Base64エンコーダー

What this tool does

Encode text to Base64, or decode a Base64 string back to text, using UTF-8. Developers embedding a short string, or checking a value that is only encoded, can round-trip it here. Anyone can decode the result, so this is not a way to hide a password.

How to use

1. Paste text to encode, or Base64 to decode, in the input box.
2. Press Encode or Decode.
3. Copy the output, swap the boxes, or Clear both.

Examples

• ASCII

  “Hi” encodes to SGk=.

• Unicode

  Accented letters and emoji are encoded with UTF-8 before Base64, so they round-trip correctly.

How it works

Base64 turns binary data into letters, numbers, + and /. It is encoding, not encryption: anyone can decode it. This tool converts text to UTF-8 bytes, then Base64, and the reverse for decoding.

Limitations

Anyone can decode the result, because Base64 is not encryption. Input is treated as text and converted with UTF-8. A file drop is not accepted, and a broken Base64 string is rejected instead of guessed.

See the disclaimer for what these tools do not cover.

FAQ

Is the Base64 Encoder free?

Yes. Encoding text to Base64 and decoding it back is free here, with no signup.

Is Base64 secure?

No. It only changes the representation of the data. Do not use it to hide passwords or private information.

Does this leave my browser?

No. Encoding and decoding run locally.

What is Base64 used for?

Base64 turns bytes into plain letters, digits, + and /, so data can travel through systems that expect text, such as email attachments, data URLs, and some API fields.

Why is Base64 text longer than the original?

Every 3 bytes become 4 characters, so Base64 output is about one third larger than the input.