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Developer Utilities
IPv6 Subnet & Prefix Calculator
Expand, compress, and calculate IPv6 prefix ranges, CIDR subnets, and address types.
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How to Use IPv6 Subnet & Prefix Calculator
- Enter an IPv6 address (compressed or expanded).
- Select the subnet prefix length (e.g. /64, /48).
- Copy the breakdown or full JSON subnet details.
Frequently Asked Questions
What is the standard subnet prefix for IPv6 local networks?
- A /64 prefix is the standard subnet size for IPv6 local network segments according to RFC 4291.
Sources & References
Primary references: RFC 791: Internet Protocol; RFC 4632: Classless Inter-domain Routing.
Review policy: references and behavior notes are checked whenever the tool implementation changes.