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Base64エンコーダー/デコーダー

テキストをBase64にエンコード、またはBase64をテキストにデコードします。Unicode/UTF-8対応でバイトサイズを表示します。

プレーンテキストをBase64エンコード文字列に変換

0 バイト
結果
変換するテキストを入力してください
Base64エンコードはバイナリデータをASCIIテキストに変換します。URL、メール、JSONにデータを埋め込む際に便利です。完全なUnicode/UTF-8をサポート。

How to Use This Tool

  1. 1

    Choose Encode or Decode mode

    Select 'Encode' to convert plain text to Base64, or 'Decode' to convert a Base64 string back to readable text.

  2. 2

    Enter your input

    Paste or type your text (for encoding) or Base64 string (for decoding) into the input text area.

  3. 3

    View the result instantly

    The conversion happens in real time. The output appears below with input and output byte sizes displayed.

  4. 4

    Copy the output

    Click the 'Copy' button to copy the encoded or decoded result to your clipboard.

Frequently Asked Questions

What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters (A–Z, a–z, 0–9, +, /). It is commonly used to embed binary data in text-based formats like JSON, XML, and email.
Does Base64 encoding encrypt my data?
No. Base64 is an encoding, not encryption. Anyone can decode a Base64 string. It is meant for data transport, not security. For encryption, use tools like AES or RSA.
Why is the Base64 output larger than the input?
Base64 encoding increases data size by approximately 33%. Every 3 bytes of input become 4 Base64 characters, plus padding characters (=) if needed.
Does this tool support Unicode and emoji?
Yes. The encoder handles full Unicode text including emoji, CJK characters, and special symbols by first converting to UTF-8 bytes before Base64 encoding.