IPv6 Expand Compress

Expand or compress IPv6 addresses in the browser

IPv6 addresses are often written in compressed form with :: shorthand defined by RFC 5952. Firewalls, routing tables, and log parsers sometimes require the fully expanded eight-hextet representation instead. Paste an address here to expand it to 32 hexadecimal digits with colons, or compress a verbose address to canonical lowercase shorthand.

When to expand vs compress

1. Expand before comparing strings, diffing configs, or feeding tools that reject ::.
2. Compress when publishing documentation, DNS records, or user-facing network diagrams.
3. Embedded IPv4 tails (for example ::ffff:192.0.2.1) are normalized before expansion.

Validate CIDR membership for a list of hosts with the IP CIDR Membership Checker or convert between address families using the IPv4 to IPv6 Converter.