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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
3cb2::/16
First address
3cb2::
Last address
3cb2: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
3cb2:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
2.b.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)

3cb2::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
13cb2::/243cb2:ff:ffff:ffff:ffff:ffff:ffff:ffff
23cb2:100::/243cb2:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33cb2:200::/243cb2:2ff:ffff:ffff:ffff:ffff:ffff:ffff
43cb2:300::/243cb2:3ff:ffff:ffff:ffff:ffff:ffff:ffff
53cb2:400::/243cb2:4ff:ffff:ffff:ffff:ffff:ffff:ffff
63cb2:500::/243cb2:5ff:ffff:ffff:ffff:ffff:ffff:ffff
73cb2:600::/243cb2:6ff:ffff:ffff:ffff:ffff:ffff:ffff
83cb2:700::/243cb2:7ff:ffff:ffff:ffff:ffff:ffff:ffff
93cb2:800::/243cb2:8ff:ffff:ffff:ffff:ffff:ffff:ffff
103cb2:900::/243cb2:9ff:ffff:ffff:ffff:ffff:ffff:ffff
113cb2:a00::/243cb2:aff:ffff:ffff:ffff:ffff:ffff:ffff
123cb2:b00::/243cb2:bff:ffff:ffff:ffff:ffff:ffff:ffff
133cb2:c00::/243cb2:cff:ffff:ffff:ffff:ffff:ffff:ffff
143cb2:d00::/243cb2:dff:ffff:ffff:ffff:ffff:ffff:ffff
153cb2:e00::/243cb2:eff:ffff:ffff:ffff:ffff:ffff:ffff
163cb2:f00::/243cb2:fff:ffff:ffff:ffff:ffff:ffff:ffff
173cb2:1000::/243cb2:10ff:ffff:ffff:ffff:ffff:ffff:ffff
183cb2:1100::/243cb2:11ff:ffff:ffff:ffff:ffff:ffff:ffff
193cb2:1200::/243cb2:12ff:ffff:ffff:ffff:ffff:ffff:ffff
203cb2:1300::/243cb2:13ff:ffff:ffff:ffff:ffff:ffff:ffff
213cb2:1400::/243cb2:14ff:ffff:ffff:ffff:ffff:ffff:ffff
223cb2:1500::/243cb2:15ff:ffff:ffff:ffff:ffff:ffff:ffff
233cb2:1600::/243cb2:16ff:ffff:ffff:ffff:ffff:ffff:ffff
243cb2:1700::/243cb2:17ff:ffff:ffff:ffff:ffff:ffff:ffff
253cb2:1800::/243cb2:18ff:ffff:ffff:ffff:ffff:ffff:ffff
263cb2:1900::/243cb2:19ff:ffff:ffff:ffff:ffff:ffff:ffff
273cb2:1a00::/243cb2:1aff:ffff:ffff:ffff:ffff:ffff:ffff
283cb2:1b00::/243cb2:1bff:ffff:ffff:ffff:ffff:ffff:ffff
293cb2:1c00::/243cb2:1cff:ffff:ffff:ffff:ffff:ffff:ffff
303cb2:1d00::/243cb2:1dff:ffff:ffff:ffff:ffff:ffff:ffff
313cb2:1e00::/243cb2:1eff:ffff:ffff:ffff:ffff:ffff:ffff
323cb2:1f00::/243cb2:1fff:ffff:ffff:ffff:ffff:ffff:ffff
333cb2:2000::/243cb2:20ff:ffff:ffff:ffff:ffff:ffff:ffff
343cb2:2100::/243cb2:21ff:ffff:ffff:ffff:ffff:ffff:ffff
353cb2:2200::/243cb2:22ff:ffff:ffff:ffff:ffff:ffff:ffff
363cb2:2300::/243cb2:23ff:ffff:ffff:ffff:ffff:ffff:ffff
373cb2:2400::/243cb2:24ff:ffff:ffff:ffff:ffff:ffff:ffff
383cb2:2500::/243cb2:25ff:ffff:ffff:ffff:ffff:ffff:ffff
393cb2:2600::/243cb2:26ff:ffff:ffff:ffff:ffff:ffff:ffff
403cb2:2700::/243cb2:27ff:ffff:ffff:ffff:ffff:ffff:ffff
413cb2:2800::/243cb2:28ff:ffff:ffff:ffff:ffff:ffff:ffff
423cb2:2900::/243cb2:29ff:ffff:ffff:ffff:ffff:ffff:ffff
433cb2:2a00::/243cb2:2aff:ffff:ffff:ffff:ffff:ffff:ffff
443cb2:2b00::/243cb2:2bff:ffff:ffff:ffff:ffff:ffff:ffff
453cb2:2c00::/243cb2:2cff:ffff:ffff:ffff:ffff:ffff:ffff
463cb2:2d00::/243cb2:2dff:ffff:ffff:ffff:ffff:ffff:ffff
473cb2:2e00::/243cb2:2eff:ffff:ffff:ffff:ffff:ffff:ffff
483cb2:2f00::/243cb2:2fff:ffff:ffff:ffff:ffff:ffff:ffff
493cb2:3000::/243cb2:30ff:ffff:ffff:ffff:ffff:ffff:ffff
503cb2:3100::/243cb2:31ff:ffff:ffff:ffff:ffff:ffff:ffff
513cb2:3200::/243cb2:32ff:ffff:ffff:ffff:ffff:ffff:ffff
523cb2:3300::/243cb2:33ff:ffff:ffff:ffff:ffff:ffff:ffff
533cb2:3400::/243cb2:34ff:ffff:ffff:ffff:ffff:ffff:ffff
543cb2:3500::/243cb2:35ff:ffff:ffff:ffff:ffff:ffff:ffff
553cb2:3600::/243cb2:36ff:ffff:ffff:ffff:ffff:ffff:ffff
563cb2:3700::/243cb2:37ff:ffff:ffff:ffff:ffff:ffff:ffff
573cb2:3800::/243cb2:38ff:ffff:ffff:ffff:ffff:ffff:ffff
583cb2:3900::/243cb2:39ff:ffff:ffff:ffff:ffff:ffff:ffff
593cb2:3a00::/243cb2:3aff:ffff:ffff:ffff:ffff:ffff:ffff
603cb2:3b00::/243cb2:3bff:ffff:ffff:ffff:ffff:ffff:ffff
613cb2:3c00::/243cb2:3cff:ffff:ffff:ffff:ffff:ffff:ffff
623cb2:3d00::/243cb2:3dff:ffff:ffff:ffff:ffff:ffff:ffff
633cb2:3e00::/243cb2:3eff:ffff:ffff:ffff:ffff:ffff:ffff
643cb2:3f00::/243cb2:3fff:ffff:ffff:ffff:ffff:ffff:ffff
653cb2:4000::/243cb2:40ff:ffff:ffff:ffff:ffff:ffff:ffff
663cb2:4100::/243cb2:41ff:ffff:ffff:ffff:ffff:ffff:ffff
673cb2:4200::/243cb2:42ff:ffff:ffff:ffff:ffff:ffff:ffff
683cb2:4300::/243cb2:43ff:ffff:ffff:ffff:ffff:ffff:ffff
693cb2:4400::/243cb2:44ff:ffff:ffff:ffff:ffff:ffff:ffff
703cb2:4500::/243cb2:45ff:ffff:ffff:ffff:ffff:ffff:ffff
713cb2:4600::/243cb2:46ff:ffff:ffff:ffff:ffff:ffff:ffff
723cb2:4700::/243cb2:47ff:ffff:ffff:ffff:ffff:ffff:ffff
733cb2:4800::/243cb2:48ff:ffff:ffff:ffff:ffff:ffff:ffff
743cb2:4900::/243cb2:49ff:ffff:ffff:ffff:ffff:ffff:ffff
753cb2:4a00::/243cb2:4aff:ffff:ffff:ffff:ffff:ffff:ffff
763cb2:4b00::/243cb2:4bff:ffff:ffff:ffff:ffff:ffff:ffff
773cb2:4c00::/243cb2:4cff:ffff:ffff:ffff:ffff:ffff:ffff
783cb2:4d00::/243cb2:4dff:ffff:ffff:ffff:ffff:ffff:ffff
793cb2:4e00::/243cb2:4eff:ffff:ffff:ffff:ffff:ffff:ffff
803cb2:4f00::/243cb2:4fff:ffff:ffff:ffff:ffff:ffff:ffff
813cb2:5000::/243cb2:50ff:ffff:ffff:ffff:ffff:ffff:ffff
823cb2:5100::/243cb2:51ff:ffff:ffff:ffff:ffff:ffff:ffff
833cb2:5200::/243cb2:52ff:ffff:ffff:ffff:ffff:ffff:ffff
843cb2:5300::/243cb2:53ff:ffff:ffff:ffff:ffff:ffff:ffff
853cb2:5400::/243cb2:54ff:ffff:ffff:ffff:ffff:ffff:ffff
863cb2:5500::/243cb2:55ff:ffff:ffff:ffff:ffff:ffff:ffff
873cb2:5600::/243cb2:56ff:ffff:ffff:ffff:ffff:ffff:ffff
883cb2:5700::/243cb2:57ff:ffff:ffff:ffff:ffff:ffff:ffff
893cb2:5800::/243cb2:58ff:ffff:ffff:ffff:ffff:ffff:ffff
903cb2:5900::/243cb2:59ff:ffff:ffff:ffff:ffff:ffff:ffff
913cb2:5a00::/243cb2:5aff:ffff:ffff:ffff:ffff:ffff:ffff
923cb2:5b00::/243cb2:5bff:ffff:ffff:ffff:ffff:ffff:ffff
933cb2:5c00::/243cb2:5cff:ffff:ffff:ffff:ffff:ffff:ffff
943cb2:5d00::/243cb2:5dff:ffff:ffff:ffff:ffff:ffff:ffff
953cb2:5e00::/243cb2:5eff:ffff:ffff:ffff:ffff:ffff:ffff
963cb2:5f00::/243cb2:5fff:ffff:ffff:ffff:ffff:ffff:ffff
973cb2:6000::/243cb2:60ff:ffff:ffff:ffff:ffff:ffff:ffff
983cb2:6100::/243cb2:61ff:ffff:ffff:ffff:ffff:ffff:ffff
993cb2:6200::/243cb2:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1003cb2:6300::/243cb2:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1013cb2:6400::/243cb2:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1023cb2:6500::/243cb2:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1033cb2:6600::/243cb2:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1043cb2:6700::/243cb2:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1053cb2:6800::/243cb2:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1063cb2:6900::/243cb2:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1073cb2:6a00::/243cb2:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1083cb2:6b00::/243cb2:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1093cb2:6c00::/243cb2:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1103cb2:6d00::/243cb2:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1113cb2:6e00::/243cb2:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1123cb2:6f00::/243cb2:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1133cb2:7000::/243cb2:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1143cb2:7100::/243cb2:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1153cb2:7200::/243cb2:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1163cb2:7300::/243cb2:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1173cb2:7400::/243cb2:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1183cb2:7500::/243cb2:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1193cb2:7600::/243cb2:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1203cb2:7700::/243cb2:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1213cb2:7800::/243cb2:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1223cb2:7900::/243cb2:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1233cb2:7a00::/243cb2:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1243cb2:7b00::/243cb2:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1253cb2:7c00::/243cb2:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1263cb2:7d00::/243cb2:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1273cb2:7e00::/243cb2:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1283cb2:7f00::/243cb2:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1293cb2:8000::/243cb2:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1303cb2:8100::/243cb2:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1313cb2:8200::/243cb2:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1323cb2:8300::/243cb2:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1333cb2:8400::/243cb2:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1343cb2:8500::/243cb2:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1353cb2:8600::/243cb2:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1363cb2:8700::/243cb2:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1373cb2:8800::/243cb2:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1383cb2:8900::/243cb2:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1393cb2:8a00::/243cb2:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1403cb2:8b00::/243cb2:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1413cb2:8c00::/243cb2:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1423cb2:8d00::/243cb2:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1433cb2:8e00::/243cb2:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1443cb2:8f00::/243cb2:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1453cb2:9000::/243cb2:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1463cb2:9100::/243cb2:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1473cb2:9200::/243cb2:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1483cb2:9300::/243cb2:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1493cb2:9400::/243cb2:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1503cb2:9500::/243cb2:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1513cb2:9600::/243cb2:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1523cb2:9700::/243cb2:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1533cb2:9800::/243cb2:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1543cb2:9900::/243cb2:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1553cb2:9a00::/243cb2:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1563cb2:9b00::/243cb2:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1573cb2:9c00::/243cb2:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1583cb2:9d00::/243cb2:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1593cb2:9e00::/243cb2:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1603cb2:9f00::/243cb2:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1613cb2:a000::/243cb2:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1623cb2:a100::/243cb2:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1633cb2:a200::/243cb2:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1643cb2:a300::/243cb2:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1653cb2:a400::/243cb2:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1663cb2:a500::/243cb2:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1673cb2:a600::/243cb2:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1683cb2:a700::/243cb2:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1693cb2:a800::/243cb2:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1703cb2:a900::/243cb2:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1713cb2:aa00::/243cb2:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1723cb2:ab00::/243cb2:abff:ffff:ffff:ffff:ffff:ffff:ffff
1733cb2:ac00::/243cb2:acff:ffff:ffff:ffff:ffff:ffff:ffff
1743cb2:ad00::/243cb2:adff:ffff:ffff:ffff:ffff:ffff:ffff
1753cb2:ae00::/243cb2:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1763cb2:af00::/243cb2:afff:ffff:ffff:ffff:ffff:ffff:ffff
1773cb2:b000::/243cb2:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1783cb2:b100::/243cb2:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1793cb2:b200::/243cb2:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1803cb2:b300::/243cb2:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1813cb2:b400::/243cb2:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1823cb2:b500::/243cb2:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1833cb2:b600::/243cb2:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1843cb2:b700::/243cb2:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1853cb2:b800::/243cb2:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1863cb2:b900::/243cb2:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1873cb2:ba00::/243cb2:baff:ffff:ffff:ffff:ffff:ffff:ffff
1883cb2:bb00::/243cb2:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1893cb2:bc00::/243cb2:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1903cb2:bd00::/243cb2:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1913cb2:be00::/243cb2:beff:ffff:ffff:ffff:ffff:ffff:ffff
1923cb2:bf00::/243cb2:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1933cb2:c000::/243cb2:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1943cb2:c100::/243cb2:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1953cb2:c200::/243cb2:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1963cb2:c300::/243cb2:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1973cb2:c400::/243cb2:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1983cb2:c500::/243cb2:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1993cb2:c600::/243cb2:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2003cb2:c700::/243cb2:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2013cb2:c800::/243cb2:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2023cb2:c900::/243cb2:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2033cb2:ca00::/243cb2:caff:ffff:ffff:ffff:ffff:ffff:ffff
2043cb2:cb00::/243cb2:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2053cb2:cc00::/243cb2:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2063cb2:cd00::/243cb2:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2073cb2:ce00::/243cb2:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2083cb2:cf00::/243cb2:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2093cb2:d000::/243cb2:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2103cb2:d100::/243cb2:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2113cb2:d200::/243cb2:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2123cb2:d300::/243cb2:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2133cb2:d400::/243cb2:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2143cb2:d500::/243cb2:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2153cb2:d600::/243cb2:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2163cb2:d700::/243cb2:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2173cb2:d800::/243cb2:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2183cb2:d900::/243cb2:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2193cb2:da00::/243cb2:daff:ffff:ffff:ffff:ffff:ffff:ffff
2203cb2:db00::/243cb2:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2213cb2:dc00::/243cb2:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2223cb2:dd00::/243cb2:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2233cb2:de00::/243cb2:deff:ffff:ffff:ffff:ffff:ffff:ffff
2243cb2:df00::/243cb2:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2253cb2:e000::/243cb2:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2263cb2:e100::/243cb2:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2273cb2:e200::/243cb2:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2283cb2:e300::/243cb2:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2293cb2:e400::/243cb2:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2303cb2:e500::/243cb2:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2313cb2:e600::/243cb2:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2323cb2:e700::/243cb2:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2333cb2:e800::/243cb2:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2343cb2:e900::/243cb2:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2353cb2:ea00::/243cb2:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2363cb2:eb00::/243cb2:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2373cb2:ec00::/243cb2:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2383cb2:ed00::/243cb2:edff:ffff:ffff:ffff:ffff:ffff:ffff
2393cb2:ee00::/243cb2:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2403cb2:ef00::/243cb2:efff:ffff:ffff:ffff:ffff:ffff:ffff
2413cb2:f000::/243cb2:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2423cb2:f100::/243cb2:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2433cb2:f200::/243cb2:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2443cb2:f300::/243cb2:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2453cb2:f400::/243cb2:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2463cb2:f500::/243cb2:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2473cb2:f600::/243cb2:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2483cb2:f700::/243cb2:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2493cb2:f800::/243cb2:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2503cb2:f900::/243cb2:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2513cb2:fa00::/243cb2:faff:ffff:ffff:ffff:ffff:ffff:ffff
2523cb2:fb00::/243cb2:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2533cb2:fc00::/243cb2:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2543cb2:fd00::/243cb2:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2553cb2:fe00::/243cb2:feff:ffff:ffff:ffff:ffff:ffff:ffff
2563cb2:ff00::/243cb2: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.