Base64エンコード/デコードツール

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共有リンク

はじめに

Base64 Encoder/Decoder — Encode and decode text with Base64. Enter Mode, Text to get an instant, accurate result.

計算式

Base64 maps every 3 bytes of input to 4 printable ASCII characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /).

ステップごとの説明

1. Enter the Mode.
2. Enter the Text.
3. Click Calculate to see your result instantly.

実例

Example: With Mode = encode, the Base64 Encoder/Decoder gives Encoded: SGVsbG8sIENhbGNIdWIh.

よくある質問

Is Base64 encryption?

No — it's an encoding, not encryption. It provides no confidentiality, only a way to represent binary data as text.

What happens if I try to decode invalid Base64?

The decode will fail since the input doesn't match valid Base64 structure.

What inputs does the Base64 Encoder/Decoder need?

You'll need to provide: Mode, Text. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.

How accurate is the Base64 Encoder/Decoder?

The Base64 Encoder/Decoder applies the formula exactly as calculated — Base64 maps every 3 bytes of input to 4 printable ASCII characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /). — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.

Is the Base64 Encoder/Decoder free to use?

Yes, the Base64 Encoder/Decoder is completely free, requires no signup, and runs instantly in your browser.

Base64エンコード/デコードツールについて

The Base64 Encoder/Decoder uses a real, verifiable formula — Base64 maps every 3 bytes of input to 4 printable ASCII characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /). — so results are accurate every time, not an approximation.