Base85 Encoder / Decoder
Convert text or hex bytes with Ascii85, ZeroMQ Z85, or RFC 1924 Base85. Decode back to text or hex locally in your browser — no upload, no sign-up.
What this tool does
Encode text or hex bytes to Base85, or decode a Base85 string back to text or hex. Base85 packs four bytes into five printable characters, making it more compact than hex and often shorter than Base64 while staying copy-and-paste friendly.
Everything runs locally in WebAssembly. Your input is not uploaded.
Supported variants
| Variant | Best for | Notes |
|---|---|---|
| Ascii85 | Adobe/PostScript/PDF-style Base85 | Uses the ! through u alphabet, supports the z all-zero shortcut, allows partial final groups, and can wrap encoded output in <~ ... ~>. |
| Z85 | ZeroMQ / fixed-block binary tokens | Uses the ZeroMQ alphabet. Input bytes must be a multiple of 4 when encoding, and encoded strings must be a multiple of 5 when decoding. |
| RFC 1924 | Python base64.b85encode compatibility | Uses the RFC 1924 alphabet and supports partial final groups. |
Data formats
- text (default): encode UTF-8 text, or decode bytes back to UTF-8 text.
- hex: encode raw bytes written as hex (
48 65 6cor0x48656c), or decode Base85 back to hex. Use this for binary data or outputs that are not valid UTF-8.
Examples
| Input | Settings | Output |
|---|---|---|
Hello World! | encode · ascii85 · text | 87cURD]i,"Ebo80 |
87cURD]i,"Ebo80 | decode · ascii85 · text | Hello World! |
864fd26fb559f75b | encode · z85 · hex | HelloWorld |
Man | encode · rfc1924 · text | O<`^z |
Tips
- Turn on Adobe frame when you need Ascii85 output wrapped as
<~...~>for tools that expect Adobe-style delimiters. - Z85 is strict by design: use hex mode and make sure the byte count is divisible by 4 before encoding.
- If decoding to text fails, switch Data format to hex to inspect the raw bytes.
FAQ
Which variant matches Python's base64.b85encode?
The RFC 1924 variant. Python's b85encode/b85decode use the RFC 1924 alphabet, so pick that variant to round-trip with Python. a85encode output matches the Ascii85 variant instead.
Why does Z85 reject my input?
Z85 is defined only for whole 4-byte groups: encoding requires the byte count to be a multiple of 4, and decoding requires the string length (ignoring whitespace) to be a multiple of 5. If your data isn't block-aligned, pad it or switch to Ascii85 or RFC 1924, which accept any length.
Do I need to strip the <~ ... ~> wrapper before decoding?
No. When decoding Ascii85, the tool strips a leading <~ and trailing ~> automatically, and it ignores whitespace and line breaks inside the string. The Adobe frame option only affects encoding, where it wraps the output in those delimiters.
Decoding says the result is not valid UTF-8 — what now?
The decoded bytes are binary rather than text. Switch Data format to hex and decode again: you'll get the exact bytes as a hex string instead of a UTF-8 error.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool base85-codec "Hello World!"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/base85-codec/?input=Hello%20World%21&mode=encode&variant=ascii85&format=text&adobe_frame=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.