ASCII85 encode & decode (Adobe)

Client

Adobe ASCII85 (sometimes called Base85 in filter docs) encodes every four bytes as five printable characters in the ! through u range—common in PostScript and PDF stream filters. Encode or decode UTF-8 text; same strict UTF-8 readout as the Base32 and Base64 workspaces.

Part of encoding tools.

Workspace

Paste text, run encode or decode—the field updates in place for quick copy.

Adobe ASCII85

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Also called Base85 in PDF and PostScript. Five printable characters in !–u per four bytes; a run of four 0x00 bytes can encode as z (full block only). Decoding ignores whitespace and optional <~ / ~> fences.

This is not Z85 (ZeroMQ), Base64, or Base58—open those pages for the matching alphabet.

Common use cases

  • Decode a short /ASCII85Decode or stream snippet copied from a PDF or PostScript file.
  • Compare expansion vs Base64 when debugging binary-to-text in graphics pipelines.
  • Round-trip placeholder UTF-8 through ASCII85 when you need the PostScript filter alphabet.

Common mistakes to avoid

  • Confusing with Z85, Base64, or Base85Check

    This page implements Adobe’s filter (common in PDF). For ZeroMQ / RFC 32 use the Z85 tool. Base64 or Base32 follow RFC 4648.

  • Expecting encryption

    ASCII85 is reversible binary-to-text, not a cipher—anyone can decode the string.

  • Decoding binary as UTF-8

    Decoded bytes are interpreted as strict UTF-8. Random binary from an opaque stream may fail—use a hex or file tool for raw bytes.

FAQ

Why does a block sometimes encode to a single z?

A full 4-byte group of zero bytes (0x00 0x00 0x00 0x00) is often written as the single character z, per Adobe’s convention.

Can I paste &lt;~ and ~&gt; from a PDF?

Yes. Decoding strips those delimiters and ignores whitespace, like typical PDF/ASCII85 filters.

Does data leave my browser?

No. All encoding and decoding run locally in the page.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • ascii85 encode decode online
  • adobe base85 pdf stream decoder
  • ascii85 postscript filter online
  • decode pdf ascii85 filter browser

More tools

Related utilities you can open in another tab—mostly client-side.