BIP 173 is a proposal for a new SegWit address format to replace BIP 142. This format is not required for using segwit, but is more efficient, flexible, and nicer to use.

The format is base 32 and uses a simple checksum algorithm with strong error detection properties. Reference code in several languages as well as a website demonstrating it are included.

Furthermore, it is possible to locate the characters which are likely wrong as shown by the demo below.