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IPv6 Subnet Calculator

Calculate subnets, address ranges and reverse DNS for IPv6

Enter an IPv6 address with a CIDR prefix and instantly get the network range, address forms, reverse DNS and address type annotation.

Instant subnet calculation

Get network address, last address, total IPs (with 2^N notation) and prefix details immediately.

Multiple address forms

View compressed, expanded, full and reverse DNS (ip6.arpa.) forms of any IPv6 address.

Address type detection

Automatically identifies Global Unicast, Link-Local, ULA, Multicast, Loopback and other address types.

Smart diagnostics

Contextual info and warnings: non-standard subnets, deprecated ranges, IPv4-mapped addresses.

100% free

No registration required. Calculate as many IPv6 subnets as needed without limits.

Why use this IPv6 subnet calculator?

Calculate the network range, address forms and reverse DNS for any IPv6 CIDR block in one click.

Use cases:

  • Network planning: Size IPv6 subnets for your infrastructure
  • Reverse DNS: Generate ip6.arpa. entries for PTR records
  • Address verification: Validate IPv6 addresses and prefix lengths
  • Documentation: Document IPv6 addressing plans with expanded forms

IPv6 addressing basics

IPv6 uses 128-bit addresses written as 8 groups of 4 hexadecimal digits separated by colons. The :: notation compresses consecutive groups of zeros.

PrefixTypical useAddresses
/128Single host1
/127Point-to-point link2
/64Standard LAN subnet2^64
/48Site allocation65,536 x /64
/32ISP allocation2^96

Key differences from IPv4

  • No broadcast: IPv6 uses multicast instead
  • No wildcard mask: Only CIDR prefix notation
  • No dotted-decimal mask: Always /N notation
  • Standard /64 subnets: Convention for all LANs
  • Huge address space: 2^128 total addresses