Network calculators
Pure IP and subnet math — CIDR, mask, host counts, range conversions. Every calculation runs locally, no DNS or WHOIS round-trips. For live network lookups see the lookups hub.
IPv4 subnet, mask, range and host counts.
CIDR notation → range, mask, hosts.
Convert between mask, CIDR prefix and host count.
Map an IPv4 address to its IPv6 form.
IPv4 address ↔ binary and decimal int.
Subnetting without the headache
For planning, the subnet calculator shows network address, broadcast, usable host range and total hosts for any IPv4 + prefix. The CIDR calculator and subnet mask tools convert between the three ways the same fact is written: prefix length, dotted-decimal mask, and host-count. For transitions, the IPv4 to IPv6 converter produces the IPv4-mapped IPv6 form for dual-stack work, and IP to binary shows the bit pattern when you need to explain a mask to someone who has never seen one before.
Frequently asked questions
- Yes. Every tool here is free, needs no sign-up, and runs entirely in your browser — the math is all client-side.
- These are pure math: subnet ranges, CIDR conversion, IPv4↔IPv6 mapping. They don't make a network call. For live network queries (WHOIS, DNS, SSL) see the lookups hub.
- The IPv4↔IPv6 converter maps an IPv4 to its IPv4-mapped IPv6 form. Pure IPv6 subnet planning is on the roadmap.