How does ASCII85 differ from Z85?

Both pack four bytes into five characters, but Adobe ASCII85 uses the character range ! to u, wraps output in delimiters, and uses z as shorthand for an all-zero group. It is the variant found in PostScript and PDF.

Can I decode ASCII85 without the delimiters?

Yes. The decoder accepts input with or without the leading , and ignores whitespace between characters.

Why is ASCII85 more efficient than Base64?

ASCII85 packs 4 bytes into 5 characters, a 25% size overhead, whereas Base64 packs 3 bytes into 4 characters, a 33% overhead. So ASCII85 produces noticeably smaller output for binary data carried as text.

What does the z character mean in ASCII85?

A single z is shorthand for a group of four zero bytes, which would otherwise encode as the five characters !!!!!. This compression makes runs of zeros much shorter.

ASCII85 Encoder — Gera Tools

Q: Is anything uploaded?

No. ASCII85 encoding and decoding run entirely in your browser; your data stays on your device.

ASCII85 (also called Adobe Base85) is a binary-to-text encoding used inside PostScript and PDF files to embed binary data such as images and fonts as printable ASCII. This tool encodes text into ASCII85 and decodes ASCII85 back to text, which is useful for developers inspecting or building PDF/PostScript streams.

How it works

ASCII85 takes four input bytes at a time, treats them as a single 32-bit number, and converts that number to base 85, producing five characters in the range ! (33) to u (117). This 4-to-5 expansion is more compact than Base64’s 3-to-4. Adobe’s variant adds two conventions:

The full stream is wrapped in <~ at the start and ~> at the end.
A group of four zero bytes is written as a single z instead of !!!!!.

A final partial group of n bytes encodes to n+1 characters. When decoding, the tool tolerates missing delimiters and ignores whitespace between characters.

Example

Encoding the text “Man ” (four bytes) gives the ASCII85 group 9jqo^, wrapped as:

<~9jqo^~>

Format	”Man ” encoded
Raw bytes	M a n (space)
ASCII85	9jqo^
With delimiters	`<~9jqo^~>`

ASCII85 encoding and decoding run entirely in your browser; your data stays on your device.