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.
The Uptool home lists date calculators, time zone utilities, and more browser tools as we ship them.
Free to use
Every tool here is free: no paywall, no account. Open a page and use it in the browser.
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.
