Classic IPv4 and IPv6 subnet helpers sit next to a single IPv8 draft hub. IPv8 content tracks Internet-Draft thain-ipv8 for study only, not production claims.
Enter a.b.c.d/prefix, a.b.c.d with a second line for prefix or mask, or two tokens a.b.c.d m.m.m.m. Then pick a longer child prefix (or the matching usable-host count) to list every equal subnet inside the parent block. A sample calculation loads by default so you can explore binary view, class, scope, and the subnet table before you change the inputs.
IPv6 has no IPv4-style broadcast; this tool shows the subnet ID (network), last address in the prefix, and how many addresses the prefix covers. A sample result is calculated when the page opens.
IPv8 on this site always means the IETF draft proposal, not a finished standard or vendor feature set. Use it to read along with the draft; compare anything operational with your own design docs and routers.
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Every tool here is free: no paywall, no account, and no setup required. Open any tool and get to work.
IPv4 and IPv6 pages are ordinary CIDR classroom helpers. The IPv8 area groups draft-only material: Internet-Draft thain-ipv8-00 describes a 64-bit form (r.r.r.r plus n.n.n.n), ASN dot notation, routing classes, and reserved spaces such as 127/8 and 100/8 in r. Treat that hub as exploratory documentation, not a roadmap for the public Internet.
