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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
2cd3::/16
First address
2cd3::
Last address
2cd3: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
2cd3:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
3.d.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)

2cd3::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
12cd3::/242cd3:ff:ffff:ffff:ffff:ffff:ffff:ffff
22cd3:100::/242cd3:1ff:ffff:ffff:ffff:ffff:ffff:ffff
32cd3:200::/242cd3:2ff:ffff:ffff:ffff:ffff:ffff:ffff
42cd3:300::/242cd3:3ff:ffff:ffff:ffff:ffff:ffff:ffff
52cd3:400::/242cd3:4ff:ffff:ffff:ffff:ffff:ffff:ffff
62cd3:500::/242cd3:5ff:ffff:ffff:ffff:ffff:ffff:ffff
72cd3:600::/242cd3:6ff:ffff:ffff:ffff:ffff:ffff:ffff
82cd3:700::/242cd3:7ff:ffff:ffff:ffff:ffff:ffff:ffff
92cd3:800::/242cd3:8ff:ffff:ffff:ffff:ffff:ffff:ffff
102cd3:900::/242cd3:9ff:ffff:ffff:ffff:ffff:ffff:ffff
112cd3:a00::/242cd3:aff:ffff:ffff:ffff:ffff:ffff:ffff
122cd3:b00::/242cd3:bff:ffff:ffff:ffff:ffff:ffff:ffff
132cd3:c00::/242cd3:cff:ffff:ffff:ffff:ffff:ffff:ffff
142cd3:d00::/242cd3:dff:ffff:ffff:ffff:ffff:ffff:ffff
152cd3:e00::/242cd3:eff:ffff:ffff:ffff:ffff:ffff:ffff
162cd3:f00::/242cd3:fff:ffff:ffff:ffff:ffff:ffff:ffff
172cd3:1000::/242cd3:10ff:ffff:ffff:ffff:ffff:ffff:ffff
182cd3:1100::/242cd3:11ff:ffff:ffff:ffff:ffff:ffff:ffff
192cd3:1200::/242cd3:12ff:ffff:ffff:ffff:ffff:ffff:ffff
202cd3:1300::/242cd3:13ff:ffff:ffff:ffff:ffff:ffff:ffff
212cd3:1400::/242cd3:14ff:ffff:ffff:ffff:ffff:ffff:ffff
222cd3:1500::/242cd3:15ff:ffff:ffff:ffff:ffff:ffff:ffff
232cd3:1600::/242cd3:16ff:ffff:ffff:ffff:ffff:ffff:ffff
242cd3:1700::/242cd3:17ff:ffff:ffff:ffff:ffff:ffff:ffff
252cd3:1800::/242cd3:18ff:ffff:ffff:ffff:ffff:ffff:ffff
262cd3:1900::/242cd3:19ff:ffff:ffff:ffff:ffff:ffff:ffff
272cd3:1a00::/242cd3:1aff:ffff:ffff:ffff:ffff:ffff:ffff
282cd3:1b00::/242cd3:1bff:ffff:ffff:ffff:ffff:ffff:ffff
292cd3:1c00::/242cd3:1cff:ffff:ffff:ffff:ffff:ffff:ffff
302cd3:1d00::/242cd3:1dff:ffff:ffff:ffff:ffff:ffff:ffff
312cd3:1e00::/242cd3:1eff:ffff:ffff:ffff:ffff:ffff:ffff
322cd3:1f00::/242cd3:1fff:ffff:ffff:ffff:ffff:ffff:ffff
332cd3:2000::/242cd3:20ff:ffff:ffff:ffff:ffff:ffff:ffff
342cd3:2100::/242cd3:21ff:ffff:ffff:ffff:ffff:ffff:ffff
352cd3:2200::/242cd3:22ff:ffff:ffff:ffff:ffff:ffff:ffff
362cd3:2300::/242cd3:23ff:ffff:ffff:ffff:ffff:ffff:ffff
372cd3:2400::/242cd3:24ff:ffff:ffff:ffff:ffff:ffff:ffff
382cd3:2500::/242cd3:25ff:ffff:ffff:ffff:ffff:ffff:ffff
392cd3:2600::/242cd3:26ff:ffff:ffff:ffff:ffff:ffff:ffff
402cd3:2700::/242cd3:27ff:ffff:ffff:ffff:ffff:ffff:ffff
412cd3:2800::/242cd3:28ff:ffff:ffff:ffff:ffff:ffff:ffff
422cd3:2900::/242cd3:29ff:ffff:ffff:ffff:ffff:ffff:ffff
432cd3:2a00::/242cd3:2aff:ffff:ffff:ffff:ffff:ffff:ffff
442cd3:2b00::/242cd3:2bff:ffff:ffff:ffff:ffff:ffff:ffff
452cd3:2c00::/242cd3:2cff:ffff:ffff:ffff:ffff:ffff:ffff
462cd3:2d00::/242cd3:2dff:ffff:ffff:ffff:ffff:ffff:ffff
472cd3:2e00::/242cd3:2eff:ffff:ffff:ffff:ffff:ffff:ffff
482cd3:2f00::/242cd3:2fff:ffff:ffff:ffff:ffff:ffff:ffff
492cd3:3000::/242cd3:30ff:ffff:ffff:ffff:ffff:ffff:ffff
502cd3:3100::/242cd3:31ff:ffff:ffff:ffff:ffff:ffff:ffff
512cd3:3200::/242cd3:32ff:ffff:ffff:ffff:ffff:ffff:ffff
522cd3:3300::/242cd3:33ff:ffff:ffff:ffff:ffff:ffff:ffff
532cd3:3400::/242cd3:34ff:ffff:ffff:ffff:ffff:ffff:ffff
542cd3:3500::/242cd3:35ff:ffff:ffff:ffff:ffff:ffff:ffff
552cd3:3600::/242cd3:36ff:ffff:ffff:ffff:ffff:ffff:ffff
562cd3:3700::/242cd3:37ff:ffff:ffff:ffff:ffff:ffff:ffff
572cd3:3800::/242cd3:38ff:ffff:ffff:ffff:ffff:ffff:ffff
582cd3:3900::/242cd3:39ff:ffff:ffff:ffff:ffff:ffff:ffff
592cd3:3a00::/242cd3:3aff:ffff:ffff:ffff:ffff:ffff:ffff
602cd3:3b00::/242cd3:3bff:ffff:ffff:ffff:ffff:ffff:ffff
612cd3:3c00::/242cd3:3cff:ffff:ffff:ffff:ffff:ffff:ffff
622cd3:3d00::/242cd3:3dff:ffff:ffff:ffff:ffff:ffff:ffff
632cd3:3e00::/242cd3:3eff:ffff:ffff:ffff:ffff:ffff:ffff
642cd3:3f00::/242cd3:3fff:ffff:ffff:ffff:ffff:ffff:ffff
652cd3:4000::/242cd3:40ff:ffff:ffff:ffff:ffff:ffff:ffff
662cd3:4100::/242cd3:41ff:ffff:ffff:ffff:ffff:ffff:ffff
672cd3:4200::/242cd3:42ff:ffff:ffff:ffff:ffff:ffff:ffff
682cd3:4300::/242cd3:43ff:ffff:ffff:ffff:ffff:ffff:ffff
692cd3:4400::/242cd3:44ff:ffff:ffff:ffff:ffff:ffff:ffff
702cd3:4500::/242cd3:45ff:ffff:ffff:ffff:ffff:ffff:ffff
712cd3:4600::/242cd3:46ff:ffff:ffff:ffff:ffff:ffff:ffff
722cd3:4700::/242cd3:47ff:ffff:ffff:ffff:ffff:ffff:ffff
732cd3:4800::/242cd3:48ff:ffff:ffff:ffff:ffff:ffff:ffff
742cd3:4900::/242cd3:49ff:ffff:ffff:ffff:ffff:ffff:ffff
752cd3:4a00::/242cd3:4aff:ffff:ffff:ffff:ffff:ffff:ffff
762cd3:4b00::/242cd3:4bff:ffff:ffff:ffff:ffff:ffff:ffff
772cd3:4c00::/242cd3:4cff:ffff:ffff:ffff:ffff:ffff:ffff
782cd3:4d00::/242cd3:4dff:ffff:ffff:ffff:ffff:ffff:ffff
792cd3:4e00::/242cd3:4eff:ffff:ffff:ffff:ffff:ffff:ffff
802cd3:4f00::/242cd3:4fff:ffff:ffff:ffff:ffff:ffff:ffff
812cd3:5000::/242cd3:50ff:ffff:ffff:ffff:ffff:ffff:ffff
822cd3:5100::/242cd3:51ff:ffff:ffff:ffff:ffff:ffff:ffff
832cd3:5200::/242cd3:52ff:ffff:ffff:ffff:ffff:ffff:ffff
842cd3:5300::/242cd3:53ff:ffff:ffff:ffff:ffff:ffff:ffff
852cd3:5400::/242cd3:54ff:ffff:ffff:ffff:ffff:ffff:ffff
862cd3:5500::/242cd3:55ff:ffff:ffff:ffff:ffff:ffff:ffff
872cd3:5600::/242cd3:56ff:ffff:ffff:ffff:ffff:ffff:ffff
882cd3:5700::/242cd3:57ff:ffff:ffff:ffff:ffff:ffff:ffff
892cd3:5800::/242cd3:58ff:ffff:ffff:ffff:ffff:ffff:ffff
902cd3:5900::/242cd3:59ff:ffff:ffff:ffff:ffff:ffff:ffff
912cd3:5a00::/242cd3:5aff:ffff:ffff:ffff:ffff:ffff:ffff
922cd3:5b00::/242cd3:5bff:ffff:ffff:ffff:ffff:ffff:ffff
932cd3:5c00::/242cd3:5cff:ffff:ffff:ffff:ffff:ffff:ffff
942cd3:5d00::/242cd3:5dff:ffff:ffff:ffff:ffff:ffff:ffff
952cd3:5e00::/242cd3:5eff:ffff:ffff:ffff:ffff:ffff:ffff
962cd3:5f00::/242cd3:5fff:ffff:ffff:ffff:ffff:ffff:ffff
972cd3:6000::/242cd3:60ff:ffff:ffff:ffff:ffff:ffff:ffff
982cd3:6100::/242cd3:61ff:ffff:ffff:ffff:ffff:ffff:ffff
992cd3:6200::/242cd3:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1002cd3:6300::/242cd3:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1012cd3:6400::/242cd3:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1022cd3:6500::/242cd3:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1032cd3:6600::/242cd3:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1042cd3:6700::/242cd3:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1052cd3:6800::/242cd3:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1062cd3:6900::/242cd3:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1072cd3:6a00::/242cd3:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1082cd3:6b00::/242cd3:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1092cd3:6c00::/242cd3:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1102cd3:6d00::/242cd3:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1112cd3:6e00::/242cd3:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1122cd3:6f00::/242cd3:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1132cd3:7000::/242cd3:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1142cd3:7100::/242cd3:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1152cd3:7200::/242cd3:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1162cd3:7300::/242cd3:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1172cd3:7400::/242cd3:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1182cd3:7500::/242cd3:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1192cd3:7600::/242cd3:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1202cd3:7700::/242cd3:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1212cd3:7800::/242cd3:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1222cd3:7900::/242cd3:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1232cd3:7a00::/242cd3:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1242cd3:7b00::/242cd3:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1252cd3:7c00::/242cd3:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1262cd3:7d00::/242cd3:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1272cd3:7e00::/242cd3:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1282cd3:7f00::/242cd3:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1292cd3:8000::/242cd3:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1302cd3:8100::/242cd3:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1312cd3:8200::/242cd3:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1322cd3:8300::/242cd3:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1332cd3:8400::/242cd3:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1342cd3:8500::/242cd3:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1352cd3:8600::/242cd3:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1362cd3:8700::/242cd3:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1372cd3:8800::/242cd3:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1382cd3:8900::/242cd3:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1392cd3:8a00::/242cd3:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1402cd3:8b00::/242cd3:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1412cd3:8c00::/242cd3:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1422cd3:8d00::/242cd3:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1432cd3:8e00::/242cd3:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1442cd3:8f00::/242cd3:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1452cd3:9000::/242cd3:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1462cd3:9100::/242cd3:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1472cd3:9200::/242cd3:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1482cd3:9300::/242cd3:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1492cd3:9400::/242cd3:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1502cd3:9500::/242cd3:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1512cd3:9600::/242cd3:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1522cd3:9700::/242cd3:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1532cd3:9800::/242cd3:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1542cd3:9900::/242cd3:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1552cd3:9a00::/242cd3:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1562cd3:9b00::/242cd3:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1572cd3:9c00::/242cd3:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1582cd3:9d00::/242cd3:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1592cd3:9e00::/242cd3:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1602cd3:9f00::/242cd3:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1612cd3:a000::/242cd3:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1622cd3:a100::/242cd3:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1632cd3:a200::/242cd3:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1642cd3:a300::/242cd3:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1652cd3:a400::/242cd3:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1662cd3:a500::/242cd3:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1672cd3:a600::/242cd3:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1682cd3:a700::/242cd3:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1692cd3:a800::/242cd3:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1702cd3:a900::/242cd3:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1712cd3:aa00::/242cd3:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1722cd3:ab00::/242cd3:abff:ffff:ffff:ffff:ffff:ffff:ffff
1732cd3:ac00::/242cd3:acff:ffff:ffff:ffff:ffff:ffff:ffff
1742cd3:ad00::/242cd3:adff:ffff:ffff:ffff:ffff:ffff:ffff
1752cd3:ae00::/242cd3:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1762cd3:af00::/242cd3:afff:ffff:ffff:ffff:ffff:ffff:ffff
1772cd3:b000::/242cd3:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1782cd3:b100::/242cd3:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1792cd3:b200::/242cd3:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1802cd3:b300::/242cd3:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1812cd3:b400::/242cd3:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1822cd3:b500::/242cd3:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1832cd3:b600::/242cd3:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1842cd3:b700::/242cd3:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1852cd3:b800::/242cd3:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1862cd3:b900::/242cd3:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1872cd3:ba00::/242cd3:baff:ffff:ffff:ffff:ffff:ffff:ffff
1882cd3:bb00::/242cd3:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1892cd3:bc00::/242cd3:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1902cd3:bd00::/242cd3:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1912cd3:be00::/242cd3:beff:ffff:ffff:ffff:ffff:ffff:ffff
1922cd3:bf00::/242cd3:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1932cd3:c000::/242cd3:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1942cd3:c100::/242cd3:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1952cd3:c200::/242cd3:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1962cd3:c300::/242cd3:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1972cd3:c400::/242cd3:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1982cd3:c500::/242cd3:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1992cd3:c600::/242cd3:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2002cd3:c700::/242cd3:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2012cd3:c800::/242cd3:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2022cd3:c900::/242cd3:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2032cd3:ca00::/242cd3:caff:ffff:ffff:ffff:ffff:ffff:ffff
2042cd3:cb00::/242cd3:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2052cd3:cc00::/242cd3:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2062cd3:cd00::/242cd3:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2072cd3:ce00::/242cd3:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2082cd3:cf00::/242cd3:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2092cd3:d000::/242cd3:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2102cd3:d100::/242cd3:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2112cd3:d200::/242cd3:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2122cd3:d300::/242cd3:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2132cd3:d400::/242cd3:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2142cd3:d500::/242cd3:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2152cd3:d600::/242cd3:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2162cd3:d700::/242cd3:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2172cd3:d800::/242cd3:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2182cd3:d900::/242cd3:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2192cd3:da00::/242cd3:daff:ffff:ffff:ffff:ffff:ffff:ffff
2202cd3:db00::/242cd3:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2212cd3:dc00::/242cd3:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2222cd3:dd00::/242cd3:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2232cd3:de00::/242cd3:deff:ffff:ffff:ffff:ffff:ffff:ffff
2242cd3:df00::/242cd3:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2252cd3:e000::/242cd3:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2262cd3:e100::/242cd3:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2272cd3:e200::/242cd3:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2282cd3:e300::/242cd3:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2292cd3:e400::/242cd3:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2302cd3:e500::/242cd3:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2312cd3:e600::/242cd3:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2322cd3:e700::/242cd3:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2332cd3:e800::/242cd3:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2342cd3:e900::/242cd3:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2352cd3:ea00::/242cd3:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2362cd3:eb00::/242cd3:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2372cd3:ec00::/242cd3:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2382cd3:ed00::/242cd3:edff:ffff:ffff:ffff:ffff:ffff:ffff
2392cd3:ee00::/242cd3:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2402cd3:ef00::/242cd3:efff:ffff:ffff:ffff:ffff:ffff:ffff
2412cd3:f000::/242cd3:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2422cd3:f100::/242cd3:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2432cd3:f200::/242cd3:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2442cd3:f300::/242cd3:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2452cd3:f400::/242cd3:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2462cd3:f500::/242cd3:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2472cd3:f600::/242cd3:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2482cd3:f700::/242cd3:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2492cd3:f800::/242cd3:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2502cd3:f900::/242cd3:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2512cd3:fa00::/242cd3:faff:ffff:ffff:ffff:ffff:ffff:ffff
2522cd3:fb00::/242cd3:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2532cd3:fc00::/242cd3:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2542cd3:fd00::/242cd3:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2552cd3:fe00::/242cd3:feff:ffff:ffff:ffff:ffff:ffff:ffff
2562cd3:ff00::/242cd3: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.