#176 · Converters & Encoding Text Tool

Base64 Decoder

Base64 Decoder restores Base64-encoded UTF-8 text and reports invalid characters, missing padding, and likely decoded content type.

Text Input

Converter input

Recent History

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How to use this text tool

  • Paste or upload your text into the input box.
  • Choose the conversion format and any repair or live-preview options.
  • Run the tool, then copy, download, or export the result.

What this tool does

Decoded text = Base64 alphabet mapped back to bytes, then interpreted as UTF-8 text.

Decoded text = Base64 alphabet mapped back to bytes, then interpreted as UTF-8 text.

If decoding fails, check padding, URL-safe characters, line breaks, or whether the content is binary rather than text.

Example

Example input: SGVsbG8gQ2FsbFRleHQ=. Run the tool to generate the converted result and view integrity metrics.

Use cases

  • Programming and debugging
  • API and web development
  • Encoding lessons and documentation
  • Data cleanup before import or export

Tips for better output

  • Use auto-detect when pasted data has mixed separators or formats.
  • Check the data integrity score before copying output into code.
  • Use JSON or CSV export when documenting conversion results.
  • For non-ASCII text, prefer Unicode or UTF-8 workflows.

Processing details

This tool runs locally in the browser and performs deterministic text conversion without uploading your input. Metrics include size, validity, and character-level analysis where relevant.

Browser text decoding may display binary data as replacement characters. For sensitive secrets, remember that encoding is not encryption.

FAQ

How do I decode a Base64 string into text?

Paste the Base64 string and run the decoder. Valid UTF-8 output appears in the result box.

Why does Base64 decoding fail because of padding?

Base64 length should usually be divisible by four. Enable auto padding repair to add missing = characters when possible.

How do I decode URL-safe Base64?

Enable URL-safe mode so - and _ are converted back to standard Base64 characters before decoding.

Can a Base64 decoder detect JSON output?

This tool checks whether decoded text parses as JSON and reports the likely content type.

Why does decoded Base64 look like unreadable symbols?

The encoded data may be binary, compressed, encrypted, or not UTF-8 text. Use the status report before copying it as plain text.

Conversion modules

ModulePurpose
Conversion EngineApplies the selected encoder or decoder.
ValidationDetects invalid input, malformed sequences, or unsupported characters.
Data Integrity ScoreScores conversion safety from 0 to 100.
Export ToolsCopies or downloads output as TXT, CSV, or JSON.

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