ASCII85 Encoder / Decoder

Encoded 5 character(s) of UTF-8 text to 7 ASCII85 character(s).

How it works

• Read the input as UTF-8 bytes.
• Grouped the bytes in fours, treating each group as a 32-bit big-endian integer and emitting five base-85 characters from '!' to 'u'.
• Wrote a full zero group as 'z' and truncated the padded final group to its real length.

• ASCII85 is an encoding, not encryption; it provides no confidentiality.
• The 'z' shorthand is only valid for a complete four-zero-byte group.

Methodology

1. Encode by reading four UTF-8 bytes as a 32-bit big-endian integer and emitting five base-85 digits biased by 33, with the 'z' shorthand for a zero group.
2. Truncate the final group to the real number of input bytes plus one.
3. Decode by reversing the digit mapping, rejecting groups that overflow 32 bits, and dropping the padding bytes of a partial final group.

Usage

1. Choose encode or decode.
2. Paste text to encode, or an ASCII85 value to decode.
3. Read the result; use Copy result to reuse it.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

Encode ASCII

{
  "mode": "encode",
  "value": "hello"
}

Encode Unicode

{
  "mode": "encode",
  "value": "café 🌍"
}

Decode an ASCII85 value

{
  "mode": "decode",
  "value": "BOu!rDZ"
}

Limitations

Where ASCII85 is used

Adobe systems use ASCII85 to carry binary data through text-only PostScript and PDF streams. It is more compact than Base64 (four bytes to five characters) at the cost of punctuation-heavy output.