IPv6 addresses are long and easy to mistype, and subnetting them by hand is impractical. These tools handle the maths and formatting in your browser.
IPv6 address converter
Expand or compress an address (RFC 5952), and see it as binary, decimal, hex groups and its ip6.arpa reverse-DNS name.
IPv6 validator
Paste one address or a whole list to check which are valid and what type each is.
IPv6 subnet calculator
Enter the prefix from your ISP and split it into /64 LANs or per-site /56s.
Learn the essentials
Address types, special prefixes, prefix sizes and handy commands are on one page: the IPv6 cheat sheet.

