Searchable reference of CIDR prefixes, subnet masks, host counts and private IP ranges.
10.0.0.0 – 10.255.255.255
Class A private range — large internal networks
172.16.0.0 – 172.31.255.255
Class B private range — medium internal networks
192.168.0.0 – 192.168.255.255
Class C private range — home & small office networks
169.254.0.0 – 169.254.255.255
Link-local (APIPA) — auto-assigned when no DHCP
127.0.0.0 – 127.255.255.255
Loopback — localhost addresses
100.64.0.0 – 100.127.255.255
Carrier-grade NAT (CGNAT) shared address space
192.0.2.0 – 192.0.2.255
TEST-NET-1 — documentation & examples
198.51.100.0 – 198.51.100.255
TEST-NET-2 — documentation & examples
203.0.113.0 – 203.0.113.255
TEST-NET-3 — documentation & examples
224.0.0.0 – 239.255.255.255
Multicast address range (Class D)
240.0.0.0 – 255.255.255.255
Reserved for future use (Class E)
::1
IPv6 loopback address
fc00:: – fdff:ffff:…
IPv6 unique local addresses (private)
fe80:: – febf:ffff:…
IPv6 link-local addresses
2001:db8:: – 2001:db8:ffff:…
IPv6 documentation range