IPv6 Subnet & Prefix Calculator
Compute IPv6 CIDR prefix ranges, expanded 128-bit addresses, and host capacities.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. No data is ever transmitted across the network.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
How to Use IPv6 Subnet & Prefix Calculator
Type or paste your IPv6 address (compressed or uncompressed).
Choose prefix length (/32, /48, /56, /64, /128) with slider or presets.
Inspect fully expanded hex notation, network prefix, and address scope type.
Frequently Asked Questions
What is a standard IPv6 subnet size for home or enterprise networks?
A /64 prefix is the standard subnet size for IPv6 local area networks (LANs) and is required for SLAAC stateless auto-configuration.
How many addresses are in a /64 IPv6 subnet?
A /64 subnet contains 2^64 addresses, which equals approximately 18.4 quintillion unique IP addresses.
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