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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
2073::/16
First address
2073::
Last address
2073: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
2073:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
3.7.0.2.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2073::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
12073::/242073:ff:ffff:ffff:ffff:ffff:ffff:ffff
22073:100::/242073:1ff:ffff:ffff:ffff:ffff:ffff:ffff
32073:200::/242073:2ff:ffff:ffff:ffff:ffff:ffff:ffff
42073:300::/242073:3ff:ffff:ffff:ffff:ffff:ffff:ffff
52073:400::/242073:4ff:ffff:ffff:ffff:ffff:ffff:ffff
62073:500::/242073:5ff:ffff:ffff:ffff:ffff:ffff:ffff
72073:600::/242073:6ff:ffff:ffff:ffff:ffff:ffff:ffff
82073:700::/242073:7ff:ffff:ffff:ffff:ffff:ffff:ffff
92073:800::/242073:8ff:ffff:ffff:ffff:ffff:ffff:ffff
102073:900::/242073:9ff:ffff:ffff:ffff:ffff:ffff:ffff
112073:a00::/242073:aff:ffff:ffff:ffff:ffff:ffff:ffff
122073:b00::/242073:bff:ffff:ffff:ffff:ffff:ffff:ffff
132073:c00::/242073:cff:ffff:ffff:ffff:ffff:ffff:ffff
142073:d00::/242073:dff:ffff:ffff:ffff:ffff:ffff:ffff
152073:e00::/242073:eff:ffff:ffff:ffff:ffff:ffff:ffff
162073:f00::/242073:fff:ffff:ffff:ffff:ffff:ffff:ffff
172073:1000::/242073:10ff:ffff:ffff:ffff:ffff:ffff:ffff
182073:1100::/242073:11ff:ffff:ffff:ffff:ffff:ffff:ffff
192073:1200::/242073:12ff:ffff:ffff:ffff:ffff:ffff:ffff
202073:1300::/242073:13ff:ffff:ffff:ffff:ffff:ffff:ffff
212073:1400::/242073:14ff:ffff:ffff:ffff:ffff:ffff:ffff
222073:1500::/242073:15ff:ffff:ffff:ffff:ffff:ffff:ffff
232073:1600::/242073:16ff:ffff:ffff:ffff:ffff:ffff:ffff
242073:1700::/242073:17ff:ffff:ffff:ffff:ffff:ffff:ffff
252073:1800::/242073:18ff:ffff:ffff:ffff:ffff:ffff:ffff
262073:1900::/242073:19ff:ffff:ffff:ffff:ffff:ffff:ffff
272073:1a00::/242073:1aff:ffff:ffff:ffff:ffff:ffff:ffff
282073:1b00::/242073:1bff:ffff:ffff:ffff:ffff:ffff:ffff
292073:1c00::/242073:1cff:ffff:ffff:ffff:ffff:ffff:ffff
302073:1d00::/242073:1dff:ffff:ffff:ffff:ffff:ffff:ffff
312073:1e00::/242073:1eff:ffff:ffff:ffff:ffff:ffff:ffff
322073:1f00::/242073:1fff:ffff:ffff:ffff:ffff:ffff:ffff
332073:2000::/242073:20ff:ffff:ffff:ffff:ffff:ffff:ffff
342073:2100::/242073:21ff:ffff:ffff:ffff:ffff:ffff:ffff
352073:2200::/242073:22ff:ffff:ffff:ffff:ffff:ffff:ffff
362073:2300::/242073:23ff:ffff:ffff:ffff:ffff:ffff:ffff
372073:2400::/242073:24ff:ffff:ffff:ffff:ffff:ffff:ffff
382073:2500::/242073:25ff:ffff:ffff:ffff:ffff:ffff:ffff
392073:2600::/242073:26ff:ffff:ffff:ffff:ffff:ffff:ffff
402073:2700::/242073:27ff:ffff:ffff:ffff:ffff:ffff:ffff
412073:2800::/242073:28ff:ffff:ffff:ffff:ffff:ffff:ffff
422073:2900::/242073:29ff:ffff:ffff:ffff:ffff:ffff:ffff
432073:2a00::/242073:2aff:ffff:ffff:ffff:ffff:ffff:ffff
442073:2b00::/242073:2bff:ffff:ffff:ffff:ffff:ffff:ffff
452073:2c00::/242073:2cff:ffff:ffff:ffff:ffff:ffff:ffff
462073:2d00::/242073:2dff:ffff:ffff:ffff:ffff:ffff:ffff
472073:2e00::/242073:2eff:ffff:ffff:ffff:ffff:ffff:ffff
482073:2f00::/242073:2fff:ffff:ffff:ffff:ffff:ffff:ffff
492073:3000::/242073:30ff:ffff:ffff:ffff:ffff:ffff:ffff
502073:3100::/242073:31ff:ffff:ffff:ffff:ffff:ffff:ffff
512073:3200::/242073:32ff:ffff:ffff:ffff:ffff:ffff:ffff
522073:3300::/242073:33ff:ffff:ffff:ffff:ffff:ffff:ffff
532073:3400::/242073:34ff:ffff:ffff:ffff:ffff:ffff:ffff
542073:3500::/242073:35ff:ffff:ffff:ffff:ffff:ffff:ffff
552073:3600::/242073:36ff:ffff:ffff:ffff:ffff:ffff:ffff
562073:3700::/242073:37ff:ffff:ffff:ffff:ffff:ffff:ffff
572073:3800::/242073:38ff:ffff:ffff:ffff:ffff:ffff:ffff
582073:3900::/242073:39ff:ffff:ffff:ffff:ffff:ffff:ffff
592073:3a00::/242073:3aff:ffff:ffff:ffff:ffff:ffff:ffff
602073:3b00::/242073:3bff:ffff:ffff:ffff:ffff:ffff:ffff
612073:3c00::/242073:3cff:ffff:ffff:ffff:ffff:ffff:ffff
622073:3d00::/242073:3dff:ffff:ffff:ffff:ffff:ffff:ffff
632073:3e00::/242073:3eff:ffff:ffff:ffff:ffff:ffff:ffff
642073:3f00::/242073:3fff:ffff:ffff:ffff:ffff:ffff:ffff
652073:4000::/242073:40ff:ffff:ffff:ffff:ffff:ffff:ffff
662073:4100::/242073:41ff:ffff:ffff:ffff:ffff:ffff:ffff
672073:4200::/242073:42ff:ffff:ffff:ffff:ffff:ffff:ffff
682073:4300::/242073:43ff:ffff:ffff:ffff:ffff:ffff:ffff
692073:4400::/242073:44ff:ffff:ffff:ffff:ffff:ffff:ffff
702073:4500::/242073:45ff:ffff:ffff:ffff:ffff:ffff:ffff
712073:4600::/242073:46ff:ffff:ffff:ffff:ffff:ffff:ffff
722073:4700::/242073:47ff:ffff:ffff:ffff:ffff:ffff:ffff
732073:4800::/242073:48ff:ffff:ffff:ffff:ffff:ffff:ffff
742073:4900::/242073:49ff:ffff:ffff:ffff:ffff:ffff:ffff
752073:4a00::/242073:4aff:ffff:ffff:ffff:ffff:ffff:ffff
762073:4b00::/242073:4bff:ffff:ffff:ffff:ffff:ffff:ffff
772073:4c00::/242073:4cff:ffff:ffff:ffff:ffff:ffff:ffff
782073:4d00::/242073:4dff:ffff:ffff:ffff:ffff:ffff:ffff
792073:4e00::/242073:4eff:ffff:ffff:ffff:ffff:ffff:ffff
802073:4f00::/242073:4fff:ffff:ffff:ffff:ffff:ffff:ffff
812073:5000::/242073:50ff:ffff:ffff:ffff:ffff:ffff:ffff
822073:5100::/242073:51ff:ffff:ffff:ffff:ffff:ffff:ffff
832073:5200::/242073:52ff:ffff:ffff:ffff:ffff:ffff:ffff
842073:5300::/242073:53ff:ffff:ffff:ffff:ffff:ffff:ffff
852073:5400::/242073:54ff:ffff:ffff:ffff:ffff:ffff:ffff
862073:5500::/242073:55ff:ffff:ffff:ffff:ffff:ffff:ffff
872073:5600::/242073:56ff:ffff:ffff:ffff:ffff:ffff:ffff
882073:5700::/242073:57ff:ffff:ffff:ffff:ffff:ffff:ffff
892073:5800::/242073:58ff:ffff:ffff:ffff:ffff:ffff:ffff
902073:5900::/242073:59ff:ffff:ffff:ffff:ffff:ffff:ffff
912073:5a00::/242073:5aff:ffff:ffff:ffff:ffff:ffff:ffff
922073:5b00::/242073:5bff:ffff:ffff:ffff:ffff:ffff:ffff
932073:5c00::/242073:5cff:ffff:ffff:ffff:ffff:ffff:ffff
942073:5d00::/242073:5dff:ffff:ffff:ffff:ffff:ffff:ffff
952073:5e00::/242073:5eff:ffff:ffff:ffff:ffff:ffff:ffff
962073:5f00::/242073:5fff:ffff:ffff:ffff:ffff:ffff:ffff
972073:6000::/242073:60ff:ffff:ffff:ffff:ffff:ffff:ffff
982073:6100::/242073:61ff:ffff:ffff:ffff:ffff:ffff:ffff
992073:6200::/242073:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1002073:6300::/242073:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1012073:6400::/242073:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1022073:6500::/242073:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1032073:6600::/242073:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1042073:6700::/242073:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1052073:6800::/242073:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1062073:6900::/242073:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1072073:6a00::/242073:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1082073:6b00::/242073:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1092073:6c00::/242073:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1102073:6d00::/242073:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1112073:6e00::/242073:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1122073:6f00::/242073:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1132073:7000::/242073:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1142073:7100::/242073:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1152073:7200::/242073:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1162073:7300::/242073:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1172073:7400::/242073:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1182073:7500::/242073:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1192073:7600::/242073:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1202073:7700::/242073:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1212073:7800::/242073:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1222073:7900::/242073:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1232073:7a00::/242073:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1242073:7b00::/242073:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1252073:7c00::/242073:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1262073:7d00::/242073:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1272073:7e00::/242073:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1282073:7f00::/242073:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1292073:8000::/242073:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1302073:8100::/242073:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1312073:8200::/242073:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1322073:8300::/242073:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1332073:8400::/242073:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1342073:8500::/242073:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1352073:8600::/242073:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1362073:8700::/242073:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1372073:8800::/242073:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1382073:8900::/242073:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1392073:8a00::/242073:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1402073:8b00::/242073:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1412073:8c00::/242073:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1422073:8d00::/242073:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1432073:8e00::/242073:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1442073:8f00::/242073:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1452073:9000::/242073:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1462073:9100::/242073:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1472073:9200::/242073:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1482073:9300::/242073:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1492073:9400::/242073:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1502073:9500::/242073:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1512073:9600::/242073:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1522073:9700::/242073:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1532073:9800::/242073:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1542073:9900::/242073:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1552073:9a00::/242073:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1562073:9b00::/242073:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1572073:9c00::/242073:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1582073:9d00::/242073:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1592073:9e00::/242073:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1602073:9f00::/242073:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1612073:a000::/242073:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1622073:a100::/242073:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1632073:a200::/242073:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1642073:a300::/242073:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1652073:a400::/242073:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1662073:a500::/242073:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1672073:a600::/242073:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1682073:a700::/242073:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1692073:a800::/242073:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1702073:a900::/242073:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1712073:aa00::/242073:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1722073:ab00::/242073:abff:ffff:ffff:ffff:ffff:ffff:ffff
1732073:ac00::/242073:acff:ffff:ffff:ffff:ffff:ffff:ffff
1742073:ad00::/242073:adff:ffff:ffff:ffff:ffff:ffff:ffff
1752073:ae00::/242073:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1762073:af00::/242073:afff:ffff:ffff:ffff:ffff:ffff:ffff
1772073:b000::/242073:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1782073:b100::/242073:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1792073:b200::/242073:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1802073:b300::/242073:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1812073:b400::/242073:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1822073:b500::/242073:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1832073:b600::/242073:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1842073:b700::/242073:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1852073:b800::/242073:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1862073:b900::/242073:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1872073:ba00::/242073:baff:ffff:ffff:ffff:ffff:ffff:ffff
1882073:bb00::/242073:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1892073:bc00::/242073:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1902073:bd00::/242073:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1912073:be00::/242073:beff:ffff:ffff:ffff:ffff:ffff:ffff
1922073:bf00::/242073:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1932073:c000::/242073:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1942073:c100::/242073:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1952073:c200::/242073:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1962073:c300::/242073:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1972073:c400::/242073:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1982073:c500::/242073:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1992073:c600::/242073:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2002073:c700::/242073:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2012073:c800::/242073:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2022073:c900::/242073:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2032073:ca00::/242073:caff:ffff:ffff:ffff:ffff:ffff:ffff
2042073:cb00::/242073:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2052073:cc00::/242073:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2062073:cd00::/242073:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2072073:ce00::/242073:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2082073:cf00::/242073:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2092073:d000::/242073:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2102073:d100::/242073:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2112073:d200::/242073:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2122073:d300::/242073:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2132073:d400::/242073:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2142073:d500::/242073:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2152073:d600::/242073:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2162073:d700::/242073:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2172073:d800::/242073:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2182073:d900::/242073:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2192073:da00::/242073:daff:ffff:ffff:ffff:ffff:ffff:ffff
2202073:db00::/242073:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2212073:dc00::/242073:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2222073:dd00::/242073:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2232073:de00::/242073:deff:ffff:ffff:ffff:ffff:ffff:ffff
2242073:df00::/242073:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2252073:e000::/242073:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2262073:e100::/242073:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2272073:e200::/242073:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2282073:e300::/242073:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2292073:e400::/242073:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2302073:e500::/242073:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2312073:e600::/242073:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2322073:e700::/242073:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2332073:e800::/242073:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2342073:e900::/242073:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2352073:ea00::/242073:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2362073:eb00::/242073:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2372073:ec00::/242073:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2382073:ed00::/242073:edff:ffff:ffff:ffff:ffff:ffff:ffff
2392073:ee00::/242073:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2402073:ef00::/242073:efff:ffff:ffff:ffff:ffff:ffff:ffff
2412073:f000::/242073:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2422073:f100::/242073:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2432073:f200::/242073:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2442073:f300::/242073:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2452073:f400::/242073:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2462073:f500::/242073:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2472073:f600::/242073:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2482073:f700::/242073:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2492073:f800::/242073:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2502073:f900::/242073:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2512073:fa00::/242073:faff:ffff:ffff:ffff:ffff:ffff:ffff
2522073:fb00::/242073:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2532073:fc00::/242073:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2542073:fd00::/242073:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2552073:fe00::/242073:feff:ffff:ffff:ffff:ffff:ffff:ffff
2562073:ff00::/242073: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.