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Base85 (specifically the Ascii85 variant used by Adobe PostScript, PDF, and btoa) packs binary data more efficiently than Base64 — 4 raw bytes become 5 printable characters instead of Base64's 4 bytes into ~5.33 characters. This tool encodes text to Ascii85 or decodes Ascii85 back to the original text.
How it works
Bytes are grouped 4 at a time and treated as one 32-bit number, which is converted to 5 base-85 digits (each written as a printable ASCII character). An all-zero 4-byte group is shortened to the single character "z", and a final partial group is trimmed so the exact original length can be recovered on decode.
- Enter mode.
- Enter input.
- Click Calculate to see your results.
Examples
Encoding a short string
"Hello, World!" encodes to "87cURD_*#4DfTZ)+T" in Ascii85 — decoding that string back returns the exact original text.
Who should use it
- Encoding binary data for embedding in a PostScript or PDF document.
- Learning how PDF internally represents binary streams as text.
Industry applications
- Document/printing systems (PostScript, PDF)
- Software development
Advantages
- More space-efficient than Base64.
- Standard encoding used in PDF and PostScript internals.
Limitations
- Less commonly supported than Base64 in general-purpose tooling.
Common mistakes to avoid
- Assuming Base85 output is interchangeable with Base64 — they use different alphabets and aren't compatible with each other.
Best practices
- Use Base85 when you specifically need PostScript/PDF-style binary encoding; use Base64 for general web/API use since it's far more widely supported.
Tips
- Need broader compatibility instead? Use the Base64 Encoder and Decoder.