Ascii85 Encoder Decoder

Ascii85, also known as Base85, is a binary-to-text encoding that is more compact than Base64: it packs every four bytes into just five printable ASCII characters instead of the roughly 4-to-6 ratio Base64 produces.

This tool encodes plain text to Ascii85 and decodes Ascii85 back to text, using the classic Adobe variant where each output character lies in the range from “!” to “u”.

On encode, a full four-byte run of zeros is collapsed to the single shortcut character “z”, exactly as PostScript and PDF do, and partial trailing groups are padded and truncated correctly so the output is always valid.

On decode, the tool is forgiving: it strips the optional Adobe “<~ … ~>” delimiters and ignores any whitespace, then validates every remaining character, surfacing a clear message if it meets something outside the allowed range or a malformed trailing group.

Round-tripping is lossless for any UTF-8 text, including accents, emoji and non-Latin scripts, because the bytes are handled exactly rather than the characters.

Everything runs locally in your browser with no uploads, so it is safe for private data and works offline.

Ascii85 shows up in PDFs, PostScript, Adobe tooling and the btoa-style corners of older protocols, making this a handy companion when you need to read or produce that format by hand.