BASE31

BASE31 is a base-encoding scheme that encodes integers into a string of 31 characters. The encoding consists of 31 possible characters, with 30 being letters (26 letters from A to Z, excluding the letters J and Q, and two digits) and one being a special character.

The scheme is defined in the specification for BASE32, but bases different from 32 are used. These characters are different from BASE32, and a slightly modified alphabet is used. BASE31 is typically used for introducing variations to the 32-character alphabet.

BASE31 is defined as follows: A-Z omit the letters 'J' and 'Q', then use S for V, V for W, and W for X, and finally S for V, I for H, and I for neither letter and I, while the remainder assign digits (0-9 or both letters).

BASE31 differs from the popular BASE62 in that it uses more or equal (character) digits and fewer unique characters than the digit schemes alluded to and their original specifications. The BASE31 case is usually used in more or less what could be called " Exceptional error."