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Base64エンコード・デコード

テキストやファイルをBase64で変換します。

Base64エンコード・デコード

UtilBrix が提供

Base64 is an encoding, not encryption. Anyone can decode Base64 content.

入力内容はブラウザ内で処理されます。アカウントは不要です。

詳しい方法と使用例は英語で提供しています。

Step-by-step instructions (English)

  1. Choose Text to Base64, Base64 to Text, or File to Base64.
  2. Paste text for text conversion, or select the source file for file encoding.
  3. Run the conversion and copy or download the output as offered.

計算式と方法

Text is converted to UTF-8 bytes before Base64 encoding. Decoding reverses Base64 to bytes and checks that they form valid UTF-8 text. File encoding returns the raw Base64 representation of its bytes. Base64 does not protect confidentiality.

使用例

The text Hello encodes as SGVsbG8=. Indian-language text and emoji are supported through UTF-8 encoding.

When this tool is useful

Prepare small encoded payloads or inspect a Base64 string returned by an API. The text modes use UTF-8 so characters outside the basic Latin alphabet can be encoded without treating them as single-byte text.

Common mistakes and limitations

  • Base64 is reversible encoding and provides no encryption.
  • Raw Base64 and a data URL are different: a data URL adds a MIME-type prefix that a raw Base64 consumer may not accept.

Practical questions about this tool (English)

Why does decoded binary data fail the text check?

Not every byte sequence is valid UTF-8 text. An encoded image or archive should be handled as binary by the receiving application rather than interpreted as a readable string.

Does Base64 reduce file size?

No. Encoding maps each three bytes to four Base64 characters, with padding where needed. It generally increases the size before any separate transport compression.

関連ツール

UtilBrixをインストール

ホーム画面からツールをすぐに開けます。

  1. ブラウザのメニュー(⋮)を開きます。
  2. 「アプリをインストール」または「ホーム画面に追加」を選びます。
  3. 確認してUtilBrixをホーム画面に追加します。

項目がない場合はAndroid版Chromeで開いてください。

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