YUCTS Tools

Base64 Encoder & Decoder (Text and Files)

Encode text (including emoji and any language) to Base64 as UTF-8 and decode it back. Supports URL-safe Base64, optional padding, files and data URLs.

  • Runs in your browser (no upload)
Input type
Action

Result

Original data
19 bytes
Base64 length
28 characters

How to use

  1. Choose Text or File, then Encode or Decode.
  2. Type text or choose a file. Pick the alphabet (standard or URL-safe), padding and line breaks.
  3. Copy or download the result. If decoded data is not text, its type is detected so you can save it as a file.

FAQ

Are non-English characters and emoji handled correctly?

Yes. Text is converted as UTF-8 bytes, so Japanese, Chinese, Vietnamese and emoji round-trip exactly.

What happens with invalid Base64?

Invalid characters, a truncated length and wrong padding (=) are detected and shown with the line, column and exact spot. The page never crashes.

What is URL-safe Base64?

It is base64url from RFC 4648: - and _ replace + and / so the result can be used in URLs and file names. Decoding accepts both alphabets automatically.

Notes & limitations

  • What you enter is processed only on this page and is not sent to YUCTS servers.
  • Text up to 10 MB and files up to 10 MB. Long results are previewed, but copy and download always include everything.
  • Text is treated as UTF-8. Bytes in other encodings such as Shift_JIS should be downloaded as a file.
  • File type detection uses the first bytes only and is a best guess.

Data sources