# Text to Ascii85 Converter

Encode text to Ascii85 or decode Ascii85 back to text, the Base85 encoding used in PostScript, PDF streams and Git binary patches. The tool converts your input to UTF-8 bytes, turns every four bytes into five characters from ! to u, writes z for four zero bytes and can wrap the result in Adobe's <~ and ~> delimiters. Decoding accepts both forms and ignores whitespace.

## Frequently asked questions

### What is Ascii85?

Ascii85, also called Base85, encodes binary data as printable ASCII. It turns every 4 bytes into 5 characters from ! (33) to u (117), so it adds only 25 percent overhead compared with 33 percent for Base64. Adobe uses it in PostScript and PDF.

### What are known Ascii85 examples?

The four characters Man followed by a space give 9jqo^, and Man is distinguished gives 9jqo^BlbD-BleB1DJ+*+F(f,q. The text sure. gives F*2M7/c. The tool returns these values and decodes them back.

### What does the z character mean?

A group of four zero bytes is written as a single z instead of !!!!!. The decoder expands z back to four zero bytes. It may only appear at the start of a group.

### What are the <~ and ~> delimiters?

Adobe's format marks the start and end of Ascii85 data with <~ and ~>. Turn on the option to add them when encoding. When decoding, the tool removes them if present, so both forms work.

### How is the last partial group handled?

If the input length is not a multiple of four, the last group is padded with zero bytes, encoded, and only the first n plus one characters are kept. Decoding pads with u and drops the extra bytes, which restores the exact input.

### Why is my input rejected?

Valid characters are ! to u plus z. Characters such as v to y, a z inside a group, a single leftover character at the end or a group whose value exceeds 32 bits are invalid. Whitespace is ignored.

### Is this the same as Z85 or the RFC 1924 Base85?

No. ZeroMQ's Z85 and RFC 1924 use different 85-character alphabets. This tool implements the Adobe and btoa style Ascii85 used by PostScript, PDF and Python's base64.a85encode.

### Why does decoding report invalid UTF-8?

Ascii85 often holds binary data such as compressed PDF streams. The tool only shows decoded data that is valid UTF-8 text and reports anything else instead of printing unreadable bytes.

### How are non-ASCII characters encoded?

The text is converted to UTF-8 first, so accented letters and emoji become several bytes each before encoding. Decoding restores the same characters.

### How much data can I convert?

Up to 5 MiB of text per request. The conversion runs on the server and the input is not stored.

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