Base85 RFC 1924 Encoder

About this calculator

Base85 encoding represents binary data using 85 printable characters instead of Base64's 64, packing more information per character and producing roughly 25% shorter output than Base64 for the same input. RFC 1924 defines a specific Base85 alphabet (0–9, A–Z, a–z plus a set of punctuation symbols) originally proposed as a compact textual notation for IPv6 addresses. This encoder takes a non-negative integer and converts it to that alphabet through repeated division by 85, the same technique used to convert a number into any base.

While RFC 1924's IPv6 notation itself never saw wide adoption, its Base85 alphabet and encoding method remain useful in software engineering wherever a compact, URL-safe-ish text representation of binary or numeric data is needed — such as encoding large IDs, hashes or binary blobs more densely than Base64 allows. Developers working with binary-to-text encoding schemes use tools like this to verify their own RFC 1924 implementation or convert values by hand for debugging.