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

3eff::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
13eff::/323eff:0:ffff:ffff:ffff:ffff:ffff:ffff
23eff:1::/323eff:1:ffff:ffff:ffff:ffff:ffff:ffff
33eff:2::/323eff:2:ffff:ffff:ffff:ffff:ffff:ffff
43eff:3::/323eff:3:ffff:ffff:ffff:ffff:ffff:ffff
53eff:4::/323eff:4:ffff:ffff:ffff:ffff:ffff:ffff
63eff:5::/323eff:5:ffff:ffff:ffff:ffff:ffff:ffff
73eff:6::/323eff:6:ffff:ffff:ffff:ffff:ffff:ffff
83eff:7::/323eff:7:ffff:ffff:ffff:ffff:ffff:ffff
93eff:8::/323eff:8:ffff:ffff:ffff:ffff:ffff:ffff
103eff:9::/323eff:9:ffff:ffff:ffff:ffff:ffff:ffff
113eff:a::/323eff:a:ffff:ffff:ffff:ffff:ffff:ffff
123eff:b::/323eff:b:ffff:ffff:ffff:ffff:ffff:ffff
133eff:c::/323eff:c:ffff:ffff:ffff:ffff:ffff:ffff
143eff:d::/323eff:d:ffff:ffff:ffff:ffff:ffff:ffff
153eff:e::/323eff:e:ffff:ffff:ffff:ffff:ffff:ffff
163eff:f::/323eff:f:ffff:ffff:ffff:ffff:ffff:ffff
173eff:10::/323eff:10:ffff:ffff:ffff:ffff:ffff:ffff
183eff:11::/323eff:11:ffff:ffff:ffff:ffff:ffff:ffff
193eff:12::/323eff:12:ffff:ffff:ffff:ffff:ffff:ffff
203eff:13::/323eff:13:ffff:ffff:ffff:ffff:ffff:ffff
213eff:14::/323eff:14:ffff:ffff:ffff:ffff:ffff:ffff
223eff:15::/323eff:15:ffff:ffff:ffff:ffff:ffff:ffff
233eff:16::/323eff:16:ffff:ffff:ffff:ffff:ffff:ffff
243eff:17::/323eff:17:ffff:ffff:ffff:ffff:ffff:ffff
253eff:18::/323eff:18:ffff:ffff:ffff:ffff:ffff:ffff
263eff:19::/323eff:19:ffff:ffff:ffff:ffff:ffff:ffff
273eff:1a::/323eff:1a:ffff:ffff:ffff:ffff:ffff:ffff
283eff:1b::/323eff:1b:ffff:ffff:ffff:ffff:ffff:ffff
293eff:1c::/323eff:1c:ffff:ffff:ffff:ffff:ffff:ffff
303eff:1d::/323eff:1d:ffff:ffff:ffff:ffff:ffff:ffff
313eff:1e::/323eff:1e:ffff:ffff:ffff:ffff:ffff:ffff
323eff:1f::/323eff:1f:ffff:ffff:ffff:ffff:ffff:ffff
333eff:20::/323eff:20:ffff:ffff:ffff:ffff:ffff:ffff
343eff:21::/323eff:21:ffff:ffff:ffff:ffff:ffff:ffff
353eff:22::/323eff:22:ffff:ffff:ffff:ffff:ffff:ffff
363eff:23::/323eff:23:ffff:ffff:ffff:ffff:ffff:ffff
373eff:24::/323eff:24:ffff:ffff:ffff:ffff:ffff:ffff
383eff:25::/323eff:25:ffff:ffff:ffff:ffff:ffff:ffff
393eff:26::/323eff:26:ffff:ffff:ffff:ffff:ffff:ffff
403eff:27::/323eff:27:ffff:ffff:ffff:ffff:ffff:ffff
413eff:28::/323eff:28:ffff:ffff:ffff:ffff:ffff:ffff
423eff:29::/323eff:29:ffff:ffff:ffff:ffff:ffff:ffff
433eff:2a::/323eff:2a:ffff:ffff:ffff:ffff:ffff:ffff
443eff:2b::/323eff:2b:ffff:ffff:ffff:ffff:ffff:ffff
453eff:2c::/323eff:2c:ffff:ffff:ffff:ffff:ffff:ffff
463eff:2d::/323eff:2d:ffff:ffff:ffff:ffff:ffff:ffff
473eff:2e::/323eff:2e:ffff:ffff:ffff:ffff:ffff:ffff
483eff:2f::/323eff:2f:ffff:ffff:ffff:ffff:ffff:ffff
493eff:30::/323eff:30:ffff:ffff:ffff:ffff:ffff:ffff
503eff:31::/323eff:31:ffff:ffff:ffff:ffff:ffff:ffff
513eff:32::/323eff:32:ffff:ffff:ffff:ffff:ffff:ffff
523eff:33::/323eff:33:ffff:ffff:ffff:ffff:ffff:ffff
533eff:34::/323eff:34:ffff:ffff:ffff:ffff:ffff:ffff
543eff:35::/323eff:35:ffff:ffff:ffff:ffff:ffff:ffff
553eff:36::/323eff:36:ffff:ffff:ffff:ffff:ffff:ffff
563eff:37::/323eff:37:ffff:ffff:ffff:ffff:ffff:ffff
573eff:38::/323eff:38:ffff:ffff:ffff:ffff:ffff:ffff
583eff:39::/323eff:39:ffff:ffff:ffff:ffff:ffff:ffff
593eff:3a::/323eff:3a:ffff:ffff:ffff:ffff:ffff:ffff
603eff:3b::/323eff:3b:ffff:ffff:ffff:ffff:ffff:ffff
613eff:3c::/323eff:3c:ffff:ffff:ffff:ffff:ffff:ffff
623eff:3d::/323eff:3d:ffff:ffff:ffff:ffff:ffff:ffff
633eff:3e::/323eff:3e:ffff:ffff:ffff:ffff:ffff:ffff
643eff:3f::/323eff:3f:ffff:ffff:ffff:ffff:ffff:ffff
653eff:40::/323eff:40:ffff:ffff:ffff:ffff:ffff:ffff
663eff:41::/323eff:41:ffff:ffff:ffff:ffff:ffff:ffff
673eff:42::/323eff:42:ffff:ffff:ffff:ffff:ffff:ffff
683eff:43::/323eff:43:ffff:ffff:ffff:ffff:ffff:ffff
693eff:44::/323eff:44:ffff:ffff:ffff:ffff:ffff:ffff
703eff:45::/323eff:45:ffff:ffff:ffff:ffff:ffff:ffff
713eff:46::/323eff:46:ffff:ffff:ffff:ffff:ffff:ffff
723eff:47::/323eff:47:ffff:ffff:ffff:ffff:ffff:ffff
733eff:48::/323eff:48:ffff:ffff:ffff:ffff:ffff:ffff
743eff:49::/323eff:49:ffff:ffff:ffff:ffff:ffff:ffff
753eff:4a::/323eff:4a:ffff:ffff:ffff:ffff:ffff:ffff
763eff:4b::/323eff:4b:ffff:ffff:ffff:ffff:ffff:ffff
773eff:4c::/323eff:4c:ffff:ffff:ffff:ffff:ffff:ffff
783eff:4d::/323eff:4d:ffff:ffff:ffff:ffff:ffff:ffff
793eff:4e::/323eff:4e:ffff:ffff:ffff:ffff:ffff:ffff
803eff:4f::/323eff:4f:ffff:ffff:ffff:ffff:ffff:ffff
813eff:50::/323eff:50:ffff:ffff:ffff:ffff:ffff:ffff
823eff:51::/323eff:51:ffff:ffff:ffff:ffff:ffff:ffff
833eff:52::/323eff:52:ffff:ffff:ffff:ffff:ffff:ffff
843eff:53::/323eff:53:ffff:ffff:ffff:ffff:ffff:ffff
853eff:54::/323eff:54:ffff:ffff:ffff:ffff:ffff:ffff
863eff:55::/323eff:55:ffff:ffff:ffff:ffff:ffff:ffff
873eff:56::/323eff:56:ffff:ffff:ffff:ffff:ffff:ffff
883eff:57::/323eff:57:ffff:ffff:ffff:ffff:ffff:ffff
893eff:58::/323eff:58:ffff:ffff:ffff:ffff:ffff:ffff
903eff:59::/323eff:59:ffff:ffff:ffff:ffff:ffff:ffff
913eff:5a::/323eff:5a:ffff:ffff:ffff:ffff:ffff:ffff
923eff:5b::/323eff:5b:ffff:ffff:ffff:ffff:ffff:ffff
933eff:5c::/323eff:5c:ffff:ffff:ffff:ffff:ffff:ffff
943eff:5d::/323eff:5d:ffff:ffff:ffff:ffff:ffff:ffff
953eff:5e::/323eff:5e:ffff:ffff:ffff:ffff:ffff:ffff
963eff:5f::/323eff:5f:ffff:ffff:ffff:ffff:ffff:ffff
973eff:60::/323eff:60:ffff:ffff:ffff:ffff:ffff:ffff
983eff:61::/323eff:61:ffff:ffff:ffff:ffff:ffff:ffff
993eff:62::/323eff:62:ffff:ffff:ffff:ffff:ffff:ffff
1003eff:63::/323eff:63:ffff:ffff:ffff:ffff:ffff:ffff
1013eff:64::/323eff:64:ffff:ffff:ffff:ffff:ffff:ffff
1023eff:65::/323eff:65:ffff:ffff:ffff:ffff:ffff:ffff
1033eff:66::/323eff:66:ffff:ffff:ffff:ffff:ffff:ffff
1043eff:67::/323eff:67:ffff:ffff:ffff:ffff:ffff:ffff
1053eff:68::/323eff:68:ffff:ffff:ffff:ffff:ffff:ffff
1063eff:69::/323eff:69:ffff:ffff:ffff:ffff:ffff:ffff
1073eff:6a::/323eff:6a:ffff:ffff:ffff:ffff:ffff:ffff
1083eff:6b::/323eff:6b:ffff:ffff:ffff:ffff:ffff:ffff
1093eff:6c::/323eff:6c:ffff:ffff:ffff:ffff:ffff:ffff
1103eff:6d::/323eff:6d:ffff:ffff:ffff:ffff:ffff:ffff
1113eff:6e::/323eff:6e:ffff:ffff:ffff:ffff:ffff:ffff
1123eff:6f::/323eff:6f:ffff:ffff:ffff:ffff:ffff:ffff
1133eff:70::/323eff:70:ffff:ffff:ffff:ffff:ffff:ffff
1143eff:71::/323eff:71:ffff:ffff:ffff:ffff:ffff:ffff
1153eff:72::/323eff:72:ffff:ffff:ffff:ffff:ffff:ffff
1163eff:73::/323eff:73:ffff:ffff:ffff:ffff:ffff:ffff
1173eff:74::/323eff:74:ffff:ffff:ffff:ffff:ffff:ffff
1183eff:75::/323eff:75:ffff:ffff:ffff:ffff:ffff:ffff
1193eff:76::/323eff:76:ffff:ffff:ffff:ffff:ffff:ffff
1203eff:77::/323eff:77:ffff:ffff:ffff:ffff:ffff:ffff
1213eff:78::/323eff:78:ffff:ffff:ffff:ffff:ffff:ffff
1223eff:79::/323eff:79:ffff:ffff:ffff:ffff:ffff:ffff
1233eff:7a::/323eff:7a:ffff:ffff:ffff:ffff:ffff:ffff
1243eff:7b::/323eff:7b:ffff:ffff:ffff:ffff:ffff:ffff
1253eff:7c::/323eff:7c:ffff:ffff:ffff:ffff:ffff:ffff
1263eff:7d::/323eff:7d:ffff:ffff:ffff:ffff:ffff:ffff
1273eff:7e::/323eff:7e:ffff:ffff:ffff:ffff:ffff:ffff
1283eff:7f::/323eff:7f:ffff:ffff:ffff:ffff:ffff:ffff
1293eff:80::/323eff:80:ffff:ffff:ffff:ffff:ffff:ffff
1303eff:81::/323eff:81:ffff:ffff:ffff:ffff:ffff:ffff
1313eff:82::/323eff:82:ffff:ffff:ffff:ffff:ffff:ffff
1323eff:83::/323eff:83:ffff:ffff:ffff:ffff:ffff:ffff
1333eff:84::/323eff:84:ffff:ffff:ffff:ffff:ffff:ffff
1343eff:85::/323eff:85:ffff:ffff:ffff:ffff:ffff:ffff
1353eff:86::/323eff:86:ffff:ffff:ffff:ffff:ffff:ffff
1363eff:87::/323eff:87:ffff:ffff:ffff:ffff:ffff:ffff
1373eff:88::/323eff:88:ffff:ffff:ffff:ffff:ffff:ffff
1383eff:89::/323eff:89:ffff:ffff:ffff:ffff:ffff:ffff
1393eff:8a::/323eff:8a:ffff:ffff:ffff:ffff:ffff:ffff
1403eff:8b::/323eff:8b:ffff:ffff:ffff:ffff:ffff:ffff
1413eff:8c::/323eff:8c:ffff:ffff:ffff:ffff:ffff:ffff
1423eff:8d::/323eff:8d:ffff:ffff:ffff:ffff:ffff:ffff
1433eff:8e::/323eff:8e:ffff:ffff:ffff:ffff:ffff:ffff
1443eff:8f::/323eff:8f:ffff:ffff:ffff:ffff:ffff:ffff
1453eff:90::/323eff:90:ffff:ffff:ffff:ffff:ffff:ffff
1463eff:91::/323eff:91:ffff:ffff:ffff:ffff:ffff:ffff
1473eff:92::/323eff:92:ffff:ffff:ffff:ffff:ffff:ffff
1483eff:93::/323eff:93:ffff:ffff:ffff:ffff:ffff:ffff
1493eff:94::/323eff:94:ffff:ffff:ffff:ffff:ffff:ffff
1503eff:95::/323eff:95:ffff:ffff:ffff:ffff:ffff:ffff
1513eff:96::/323eff:96:ffff:ffff:ffff:ffff:ffff:ffff
1523eff:97::/323eff:97:ffff:ffff:ffff:ffff:ffff:ffff
1533eff:98::/323eff:98:ffff:ffff:ffff:ffff:ffff:ffff
1543eff:99::/323eff:99:ffff:ffff:ffff:ffff:ffff:ffff
1553eff:9a::/323eff:9a:ffff:ffff:ffff:ffff:ffff:ffff
1563eff:9b::/323eff:9b:ffff:ffff:ffff:ffff:ffff:ffff
1573eff:9c::/323eff:9c:ffff:ffff:ffff:ffff:ffff:ffff
1583eff:9d::/323eff:9d:ffff:ffff:ffff:ffff:ffff:ffff
1593eff:9e::/323eff:9e:ffff:ffff:ffff:ffff:ffff:ffff
1603eff:9f::/323eff:9f:ffff:ffff:ffff:ffff:ffff:ffff
1613eff:a0::/323eff:a0:ffff:ffff:ffff:ffff:ffff:ffff
1623eff:a1::/323eff:a1:ffff:ffff:ffff:ffff:ffff:ffff
1633eff:a2::/323eff:a2:ffff:ffff:ffff:ffff:ffff:ffff
1643eff:a3::/323eff:a3:ffff:ffff:ffff:ffff:ffff:ffff
1653eff:a4::/323eff:a4:ffff:ffff:ffff:ffff:ffff:ffff
1663eff:a5::/323eff:a5:ffff:ffff:ffff:ffff:ffff:ffff
1673eff:a6::/323eff:a6:ffff:ffff:ffff:ffff:ffff:ffff
1683eff:a7::/323eff:a7:ffff:ffff:ffff:ffff:ffff:ffff
1693eff:a8::/323eff:a8:ffff:ffff:ffff:ffff:ffff:ffff
1703eff:a9::/323eff:a9:ffff:ffff:ffff:ffff:ffff:ffff
1713eff:aa::/323eff:aa:ffff:ffff:ffff:ffff:ffff:ffff
1723eff:ab::/323eff:ab:ffff:ffff:ffff:ffff:ffff:ffff
1733eff:ac::/323eff:ac:ffff:ffff:ffff:ffff:ffff:ffff
1743eff:ad::/323eff:ad:ffff:ffff:ffff:ffff:ffff:ffff
1753eff:ae::/323eff:ae:ffff:ffff:ffff:ffff:ffff:ffff
1763eff:af::/323eff:af:ffff:ffff:ffff:ffff:ffff:ffff
1773eff:b0::/323eff:b0:ffff:ffff:ffff:ffff:ffff:ffff
1783eff:b1::/323eff:b1:ffff:ffff:ffff:ffff:ffff:ffff
1793eff:b2::/323eff:b2:ffff:ffff:ffff:ffff:ffff:ffff
1803eff:b3::/323eff:b3:ffff:ffff:ffff:ffff:ffff:ffff
1813eff:b4::/323eff:b4:ffff:ffff:ffff:ffff:ffff:ffff
1823eff:b5::/323eff:b5:ffff:ffff:ffff:ffff:ffff:ffff
1833eff:b6::/323eff:b6:ffff:ffff:ffff:ffff:ffff:ffff
1843eff:b7::/323eff:b7:ffff:ffff:ffff:ffff:ffff:ffff
1853eff:b8::/323eff:b8:ffff:ffff:ffff:ffff:ffff:ffff
1863eff:b9::/323eff:b9:ffff:ffff:ffff:ffff:ffff:ffff
1873eff:ba::/323eff:ba:ffff:ffff:ffff:ffff:ffff:ffff
1883eff:bb::/323eff:bb:ffff:ffff:ffff:ffff:ffff:ffff
1893eff:bc::/323eff:bc:ffff:ffff:ffff:ffff:ffff:ffff
1903eff:bd::/323eff:bd:ffff:ffff:ffff:ffff:ffff:ffff
1913eff:be::/323eff:be:ffff:ffff:ffff:ffff:ffff:ffff
1923eff:bf::/323eff:bf:ffff:ffff:ffff:ffff:ffff:ffff
1933eff:c0::/323eff:c0:ffff:ffff:ffff:ffff:ffff:ffff
1943eff:c1::/323eff:c1:ffff:ffff:ffff:ffff:ffff:ffff
1953eff:c2::/323eff:c2:ffff:ffff:ffff:ffff:ffff:ffff
1963eff:c3::/323eff:c3:ffff:ffff:ffff:ffff:ffff:ffff
1973eff:c4::/323eff:c4:ffff:ffff:ffff:ffff:ffff:ffff
1983eff:c5::/323eff:c5:ffff:ffff:ffff:ffff:ffff:ffff
1993eff:c6::/323eff:c6:ffff:ffff:ffff:ffff:ffff:ffff
2003eff:c7::/323eff:c7:ffff:ffff:ffff:ffff:ffff:ffff
2013eff:c8::/323eff:c8:ffff:ffff:ffff:ffff:ffff:ffff
2023eff:c9::/323eff:c9:ffff:ffff:ffff:ffff:ffff:ffff
2033eff:ca::/323eff:ca:ffff:ffff:ffff:ffff:ffff:ffff
2043eff:cb::/323eff:cb:ffff:ffff:ffff:ffff:ffff:ffff
2053eff:cc::/323eff:cc:ffff:ffff:ffff:ffff:ffff:ffff
2063eff:cd::/323eff:cd:ffff:ffff:ffff:ffff:ffff:ffff
2073eff:ce::/323eff:ce:ffff:ffff:ffff:ffff:ffff:ffff
2083eff:cf::/323eff:cf:ffff:ffff:ffff:ffff:ffff:ffff
2093eff:d0::/323eff:d0:ffff:ffff:ffff:ffff:ffff:ffff
2103eff:d1::/323eff:d1:ffff:ffff:ffff:ffff:ffff:ffff
2113eff:d2::/323eff:d2:ffff:ffff:ffff:ffff:ffff:ffff
2123eff:d3::/323eff:d3:ffff:ffff:ffff:ffff:ffff:ffff
2133eff:d4::/323eff:d4:ffff:ffff:ffff:ffff:ffff:ffff
2143eff:d5::/323eff:d5:ffff:ffff:ffff:ffff:ffff:ffff
2153eff:d6::/323eff:d6:ffff:ffff:ffff:ffff:ffff:ffff
2163eff:d7::/323eff:d7:ffff:ffff:ffff:ffff:ffff:ffff
2173eff:d8::/323eff:d8:ffff:ffff:ffff:ffff:ffff:ffff
2183eff:d9::/323eff:d9:ffff:ffff:ffff:ffff:ffff:ffff
2193eff:da::/323eff:da:ffff:ffff:ffff:ffff:ffff:ffff
2203eff:db::/323eff:db:ffff:ffff:ffff:ffff:ffff:ffff
2213eff:dc::/323eff:dc:ffff:ffff:ffff:ffff:ffff:ffff
2223eff:dd::/323eff:dd:ffff:ffff:ffff:ffff:ffff:ffff
2233eff:de::/323eff:de:ffff:ffff:ffff:ffff:ffff:ffff
2243eff:df::/323eff:df:ffff:ffff:ffff:ffff:ffff:ffff
2253eff:e0::/323eff:e0:ffff:ffff:ffff:ffff:ffff:ffff
2263eff:e1::/323eff:e1:ffff:ffff:ffff:ffff:ffff:ffff
2273eff:e2::/323eff:e2:ffff:ffff:ffff:ffff:ffff:ffff
2283eff:e3::/323eff:e3:ffff:ffff:ffff:ffff:ffff:ffff
2293eff:e4::/323eff:e4:ffff:ffff:ffff:ffff:ffff:ffff
2303eff:e5::/323eff:e5:ffff:ffff:ffff:ffff:ffff:ffff
2313eff:e6::/323eff:e6:ffff:ffff:ffff:ffff:ffff:ffff
2323eff:e7::/323eff:e7:ffff:ffff:ffff:ffff:ffff:ffff
2333eff:e8::/323eff:e8:ffff:ffff:ffff:ffff:ffff:ffff
2343eff:e9::/323eff:e9:ffff:ffff:ffff:ffff:ffff:ffff
2353eff:ea::/323eff:ea:ffff:ffff:ffff:ffff:ffff:ffff
2363eff:eb::/323eff:eb:ffff:ffff:ffff:ffff:ffff:ffff
2373eff:ec::/323eff:ec:ffff:ffff:ffff:ffff:ffff:ffff
2383eff:ed::/323eff:ed:ffff:ffff:ffff:ffff:ffff:ffff
2393eff:ee::/323eff:ee:ffff:ffff:ffff:ffff:ffff:ffff
2403eff:ef::/323eff:ef:ffff:ffff:ffff:ffff:ffff:ffff
2413eff:f0::/323eff:f0:ffff:ffff:ffff:ffff:ffff:ffff
2423eff:f1::/323eff:f1:ffff:ffff:ffff:ffff:ffff:ffff
2433eff:f2::/323eff:f2:ffff:ffff:ffff:ffff:ffff:ffff
2443eff:f3::/323eff:f3:ffff:ffff:ffff:ffff:ffff:ffff
2453eff:f4::/323eff:f4:ffff:ffff:ffff:ffff:ffff:ffff
2463eff:f5::/323eff:f5:ffff:ffff:ffff:ffff:ffff:ffff
2473eff:f6::/323eff:f6:ffff:ffff:ffff:ffff:ffff:ffff
2483eff:f7::/323eff:f7:ffff:ffff:ffff:ffff:ffff:ffff
2493eff:f8::/323eff:f8:ffff:ffff:ffff:ffff:ffff:ffff
2503eff:f9::/323eff:f9:ffff:ffff:ffff:ffff:ffff:ffff
2513eff:fa::/323eff:fa:ffff:ffff:ffff:ffff:ffff:ffff
2523eff:fb::/323eff:fb:ffff:ffff:ffff:ffff:ffff:ffff
2533eff:fc::/323eff:fc:ffff:ffff:ffff:ffff:ffff:ffff
2543eff:fd::/323eff:fd:ffff:ffff:ffff:ffff:ffff:ffff
2553eff:fe::/323eff:fe:ffff:ffff:ffff:ffff:ffff:ffff
2563eff:ff::/323eff: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.