IPv6 Subnet Calculator
Paste any IPv6 address - compressed, uppercase or mixed - choose a prefix length, and this calculator shows the expanded and compressed forms, the network address, the first and last addresses in the subnet, the exact subnet size, and what type of address it is. Built for the IPv6 questions on CCNA and Network+.
| Expanded form | |
|---|---|
| Compressed form | |
| Network address | |
| First address | |
| Last address | |
| Total addresses | |
| Address type |
IPv6 subnetting without the pain
Two IPv4 habits to drop: IPv6 has no broadcast address (multicast does that job) and no minus-2 hosts rule - in IPv6 the network address itself can be assigned to a host, so a subnet of 2^(128 - prefix) addresses is fully usable. The math is otherwise the same idea: keep the first prefix bits, and the subnet runs from the network address (host bits all zero) to the last address (host bits all one).
Working in IPv4 instead? Use the IPv4 subnet calculator, and learn the hand method in How to Subnet IPv4 in Under a Minute.
IPv6 shows up on CCNA and Network+ - practice free
Try the free 30-question samples for CCNA 200-301 and Network+ N10-009 and see where you stand.
Free CCNA SampleFree Network+ SampleFAQ
Does IPv6 have a broadcast address?
No. IPv6 removed broadcast entirely and uses multicast instead - for example ff02::1 reaches all nodes on a link. There is also no minus-2 rule: every address in an IPv6 subnet, including the first and the last, can be assigned to a host.
What does the compressed form of an IPv6 address mean?
Compression shortens an address for readability: leading zeros inside each group are dropped, and the longest run of all-zero groups is replaced once by a double colon (::). 2001:0db8:0000:0000:0000:0000:0000:0001 compresses to 2001:db8::1 - both forms are the same address.
What is a typical IPv6 subnet size?
Almost every IPv6 LAN uses a /64, which contains 2^64 - over 18 quintillion - addresses. Providers commonly delegate a /48 or /56 to a site, which is then split into many /64 subnets, one per VLAN.
What is the difference between link-local and unique local addresses?
Link-local addresses (fe80::/10) are auto-configured on every interface and are valid only on the local link - routers never forward them. Unique local addresses (fc00::/7) are the private ranges of IPv6: they can be routed inside an organization but not on the public internet.