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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Prefix/16
Addresses2^112
/64 networks2^48
Network
2c8a::/16
First address
2c8a::
Last address
2c8a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
2c8a:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.8.c.2.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2c8a::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
12c8a::/322c8a:0:ffff:ffff:ffff:ffff:ffff:ffff
22c8a:1::/322c8a:1:ffff:ffff:ffff:ffff:ffff:ffff
32c8a:2::/322c8a:2:ffff:ffff:ffff:ffff:ffff:ffff
42c8a:3::/322c8a:3:ffff:ffff:ffff:ffff:ffff:ffff
52c8a:4::/322c8a:4:ffff:ffff:ffff:ffff:ffff:ffff
62c8a:5::/322c8a:5:ffff:ffff:ffff:ffff:ffff:ffff
72c8a:6::/322c8a:6:ffff:ffff:ffff:ffff:ffff:ffff
82c8a:7::/322c8a:7:ffff:ffff:ffff:ffff:ffff:ffff
92c8a:8::/322c8a:8:ffff:ffff:ffff:ffff:ffff:ffff
102c8a:9::/322c8a:9:ffff:ffff:ffff:ffff:ffff:ffff
112c8a:a::/322c8a:a:ffff:ffff:ffff:ffff:ffff:ffff
122c8a:b::/322c8a:b:ffff:ffff:ffff:ffff:ffff:ffff
132c8a:c::/322c8a:c:ffff:ffff:ffff:ffff:ffff:ffff
142c8a:d::/322c8a:d:ffff:ffff:ffff:ffff:ffff:ffff
152c8a:e::/322c8a:e:ffff:ffff:ffff:ffff:ffff:ffff
162c8a:f::/322c8a:f:ffff:ffff:ffff:ffff:ffff:ffff
172c8a:10::/322c8a:10:ffff:ffff:ffff:ffff:ffff:ffff
182c8a:11::/322c8a:11:ffff:ffff:ffff:ffff:ffff:ffff
192c8a:12::/322c8a:12:ffff:ffff:ffff:ffff:ffff:ffff
202c8a:13::/322c8a:13:ffff:ffff:ffff:ffff:ffff:ffff
212c8a:14::/322c8a:14:ffff:ffff:ffff:ffff:ffff:ffff
222c8a:15::/322c8a:15:ffff:ffff:ffff:ffff:ffff:ffff
232c8a:16::/322c8a:16:ffff:ffff:ffff:ffff:ffff:ffff
242c8a:17::/322c8a:17:ffff:ffff:ffff:ffff:ffff:ffff
252c8a:18::/322c8a:18:ffff:ffff:ffff:ffff:ffff:ffff
262c8a:19::/322c8a:19:ffff:ffff:ffff:ffff:ffff:ffff
272c8a:1a::/322c8a:1a:ffff:ffff:ffff:ffff:ffff:ffff
282c8a:1b::/322c8a:1b:ffff:ffff:ffff:ffff:ffff:ffff
292c8a:1c::/322c8a:1c:ffff:ffff:ffff:ffff:ffff:ffff
302c8a:1d::/322c8a:1d:ffff:ffff:ffff:ffff:ffff:ffff
312c8a:1e::/322c8a:1e:ffff:ffff:ffff:ffff:ffff:ffff
322c8a:1f::/322c8a:1f:ffff:ffff:ffff:ffff:ffff:ffff
332c8a:20::/322c8a:20:ffff:ffff:ffff:ffff:ffff:ffff
342c8a:21::/322c8a:21:ffff:ffff:ffff:ffff:ffff:ffff
352c8a:22::/322c8a:22:ffff:ffff:ffff:ffff:ffff:ffff
362c8a:23::/322c8a:23:ffff:ffff:ffff:ffff:ffff:ffff
372c8a:24::/322c8a:24:ffff:ffff:ffff:ffff:ffff:ffff
382c8a:25::/322c8a:25:ffff:ffff:ffff:ffff:ffff:ffff
392c8a:26::/322c8a:26:ffff:ffff:ffff:ffff:ffff:ffff
402c8a:27::/322c8a:27:ffff:ffff:ffff:ffff:ffff:ffff
412c8a:28::/322c8a:28:ffff:ffff:ffff:ffff:ffff:ffff
422c8a:29::/322c8a:29:ffff:ffff:ffff:ffff:ffff:ffff
432c8a:2a::/322c8a:2a:ffff:ffff:ffff:ffff:ffff:ffff
442c8a:2b::/322c8a:2b:ffff:ffff:ffff:ffff:ffff:ffff
452c8a:2c::/322c8a:2c:ffff:ffff:ffff:ffff:ffff:ffff
462c8a:2d::/322c8a:2d:ffff:ffff:ffff:ffff:ffff:ffff
472c8a:2e::/322c8a:2e:ffff:ffff:ffff:ffff:ffff:ffff
482c8a:2f::/322c8a:2f:ffff:ffff:ffff:ffff:ffff:ffff
492c8a:30::/322c8a:30:ffff:ffff:ffff:ffff:ffff:ffff
502c8a:31::/322c8a:31:ffff:ffff:ffff:ffff:ffff:ffff
512c8a:32::/322c8a:32:ffff:ffff:ffff:ffff:ffff:ffff
522c8a:33::/322c8a:33:ffff:ffff:ffff:ffff:ffff:ffff
532c8a:34::/322c8a:34:ffff:ffff:ffff:ffff:ffff:ffff
542c8a:35::/322c8a:35:ffff:ffff:ffff:ffff:ffff:ffff
552c8a:36::/322c8a:36:ffff:ffff:ffff:ffff:ffff:ffff
562c8a:37::/322c8a:37:ffff:ffff:ffff:ffff:ffff:ffff
572c8a:38::/322c8a:38:ffff:ffff:ffff:ffff:ffff:ffff
582c8a:39::/322c8a:39:ffff:ffff:ffff:ffff:ffff:ffff
592c8a:3a::/322c8a:3a:ffff:ffff:ffff:ffff:ffff:ffff
602c8a:3b::/322c8a:3b:ffff:ffff:ffff:ffff:ffff:ffff
612c8a:3c::/322c8a:3c:ffff:ffff:ffff:ffff:ffff:ffff
622c8a:3d::/322c8a:3d:ffff:ffff:ffff:ffff:ffff:ffff
632c8a:3e::/322c8a:3e:ffff:ffff:ffff:ffff:ffff:ffff
642c8a:3f::/322c8a:3f:ffff:ffff:ffff:ffff:ffff:ffff
652c8a:40::/322c8a:40:ffff:ffff:ffff:ffff:ffff:ffff
662c8a:41::/322c8a:41:ffff:ffff:ffff:ffff:ffff:ffff
672c8a:42::/322c8a:42:ffff:ffff:ffff:ffff:ffff:ffff
682c8a:43::/322c8a:43:ffff:ffff:ffff:ffff:ffff:ffff
692c8a:44::/322c8a:44:ffff:ffff:ffff:ffff:ffff:ffff
702c8a:45::/322c8a:45:ffff:ffff:ffff:ffff:ffff:ffff
712c8a:46::/322c8a:46:ffff:ffff:ffff:ffff:ffff:ffff
722c8a:47::/322c8a:47:ffff:ffff:ffff:ffff:ffff:ffff
732c8a:48::/322c8a:48:ffff:ffff:ffff:ffff:ffff:ffff
742c8a:49::/322c8a:49:ffff:ffff:ffff:ffff:ffff:ffff
752c8a:4a::/322c8a:4a:ffff:ffff:ffff:ffff:ffff:ffff
762c8a:4b::/322c8a:4b:ffff:ffff:ffff:ffff:ffff:ffff
772c8a:4c::/322c8a:4c:ffff:ffff:ffff:ffff:ffff:ffff
782c8a:4d::/322c8a:4d:ffff:ffff:ffff:ffff:ffff:ffff
792c8a:4e::/322c8a:4e:ffff:ffff:ffff:ffff:ffff:ffff
802c8a:4f::/322c8a:4f:ffff:ffff:ffff:ffff:ffff:ffff
812c8a:50::/322c8a:50:ffff:ffff:ffff:ffff:ffff:ffff
822c8a:51::/322c8a:51:ffff:ffff:ffff:ffff:ffff:ffff
832c8a:52::/322c8a:52:ffff:ffff:ffff:ffff:ffff:ffff
842c8a:53::/322c8a:53:ffff:ffff:ffff:ffff:ffff:ffff
852c8a:54::/322c8a:54:ffff:ffff:ffff:ffff:ffff:ffff
862c8a:55::/322c8a:55:ffff:ffff:ffff:ffff:ffff:ffff
872c8a:56::/322c8a:56:ffff:ffff:ffff:ffff:ffff:ffff
882c8a:57::/322c8a:57:ffff:ffff:ffff:ffff:ffff:ffff
892c8a:58::/322c8a:58:ffff:ffff:ffff:ffff:ffff:ffff
902c8a:59::/322c8a:59:ffff:ffff:ffff:ffff:ffff:ffff
912c8a:5a::/322c8a:5a:ffff:ffff:ffff:ffff:ffff:ffff
922c8a:5b::/322c8a:5b:ffff:ffff:ffff:ffff:ffff:ffff
932c8a:5c::/322c8a:5c:ffff:ffff:ffff:ffff:ffff:ffff
942c8a:5d::/322c8a:5d:ffff:ffff:ffff:ffff:ffff:ffff
952c8a:5e::/322c8a:5e:ffff:ffff:ffff:ffff:ffff:ffff
962c8a:5f::/322c8a:5f:ffff:ffff:ffff:ffff:ffff:ffff
972c8a:60::/322c8a:60:ffff:ffff:ffff:ffff:ffff:ffff
982c8a:61::/322c8a:61:ffff:ffff:ffff:ffff:ffff:ffff
992c8a:62::/322c8a:62:ffff:ffff:ffff:ffff:ffff:ffff
1002c8a:63::/322c8a:63:ffff:ffff:ffff:ffff:ffff:ffff
1012c8a:64::/322c8a:64:ffff:ffff:ffff:ffff:ffff:ffff
1022c8a:65::/322c8a:65:ffff:ffff:ffff:ffff:ffff:ffff
1032c8a:66::/322c8a:66:ffff:ffff:ffff:ffff:ffff:ffff
1042c8a:67::/322c8a:67:ffff:ffff:ffff:ffff:ffff:ffff
1052c8a:68::/322c8a:68:ffff:ffff:ffff:ffff:ffff:ffff
1062c8a:69::/322c8a:69:ffff:ffff:ffff:ffff:ffff:ffff
1072c8a:6a::/322c8a:6a:ffff:ffff:ffff:ffff:ffff:ffff
1082c8a:6b::/322c8a:6b:ffff:ffff:ffff:ffff:ffff:ffff
1092c8a:6c::/322c8a:6c:ffff:ffff:ffff:ffff:ffff:ffff
1102c8a:6d::/322c8a:6d:ffff:ffff:ffff:ffff:ffff:ffff
1112c8a:6e::/322c8a:6e:ffff:ffff:ffff:ffff:ffff:ffff
1122c8a:6f::/322c8a:6f:ffff:ffff:ffff:ffff:ffff:ffff
1132c8a:70::/322c8a:70:ffff:ffff:ffff:ffff:ffff:ffff
1142c8a:71::/322c8a:71:ffff:ffff:ffff:ffff:ffff:ffff
1152c8a:72::/322c8a:72:ffff:ffff:ffff:ffff:ffff:ffff
1162c8a:73::/322c8a:73:ffff:ffff:ffff:ffff:ffff:ffff
1172c8a:74::/322c8a:74:ffff:ffff:ffff:ffff:ffff:ffff
1182c8a:75::/322c8a:75:ffff:ffff:ffff:ffff:ffff:ffff
1192c8a:76::/322c8a:76:ffff:ffff:ffff:ffff:ffff:ffff
1202c8a:77::/322c8a:77:ffff:ffff:ffff:ffff:ffff:ffff
1212c8a:78::/322c8a:78:ffff:ffff:ffff:ffff:ffff:ffff
1222c8a:79::/322c8a:79:ffff:ffff:ffff:ffff:ffff:ffff
1232c8a:7a::/322c8a:7a:ffff:ffff:ffff:ffff:ffff:ffff
1242c8a:7b::/322c8a:7b:ffff:ffff:ffff:ffff:ffff:ffff
1252c8a:7c::/322c8a:7c:ffff:ffff:ffff:ffff:ffff:ffff
1262c8a:7d::/322c8a:7d:ffff:ffff:ffff:ffff:ffff:ffff
1272c8a:7e::/322c8a:7e:ffff:ffff:ffff:ffff:ffff:ffff
1282c8a:7f::/322c8a:7f:ffff:ffff:ffff:ffff:ffff:ffff
1292c8a:80::/322c8a:80:ffff:ffff:ffff:ffff:ffff:ffff
1302c8a:81::/322c8a:81:ffff:ffff:ffff:ffff:ffff:ffff
1312c8a:82::/322c8a:82:ffff:ffff:ffff:ffff:ffff:ffff
1322c8a:83::/322c8a:83:ffff:ffff:ffff:ffff:ffff:ffff
1332c8a:84::/322c8a:84:ffff:ffff:ffff:ffff:ffff:ffff
1342c8a:85::/322c8a:85:ffff:ffff:ffff:ffff:ffff:ffff
1352c8a:86::/322c8a:86:ffff:ffff:ffff:ffff:ffff:ffff
1362c8a:87::/322c8a:87:ffff:ffff:ffff:ffff:ffff:ffff
1372c8a:88::/322c8a:88:ffff:ffff:ffff:ffff:ffff:ffff
1382c8a:89::/322c8a:89:ffff:ffff:ffff:ffff:ffff:ffff
1392c8a:8a::/322c8a:8a:ffff:ffff:ffff:ffff:ffff:ffff
1402c8a:8b::/322c8a:8b:ffff:ffff:ffff:ffff:ffff:ffff
1412c8a:8c::/322c8a:8c:ffff:ffff:ffff:ffff:ffff:ffff
1422c8a:8d::/322c8a:8d:ffff:ffff:ffff:ffff:ffff:ffff
1432c8a:8e::/322c8a:8e:ffff:ffff:ffff:ffff:ffff:ffff
1442c8a:8f::/322c8a:8f:ffff:ffff:ffff:ffff:ffff:ffff
1452c8a:90::/322c8a:90:ffff:ffff:ffff:ffff:ffff:ffff
1462c8a:91::/322c8a:91:ffff:ffff:ffff:ffff:ffff:ffff
1472c8a:92::/322c8a:92:ffff:ffff:ffff:ffff:ffff:ffff
1482c8a:93::/322c8a:93:ffff:ffff:ffff:ffff:ffff:ffff
1492c8a:94::/322c8a:94:ffff:ffff:ffff:ffff:ffff:ffff
1502c8a:95::/322c8a:95:ffff:ffff:ffff:ffff:ffff:ffff
1512c8a:96::/322c8a:96:ffff:ffff:ffff:ffff:ffff:ffff
1522c8a:97::/322c8a:97:ffff:ffff:ffff:ffff:ffff:ffff
1532c8a:98::/322c8a:98:ffff:ffff:ffff:ffff:ffff:ffff
1542c8a:99::/322c8a:99:ffff:ffff:ffff:ffff:ffff:ffff
1552c8a:9a::/322c8a:9a:ffff:ffff:ffff:ffff:ffff:ffff
1562c8a:9b::/322c8a:9b:ffff:ffff:ffff:ffff:ffff:ffff
1572c8a:9c::/322c8a:9c:ffff:ffff:ffff:ffff:ffff:ffff
1582c8a:9d::/322c8a:9d:ffff:ffff:ffff:ffff:ffff:ffff
1592c8a:9e::/322c8a:9e:ffff:ffff:ffff:ffff:ffff:ffff
1602c8a:9f::/322c8a:9f:ffff:ffff:ffff:ffff:ffff:ffff
1612c8a:a0::/322c8a:a0:ffff:ffff:ffff:ffff:ffff:ffff
1622c8a:a1::/322c8a:a1:ffff:ffff:ffff:ffff:ffff:ffff
1632c8a:a2::/322c8a:a2:ffff:ffff:ffff:ffff:ffff:ffff
1642c8a:a3::/322c8a:a3:ffff:ffff:ffff:ffff:ffff:ffff
1652c8a:a4::/322c8a:a4:ffff:ffff:ffff:ffff:ffff:ffff
1662c8a:a5::/322c8a:a5:ffff:ffff:ffff:ffff:ffff:ffff
1672c8a:a6::/322c8a:a6:ffff:ffff:ffff:ffff:ffff:ffff
1682c8a:a7::/322c8a:a7:ffff:ffff:ffff:ffff:ffff:ffff
1692c8a:a8::/322c8a:a8:ffff:ffff:ffff:ffff:ffff:ffff
1702c8a:a9::/322c8a:a9:ffff:ffff:ffff:ffff:ffff:ffff
1712c8a:aa::/322c8a:aa:ffff:ffff:ffff:ffff:ffff:ffff
1722c8a:ab::/322c8a:ab:ffff:ffff:ffff:ffff:ffff:ffff
1732c8a:ac::/322c8a:ac:ffff:ffff:ffff:ffff:ffff:ffff
1742c8a:ad::/322c8a:ad:ffff:ffff:ffff:ffff:ffff:ffff
1752c8a:ae::/322c8a:ae:ffff:ffff:ffff:ffff:ffff:ffff
1762c8a:af::/322c8a:af:ffff:ffff:ffff:ffff:ffff:ffff
1772c8a:b0::/322c8a:b0:ffff:ffff:ffff:ffff:ffff:ffff
1782c8a:b1::/322c8a:b1:ffff:ffff:ffff:ffff:ffff:ffff
1792c8a:b2::/322c8a:b2:ffff:ffff:ffff:ffff:ffff:ffff
1802c8a:b3::/322c8a:b3:ffff:ffff:ffff:ffff:ffff:ffff
1812c8a:b4::/322c8a:b4:ffff:ffff:ffff:ffff:ffff:ffff
1822c8a:b5::/322c8a:b5:ffff:ffff:ffff:ffff:ffff:ffff
1832c8a:b6::/322c8a:b6:ffff:ffff:ffff:ffff:ffff:ffff
1842c8a:b7::/322c8a:b7:ffff:ffff:ffff:ffff:ffff:ffff
1852c8a:b8::/322c8a:b8:ffff:ffff:ffff:ffff:ffff:ffff
1862c8a:b9::/322c8a:b9:ffff:ffff:ffff:ffff:ffff:ffff
1872c8a:ba::/322c8a:ba:ffff:ffff:ffff:ffff:ffff:ffff
1882c8a:bb::/322c8a:bb:ffff:ffff:ffff:ffff:ffff:ffff
1892c8a:bc::/322c8a:bc:ffff:ffff:ffff:ffff:ffff:ffff
1902c8a:bd::/322c8a:bd:ffff:ffff:ffff:ffff:ffff:ffff
1912c8a:be::/322c8a:be:ffff:ffff:ffff:ffff:ffff:ffff
1922c8a:bf::/322c8a:bf:ffff:ffff:ffff:ffff:ffff:ffff
1932c8a:c0::/322c8a:c0:ffff:ffff:ffff:ffff:ffff:ffff
1942c8a:c1::/322c8a:c1:ffff:ffff:ffff:ffff:ffff:ffff
1952c8a:c2::/322c8a:c2:ffff:ffff:ffff:ffff:ffff:ffff
1962c8a:c3::/322c8a:c3:ffff:ffff:ffff:ffff:ffff:ffff
1972c8a:c4::/322c8a:c4:ffff:ffff:ffff:ffff:ffff:ffff
1982c8a:c5::/322c8a:c5:ffff:ffff:ffff:ffff:ffff:ffff
1992c8a:c6::/322c8a:c6:ffff:ffff:ffff:ffff:ffff:ffff
2002c8a:c7::/322c8a:c7:ffff:ffff:ffff:ffff:ffff:ffff
2012c8a:c8::/322c8a:c8:ffff:ffff:ffff:ffff:ffff:ffff
2022c8a:c9::/322c8a:c9:ffff:ffff:ffff:ffff:ffff:ffff
2032c8a:ca::/322c8a:ca:ffff:ffff:ffff:ffff:ffff:ffff
2042c8a:cb::/322c8a:cb:ffff:ffff:ffff:ffff:ffff:ffff
2052c8a:cc::/322c8a:cc:ffff:ffff:ffff:ffff:ffff:ffff
2062c8a:cd::/322c8a:cd:ffff:ffff:ffff:ffff:ffff:ffff
2072c8a:ce::/322c8a:ce:ffff:ffff:ffff:ffff:ffff:ffff
2082c8a:cf::/322c8a:cf:ffff:ffff:ffff:ffff:ffff:ffff
2092c8a:d0::/322c8a:d0:ffff:ffff:ffff:ffff:ffff:ffff
2102c8a:d1::/322c8a:d1:ffff:ffff:ffff:ffff:ffff:ffff
2112c8a:d2::/322c8a:d2:ffff:ffff:ffff:ffff:ffff:ffff
2122c8a:d3::/322c8a:d3:ffff:ffff:ffff:ffff:ffff:ffff
2132c8a:d4::/322c8a:d4:ffff:ffff:ffff:ffff:ffff:ffff
2142c8a:d5::/322c8a:d5:ffff:ffff:ffff:ffff:ffff:ffff
2152c8a:d6::/322c8a:d6:ffff:ffff:ffff:ffff:ffff:ffff
2162c8a:d7::/322c8a:d7:ffff:ffff:ffff:ffff:ffff:ffff
2172c8a:d8::/322c8a:d8:ffff:ffff:ffff:ffff:ffff:ffff
2182c8a:d9::/322c8a:d9:ffff:ffff:ffff:ffff:ffff:ffff
2192c8a:da::/322c8a:da:ffff:ffff:ffff:ffff:ffff:ffff
2202c8a:db::/322c8a:db:ffff:ffff:ffff:ffff:ffff:ffff
2212c8a:dc::/322c8a:dc:ffff:ffff:ffff:ffff:ffff:ffff
2222c8a:dd::/322c8a:dd:ffff:ffff:ffff:ffff:ffff:ffff
2232c8a:de::/322c8a:de:ffff:ffff:ffff:ffff:ffff:ffff
2242c8a:df::/322c8a:df:ffff:ffff:ffff:ffff:ffff:ffff
2252c8a:e0::/322c8a:e0:ffff:ffff:ffff:ffff:ffff:ffff
2262c8a:e1::/322c8a:e1:ffff:ffff:ffff:ffff:ffff:ffff
2272c8a:e2::/322c8a:e2:ffff:ffff:ffff:ffff:ffff:ffff
2282c8a:e3::/322c8a:e3:ffff:ffff:ffff:ffff:ffff:ffff
2292c8a:e4::/322c8a:e4:ffff:ffff:ffff:ffff:ffff:ffff
2302c8a:e5::/322c8a:e5:ffff:ffff:ffff:ffff:ffff:ffff
2312c8a:e6::/322c8a:e6:ffff:ffff:ffff:ffff:ffff:ffff
2322c8a:e7::/322c8a:e7:ffff:ffff:ffff:ffff:ffff:ffff
2332c8a:e8::/322c8a:e8:ffff:ffff:ffff:ffff:ffff:ffff
2342c8a:e9::/322c8a:e9:ffff:ffff:ffff:ffff:ffff:ffff
2352c8a:ea::/322c8a:ea:ffff:ffff:ffff:ffff:ffff:ffff
2362c8a:eb::/322c8a:eb:ffff:ffff:ffff:ffff:ffff:ffff
2372c8a:ec::/322c8a:ec:ffff:ffff:ffff:ffff:ffff:ffff
2382c8a:ed::/322c8a:ed:ffff:ffff:ffff:ffff:ffff:ffff
2392c8a:ee::/322c8a:ee:ffff:ffff:ffff:ffff:ffff:ffff
2402c8a:ef::/322c8a:ef:ffff:ffff:ffff:ffff:ffff:ffff
2412c8a:f0::/322c8a:f0:ffff:ffff:ffff:ffff:ffff:ffff
2422c8a:f1::/322c8a:f1:ffff:ffff:ffff:ffff:ffff:ffff
2432c8a:f2::/322c8a:f2:ffff:ffff:ffff:ffff:ffff:ffff
2442c8a:f3::/322c8a:f3:ffff:ffff:ffff:ffff:ffff:ffff
2452c8a:f4::/322c8a:f4:ffff:ffff:ffff:ffff:ffff:ffff
2462c8a:f5::/322c8a:f5:ffff:ffff:ffff:ffff:ffff:ffff
2472c8a:f6::/322c8a:f6:ffff:ffff:ffff:ffff:ffff:ffff
2482c8a:f7::/322c8a:f7:ffff:ffff:ffff:ffff:ffff:ffff
2492c8a:f8::/322c8a:f8:ffff:ffff:ffff:ffff:ffff:ffff
2502c8a:f9::/322c8a:f9:ffff:ffff:ffff:ffff:ffff:ffff
2512c8a:fa::/322c8a:fa:ffff:ffff:ffff:ffff:ffff:ffff
2522c8a:fb::/322c8a:fb:ffff:ffff:ffff:ffff:ffff:ffff
2532c8a:fc::/322c8a:fc:ffff:ffff:ffff:ffff:ffff:ffff
2542c8a:fd::/322c8a:fd:ffff:ffff:ffff:ffff:ffff:ffff
2552c8a:fe::/322c8a:fe:ffff:ffff:ffff:ffff:ffff:ffff
2562c8a:ff::/322c8a:ff:ffff:ffff:ffff:ffff:ffff:ffff

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.