8️⃣5️⃣ Base85 Encoder / Decoder
Encode and decode Base85 (ASCII85) strings. More compact than Base64.
About the Base85 Encoder / Decoder
This tool lets you encode arbitrary text into Base85 (ASCII85) and decode it back. All processing happens locally in your browser — nothing is uploaded.
What is Base85 / ASCII85?
Base85, also known as ASCII85, is a binary-to-text encoding scheme that represents each group of four bytes as five printable ASCII characters (from ! to u, codes 33 to 117). It was popularized by Adobe's PostScript and PDF formats and is roughly 25% more compact than Base64, which uses four characters per three bytes.
How encoding works
- The input string is converted to UTF-8 bytes.
- Bytes are grouped into 4-byte blocks.
- Each 4-byte block is treated as a 32-bit big-endian integer and divided repeatedly by 85 to produce 5 base85 digits.
- Each digit is offset by 33 to land in the printable ASCII range
!–u. - The output is wrapped in
<~...~>markers following the standard ASCII85 convention.
Frequently asked questions
Does this tool upload my data? No. All encoding and decoding runs in your browser.
Does the decoder require the <~ ~> delimiters? They are optional. The decoder strips them if present, but also accepts raw Base85 input.
Is Base85 suitable for cryptography or passwords? No. Base85 is an encoding, not encryption. It provides no confidentiality.
What character set is used? ASCII printable characters from ! (33) through u (117).