What is Base85 / Z85?

Z85 is the ZeroMQ Base85 encoding. It packs every four bytes into five printable ASCII characters using a safe 85-character alphabet, giving roughly 25 percent better density than Base64.

Why is my input padded with zero bytes?

Z85 works on whole 4-byte groups. If your text length is not a multiple of four, this tool pads the end with zero bytes and tells you how many it added so encoding can complete.

No. All Z85 encoding and decoding happens in your browser and your input never leaves the page.

Base85 Encoder — Gera Tools

Base85 (Z85) encoder and decoder

Base85 packs binary data more densely than Base64: every four bytes become five printable characters instead of Base64’s three-to-four ratio. This tool uses Z85, the ZeroMQ variant, whose 85-character alphabet avoids quotes and backslashes so the output is safe to embed in source code and config files.

Because Z85 operates on whole 4-byte groups, text whose length is not a multiple of four is padded with zero bytes (the amount is reported). Choose a direction, paste your input, and the result appears instantly — all in your browser.