Free online Ascii85 / Base85 encoder and decoder. Convert text, hex, Base64 or files, with Adobe Ascii85, Z85 and RFC 1924 support. Runs in your browser.

Ascii85 / Base85 Encoder & Decoder

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Ascii85, also called Base85, is a binary-to-text encoding. It turns arbitrary bytes into printable characters so that binary data can travel through systems that only handle plain text. Ascii85 packs every 4 bytes into 5 characters, which makes the output about 25% larger than the input. Base64 adds roughly 33%.

This free online tool encodes text, hex bytes, Base64 or a file into Ascii85 / Base85, decodes Base85 back to text or bytes, and converts between formats. It supports three common variants: Adobe Ascii85 (the form used in PDF and PostScript), Z85 (from ZeroMQ) and Base85 with the RFC 1924 alphabet (the one used by Python’s base64.b85encode). Everything is processed in your browser, so nothing you enter or upload is sent to a server.

Key Features

• Encode and decode in one tool — switch between the two with a single click and see results as you type
• Three variants — Adobe Ascii85, Z85 and Base85 with the RFC 1924 alphabet
• Flexible input — encode plain text, hex bytes, Base64 or a binary file of up to 10 MB
• Flexible output — decode to text, hex bytes or Base64, or download the raw bytes as a file
• UTF-8 or Latin-1 text — choose how text is converted to and from bytes
• Adobe options — add or remove the <~ and ~> delimiters, and turn the z shortcut for four zero bytes on or off
• Line wrapping — wrap encoded output at 64, 72 or 76 characters
• Forgiving decoder — spaces and line breaks are ignored, and the <~ ~> delimiters are optional when decoding
• Clear error messages — if the text is not valid, the tool tells you which character is the problem and suggests another variant when that is likely the cause
• Binary data warning — if decoded bytes are not valid UTF-8, the tool says so and suggests Hex or Base64 output
• Swap input and output — move the result into the input and flip the mode for quick round-trip checks
• Copy and download — copy the result or save it as a file
• 100% private — all processing happens locally in your browser

How to Use the Ascii85 / Base85 Tool

To encode

1. Open the Encode tab.
2. Choose a Variant: Adobe Ascii85, Z85 or RFC 1924 Base85.
3. Choose the Input format: Text, Hex bytes, Base64 or File (binary).
4. Type or paste your data, or choose a file. For text, pick UTF-8 or Latin-1.
5. For Adobe Ascii85, decide whether to include the <~ ~> delimiters and the z shortcut. If you want shorter lines, choose a Wrap output lines length.
6. Copy the result or download it.

To decode

1. Open the Decode tab.
2. Choose the Variant that was used to encode the data. If you are not sure, start with Adobe Ascii85. Text containing characters above u, such as {, | or lowercase letters beyond u, is not Adobe Ascii85 and may be Z85 or RFC 1924.
3. Paste the Base85 text. You can include the <~ ~> delimiters or leave them out, and line breaks are fine.
4. Choose the Output format: Text, Hex bytes or Base64.
5. Read the result. If the data is binary rather than text, choose Hex or Base64, or use Download to save the raw bytes as a file.

To convert between formats

Encode from one format and decode into another. For example, to turn Base64 into Ascii85, pick Base64 as the input format on the Encode tab. To turn Ascii85 into hex, decode it with Hex bytes as the output format.

Quick variant reference

Variant	Typical use	Notes
Adobe Ascii85	PDF and PostScript data	Characters ! to u, optional <~ ~> delimiters, z for four zero bytes
Z85	ZeroMQ and embedding data in source code	Avoids quotes and backslashes; defined for lengths that are a multiple of 4 bytes
RFC 1924 Base85	Python b85encode / b85decode	Different alphabet, no z shortcut, no delimiters

Tip: Decoding with the wrong variant either fails with an error or produces garbled bytes, because each variant maps characters to values differently. If a result looks like nonsense, try the other variants before assuming the data is damaged.

Note: Z85 is defined for data whose length is a multiple of 4 bytes. For other lengths this tool uses the common partial-group padding and shows a note, but some strict.