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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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Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

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Surftec

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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
2c2f::/16
First address
2c2f::
Last address
2c2f: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
2c2f:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
f.2.c.2.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2c2f::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
12c2f::/242c2f:ff:ffff:ffff:ffff:ffff:ffff:ffff
22c2f:100::/242c2f:1ff:ffff:ffff:ffff:ffff:ffff:ffff
32c2f:200::/242c2f:2ff:ffff:ffff:ffff:ffff:ffff:ffff
42c2f:300::/242c2f:3ff:ffff:ffff:ffff:ffff:ffff:ffff
52c2f:400::/242c2f:4ff:ffff:ffff:ffff:ffff:ffff:ffff
62c2f:500::/242c2f:5ff:ffff:ffff:ffff:ffff:ffff:ffff
72c2f:600::/242c2f:6ff:ffff:ffff:ffff:ffff:ffff:ffff
82c2f:700::/242c2f:7ff:ffff:ffff:ffff:ffff:ffff:ffff
92c2f:800::/242c2f:8ff:ffff:ffff:ffff:ffff:ffff:ffff
102c2f:900::/242c2f:9ff:ffff:ffff:ffff:ffff:ffff:ffff
112c2f:a00::/242c2f:aff:ffff:ffff:ffff:ffff:ffff:ffff
122c2f:b00::/242c2f:bff:ffff:ffff:ffff:ffff:ffff:ffff
132c2f:c00::/242c2f:cff:ffff:ffff:ffff:ffff:ffff:ffff
142c2f:d00::/242c2f:dff:ffff:ffff:ffff:ffff:ffff:ffff
152c2f:e00::/242c2f:eff:ffff:ffff:ffff:ffff:ffff:ffff
162c2f:f00::/242c2f:fff:ffff:ffff:ffff:ffff:ffff:ffff
172c2f:1000::/242c2f:10ff:ffff:ffff:ffff:ffff:ffff:ffff
182c2f:1100::/242c2f:11ff:ffff:ffff:ffff:ffff:ffff:ffff
192c2f:1200::/242c2f:12ff:ffff:ffff:ffff:ffff:ffff:ffff
202c2f:1300::/242c2f:13ff:ffff:ffff:ffff:ffff:ffff:ffff
212c2f:1400::/242c2f:14ff:ffff:ffff:ffff:ffff:ffff:ffff
222c2f:1500::/242c2f:15ff:ffff:ffff:ffff:ffff:ffff:ffff
232c2f:1600::/242c2f:16ff:ffff:ffff:ffff:ffff:ffff:ffff
242c2f:1700::/242c2f:17ff:ffff:ffff:ffff:ffff:ffff:ffff
252c2f:1800::/242c2f:18ff:ffff:ffff:ffff:ffff:ffff:ffff
262c2f:1900::/242c2f:19ff:ffff:ffff:ffff:ffff:ffff:ffff
272c2f:1a00::/242c2f:1aff:ffff:ffff:ffff:ffff:ffff:ffff
282c2f:1b00::/242c2f:1bff:ffff:ffff:ffff:ffff:ffff:ffff
292c2f:1c00::/242c2f:1cff:ffff:ffff:ffff:ffff:ffff:ffff
302c2f:1d00::/242c2f:1dff:ffff:ffff:ffff:ffff:ffff:ffff
312c2f:1e00::/242c2f:1eff:ffff:ffff:ffff:ffff:ffff:ffff
322c2f:1f00::/242c2f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
332c2f:2000::/242c2f:20ff:ffff:ffff:ffff:ffff:ffff:ffff
342c2f:2100::/242c2f:21ff:ffff:ffff:ffff:ffff:ffff:ffff
352c2f:2200::/242c2f:22ff:ffff:ffff:ffff:ffff:ffff:ffff
362c2f:2300::/242c2f:23ff:ffff:ffff:ffff:ffff:ffff:ffff
372c2f:2400::/242c2f:24ff:ffff:ffff:ffff:ffff:ffff:ffff
382c2f:2500::/242c2f:25ff:ffff:ffff:ffff:ffff:ffff:ffff
392c2f:2600::/242c2f:26ff:ffff:ffff:ffff:ffff:ffff:ffff
402c2f:2700::/242c2f:27ff:ffff:ffff:ffff:ffff:ffff:ffff
412c2f:2800::/242c2f:28ff:ffff:ffff:ffff:ffff:ffff:ffff
422c2f:2900::/242c2f:29ff:ffff:ffff:ffff:ffff:ffff:ffff
432c2f:2a00::/242c2f:2aff:ffff:ffff:ffff:ffff:ffff:ffff
442c2f:2b00::/242c2f:2bff:ffff:ffff:ffff:ffff:ffff:ffff
452c2f:2c00::/242c2f:2cff:ffff:ffff:ffff:ffff:ffff:ffff
462c2f:2d00::/242c2f:2dff:ffff:ffff:ffff:ffff:ffff:ffff
472c2f:2e00::/242c2f:2eff:ffff:ffff:ffff:ffff:ffff:ffff
482c2f:2f00::/242c2f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
492c2f:3000::/242c2f:30ff:ffff:ffff:ffff:ffff:ffff:ffff
502c2f:3100::/242c2f:31ff:ffff:ffff:ffff:ffff:ffff:ffff
512c2f:3200::/242c2f:32ff:ffff:ffff:ffff:ffff:ffff:ffff
522c2f:3300::/242c2f:33ff:ffff:ffff:ffff:ffff:ffff:ffff
532c2f:3400::/242c2f:34ff:ffff:ffff:ffff:ffff:ffff:ffff
542c2f:3500::/242c2f:35ff:ffff:ffff:ffff:ffff:ffff:ffff
552c2f:3600::/242c2f:36ff:ffff:ffff:ffff:ffff:ffff:ffff
562c2f:3700::/242c2f:37ff:ffff:ffff:ffff:ffff:ffff:ffff
572c2f:3800::/242c2f:38ff:ffff:ffff:ffff:ffff:ffff:ffff
582c2f:3900::/242c2f:39ff:ffff:ffff:ffff:ffff:ffff:ffff
592c2f:3a00::/242c2f:3aff:ffff:ffff:ffff:ffff:ffff:ffff
602c2f:3b00::/242c2f:3bff:ffff:ffff:ffff:ffff:ffff:ffff
612c2f:3c00::/242c2f:3cff:ffff:ffff:ffff:ffff:ffff:ffff
622c2f:3d00::/242c2f:3dff:ffff:ffff:ffff:ffff:ffff:ffff
632c2f:3e00::/242c2f:3eff:ffff:ffff:ffff:ffff:ffff:ffff
642c2f:3f00::/242c2f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
652c2f:4000::/242c2f:40ff:ffff:ffff:ffff:ffff:ffff:ffff
662c2f:4100::/242c2f:41ff:ffff:ffff:ffff:ffff:ffff:ffff
672c2f:4200::/242c2f:42ff:ffff:ffff:ffff:ffff:ffff:ffff
682c2f:4300::/242c2f:43ff:ffff:ffff:ffff:ffff:ffff:ffff
692c2f:4400::/242c2f:44ff:ffff:ffff:ffff:ffff:ffff:ffff
702c2f:4500::/242c2f:45ff:ffff:ffff:ffff:ffff:ffff:ffff
712c2f:4600::/242c2f:46ff:ffff:ffff:ffff:ffff:ffff:ffff
722c2f:4700::/242c2f:47ff:ffff:ffff:ffff:ffff:ffff:ffff
732c2f:4800::/242c2f:48ff:ffff:ffff:ffff:ffff:ffff:ffff
742c2f:4900::/242c2f:49ff:ffff:ffff:ffff:ffff:ffff:ffff
752c2f:4a00::/242c2f:4aff:ffff:ffff:ffff:ffff:ffff:ffff
762c2f:4b00::/242c2f:4bff:ffff:ffff:ffff:ffff:ffff:ffff
772c2f:4c00::/242c2f:4cff:ffff:ffff:ffff:ffff:ffff:ffff
782c2f:4d00::/242c2f:4dff:ffff:ffff:ffff:ffff:ffff:ffff
792c2f:4e00::/242c2f:4eff:ffff:ffff:ffff:ffff:ffff:ffff
802c2f:4f00::/242c2f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
812c2f:5000::/242c2f:50ff:ffff:ffff:ffff:ffff:ffff:ffff
822c2f:5100::/242c2f:51ff:ffff:ffff:ffff:ffff:ffff:ffff
832c2f:5200::/242c2f:52ff:ffff:ffff:ffff:ffff:ffff:ffff
842c2f:5300::/242c2f:53ff:ffff:ffff:ffff:ffff:ffff:ffff
852c2f:5400::/242c2f:54ff:ffff:ffff:ffff:ffff:ffff:ffff
862c2f:5500::/242c2f:55ff:ffff:ffff:ffff:ffff:ffff:ffff
872c2f:5600::/242c2f:56ff:ffff:ffff:ffff:ffff:ffff:ffff
882c2f:5700::/242c2f:57ff:ffff:ffff:ffff:ffff:ffff:ffff
892c2f:5800::/242c2f:58ff:ffff:ffff:ffff:ffff:ffff:ffff
902c2f:5900::/242c2f:59ff:ffff:ffff:ffff:ffff:ffff:ffff
912c2f:5a00::/242c2f:5aff:ffff:ffff:ffff:ffff:ffff:ffff
922c2f:5b00::/242c2f:5bff:ffff:ffff:ffff:ffff:ffff:ffff
932c2f:5c00::/242c2f:5cff:ffff:ffff:ffff:ffff:ffff:ffff
942c2f:5d00::/242c2f:5dff:ffff:ffff:ffff:ffff:ffff:ffff
952c2f:5e00::/242c2f:5eff:ffff:ffff:ffff:ffff:ffff:ffff
962c2f:5f00::/242c2f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
972c2f:6000::/242c2f:60ff:ffff:ffff:ffff:ffff:ffff:ffff
982c2f:6100::/242c2f:61ff:ffff:ffff:ffff:ffff:ffff:ffff
992c2f:6200::/242c2f:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1002c2f:6300::/242c2f:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1012c2f:6400::/242c2f:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1022c2f:6500::/242c2f:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1032c2f:6600::/242c2f:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1042c2f:6700::/242c2f:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1052c2f:6800::/242c2f:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1062c2f:6900::/242c2f:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1072c2f:6a00::/242c2f:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1082c2f:6b00::/242c2f:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1092c2f:6c00::/242c2f:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1102c2f:6d00::/242c2f:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1112c2f:6e00::/242c2f:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1122c2f:6f00::/242c2f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1132c2f:7000::/242c2f:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1142c2f:7100::/242c2f:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1152c2f:7200::/242c2f:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1162c2f:7300::/242c2f:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1172c2f:7400::/242c2f:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1182c2f:7500::/242c2f:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1192c2f:7600::/242c2f:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1202c2f:7700::/242c2f:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1212c2f:7800::/242c2f:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1222c2f:7900::/242c2f:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1232c2f:7a00::/242c2f:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1242c2f:7b00::/242c2f:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1252c2f:7c00::/242c2f:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1262c2f:7d00::/242c2f:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1272c2f:7e00::/242c2f:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1282c2f:7f00::/242c2f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1292c2f:8000::/242c2f:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1302c2f:8100::/242c2f:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1312c2f:8200::/242c2f:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1322c2f:8300::/242c2f:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1332c2f:8400::/242c2f:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1342c2f:8500::/242c2f:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1352c2f:8600::/242c2f:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1362c2f:8700::/242c2f:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1372c2f:8800::/242c2f:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1382c2f:8900::/242c2f:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1392c2f:8a00::/242c2f:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1402c2f:8b00::/242c2f:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1412c2f:8c00::/242c2f:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1422c2f:8d00::/242c2f:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1432c2f:8e00::/242c2f:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1442c2f:8f00::/242c2f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1452c2f:9000::/242c2f:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1462c2f:9100::/242c2f:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1472c2f:9200::/242c2f:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1482c2f:9300::/242c2f:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1492c2f:9400::/242c2f:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1502c2f:9500::/242c2f:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1512c2f:9600::/242c2f:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1522c2f:9700::/242c2f:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1532c2f:9800::/242c2f:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1542c2f:9900::/242c2f:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1552c2f:9a00::/242c2f:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1562c2f:9b00::/242c2f:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1572c2f:9c00::/242c2f:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1582c2f:9d00::/242c2f:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1592c2f:9e00::/242c2f:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1602c2f:9f00::/242c2f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1612c2f:a000::/242c2f:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1622c2f:a100::/242c2f:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1632c2f:a200::/242c2f:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1642c2f:a300::/242c2f:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1652c2f:a400::/242c2f:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1662c2f:a500::/242c2f:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1672c2f:a600::/242c2f:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1682c2f:a700::/242c2f:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1692c2f:a800::/242c2f:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1702c2f:a900::/242c2f:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1712c2f:aa00::/242c2f:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1722c2f:ab00::/242c2f:abff:ffff:ffff:ffff:ffff:ffff:ffff
1732c2f:ac00::/242c2f:acff:ffff:ffff:ffff:ffff:ffff:ffff
1742c2f:ad00::/242c2f:adff:ffff:ffff:ffff:ffff:ffff:ffff
1752c2f:ae00::/242c2f:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1762c2f:af00::/242c2f:afff:ffff:ffff:ffff:ffff:ffff:ffff
1772c2f:b000::/242c2f:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1782c2f:b100::/242c2f:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1792c2f:b200::/242c2f:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1802c2f:b300::/242c2f:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1812c2f:b400::/242c2f:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1822c2f:b500::/242c2f:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1832c2f:b600::/242c2f:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1842c2f:b700::/242c2f:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1852c2f:b800::/242c2f:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1862c2f:b900::/242c2f:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1872c2f:ba00::/242c2f:baff:ffff:ffff:ffff:ffff:ffff:ffff
1882c2f:bb00::/242c2f:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1892c2f:bc00::/242c2f:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1902c2f:bd00::/242c2f:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1912c2f:be00::/242c2f:beff:ffff:ffff:ffff:ffff:ffff:ffff
1922c2f:bf00::/242c2f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1932c2f:c000::/242c2f:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1942c2f:c100::/242c2f:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1952c2f:c200::/242c2f:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1962c2f:c300::/242c2f:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1972c2f:c400::/242c2f:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1982c2f:c500::/242c2f:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1992c2f:c600::/242c2f:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2002c2f:c700::/242c2f:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2012c2f:c800::/242c2f:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2022c2f:c900::/242c2f:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2032c2f:ca00::/242c2f:caff:ffff:ffff:ffff:ffff:ffff:ffff
2042c2f:cb00::/242c2f:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2052c2f:cc00::/242c2f:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2062c2f:cd00::/242c2f:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2072c2f:ce00::/242c2f:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2082c2f:cf00::/242c2f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2092c2f:d000::/242c2f:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2102c2f:d100::/242c2f:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2112c2f:d200::/242c2f:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2122c2f:d300::/242c2f:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2132c2f:d400::/242c2f:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2142c2f:d500::/242c2f:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2152c2f:d600::/242c2f:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2162c2f:d700::/242c2f:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2172c2f:d800::/242c2f:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2182c2f:d900::/242c2f:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2192c2f:da00::/242c2f:daff:ffff:ffff:ffff:ffff:ffff:ffff
2202c2f:db00::/242c2f:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2212c2f:dc00::/242c2f:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2222c2f:dd00::/242c2f:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2232c2f:de00::/242c2f:deff:ffff:ffff:ffff:ffff:ffff:ffff
2242c2f:df00::/242c2f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2252c2f:e000::/242c2f:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2262c2f:e100::/242c2f:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2272c2f:e200::/242c2f:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2282c2f:e300::/242c2f:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2292c2f:e400::/242c2f:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2302c2f:e500::/242c2f:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2312c2f:e600::/242c2f:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2322c2f:e700::/242c2f:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2332c2f:e800::/242c2f:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2342c2f:e900::/242c2f:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2352c2f:ea00::/242c2f:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2362c2f:eb00::/242c2f:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2372c2f:ec00::/242c2f:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2382c2f:ed00::/242c2f:edff:ffff:ffff:ffff:ffff:ffff:ffff
2392c2f:ee00::/242c2f:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2402c2f:ef00::/242c2f:efff:ffff:ffff:ffff:ffff:ffff:ffff
2412c2f:f000::/242c2f:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2422c2f:f100::/242c2f:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2432c2f:f200::/242c2f:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2442c2f:f300::/242c2f:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2452c2f:f400::/242c2f:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2462c2f:f500::/242c2f:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2472c2f:f600::/242c2f:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2482c2f:f700::/242c2f:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2492c2f:f800::/242c2f:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2502c2f:f900::/242c2f:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2512c2f:fa00::/242c2f:faff:ffff:ffff:ffff:ffff:ffff:ffff
2522c2f:fb00::/242c2f:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2532c2f:fc00::/242c2f:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2542c2f:fd00::/242c2f:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2552c2f:fe00::/242c2f:feff:ffff:ffff:ffff:ffff:ffff:ffff
2562c2f:ff00::/242c2f:ffff: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.