About IPv6 Subnet & Address Compressor/Expander
Expand compressed IPv6 addresses into full 8-quartet 32-hex notation, compress according to RFC 5952 double-colon rules, calculate total /64 subnets and host address space for /1 to /128 prefix lengths, and identify IPv6 address scope.
Key Capabilities & Features
- Full 128-bit expansion showing all 8 16-bit quartets with leading zeros
- RFC 5952 compliant compression using single :: notation
- Subnet capacity calculation showing total available /64 subnets and host addresses
- Address classification (Global Unicast, Link-Local, Unique Local, Loopback, Multicast)
- BigInt mathematical support for immense IPv6 address ranges (up to 2^128)
How to Use IPv6 Subnet & Address Compressor/Expander
Enter IPv6 Address
Paste an IPv6 address in compressed or expanded form (e.g., 2001:db8::1).
Select Prefix Length
Pick your routing prefix length (e.g., /48 or /64).
Inspect Formats
Compare fully expanded notation, RFC 5952 compressed notation, and subnet capacity.
Privacy & In-Browser Execution Guarantee
Runs 100% locally in your browser. Zero network transmission.
Frequently Asked Questions
How does RFC 5952 IPv6 address compression work?
RFC 5952 standardizes IPv6 formatting by replacing the longest run of consecutive 16-bit zero quartets with a double colon (::) and suppressing leading zeros within each quartet.
What is the standard prefix length for IPv6 local network subnets?
RFC 4291 recommends /64 as the universal subnet prefix length, accommodating 2^64 (over 18 quintillion) unique host addresses on a single local network link.
What is the difference between Link-Local (fe80::) and Global Unicast IPv6?
Link-local addresses (fe80::/10) only route within a single physical network segment or switch. Global Unicast addresses (2000::/3) are globally routable across the public internet.