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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
2ca3::/16
First address
2ca3::
Last address
2ca3: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
2ca3:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
3.a.c.2.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2ca3::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12ca3::/282ca3:f:ffff:ffff:ffff:ffff:ffff:ffff
22ca3:10::/282ca3:1f:ffff:ffff:ffff:ffff:ffff:ffff
32ca3:20::/282ca3:2f:ffff:ffff:ffff:ffff:ffff:ffff
42ca3:30::/282ca3:3f:ffff:ffff:ffff:ffff:ffff:ffff
52ca3:40::/282ca3:4f:ffff:ffff:ffff:ffff:ffff:ffff
62ca3:50::/282ca3:5f:ffff:ffff:ffff:ffff:ffff:ffff
72ca3:60::/282ca3:6f:ffff:ffff:ffff:ffff:ffff:ffff
82ca3:70::/282ca3:7f:ffff:ffff:ffff:ffff:ffff:ffff
92ca3:80::/282ca3:8f:ffff:ffff:ffff:ffff:ffff:ffff
102ca3:90::/282ca3:9f:ffff:ffff:ffff:ffff:ffff:ffff
112ca3:a0::/282ca3:af:ffff:ffff:ffff:ffff:ffff:ffff
122ca3:b0::/282ca3:bf:ffff:ffff:ffff:ffff:ffff:ffff
132ca3:c0::/282ca3:cf:ffff:ffff:ffff:ffff:ffff:ffff
142ca3:d0::/282ca3:df:ffff:ffff:ffff:ffff:ffff:ffff
152ca3:e0::/282ca3:ef:ffff:ffff:ffff:ffff:ffff:ffff
162ca3:f0::/282ca3:ff:ffff:ffff:ffff:ffff:ffff:ffff
172ca3:100::/282ca3:10f:ffff:ffff:ffff:ffff:ffff:ffff
182ca3:110::/282ca3:11f:ffff:ffff:ffff:ffff:ffff:ffff
192ca3:120::/282ca3:12f:ffff:ffff:ffff:ffff:ffff:ffff
202ca3:130::/282ca3:13f:ffff:ffff:ffff:ffff:ffff:ffff
212ca3:140::/282ca3:14f:ffff:ffff:ffff:ffff:ffff:ffff
222ca3:150::/282ca3:15f:ffff:ffff:ffff:ffff:ffff:ffff
232ca3:160::/282ca3:16f:ffff:ffff:ffff:ffff:ffff:ffff
242ca3:170::/282ca3:17f:ffff:ffff:ffff:ffff:ffff:ffff
252ca3:180::/282ca3:18f:ffff:ffff:ffff:ffff:ffff:ffff
262ca3:190::/282ca3:19f:ffff:ffff:ffff:ffff:ffff:ffff
272ca3:1a0::/282ca3:1af:ffff:ffff:ffff:ffff:ffff:ffff
282ca3:1b0::/282ca3:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292ca3:1c0::/282ca3:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302ca3:1d0::/282ca3:1df:ffff:ffff:ffff:ffff:ffff:ffff
312ca3:1e0::/282ca3:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322ca3:1f0::/282ca3:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332ca3:200::/282ca3:20f:ffff:ffff:ffff:ffff:ffff:ffff
342ca3:210::/282ca3:21f:ffff:ffff:ffff:ffff:ffff:ffff
352ca3:220::/282ca3:22f:ffff:ffff:ffff:ffff:ffff:ffff
362ca3:230::/282ca3:23f:ffff:ffff:ffff:ffff:ffff:ffff
372ca3:240::/282ca3:24f:ffff:ffff:ffff:ffff:ffff:ffff
382ca3:250::/282ca3:25f:ffff:ffff:ffff:ffff:ffff:ffff
392ca3:260::/282ca3:26f:ffff:ffff:ffff:ffff:ffff:ffff
402ca3:270::/282ca3:27f:ffff:ffff:ffff:ffff:ffff:ffff
412ca3:280::/282ca3:28f:ffff:ffff:ffff:ffff:ffff:ffff
422ca3:290::/282ca3:29f:ffff:ffff:ffff:ffff:ffff:ffff
432ca3:2a0::/282ca3:2af:ffff:ffff:ffff:ffff:ffff:ffff
442ca3:2b0::/282ca3:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452ca3:2c0::/282ca3:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462ca3:2d0::/282ca3:2df:ffff:ffff:ffff:ffff:ffff:ffff
472ca3:2e0::/282ca3:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482ca3:2f0::/282ca3:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492ca3:300::/282ca3:30f:ffff:ffff:ffff:ffff:ffff:ffff
502ca3:310::/282ca3:31f:ffff:ffff:ffff:ffff:ffff:ffff
512ca3:320::/282ca3:32f:ffff:ffff:ffff:ffff:ffff:ffff
522ca3:330::/282ca3:33f:ffff:ffff:ffff:ffff:ffff:ffff
532ca3:340::/282ca3:34f:ffff:ffff:ffff:ffff:ffff:ffff
542ca3:350::/282ca3:35f:ffff:ffff:ffff:ffff:ffff:ffff
552ca3:360::/282ca3:36f:ffff:ffff:ffff:ffff:ffff:ffff
562ca3:370::/282ca3:37f:ffff:ffff:ffff:ffff:ffff:ffff
572ca3:380::/282ca3:38f:ffff:ffff:ffff:ffff:ffff:ffff
582ca3:390::/282ca3:39f:ffff:ffff:ffff:ffff:ffff:ffff
592ca3:3a0::/282ca3:3af:ffff:ffff:ffff:ffff:ffff:ffff
602ca3:3b0::/282ca3:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612ca3:3c0::/282ca3:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622ca3:3d0::/282ca3:3df:ffff:ffff:ffff:ffff:ffff:ffff
632ca3:3e0::/282ca3:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642ca3:3f0::/282ca3:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652ca3:400::/282ca3:40f:ffff:ffff:ffff:ffff:ffff:ffff
662ca3:410::/282ca3:41f:ffff:ffff:ffff:ffff:ffff:ffff
672ca3:420::/282ca3:42f:ffff:ffff:ffff:ffff:ffff:ffff
682ca3:430::/282ca3:43f:ffff:ffff:ffff:ffff:ffff:ffff
692ca3:440::/282ca3:44f:ffff:ffff:ffff:ffff:ffff:ffff
702ca3:450::/282ca3:45f:ffff:ffff:ffff:ffff:ffff:ffff
712ca3:460::/282ca3:46f:ffff:ffff:ffff:ffff:ffff:ffff
722ca3:470::/282ca3:47f:ffff:ffff:ffff:ffff:ffff:ffff
732ca3:480::/282ca3:48f:ffff:ffff:ffff:ffff:ffff:ffff
742ca3:490::/282ca3:49f:ffff:ffff:ffff:ffff:ffff:ffff
752ca3:4a0::/282ca3:4af:ffff:ffff:ffff:ffff:ffff:ffff
762ca3:4b0::/282ca3:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772ca3:4c0::/282ca3:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782ca3:4d0::/282ca3:4df:ffff:ffff:ffff:ffff:ffff:ffff
792ca3:4e0::/282ca3:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802ca3:4f0::/282ca3:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812ca3:500::/282ca3:50f:ffff:ffff:ffff:ffff:ffff:ffff
822ca3:510::/282ca3:51f:ffff:ffff:ffff:ffff:ffff:ffff
832ca3:520::/282ca3:52f:ffff:ffff:ffff:ffff:ffff:ffff
842ca3:530::/282ca3:53f:ffff:ffff:ffff:ffff:ffff:ffff
852ca3:540::/282ca3:54f:ffff:ffff:ffff:ffff:ffff:ffff
862ca3:550::/282ca3:55f:ffff:ffff:ffff:ffff:ffff:ffff
872ca3:560::/282ca3:56f:ffff:ffff:ffff:ffff:ffff:ffff
882ca3:570::/282ca3:57f:ffff:ffff:ffff:ffff:ffff:ffff
892ca3:580::/282ca3:58f:ffff:ffff:ffff:ffff:ffff:ffff
902ca3:590::/282ca3:59f:ffff:ffff:ffff:ffff:ffff:ffff
912ca3:5a0::/282ca3:5af:ffff:ffff:ffff:ffff:ffff:ffff
922ca3:5b0::/282ca3:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932ca3:5c0::/282ca3:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942ca3:5d0::/282ca3:5df:ffff:ffff:ffff:ffff:ffff:ffff
952ca3:5e0::/282ca3:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962ca3:5f0::/282ca3:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972ca3:600::/282ca3:60f:ffff:ffff:ffff:ffff:ffff:ffff
982ca3:610::/282ca3:61f:ffff:ffff:ffff:ffff:ffff:ffff
992ca3:620::/282ca3:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002ca3:630::/282ca3:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012ca3:640::/282ca3:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022ca3:650::/282ca3:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032ca3:660::/282ca3:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042ca3:670::/282ca3:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052ca3:680::/282ca3:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062ca3:690::/282ca3:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072ca3:6a0::/282ca3:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082ca3:6b0::/282ca3:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092ca3:6c0::/282ca3:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102ca3:6d0::/282ca3:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112ca3:6e0::/282ca3:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122ca3:6f0::/282ca3:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132ca3:700::/282ca3:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142ca3:710::/282ca3:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152ca3:720::/282ca3:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162ca3:730::/282ca3:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172ca3:740::/282ca3:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182ca3:750::/282ca3:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192ca3:760::/282ca3:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202ca3:770::/282ca3:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212ca3:780::/282ca3:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222ca3:790::/282ca3:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232ca3:7a0::/282ca3:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242ca3:7b0::/282ca3:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252ca3:7c0::/282ca3:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262ca3:7d0::/282ca3:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272ca3:7e0::/282ca3:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282ca3:7f0::/282ca3:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292ca3:800::/282ca3:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302ca3:810::/282ca3:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312ca3:820::/282ca3:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322ca3:830::/282ca3:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332ca3:840::/282ca3:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342ca3:850::/282ca3:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352ca3:860::/282ca3:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362ca3:870::/282ca3:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372ca3:880::/282ca3:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382ca3:890::/282ca3:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392ca3:8a0::/282ca3:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402ca3:8b0::/282ca3:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412ca3:8c0::/282ca3:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422ca3:8d0::/282ca3:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432ca3:8e0::/282ca3:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442ca3:8f0::/282ca3:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452ca3:900::/282ca3:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462ca3:910::/282ca3:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472ca3:920::/282ca3:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482ca3:930::/282ca3:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492ca3:940::/282ca3:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502ca3:950::/282ca3:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512ca3:960::/282ca3:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522ca3:970::/282ca3:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532ca3:980::/282ca3:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542ca3:990::/282ca3:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552ca3:9a0::/282ca3:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562ca3:9b0::/282ca3:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572ca3:9c0::/282ca3:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582ca3:9d0::/282ca3:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592ca3:9e0::/282ca3:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602ca3:9f0::/282ca3:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612ca3:a00::/282ca3:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622ca3:a10::/282ca3:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632ca3:a20::/282ca3:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642ca3:a30::/282ca3:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652ca3:a40::/282ca3:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662ca3:a50::/282ca3:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672ca3:a60::/282ca3:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682ca3:a70::/282ca3:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692ca3:a80::/282ca3:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702ca3:a90::/282ca3:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712ca3:aa0::/282ca3:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722ca3:ab0::/282ca3:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732ca3:ac0::/282ca3:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742ca3:ad0::/282ca3:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752ca3:ae0::/282ca3:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762ca3:af0::/282ca3:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772ca3:b00::/282ca3:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782ca3:b10::/282ca3:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792ca3:b20::/282ca3:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802ca3:b30::/282ca3:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812ca3:b40::/282ca3:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822ca3:b50::/282ca3:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832ca3:b60::/282ca3:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842ca3:b70::/282ca3:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852ca3:b80::/282ca3:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862ca3:b90::/282ca3:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872ca3:ba0::/282ca3:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882ca3:bb0::/282ca3:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892ca3:bc0::/282ca3:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902ca3:bd0::/282ca3:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912ca3:be0::/282ca3:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922ca3:bf0::/282ca3:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932ca3:c00::/282ca3:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942ca3:c10::/282ca3:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952ca3:c20::/282ca3:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962ca3:c30::/282ca3:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972ca3:c40::/282ca3:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982ca3:c50::/282ca3:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992ca3:c60::/282ca3:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002ca3:c70::/282ca3:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012ca3:c80::/282ca3:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022ca3:c90::/282ca3:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032ca3:ca0::/282ca3:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042ca3:cb0::/282ca3:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052ca3:cc0::/282ca3:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062ca3:cd0::/282ca3:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072ca3:ce0::/282ca3:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082ca3:cf0::/282ca3:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092ca3:d00::/282ca3:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102ca3:d10::/282ca3:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112ca3:d20::/282ca3:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122ca3:d30::/282ca3:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132ca3:d40::/282ca3:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142ca3:d50::/282ca3:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152ca3:d60::/282ca3:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162ca3:d70::/282ca3:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172ca3:d80::/282ca3:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182ca3:d90::/282ca3:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192ca3:da0::/282ca3:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202ca3:db0::/282ca3:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212ca3:dc0::/282ca3:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222ca3:dd0::/282ca3:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232ca3:de0::/282ca3:def:ffff:ffff:ffff:ffff:ffff:ffff
2242ca3:df0::/282ca3:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252ca3:e00::/282ca3:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262ca3:e10::/282ca3:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272ca3:e20::/282ca3:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282ca3:e30::/282ca3:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292ca3:e40::/282ca3:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302ca3:e50::/282ca3:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312ca3:e60::/282ca3:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322ca3:e70::/282ca3:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332ca3:e80::/282ca3:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342ca3:e90::/282ca3:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352ca3:ea0::/282ca3:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362ca3:eb0::/282ca3:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372ca3:ec0::/282ca3:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382ca3:ed0::/282ca3:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392ca3:ee0::/282ca3:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402ca3:ef0::/282ca3:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412ca3:f00::/282ca3:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422ca3:f10::/282ca3:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432ca3:f20::/282ca3:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442ca3:f30::/282ca3:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452ca3:f40::/282ca3:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462ca3:f50::/282ca3:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472ca3:f60::/282ca3:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482ca3:f70::/282ca3:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492ca3:f80::/282ca3:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502ca3:f90::/282ca3:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512ca3:fa0::/282ca3:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522ca3:fb0::/282ca3:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532ca3:fc0::/282ca3:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542ca3:fd0::/282ca3:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552ca3:fe0::/282ca3:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562ca3:ff0::/282ca3:fff: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.