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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
2cb2::/16
First address
2cb2::
Last address
2cb2: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
2cb2:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
2.b.c.2.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2cb2::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
12cb2::/322cb2:0:ffff:ffff:ffff:ffff:ffff:ffff
22cb2:1::/322cb2:1:ffff:ffff:ffff:ffff:ffff:ffff
32cb2:2::/322cb2:2:ffff:ffff:ffff:ffff:ffff:ffff
42cb2:3::/322cb2:3:ffff:ffff:ffff:ffff:ffff:ffff
52cb2:4::/322cb2:4:ffff:ffff:ffff:ffff:ffff:ffff
62cb2:5::/322cb2:5:ffff:ffff:ffff:ffff:ffff:ffff
72cb2:6::/322cb2:6:ffff:ffff:ffff:ffff:ffff:ffff
82cb2:7::/322cb2:7:ffff:ffff:ffff:ffff:ffff:ffff
92cb2:8::/322cb2:8:ffff:ffff:ffff:ffff:ffff:ffff
102cb2:9::/322cb2:9:ffff:ffff:ffff:ffff:ffff:ffff
112cb2:a::/322cb2:a:ffff:ffff:ffff:ffff:ffff:ffff
122cb2:b::/322cb2:b:ffff:ffff:ffff:ffff:ffff:ffff
132cb2:c::/322cb2:c:ffff:ffff:ffff:ffff:ffff:ffff
142cb2:d::/322cb2:d:ffff:ffff:ffff:ffff:ffff:ffff
152cb2:e::/322cb2:e:ffff:ffff:ffff:ffff:ffff:ffff
162cb2:f::/322cb2:f:ffff:ffff:ffff:ffff:ffff:ffff
172cb2:10::/322cb2:10:ffff:ffff:ffff:ffff:ffff:ffff
182cb2:11::/322cb2:11:ffff:ffff:ffff:ffff:ffff:ffff
192cb2:12::/322cb2:12:ffff:ffff:ffff:ffff:ffff:ffff
202cb2:13::/322cb2:13:ffff:ffff:ffff:ffff:ffff:ffff
212cb2:14::/322cb2:14:ffff:ffff:ffff:ffff:ffff:ffff
222cb2:15::/322cb2:15:ffff:ffff:ffff:ffff:ffff:ffff
232cb2:16::/322cb2:16:ffff:ffff:ffff:ffff:ffff:ffff
242cb2:17::/322cb2:17:ffff:ffff:ffff:ffff:ffff:ffff
252cb2:18::/322cb2:18:ffff:ffff:ffff:ffff:ffff:ffff
262cb2:19::/322cb2:19:ffff:ffff:ffff:ffff:ffff:ffff
272cb2:1a::/322cb2:1a:ffff:ffff:ffff:ffff:ffff:ffff
282cb2:1b::/322cb2:1b:ffff:ffff:ffff:ffff:ffff:ffff
292cb2:1c::/322cb2:1c:ffff:ffff:ffff:ffff:ffff:ffff
302cb2:1d::/322cb2:1d:ffff:ffff:ffff:ffff:ffff:ffff
312cb2:1e::/322cb2:1e:ffff:ffff:ffff:ffff:ffff:ffff
322cb2:1f::/322cb2:1f:ffff:ffff:ffff:ffff:ffff:ffff
332cb2:20::/322cb2:20:ffff:ffff:ffff:ffff:ffff:ffff
342cb2:21::/322cb2:21:ffff:ffff:ffff:ffff:ffff:ffff
352cb2:22::/322cb2:22:ffff:ffff:ffff:ffff:ffff:ffff
362cb2:23::/322cb2:23:ffff:ffff:ffff:ffff:ffff:ffff
372cb2:24::/322cb2:24:ffff:ffff:ffff:ffff:ffff:ffff
382cb2:25::/322cb2:25:ffff:ffff:ffff:ffff:ffff:ffff
392cb2:26::/322cb2:26:ffff:ffff:ffff:ffff:ffff:ffff
402cb2:27::/322cb2:27:ffff:ffff:ffff:ffff:ffff:ffff
412cb2:28::/322cb2:28:ffff:ffff:ffff:ffff:ffff:ffff
422cb2:29::/322cb2:29:ffff:ffff:ffff:ffff:ffff:ffff
432cb2:2a::/322cb2:2a:ffff:ffff:ffff:ffff:ffff:ffff
442cb2:2b::/322cb2:2b:ffff:ffff:ffff:ffff:ffff:ffff
452cb2:2c::/322cb2:2c:ffff:ffff:ffff:ffff:ffff:ffff
462cb2:2d::/322cb2:2d:ffff:ffff:ffff:ffff:ffff:ffff
472cb2:2e::/322cb2:2e:ffff:ffff:ffff:ffff:ffff:ffff
482cb2:2f::/322cb2:2f:ffff:ffff:ffff:ffff:ffff:ffff
492cb2:30::/322cb2:30:ffff:ffff:ffff:ffff:ffff:ffff
502cb2:31::/322cb2:31:ffff:ffff:ffff:ffff:ffff:ffff
512cb2:32::/322cb2:32:ffff:ffff:ffff:ffff:ffff:ffff
522cb2:33::/322cb2:33:ffff:ffff:ffff:ffff:ffff:ffff
532cb2:34::/322cb2:34:ffff:ffff:ffff:ffff:ffff:ffff
542cb2:35::/322cb2:35:ffff:ffff:ffff:ffff:ffff:ffff
552cb2:36::/322cb2:36:ffff:ffff:ffff:ffff:ffff:ffff
562cb2:37::/322cb2:37:ffff:ffff:ffff:ffff:ffff:ffff
572cb2:38::/322cb2:38:ffff:ffff:ffff:ffff:ffff:ffff
582cb2:39::/322cb2:39:ffff:ffff:ffff:ffff:ffff:ffff
592cb2:3a::/322cb2:3a:ffff:ffff:ffff:ffff:ffff:ffff
602cb2:3b::/322cb2:3b:ffff:ffff:ffff:ffff:ffff:ffff
612cb2:3c::/322cb2:3c:ffff:ffff:ffff:ffff:ffff:ffff
622cb2:3d::/322cb2:3d:ffff:ffff:ffff:ffff:ffff:ffff
632cb2:3e::/322cb2:3e:ffff:ffff:ffff:ffff:ffff:ffff
642cb2:3f::/322cb2:3f:ffff:ffff:ffff:ffff:ffff:ffff
652cb2:40::/322cb2:40:ffff:ffff:ffff:ffff:ffff:ffff
662cb2:41::/322cb2:41:ffff:ffff:ffff:ffff:ffff:ffff
672cb2:42::/322cb2:42:ffff:ffff:ffff:ffff:ffff:ffff
682cb2:43::/322cb2:43:ffff:ffff:ffff:ffff:ffff:ffff
692cb2:44::/322cb2:44:ffff:ffff:ffff:ffff:ffff:ffff
702cb2:45::/322cb2:45:ffff:ffff:ffff:ffff:ffff:ffff
712cb2:46::/322cb2:46:ffff:ffff:ffff:ffff:ffff:ffff
722cb2:47::/322cb2:47:ffff:ffff:ffff:ffff:ffff:ffff
732cb2:48::/322cb2:48:ffff:ffff:ffff:ffff:ffff:ffff
742cb2:49::/322cb2:49:ffff:ffff:ffff:ffff:ffff:ffff
752cb2:4a::/322cb2:4a:ffff:ffff:ffff:ffff:ffff:ffff
762cb2:4b::/322cb2:4b:ffff:ffff:ffff:ffff:ffff:ffff
772cb2:4c::/322cb2:4c:ffff:ffff:ffff:ffff:ffff:ffff
782cb2:4d::/322cb2:4d:ffff:ffff:ffff:ffff:ffff:ffff
792cb2:4e::/322cb2:4e:ffff:ffff:ffff:ffff:ffff:ffff
802cb2:4f::/322cb2:4f:ffff:ffff:ffff:ffff:ffff:ffff
812cb2:50::/322cb2:50:ffff:ffff:ffff:ffff:ffff:ffff
822cb2:51::/322cb2:51:ffff:ffff:ffff:ffff:ffff:ffff
832cb2:52::/322cb2:52:ffff:ffff:ffff:ffff:ffff:ffff
842cb2:53::/322cb2:53:ffff:ffff:ffff:ffff:ffff:ffff
852cb2:54::/322cb2:54:ffff:ffff:ffff:ffff:ffff:ffff
862cb2:55::/322cb2:55:ffff:ffff:ffff:ffff:ffff:ffff
872cb2:56::/322cb2:56:ffff:ffff:ffff:ffff:ffff:ffff
882cb2:57::/322cb2:57:ffff:ffff:ffff:ffff:ffff:ffff
892cb2:58::/322cb2:58:ffff:ffff:ffff:ffff:ffff:ffff
902cb2:59::/322cb2:59:ffff:ffff:ffff:ffff:ffff:ffff
912cb2:5a::/322cb2:5a:ffff:ffff:ffff:ffff:ffff:ffff
922cb2:5b::/322cb2:5b:ffff:ffff:ffff:ffff:ffff:ffff
932cb2:5c::/322cb2:5c:ffff:ffff:ffff:ffff:ffff:ffff
942cb2:5d::/322cb2:5d:ffff:ffff:ffff:ffff:ffff:ffff
952cb2:5e::/322cb2:5e:ffff:ffff:ffff:ffff:ffff:ffff
962cb2:5f::/322cb2:5f:ffff:ffff:ffff:ffff:ffff:ffff
972cb2:60::/322cb2:60:ffff:ffff:ffff:ffff:ffff:ffff
982cb2:61::/322cb2:61:ffff:ffff:ffff:ffff:ffff:ffff
992cb2:62::/322cb2:62:ffff:ffff:ffff:ffff:ffff:ffff
1002cb2:63::/322cb2:63:ffff:ffff:ffff:ffff:ffff:ffff
1012cb2:64::/322cb2:64:ffff:ffff:ffff:ffff:ffff:ffff
1022cb2:65::/322cb2:65:ffff:ffff:ffff:ffff:ffff:ffff
1032cb2:66::/322cb2:66:ffff:ffff:ffff:ffff:ffff:ffff
1042cb2:67::/322cb2:67:ffff:ffff:ffff:ffff:ffff:ffff
1052cb2:68::/322cb2:68:ffff:ffff:ffff:ffff:ffff:ffff
1062cb2:69::/322cb2:69:ffff:ffff:ffff:ffff:ffff:ffff
1072cb2:6a::/322cb2:6a:ffff:ffff:ffff:ffff:ffff:ffff
1082cb2:6b::/322cb2:6b:ffff:ffff:ffff:ffff:ffff:ffff
1092cb2:6c::/322cb2:6c:ffff:ffff:ffff:ffff:ffff:ffff
1102cb2:6d::/322cb2:6d:ffff:ffff:ffff:ffff:ffff:ffff
1112cb2:6e::/322cb2:6e:ffff:ffff:ffff:ffff:ffff:ffff
1122cb2:6f::/322cb2:6f:ffff:ffff:ffff:ffff:ffff:ffff
1132cb2:70::/322cb2:70:ffff:ffff:ffff:ffff:ffff:ffff
1142cb2:71::/322cb2:71:ffff:ffff:ffff:ffff:ffff:ffff
1152cb2:72::/322cb2:72:ffff:ffff:ffff:ffff:ffff:ffff
1162cb2:73::/322cb2:73:ffff:ffff:ffff:ffff:ffff:ffff
1172cb2:74::/322cb2:74:ffff:ffff:ffff:ffff:ffff:ffff
1182cb2:75::/322cb2:75:ffff:ffff:ffff:ffff:ffff:ffff
1192cb2:76::/322cb2:76:ffff:ffff:ffff:ffff:ffff:ffff
1202cb2:77::/322cb2:77:ffff:ffff:ffff:ffff:ffff:ffff
1212cb2:78::/322cb2:78:ffff:ffff:ffff:ffff:ffff:ffff
1222cb2:79::/322cb2:79:ffff:ffff:ffff:ffff:ffff:ffff
1232cb2:7a::/322cb2:7a:ffff:ffff:ffff:ffff:ffff:ffff
1242cb2:7b::/322cb2:7b:ffff:ffff:ffff:ffff:ffff:ffff
1252cb2:7c::/322cb2:7c:ffff:ffff:ffff:ffff:ffff:ffff
1262cb2:7d::/322cb2:7d:ffff:ffff:ffff:ffff:ffff:ffff
1272cb2:7e::/322cb2:7e:ffff:ffff:ffff:ffff:ffff:ffff
1282cb2:7f::/322cb2:7f:ffff:ffff:ffff:ffff:ffff:ffff
1292cb2:80::/322cb2:80:ffff:ffff:ffff:ffff:ffff:ffff
1302cb2:81::/322cb2:81:ffff:ffff:ffff:ffff:ffff:ffff
1312cb2:82::/322cb2:82:ffff:ffff:ffff:ffff:ffff:ffff
1322cb2:83::/322cb2:83:ffff:ffff:ffff:ffff:ffff:ffff
1332cb2:84::/322cb2:84:ffff:ffff:ffff:ffff:ffff:ffff
1342cb2:85::/322cb2:85:ffff:ffff:ffff:ffff:ffff:ffff
1352cb2:86::/322cb2:86:ffff:ffff:ffff:ffff:ffff:ffff
1362cb2:87::/322cb2:87:ffff:ffff:ffff:ffff:ffff:ffff
1372cb2:88::/322cb2:88:ffff:ffff:ffff:ffff:ffff:ffff
1382cb2:89::/322cb2:89:ffff:ffff:ffff:ffff:ffff:ffff
1392cb2:8a::/322cb2:8a:ffff:ffff:ffff:ffff:ffff:ffff
1402cb2:8b::/322cb2:8b:ffff:ffff:ffff:ffff:ffff:ffff
1412cb2:8c::/322cb2:8c:ffff:ffff:ffff:ffff:ffff:ffff
1422cb2:8d::/322cb2:8d:ffff:ffff:ffff:ffff:ffff:ffff
1432cb2:8e::/322cb2:8e:ffff:ffff:ffff:ffff:ffff:ffff
1442cb2:8f::/322cb2:8f:ffff:ffff:ffff:ffff:ffff:ffff
1452cb2:90::/322cb2:90:ffff:ffff:ffff:ffff:ffff:ffff
1462cb2:91::/322cb2:91:ffff:ffff:ffff:ffff:ffff:ffff
1472cb2:92::/322cb2:92:ffff:ffff:ffff:ffff:ffff:ffff
1482cb2:93::/322cb2:93:ffff:ffff:ffff:ffff:ffff:ffff
1492cb2:94::/322cb2:94:ffff:ffff:ffff:ffff:ffff:ffff
1502cb2:95::/322cb2:95:ffff:ffff:ffff:ffff:ffff:ffff
1512cb2:96::/322cb2:96:ffff:ffff:ffff:ffff:ffff:ffff
1522cb2:97::/322cb2:97:ffff:ffff:ffff:ffff:ffff:ffff
1532cb2:98::/322cb2:98:ffff:ffff:ffff:ffff:ffff:ffff
1542cb2:99::/322cb2:99:ffff:ffff:ffff:ffff:ffff:ffff
1552cb2:9a::/322cb2:9a:ffff:ffff:ffff:ffff:ffff:ffff
1562cb2:9b::/322cb2:9b:ffff:ffff:ffff:ffff:ffff:ffff
1572cb2:9c::/322cb2:9c:ffff:ffff:ffff:ffff:ffff:ffff
1582cb2:9d::/322cb2:9d:ffff:ffff:ffff:ffff:ffff:ffff
1592cb2:9e::/322cb2:9e:ffff:ffff:ffff:ffff:ffff:ffff
1602cb2:9f::/322cb2:9f:ffff:ffff:ffff:ffff:ffff:ffff
1612cb2:a0::/322cb2:a0:ffff:ffff:ffff:ffff:ffff:ffff
1622cb2:a1::/322cb2:a1:ffff:ffff:ffff:ffff:ffff:ffff
1632cb2:a2::/322cb2:a2:ffff:ffff:ffff:ffff:ffff:ffff
1642cb2:a3::/322cb2:a3:ffff:ffff:ffff:ffff:ffff:ffff
1652cb2:a4::/322cb2:a4:ffff:ffff:ffff:ffff:ffff:ffff
1662cb2:a5::/322cb2:a5:ffff:ffff:ffff:ffff:ffff:ffff
1672cb2:a6::/322cb2:a6:ffff:ffff:ffff:ffff:ffff:ffff
1682cb2:a7::/322cb2:a7:ffff:ffff:ffff:ffff:ffff:ffff
1692cb2:a8::/322cb2:a8:ffff:ffff:ffff:ffff:ffff:ffff
1702cb2:a9::/322cb2:a9:ffff:ffff:ffff:ffff:ffff:ffff
1712cb2:aa::/322cb2:aa:ffff:ffff:ffff:ffff:ffff:ffff
1722cb2:ab::/322cb2:ab:ffff:ffff:ffff:ffff:ffff:ffff
1732cb2:ac::/322cb2:ac:ffff:ffff:ffff:ffff:ffff:ffff
1742cb2:ad::/322cb2:ad:ffff:ffff:ffff:ffff:ffff:ffff
1752cb2:ae::/322cb2:ae:ffff:ffff:ffff:ffff:ffff:ffff
1762cb2:af::/322cb2:af:ffff:ffff:ffff:ffff:ffff:ffff
1772cb2:b0::/322cb2:b0:ffff:ffff:ffff:ffff:ffff:ffff
1782cb2:b1::/322cb2:b1:ffff:ffff:ffff:ffff:ffff:ffff
1792cb2:b2::/322cb2:b2:ffff:ffff:ffff:ffff:ffff:ffff
1802cb2:b3::/322cb2:b3:ffff:ffff:ffff:ffff:ffff:ffff
1812cb2:b4::/322cb2:b4:ffff:ffff:ffff:ffff:ffff:ffff
1822cb2:b5::/322cb2:b5:ffff:ffff:ffff:ffff:ffff:ffff
1832cb2:b6::/322cb2:b6:ffff:ffff:ffff:ffff:ffff:ffff
1842cb2:b7::/322cb2:b7:ffff:ffff:ffff:ffff:ffff:ffff
1852cb2:b8::/322cb2:b8:ffff:ffff:ffff:ffff:ffff:ffff
1862cb2:b9::/322cb2:b9:ffff:ffff:ffff:ffff:ffff:ffff
1872cb2:ba::/322cb2:ba:ffff:ffff:ffff:ffff:ffff:ffff
1882cb2:bb::/322cb2:bb:ffff:ffff:ffff:ffff:ffff:ffff
1892cb2:bc::/322cb2:bc:ffff:ffff:ffff:ffff:ffff:ffff
1902cb2:bd::/322cb2:bd:ffff:ffff:ffff:ffff:ffff:ffff
1912cb2:be::/322cb2:be:ffff:ffff:ffff:ffff:ffff:ffff
1922cb2:bf::/322cb2:bf:ffff:ffff:ffff:ffff:ffff:ffff
1932cb2:c0::/322cb2:c0:ffff:ffff:ffff:ffff:ffff:ffff
1942cb2:c1::/322cb2:c1:ffff:ffff:ffff:ffff:ffff:ffff
1952cb2:c2::/322cb2:c2:ffff:ffff:ffff:ffff:ffff:ffff
1962cb2:c3::/322cb2:c3:ffff:ffff:ffff:ffff:ffff:ffff
1972cb2:c4::/322cb2:c4:ffff:ffff:ffff:ffff:ffff:ffff
1982cb2:c5::/322cb2:c5:ffff:ffff:ffff:ffff:ffff:ffff
1992cb2:c6::/322cb2:c6:ffff:ffff:ffff:ffff:ffff:ffff
2002cb2:c7::/322cb2:c7:ffff:ffff:ffff:ffff:ffff:ffff
2012cb2:c8::/322cb2:c8:ffff:ffff:ffff:ffff:ffff:ffff
2022cb2:c9::/322cb2:c9:ffff:ffff:ffff:ffff:ffff:ffff
2032cb2:ca::/322cb2:ca:ffff:ffff:ffff:ffff:ffff:ffff
2042cb2:cb::/322cb2:cb:ffff:ffff:ffff:ffff:ffff:ffff
2052cb2:cc::/322cb2:cc:ffff:ffff:ffff:ffff:ffff:ffff
2062cb2:cd::/322cb2:cd:ffff:ffff:ffff:ffff:ffff:ffff
2072cb2:ce::/322cb2:ce:ffff:ffff:ffff:ffff:ffff:ffff
2082cb2:cf::/322cb2:cf:ffff:ffff:ffff:ffff:ffff:ffff
2092cb2:d0::/322cb2:d0:ffff:ffff:ffff:ffff:ffff:ffff
2102cb2:d1::/322cb2:d1:ffff:ffff:ffff:ffff:ffff:ffff
2112cb2:d2::/322cb2:d2:ffff:ffff:ffff:ffff:ffff:ffff
2122cb2:d3::/322cb2:d3:ffff:ffff:ffff:ffff:ffff:ffff
2132cb2:d4::/322cb2:d4:ffff:ffff:ffff:ffff:ffff:ffff
2142cb2:d5::/322cb2:d5:ffff:ffff:ffff:ffff:ffff:ffff
2152cb2:d6::/322cb2:d6:ffff:ffff:ffff:ffff:ffff:ffff
2162cb2:d7::/322cb2:d7:ffff:ffff:ffff:ffff:ffff:ffff
2172cb2:d8::/322cb2:d8:ffff:ffff:ffff:ffff:ffff:ffff
2182cb2:d9::/322cb2:d9:ffff:ffff:ffff:ffff:ffff:ffff
2192cb2:da::/322cb2:da:ffff:ffff:ffff:ffff:ffff:ffff
2202cb2:db::/322cb2:db:ffff:ffff:ffff:ffff:ffff:ffff
2212cb2:dc::/322cb2:dc:ffff:ffff:ffff:ffff:ffff:ffff
2222cb2:dd::/322cb2:dd:ffff:ffff:ffff:ffff:ffff:ffff
2232cb2:de::/322cb2:de:ffff:ffff:ffff:ffff:ffff:ffff
2242cb2:df::/322cb2:df:ffff:ffff:ffff:ffff:ffff:ffff
2252cb2:e0::/322cb2:e0:ffff:ffff:ffff:ffff:ffff:ffff
2262cb2:e1::/322cb2:e1:ffff:ffff:ffff:ffff:ffff:ffff
2272cb2:e2::/322cb2:e2:ffff:ffff:ffff:ffff:ffff:ffff
2282cb2:e3::/322cb2:e3:ffff:ffff:ffff:ffff:ffff:ffff
2292cb2:e4::/322cb2:e4:ffff:ffff:ffff:ffff:ffff:ffff
2302cb2:e5::/322cb2:e5:ffff:ffff:ffff:ffff:ffff:ffff
2312cb2:e6::/322cb2:e6:ffff:ffff:ffff:ffff:ffff:ffff
2322cb2:e7::/322cb2:e7:ffff:ffff:ffff:ffff:ffff:ffff
2332cb2:e8::/322cb2:e8:ffff:ffff:ffff:ffff:ffff:ffff
2342cb2:e9::/322cb2:e9:ffff:ffff:ffff:ffff:ffff:ffff
2352cb2:ea::/322cb2:ea:ffff:ffff:ffff:ffff:ffff:ffff
2362cb2:eb::/322cb2:eb:ffff:ffff:ffff:ffff:ffff:ffff
2372cb2:ec::/322cb2:ec:ffff:ffff:ffff:ffff:ffff:ffff
2382cb2:ed::/322cb2:ed:ffff:ffff:ffff:ffff:ffff:ffff
2392cb2:ee::/322cb2:ee:ffff:ffff:ffff:ffff:ffff:ffff
2402cb2:ef::/322cb2:ef:ffff:ffff:ffff:ffff:ffff:ffff
2412cb2:f0::/322cb2:f0:ffff:ffff:ffff:ffff:ffff:ffff
2422cb2:f1::/322cb2:f1:ffff:ffff:ffff:ffff:ffff:ffff
2432cb2:f2::/322cb2:f2:ffff:ffff:ffff:ffff:ffff:ffff
2442cb2:f3::/322cb2:f3:ffff:ffff:ffff:ffff:ffff:ffff
2452cb2:f4::/322cb2:f4:ffff:ffff:ffff:ffff:ffff:ffff
2462cb2:f5::/322cb2:f5:ffff:ffff:ffff:ffff:ffff:ffff
2472cb2:f6::/322cb2:f6:ffff:ffff:ffff:ffff:ffff:ffff
2482cb2:f7::/322cb2:f7:ffff:ffff:ffff:ffff:ffff:ffff
2492cb2:f8::/322cb2:f8:ffff:ffff:ffff:ffff:ffff:ffff
2502cb2:f9::/322cb2:f9:ffff:ffff:ffff:ffff:ffff:ffff
2512cb2:fa::/322cb2:fa:ffff:ffff:ffff:ffff:ffff:ffff
2522cb2:fb::/322cb2:fb:ffff:ffff:ffff:ffff:ffff:ffff
2532cb2:fc::/322cb2:fc:ffff:ffff:ffff:ffff:ffff:ffff
2542cb2:fd::/322cb2:fd:ffff:ffff:ffff:ffff:ffff:ffff
2552cb2:fe::/322cb2:fe:ffff:ffff:ffff:ffff:ffff:ffff
2562cb2:ff::/322cb2:ff: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.