  • 100% free
  • No registration
  • On your device
  • Modern browser
  1. 1Enter details
  2. 2Adjust options
  3. 3View result
Decoded Plain TextLive
Hello Antigravity!

Your input stays on this device for this operation. We don’t upload or store it.

About Base64 Decoder

Read text that has been represented as standard Base64. The decoder interprets the decoded bytes as UTF-8 and reports an error for invalid input or invalid UTF-8. Base64 is a representation of bytes, not a security boundary or a way to decrypt protected content.

UTF-8 decoding

Decoded bytes must form valid UTF-8 text.

Immediate error feedback

Invalid Base64 or invalid UTF-8 produces an error instead of a successful text result.

Copyable plain text

The output is shown as text; it is not executed as HTML or code.

How to use Base64 Decoder

  1. 1

    Paste the Base64 string

    Use the encoded value itself, without a data-URL prefix or JSON quotation marks.

  2. 2

    Read the live result

    The text is decoded automatically. If an error appears, confirm both the Base64 alphabet and the source text encoding.

  3. 3

    Copy readable text

    Use the result's copy control. For a token with dot-separated parts, use JWT Decoder instead.

Formats and practical limits

Input: a standard Base64 text string. Output: UTF-8 plain text or a decoding error.

  • No file export, data-URL prefix handling or Base64url normalization is provided here.
  • Decoding is not decryption; protect credentials and use redacted fixtures when sharing examples.

Practical example

SGVsbG8= decodes to Hello. A Base64-encoded JPEG is a different use case and should not be interpreted as UTF-8 prose.

Frequently Asked Questions

3 answers
Can this download a decoded image or PDF?

No. This workspace outputs UTF-8 text, not arbitrary binary files. Binary data can fail the text-decoding step.

Does it accept Base64url?

This decoder does not normalize the URL-safe minus and underscore alphabet. Use JWT Decoder for a supported three-part JWT.

Does an error always mean the Base64 is malformed?

No. The bytes can be valid Base64 but represent a binary file or a different text encoding rather than valid UTF-8.

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