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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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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
3c4e::/16
First address
3c4e::
Last address
3c4e: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
3c4e:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
e.4.c.3.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

3c4e::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
13c4e::/243c4e:ff:ffff:ffff:ffff:ffff:ffff:ffff
23c4e:100::/243c4e:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33c4e:200::/243c4e:2ff:ffff:ffff:ffff:ffff:ffff:ffff
43c4e:300::/243c4e:3ff:ffff:ffff:ffff:ffff:ffff:ffff
53c4e:400::/243c4e:4ff:ffff:ffff:ffff:ffff:ffff:ffff
63c4e:500::/243c4e:5ff:ffff:ffff:ffff:ffff:ffff:ffff
73c4e:600::/243c4e:6ff:ffff:ffff:ffff:ffff:ffff:ffff
83c4e:700::/243c4e:7ff:ffff:ffff:ffff:ffff:ffff:ffff
93c4e:800::/243c4e:8ff:ffff:ffff:ffff:ffff:ffff:ffff
103c4e:900::/243c4e:9ff:ffff:ffff:ffff:ffff:ffff:ffff
113c4e:a00::/243c4e:aff:ffff:ffff:ffff:ffff:ffff:ffff
123c4e:b00::/243c4e:bff:ffff:ffff:ffff:ffff:ffff:ffff
133c4e:c00::/243c4e:cff:ffff:ffff:ffff:ffff:ffff:ffff
143c4e:d00::/243c4e:dff:ffff:ffff:ffff:ffff:ffff:ffff
153c4e:e00::/243c4e:eff:ffff:ffff:ffff:ffff:ffff:ffff
163c4e:f00::/243c4e:fff:ffff:ffff:ffff:ffff:ffff:ffff
173c4e:1000::/243c4e:10ff:ffff:ffff:ffff:ffff:ffff:ffff
183c4e:1100::/243c4e:11ff:ffff:ffff:ffff:ffff:ffff:ffff
193c4e:1200::/243c4e:12ff:ffff:ffff:ffff:ffff:ffff:ffff
203c4e:1300::/243c4e:13ff:ffff:ffff:ffff:ffff:ffff:ffff
213c4e:1400::/243c4e:14ff:ffff:ffff:ffff:ffff:ffff:ffff
223c4e:1500::/243c4e:15ff:ffff:ffff:ffff:ffff:ffff:ffff
233c4e:1600::/243c4e:16ff:ffff:ffff:ffff:ffff:ffff:ffff
243c4e:1700::/243c4e:17ff:ffff:ffff:ffff:ffff:ffff:ffff
253c4e:1800::/243c4e:18ff:ffff:ffff:ffff:ffff:ffff:ffff
263c4e:1900::/243c4e:19ff:ffff:ffff:ffff:ffff:ffff:ffff
273c4e:1a00::/243c4e:1aff:ffff:ffff:ffff:ffff:ffff:ffff
283c4e:1b00::/243c4e:1bff:ffff:ffff:ffff:ffff:ffff:ffff
293c4e:1c00::/243c4e:1cff:ffff:ffff:ffff:ffff:ffff:ffff
303c4e:1d00::/243c4e:1dff:ffff:ffff:ffff:ffff:ffff:ffff
313c4e:1e00::/243c4e:1eff:ffff:ffff:ffff:ffff:ffff:ffff
323c4e:1f00::/243c4e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
333c4e:2000::/243c4e:20ff:ffff:ffff:ffff:ffff:ffff:ffff
343c4e:2100::/243c4e:21ff:ffff:ffff:ffff:ffff:ffff:ffff
353c4e:2200::/243c4e:22ff:ffff:ffff:ffff:ffff:ffff:ffff
363c4e:2300::/243c4e:23ff:ffff:ffff:ffff:ffff:ffff:ffff
373c4e:2400::/243c4e:24ff:ffff:ffff:ffff:ffff:ffff:ffff
383c4e:2500::/243c4e:25ff:ffff:ffff:ffff:ffff:ffff:ffff
393c4e:2600::/243c4e:26ff:ffff:ffff:ffff:ffff:ffff:ffff
403c4e:2700::/243c4e:27ff:ffff:ffff:ffff:ffff:ffff:ffff
413c4e:2800::/243c4e:28ff:ffff:ffff:ffff:ffff:ffff:ffff
423c4e:2900::/243c4e:29ff:ffff:ffff:ffff:ffff:ffff:ffff
433c4e:2a00::/243c4e:2aff:ffff:ffff:ffff:ffff:ffff:ffff
443c4e:2b00::/243c4e:2bff:ffff:ffff:ffff:ffff:ffff:ffff
453c4e:2c00::/243c4e:2cff:ffff:ffff:ffff:ffff:ffff:ffff
463c4e:2d00::/243c4e:2dff:ffff:ffff:ffff:ffff:ffff:ffff
473c4e:2e00::/243c4e:2eff:ffff:ffff:ffff:ffff:ffff:ffff
483c4e:2f00::/243c4e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
493c4e:3000::/243c4e:30ff:ffff:ffff:ffff:ffff:ffff:ffff
503c4e:3100::/243c4e:31ff:ffff:ffff:ffff:ffff:ffff:ffff
513c4e:3200::/243c4e:32ff:ffff:ffff:ffff:ffff:ffff:ffff
523c4e:3300::/243c4e:33ff:ffff:ffff:ffff:ffff:ffff:ffff
533c4e:3400::/243c4e:34ff:ffff:ffff:ffff:ffff:ffff:ffff
543c4e:3500::/243c4e:35ff:ffff:ffff:ffff:ffff:ffff:ffff
553c4e:3600::/243c4e:36ff:ffff:ffff:ffff:ffff:ffff:ffff
563c4e:3700::/243c4e:37ff:ffff:ffff:ffff:ffff:ffff:ffff
573c4e:3800::/243c4e:38ff:ffff:ffff:ffff:ffff:ffff:ffff
583c4e:3900::/243c4e:39ff:ffff:ffff:ffff:ffff:ffff:ffff
593c4e:3a00::/243c4e:3aff:ffff:ffff:ffff:ffff:ffff:ffff
603c4e:3b00::/243c4e:3bff:ffff:ffff:ffff:ffff:ffff:ffff
613c4e:3c00::/243c4e:3cff:ffff:ffff:ffff:ffff:ffff:ffff
623c4e:3d00::/243c4e:3dff:ffff:ffff:ffff:ffff:ffff:ffff
633c4e:3e00::/243c4e:3eff:ffff:ffff:ffff:ffff:ffff:ffff
643c4e:3f00::/243c4e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
653c4e:4000::/243c4e:40ff:ffff:ffff:ffff:ffff:ffff:ffff
663c4e:4100::/243c4e:41ff:ffff:ffff:ffff:ffff:ffff:ffff
673c4e:4200::/243c4e:42ff:ffff:ffff:ffff:ffff:ffff:ffff
683c4e:4300::/243c4e:43ff:ffff:ffff:ffff:ffff:ffff:ffff
693c4e:4400::/243c4e:44ff:ffff:ffff:ffff:ffff:ffff:ffff
703c4e:4500::/243c4e:45ff:ffff:ffff:ffff:ffff:ffff:ffff
713c4e:4600::/243c4e:46ff:ffff:ffff:ffff:ffff:ffff:ffff
723c4e:4700::/243c4e:47ff:ffff:ffff:ffff:ffff:ffff:ffff
733c4e:4800::/243c4e:48ff:ffff:ffff:ffff:ffff:ffff:ffff
743c4e:4900::/243c4e:49ff:ffff:ffff:ffff:ffff:ffff:ffff
753c4e:4a00::/243c4e:4aff:ffff:ffff:ffff:ffff:ffff:ffff
763c4e:4b00::/243c4e:4bff:ffff:ffff:ffff:ffff:ffff:ffff
773c4e:4c00::/243c4e:4cff:ffff:ffff:ffff:ffff:ffff:ffff
783c4e:4d00::/243c4e:4dff:ffff:ffff:ffff:ffff:ffff:ffff
793c4e:4e00::/243c4e:4eff:ffff:ffff:ffff:ffff:ffff:ffff
803c4e:4f00::/243c4e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
813c4e:5000::/243c4e:50ff:ffff:ffff:ffff:ffff:ffff:ffff
823c4e:5100::/243c4e:51ff:ffff:ffff:ffff:ffff:ffff:ffff
833c4e:5200::/243c4e:52ff:ffff:ffff:ffff:ffff:ffff:ffff
843c4e:5300::/243c4e:53ff:ffff:ffff:ffff:ffff:ffff:ffff
853c4e:5400::/243c4e:54ff:ffff:ffff:ffff:ffff:ffff:ffff
863c4e:5500::/243c4e:55ff:ffff:ffff:ffff:ffff:ffff:ffff
873c4e:5600::/243c4e:56ff:ffff:ffff:ffff:ffff:ffff:ffff
883c4e:5700::/243c4e:57ff:ffff:ffff:ffff:ffff:ffff:ffff
893c4e:5800::/243c4e:58ff:ffff:ffff:ffff:ffff:ffff:ffff
903c4e:5900::/243c4e:59ff:ffff:ffff:ffff:ffff:ffff:ffff
913c4e:5a00::/243c4e:5aff:ffff:ffff:ffff:ffff:ffff:ffff
923c4e:5b00::/243c4e:5bff:ffff:ffff:ffff:ffff:ffff:ffff
933c4e:5c00::/243c4e:5cff:ffff:ffff:ffff:ffff:ffff:ffff
943c4e:5d00::/243c4e:5dff:ffff:ffff:ffff:ffff:ffff:ffff
953c4e:5e00::/243c4e:5eff:ffff:ffff:ffff:ffff:ffff:ffff
963c4e:5f00::/243c4e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
973c4e:6000::/243c4e:60ff:ffff:ffff:ffff:ffff:ffff:ffff
983c4e:6100::/243c4e:61ff:ffff:ffff:ffff:ffff:ffff:ffff
993c4e:6200::/243c4e:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1003c4e:6300::/243c4e:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1013c4e:6400::/243c4e:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1023c4e:6500::/243c4e:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1033c4e:6600::/243c4e:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1043c4e:6700::/243c4e:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1053c4e:6800::/243c4e:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1063c4e:6900::/243c4e:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1073c4e:6a00::/243c4e:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1083c4e:6b00::/243c4e:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1093c4e:6c00::/243c4e:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1103c4e:6d00::/243c4e:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1113c4e:6e00::/243c4e:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1123c4e:6f00::/243c4e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1133c4e:7000::/243c4e:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1143c4e:7100::/243c4e:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1153c4e:7200::/243c4e:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1163c4e:7300::/243c4e:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1173c4e:7400::/243c4e:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1183c4e:7500::/243c4e:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1193c4e:7600::/243c4e:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1203c4e:7700::/243c4e:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1213c4e:7800::/243c4e:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1223c4e:7900::/243c4e:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1233c4e:7a00::/243c4e:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1243c4e:7b00::/243c4e:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1253c4e:7c00::/243c4e:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1263c4e:7d00::/243c4e:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1273c4e:7e00::/243c4e:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1283c4e:7f00::/243c4e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1293c4e:8000::/243c4e:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1303c4e:8100::/243c4e:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1313c4e:8200::/243c4e:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1323c4e:8300::/243c4e:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1333c4e:8400::/243c4e:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1343c4e:8500::/243c4e:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1353c4e:8600::/243c4e:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1363c4e:8700::/243c4e:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1373c4e:8800::/243c4e:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1383c4e:8900::/243c4e:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1393c4e:8a00::/243c4e:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1403c4e:8b00::/243c4e:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1413c4e:8c00::/243c4e:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1423c4e:8d00::/243c4e:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1433c4e:8e00::/243c4e:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1443c4e:8f00::/243c4e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1453c4e:9000::/243c4e:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1463c4e:9100::/243c4e:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1473c4e:9200::/243c4e:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1483c4e:9300::/243c4e:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1493c4e:9400::/243c4e:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1503c4e:9500::/243c4e:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1513c4e:9600::/243c4e:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1523c4e:9700::/243c4e:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1533c4e:9800::/243c4e:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1543c4e:9900::/243c4e:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1553c4e:9a00::/243c4e:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1563c4e:9b00::/243c4e:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1573c4e:9c00::/243c4e:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1583c4e:9d00::/243c4e:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1593c4e:9e00::/243c4e:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1603c4e:9f00::/243c4e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1613c4e:a000::/243c4e:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1623c4e:a100::/243c4e:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1633c4e:a200::/243c4e:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1643c4e:a300::/243c4e:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1653c4e:a400::/243c4e:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1663c4e:a500::/243c4e:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1673c4e:a600::/243c4e:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1683c4e:a700::/243c4e:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1693c4e:a800::/243c4e:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1703c4e:a900::/243c4e:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1713c4e:aa00::/243c4e:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1723c4e:ab00::/243c4e:abff:ffff:ffff:ffff:ffff:ffff:ffff
1733c4e:ac00::/243c4e:acff:ffff:ffff:ffff:ffff:ffff:ffff
1743c4e:ad00::/243c4e:adff:ffff:ffff:ffff:ffff:ffff:ffff
1753c4e:ae00::/243c4e:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1763c4e:af00::/243c4e:afff:ffff:ffff:ffff:ffff:ffff:ffff
1773c4e:b000::/243c4e:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1783c4e:b100::/243c4e:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1793c4e:b200::/243c4e:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1803c4e:b300::/243c4e:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1813c4e:b400::/243c4e:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1823c4e:b500::/243c4e:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1833c4e:b600::/243c4e:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1843c4e:b700::/243c4e:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1853c4e:b800::/243c4e:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1863c4e:b900::/243c4e:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1873c4e:ba00::/243c4e:baff:ffff:ffff:ffff:ffff:ffff:ffff
1883c4e:bb00::/243c4e:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1893c4e:bc00::/243c4e:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1903c4e:bd00::/243c4e:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1913c4e:be00::/243c4e:beff:ffff:ffff:ffff:ffff:ffff:ffff
1923c4e:bf00::/243c4e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1933c4e:c000::/243c4e:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1943c4e:c100::/243c4e:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1953c4e:c200::/243c4e:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1963c4e:c300::/243c4e:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1973c4e:c400::/243c4e:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1983c4e:c500::/243c4e:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1993c4e:c600::/243c4e:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2003c4e:c700::/243c4e:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2013c4e:c800::/243c4e:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2023c4e:c900::/243c4e:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2033c4e:ca00::/243c4e:caff:ffff:ffff:ffff:ffff:ffff:ffff
2043c4e:cb00::/243c4e:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2053c4e:cc00::/243c4e:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2063c4e:cd00::/243c4e:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2073c4e:ce00::/243c4e:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2083c4e:cf00::/243c4e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2093c4e:d000::/243c4e:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2103c4e:d100::/243c4e:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2113c4e:d200::/243c4e:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2123c4e:d300::/243c4e:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2133c4e:d400::/243c4e:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2143c4e:d500::/243c4e:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2153c4e:d600::/243c4e:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2163c4e:d700::/243c4e:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2173c4e:d800::/243c4e:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2183c4e:d900::/243c4e:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2193c4e:da00::/243c4e:daff:ffff:ffff:ffff:ffff:ffff:ffff
2203c4e:db00::/243c4e:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2213c4e:dc00::/243c4e:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2223c4e:dd00::/243c4e:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2233c4e:de00::/243c4e:deff:ffff:ffff:ffff:ffff:ffff:ffff
2243c4e:df00::/243c4e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2253c4e:e000::/243c4e:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2263c4e:e100::/243c4e:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2273c4e:e200::/243c4e:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2283c4e:e300::/243c4e:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2293c4e:e400::/243c4e:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2303c4e:e500::/243c4e:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2313c4e:e600::/243c4e:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2323c4e:e700::/243c4e:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2333c4e:e800::/243c4e:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2343c4e:e900::/243c4e:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2353c4e:ea00::/243c4e:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2363c4e:eb00::/243c4e:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2373c4e:ec00::/243c4e:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2383c4e:ed00::/243c4e:edff:ffff:ffff:ffff:ffff:ffff:ffff
2393c4e:ee00::/243c4e:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2403c4e:ef00::/243c4e:efff:ffff:ffff:ffff:ffff:ffff:ffff
2413c4e:f000::/243c4e:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2423c4e:f100::/243c4e:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2433c4e:f200::/243c4e:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2443c4e:f300::/243c4e:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2453c4e:f400::/243c4e:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2463c4e:f500::/243c4e:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2473c4e:f600::/243c4e:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2483c4e:f700::/243c4e:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2493c4e:f800::/243c4e:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2503c4e:f900::/243c4e:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2513c4e:fa00::/243c4e:faff:ffff:ffff:ffff:ffff:ffff:ffff
2523c4e:fb00::/243c4e:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2533c4e:fc00::/243c4e:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2543c4e:fd00::/243c4e:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2553c4e:fe00::/243c4e:feff:ffff:ffff:ffff:ffff:ffff:ffff
2563c4e:ff00::/243c4e: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.