Free Ascii85 / Base85 encoder and decoder. Convert text to Adobe Ascii85 (with optional <~ ~> delimiters and the z shorthand) or decode Ascii85 back to text. Runs entirely in your browser, no data uploaded.
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How ascii85 encoder & decoder works
Ascii85 (also called Base85) is a binary-to-text encoding that represents every 4 bytes of input as 5 printable ASCII characters, using the range 33 ("!") to 117 ("u"). It is about 25% more compact than Base64 (which uses 4 characters per 3 bytes), so it was popularized by Adobe PostScript and PDF for embedding binary streams.
This tool encodes your text into Ascii85 using the standard alphabet. Enable the <~ ~> wrap option to add the Adobe delimiters, and the encoder uses the "z" shorthand for groups of four zero bytes. Decoding strips whitespace and the Adobe delimiters, expands "z" back to four zero bytes, and handles the final partial group correctly.
Ascii85 is an encoding, not encryption — it provides no security or confidentiality and anyone can decode it. Use it for compact transport and embedding, never to protect secrets. All processing happens in your browser using the built-in UTF-8 byte conversion.
Frequently asked questions
What is the difference between Ascii85 and Base64?
Ascii85 encodes 4 bytes as 5 characters (a 25% overhead), while Base64 encodes 3 bytes as 4 characters (a 33% overhead). Ascii85 is more compact but uses a wider character range (33–117) that includes characters unsafe in URLs, so Base64 remains the safer default for web transport.
What are the <~ and ~> delimiters?
They are the Adobe PostScript/PDF delimiters that mark the start and end of an Ascii85-encoded stream. Many decoders look for them to locate the encoded data; you can toggle them on or off with the wrap option.
What does the "z" character mean in Ascii85?
The lowercase z is a shorthand for a full group of four zero bytes, which would otherwise be encoded as "!!!!!". Using z makes zero-heavy binary data much shorter. It is only emitted for complete groups, never in a final partial group.
Is Ascii85 encryption?
No. Ascii85 is an encoding, not encryption. It provides no security and anyone can decode it. Use it for compact data representation and transport, not for protecting secrets.
