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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/9
Addresses2^119
/64 networks2^55
Network
2500::/9
First address
2500::
Last address
257f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
664,613,997,892,457,936,451,903,530,140,172,288 (2^119)
/64 networks (LANs)
36,028,797,018,963,968 (2^55)
Full form
2500:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
0.5.2.ip6.arpa
1.5.2.ip6.arpa
2.5.2.ip6.arpa
3.5.2.ip6.arpa
4.5.2.ip6.arpa
5.5.2.ip6.arpa
6.5.2.ip6.arpa
7.5.2.ip6.arpa
/9 is not on a 4-bit boundary, so it takes 8 /12 zones.
Split into smaller subnets/24
/10 (2)/11 (4)/12 (8)/13 (16)/16 (128)/20 (2,048)/24 (32,768)

2500::/9 makes 32,768 subnets of /24; the first 256 are listed.

Subnets
#SubnetLast address
12500::/242500:ff:ffff:ffff:ffff:ffff:ffff:ffff
22500:100::/242500:1ff:ffff:ffff:ffff:ffff:ffff:ffff
32500:200::/242500:2ff:ffff:ffff:ffff:ffff:ffff:ffff
42500:300::/242500:3ff:ffff:ffff:ffff:ffff:ffff:ffff
52500:400::/242500:4ff:ffff:ffff:ffff:ffff:ffff:ffff
62500:500::/242500:5ff:ffff:ffff:ffff:ffff:ffff:ffff
72500:600::/242500:6ff:ffff:ffff:ffff:ffff:ffff:ffff
82500:700::/242500:7ff:ffff:ffff:ffff:ffff:ffff:ffff
92500:800::/242500:8ff:ffff:ffff:ffff:ffff:ffff:ffff
102500:900::/242500:9ff:ffff:ffff:ffff:ffff:ffff:ffff
112500:a00::/242500:aff:ffff:ffff:ffff:ffff:ffff:ffff
122500:b00::/242500:bff:ffff:ffff:ffff:ffff:ffff:ffff
132500:c00::/242500:cff:ffff:ffff:ffff:ffff:ffff:ffff
142500:d00::/242500:dff:ffff:ffff:ffff:ffff:ffff:ffff
152500:e00::/242500:eff:ffff:ffff:ffff:ffff:ffff:ffff
162500:f00::/242500:fff:ffff:ffff:ffff:ffff:ffff:ffff
172500:1000::/242500:10ff:ffff:ffff:ffff:ffff:ffff:ffff
182500:1100::/242500:11ff:ffff:ffff:ffff:ffff:ffff:ffff
192500:1200::/242500:12ff:ffff:ffff:ffff:ffff:ffff:ffff
202500:1300::/242500:13ff:ffff:ffff:ffff:ffff:ffff:ffff
212500:1400::/242500:14ff:ffff:ffff:ffff:ffff:ffff:ffff
222500:1500::/242500:15ff:ffff:ffff:ffff:ffff:ffff:ffff
232500:1600::/242500:16ff:ffff:ffff:ffff:ffff:ffff:ffff
242500:1700::/242500:17ff:ffff:ffff:ffff:ffff:ffff:ffff
252500:1800::/242500:18ff:ffff:ffff:ffff:ffff:ffff:ffff
262500:1900::/242500:19ff:ffff:ffff:ffff:ffff:ffff:ffff
272500:1a00::/242500:1aff:ffff:ffff:ffff:ffff:ffff:ffff
282500:1b00::/242500:1bff:ffff:ffff:ffff:ffff:ffff:ffff
292500:1c00::/242500:1cff:ffff:ffff:ffff:ffff:ffff:ffff
302500:1d00::/242500:1dff:ffff:ffff:ffff:ffff:ffff:ffff
312500:1e00::/242500:1eff:ffff:ffff:ffff:ffff:ffff:ffff
322500:1f00::/242500:1fff:ffff:ffff:ffff:ffff:ffff:ffff
332500:2000::/242500:20ff:ffff:ffff:ffff:ffff:ffff:ffff
342500:2100::/242500:21ff:ffff:ffff:ffff:ffff:ffff:ffff
352500:2200::/242500:22ff:ffff:ffff:ffff:ffff:ffff:ffff
362500:2300::/242500:23ff:ffff:ffff:ffff:ffff:ffff:ffff
372500:2400::/242500:24ff:ffff:ffff:ffff:ffff:ffff:ffff
382500:2500::/242500:25ff:ffff:ffff:ffff:ffff:ffff:ffff
392500:2600::/242500:26ff:ffff:ffff:ffff:ffff:ffff:ffff
402500:2700::/242500:27ff:ffff:ffff:ffff:ffff:ffff:ffff
412500:2800::/242500:28ff:ffff:ffff:ffff:ffff:ffff:ffff
422500:2900::/242500:29ff:ffff:ffff:ffff:ffff:ffff:ffff
432500:2a00::/242500:2aff:ffff:ffff:ffff:ffff:ffff:ffff
442500:2b00::/242500:2bff:ffff:ffff:ffff:ffff:ffff:ffff
452500:2c00::/242500:2cff:ffff:ffff:ffff:ffff:ffff:ffff
462500:2d00::/242500:2dff:ffff:ffff:ffff:ffff:ffff:ffff
472500:2e00::/242500:2eff:ffff:ffff:ffff:ffff:ffff:ffff
482500:2f00::/242500:2fff:ffff:ffff:ffff:ffff:ffff:ffff
492500:3000::/242500:30ff:ffff:ffff:ffff:ffff:ffff:ffff
502500:3100::/242500:31ff:ffff:ffff:ffff:ffff:ffff:ffff
512500:3200::/242500:32ff:ffff:ffff:ffff:ffff:ffff:ffff
522500:3300::/242500:33ff:ffff:ffff:ffff:ffff:ffff:ffff
532500:3400::/242500:34ff:ffff:ffff:ffff:ffff:ffff:ffff
542500:3500::/242500:35ff:ffff:ffff:ffff:ffff:ffff:ffff
552500:3600::/242500:36ff:ffff:ffff:ffff:ffff:ffff:ffff
562500:3700::/242500:37ff:ffff:ffff:ffff:ffff:ffff:ffff
572500:3800::/242500:38ff:ffff:ffff:ffff:ffff:ffff:ffff
582500:3900::/242500:39ff:ffff:ffff:ffff:ffff:ffff:ffff
592500:3a00::/242500:3aff:ffff:ffff:ffff:ffff:ffff:ffff
602500:3b00::/242500:3bff:ffff:ffff:ffff:ffff:ffff:ffff
612500:3c00::/242500:3cff:ffff:ffff:ffff:ffff:ffff:ffff
622500:3d00::/242500:3dff:ffff:ffff:ffff:ffff:ffff:ffff
632500:3e00::/242500:3eff:ffff:ffff:ffff:ffff:ffff:ffff
642500:3f00::/242500:3fff:ffff:ffff:ffff:ffff:ffff:ffff
652500:4000::/242500:40ff:ffff:ffff:ffff:ffff:ffff:ffff
662500:4100::/242500:41ff:ffff:ffff:ffff:ffff:ffff:ffff
672500:4200::/242500:42ff:ffff:ffff:ffff:ffff:ffff:ffff
682500:4300::/242500:43ff:ffff:ffff:ffff:ffff:ffff:ffff
692500:4400::/242500:44ff:ffff:ffff:ffff:ffff:ffff:ffff
702500:4500::/242500:45ff:ffff:ffff:ffff:ffff:ffff:ffff
712500:4600::/242500:46ff:ffff:ffff:ffff:ffff:ffff:ffff
722500:4700::/242500:47ff:ffff:ffff:ffff:ffff:ffff:ffff
732500:4800::/242500:48ff:ffff:ffff:ffff:ffff:ffff:ffff
742500:4900::/242500:49ff:ffff:ffff:ffff:ffff:ffff:ffff
752500:4a00::/242500:4aff:ffff:ffff:ffff:ffff:ffff:ffff
762500:4b00::/242500:4bff:ffff:ffff:ffff:ffff:ffff:ffff
772500:4c00::/242500:4cff:ffff:ffff:ffff:ffff:ffff:ffff
782500:4d00::/242500:4dff:ffff:ffff:ffff:ffff:ffff:ffff
792500:4e00::/242500:4eff:ffff:ffff:ffff:ffff:ffff:ffff
802500:4f00::/242500:4fff:ffff:ffff:ffff:ffff:ffff:ffff
812500:5000::/242500:50ff:ffff:ffff:ffff:ffff:ffff:ffff
822500:5100::/242500:51ff:ffff:ffff:ffff:ffff:ffff:ffff
832500:5200::/242500:52ff:ffff:ffff:ffff:ffff:ffff:ffff
842500:5300::/242500:53ff:ffff:ffff:ffff:ffff:ffff:ffff
852500:5400::/242500:54ff:ffff:ffff:ffff:ffff:ffff:ffff
862500:5500::/242500:55ff:ffff:ffff:ffff:ffff:ffff:ffff
872500:5600::/242500:56ff:ffff:ffff:ffff:ffff:ffff:ffff
882500:5700::/242500:57ff:ffff:ffff:ffff:ffff:ffff:ffff
892500:5800::/242500:58ff:ffff:ffff:ffff:ffff:ffff:ffff
902500:5900::/242500:59ff:ffff:ffff:ffff:ffff:ffff:ffff
912500:5a00::/242500:5aff:ffff:ffff:ffff:ffff:ffff:ffff
922500:5b00::/242500:5bff:ffff:ffff:ffff:ffff:ffff:ffff
932500:5c00::/242500:5cff:ffff:ffff:ffff:ffff:ffff:ffff
942500:5d00::/242500:5dff:ffff:ffff:ffff:ffff:ffff:ffff
952500:5e00::/242500:5eff:ffff:ffff:ffff:ffff:ffff:ffff
962500:5f00::/242500:5fff:ffff:ffff:ffff:ffff:ffff:ffff
972500:6000::/242500:60ff:ffff:ffff:ffff:ffff:ffff:ffff
982500:6100::/242500:61ff:ffff:ffff:ffff:ffff:ffff:ffff
992500:6200::/242500:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1002500:6300::/242500:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1012500:6400::/242500:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1022500:6500::/242500:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1032500:6600::/242500:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1042500:6700::/242500:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1052500:6800::/242500:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1062500:6900::/242500:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1072500:6a00::/242500:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1082500:6b00::/242500:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1092500:6c00::/242500:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1102500:6d00::/242500:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1112500:6e00::/242500:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1122500:6f00::/242500:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1132500:7000::/242500:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1142500:7100::/242500:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1152500:7200::/242500:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1162500:7300::/242500:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1172500:7400::/242500:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1182500:7500::/242500:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1192500:7600::/242500:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1202500:7700::/242500:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1212500:7800::/242500:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1222500:7900::/242500:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1232500:7a00::/242500:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1242500:7b00::/242500:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1252500:7c00::/242500:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1262500:7d00::/242500:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1272500:7e00::/242500:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1282500:7f00::/242500:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1292500:8000::/242500:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1302500:8100::/242500:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1312500:8200::/242500:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1322500:8300::/242500:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1332500:8400::/242500:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1342500:8500::/242500:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1352500:8600::/242500:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1362500:8700::/242500:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1372500:8800::/242500:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1382500:8900::/242500:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1392500:8a00::/242500:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1402500:8b00::/242500:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1412500:8c00::/242500:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1422500:8d00::/242500:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1432500:8e00::/242500:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1442500:8f00::/242500:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1452500:9000::/242500:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1462500:9100::/242500:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1472500:9200::/242500:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1482500:9300::/242500:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1492500:9400::/242500:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1502500:9500::/242500:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1512500:9600::/242500:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1522500:9700::/242500:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1532500:9800::/242500:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1542500:9900::/242500:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1552500:9a00::/242500:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1562500:9b00::/242500:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1572500:9c00::/242500:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1582500:9d00::/242500:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1592500:9e00::/242500:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1602500:9f00::/242500:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1612500:a000::/242500:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1622500:a100::/242500:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1632500:a200::/242500:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1642500:a300::/242500:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1652500:a400::/242500:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1662500:a500::/242500:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1672500:a600::/242500:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1682500:a700::/242500:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1692500:a800::/242500:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1702500:a900::/242500:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1712500:aa00::/242500:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1722500:ab00::/242500:abff:ffff:ffff:ffff:ffff:ffff:ffff
1732500:ac00::/242500:acff:ffff:ffff:ffff:ffff:ffff:ffff
1742500:ad00::/242500:adff:ffff:ffff:ffff:ffff:ffff:ffff
1752500:ae00::/242500:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1762500:af00::/242500:afff:ffff:ffff:ffff:ffff:ffff:ffff
1772500:b000::/242500:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1782500:b100::/242500:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1792500:b200::/242500:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1802500:b300::/242500:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1812500:b400::/242500:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1822500:b500::/242500:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1832500:b600::/242500:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1842500:b700::/242500:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1852500:b800::/242500:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1862500:b900::/242500:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1872500:ba00::/242500:baff:ffff:ffff:ffff:ffff:ffff:ffff
1882500:bb00::/242500:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1892500:bc00::/242500:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1902500:bd00::/242500:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1912500:be00::/242500:beff:ffff:ffff:ffff:ffff:ffff:ffff
1922500:bf00::/242500:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1932500:c000::/242500:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1942500:c100::/242500:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1952500:c200::/242500:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1962500:c300::/242500:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1972500:c400::/242500:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1982500:c500::/242500:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1992500:c600::/242500:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2002500:c700::/242500:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2012500:c800::/242500:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2022500:c900::/242500:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2032500:ca00::/242500:caff:ffff:ffff:ffff:ffff:ffff:ffff
2042500:cb00::/242500:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2052500:cc00::/242500:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2062500:cd00::/242500:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2072500:ce00::/242500:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2082500:cf00::/242500:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2092500:d000::/242500:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2102500:d100::/242500:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2112500:d200::/242500:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2122500:d300::/242500:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2132500:d400::/242500:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2142500:d500::/242500:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2152500:d600::/242500:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2162500:d700::/242500:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2172500:d800::/242500:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2182500:d900::/242500:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2192500:da00::/242500:daff:ffff:ffff:ffff:ffff:ffff:ffff
2202500:db00::/242500:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2212500:dc00::/242500:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2222500:dd00::/242500:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2232500:de00::/242500:deff:ffff:ffff:ffff:ffff:ffff:ffff
2242500:df00::/242500:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2252500:e000::/242500:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2262500:e100::/242500:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2272500:e200::/242500:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2282500:e300::/242500:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2292500:e400::/242500:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2302500:e500::/242500:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2312500:e600::/242500:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2322500:e700::/242500:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2332500:e800::/242500:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2342500:e900::/242500:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2352500:ea00::/242500:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2362500:eb00::/242500:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2372500:ec00::/242500:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2382500:ed00::/242500:edff:ffff:ffff:ffff:ffff:ffff:ffff
2392500:ee00::/242500:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2402500:ef00::/242500:efff:ffff:ffff:ffff:ffff:ffff:ffff
2412500:f000::/242500:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2422500:f100::/242500:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2432500:f200::/242500:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2442500:f300::/242500:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2452500:f400::/242500:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2462500:f500::/242500:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2472500:f600::/242500:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2482500:f700::/242500:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2492500:f800::/242500:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2502500:f900::/242500:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2512500:fa00::/242500:faff:ffff:ffff:ffff:ffff:ffff:ffff
2522500:fb00::/242500:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2532500:fc00::/242500:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2542500:fd00::/242500:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2552500:fe00::/242500:feff:ffff:ffff:ffff:ffff:ffff:ffff
2562500:ff00::/242500: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.