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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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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
2c8b::/16
First address
2c8b::
Last address
2c8b: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
2c8b:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
b.8.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)

2c8b::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12c8b::/282c8b:f:ffff:ffff:ffff:ffff:ffff:ffff
22c8b:10::/282c8b:1f:ffff:ffff:ffff:ffff:ffff:ffff
32c8b:20::/282c8b:2f:ffff:ffff:ffff:ffff:ffff:ffff
42c8b:30::/282c8b:3f:ffff:ffff:ffff:ffff:ffff:ffff
52c8b:40::/282c8b:4f:ffff:ffff:ffff:ffff:ffff:ffff
62c8b:50::/282c8b:5f:ffff:ffff:ffff:ffff:ffff:ffff
72c8b:60::/282c8b:6f:ffff:ffff:ffff:ffff:ffff:ffff
82c8b:70::/282c8b:7f:ffff:ffff:ffff:ffff:ffff:ffff
92c8b:80::/282c8b:8f:ffff:ffff:ffff:ffff:ffff:ffff
102c8b:90::/282c8b:9f:ffff:ffff:ffff:ffff:ffff:ffff
112c8b:a0::/282c8b:af:ffff:ffff:ffff:ffff:ffff:ffff
122c8b:b0::/282c8b:bf:ffff:ffff:ffff:ffff:ffff:ffff
132c8b:c0::/282c8b:cf:ffff:ffff:ffff:ffff:ffff:ffff
142c8b:d0::/282c8b:df:ffff:ffff:ffff:ffff:ffff:ffff
152c8b:e0::/282c8b:ef:ffff:ffff:ffff:ffff:ffff:ffff
162c8b:f0::/282c8b:ff:ffff:ffff:ffff:ffff:ffff:ffff
172c8b:100::/282c8b:10f:ffff:ffff:ffff:ffff:ffff:ffff
182c8b:110::/282c8b:11f:ffff:ffff:ffff:ffff:ffff:ffff
192c8b:120::/282c8b:12f:ffff:ffff:ffff:ffff:ffff:ffff
202c8b:130::/282c8b:13f:ffff:ffff:ffff:ffff:ffff:ffff
212c8b:140::/282c8b:14f:ffff:ffff:ffff:ffff:ffff:ffff
222c8b:150::/282c8b:15f:ffff:ffff:ffff:ffff:ffff:ffff
232c8b:160::/282c8b:16f:ffff:ffff:ffff:ffff:ffff:ffff
242c8b:170::/282c8b:17f:ffff:ffff:ffff:ffff:ffff:ffff
252c8b:180::/282c8b:18f:ffff:ffff:ffff:ffff:ffff:ffff
262c8b:190::/282c8b:19f:ffff:ffff:ffff:ffff:ffff:ffff
272c8b:1a0::/282c8b:1af:ffff:ffff:ffff:ffff:ffff:ffff
282c8b:1b0::/282c8b:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292c8b:1c0::/282c8b:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302c8b:1d0::/282c8b:1df:ffff:ffff:ffff:ffff:ffff:ffff
312c8b:1e0::/282c8b:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322c8b:1f0::/282c8b:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332c8b:200::/282c8b:20f:ffff:ffff:ffff:ffff:ffff:ffff
342c8b:210::/282c8b:21f:ffff:ffff:ffff:ffff:ffff:ffff
352c8b:220::/282c8b:22f:ffff:ffff:ffff:ffff:ffff:ffff
362c8b:230::/282c8b:23f:ffff:ffff:ffff:ffff:ffff:ffff
372c8b:240::/282c8b:24f:ffff:ffff:ffff:ffff:ffff:ffff
382c8b:250::/282c8b:25f:ffff:ffff:ffff:ffff:ffff:ffff
392c8b:260::/282c8b:26f:ffff:ffff:ffff:ffff:ffff:ffff
402c8b:270::/282c8b:27f:ffff:ffff:ffff:ffff:ffff:ffff
412c8b:280::/282c8b:28f:ffff:ffff:ffff:ffff:ffff:ffff
422c8b:290::/282c8b:29f:ffff:ffff:ffff:ffff:ffff:ffff
432c8b:2a0::/282c8b:2af:ffff:ffff:ffff:ffff:ffff:ffff
442c8b:2b0::/282c8b:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452c8b:2c0::/282c8b:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462c8b:2d0::/282c8b:2df:ffff:ffff:ffff:ffff:ffff:ffff
472c8b:2e0::/282c8b:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482c8b:2f0::/282c8b:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492c8b:300::/282c8b:30f:ffff:ffff:ffff:ffff:ffff:ffff
502c8b:310::/282c8b:31f:ffff:ffff:ffff:ffff:ffff:ffff
512c8b:320::/282c8b:32f:ffff:ffff:ffff:ffff:ffff:ffff
522c8b:330::/282c8b:33f:ffff:ffff:ffff:ffff:ffff:ffff
532c8b:340::/282c8b:34f:ffff:ffff:ffff:ffff:ffff:ffff
542c8b:350::/282c8b:35f:ffff:ffff:ffff:ffff:ffff:ffff
552c8b:360::/282c8b:36f:ffff:ffff:ffff:ffff:ffff:ffff
562c8b:370::/282c8b:37f:ffff:ffff:ffff:ffff:ffff:ffff
572c8b:380::/282c8b:38f:ffff:ffff:ffff:ffff:ffff:ffff
582c8b:390::/282c8b:39f:ffff:ffff:ffff:ffff:ffff:ffff
592c8b:3a0::/282c8b:3af:ffff:ffff:ffff:ffff:ffff:ffff
602c8b:3b0::/282c8b:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612c8b:3c0::/282c8b:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622c8b:3d0::/282c8b:3df:ffff:ffff:ffff:ffff:ffff:ffff
632c8b:3e0::/282c8b:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642c8b:3f0::/282c8b:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652c8b:400::/282c8b:40f:ffff:ffff:ffff:ffff:ffff:ffff
662c8b:410::/282c8b:41f:ffff:ffff:ffff:ffff:ffff:ffff
672c8b:420::/282c8b:42f:ffff:ffff:ffff:ffff:ffff:ffff
682c8b:430::/282c8b:43f:ffff:ffff:ffff:ffff:ffff:ffff
692c8b:440::/282c8b:44f:ffff:ffff:ffff:ffff:ffff:ffff
702c8b:450::/282c8b:45f:ffff:ffff:ffff:ffff:ffff:ffff
712c8b:460::/282c8b:46f:ffff:ffff:ffff:ffff:ffff:ffff
722c8b:470::/282c8b:47f:ffff:ffff:ffff:ffff:ffff:ffff
732c8b:480::/282c8b:48f:ffff:ffff:ffff:ffff:ffff:ffff
742c8b:490::/282c8b:49f:ffff:ffff:ffff:ffff:ffff:ffff
752c8b:4a0::/282c8b:4af:ffff:ffff:ffff:ffff:ffff:ffff
762c8b:4b0::/282c8b:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772c8b:4c0::/282c8b:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782c8b:4d0::/282c8b:4df:ffff:ffff:ffff:ffff:ffff:ffff
792c8b:4e0::/282c8b:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802c8b:4f0::/282c8b:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812c8b:500::/282c8b:50f:ffff:ffff:ffff:ffff:ffff:ffff
822c8b:510::/282c8b:51f:ffff:ffff:ffff:ffff:ffff:ffff
832c8b:520::/282c8b:52f:ffff:ffff:ffff:ffff:ffff:ffff
842c8b:530::/282c8b:53f:ffff:ffff:ffff:ffff:ffff:ffff
852c8b:540::/282c8b:54f:ffff:ffff:ffff:ffff:ffff:ffff
862c8b:550::/282c8b:55f:ffff:ffff:ffff:ffff:ffff:ffff
872c8b:560::/282c8b:56f:ffff:ffff:ffff:ffff:ffff:ffff
882c8b:570::/282c8b:57f:ffff:ffff:ffff:ffff:ffff:ffff
892c8b:580::/282c8b:58f:ffff:ffff:ffff:ffff:ffff:ffff
902c8b:590::/282c8b:59f:ffff:ffff:ffff:ffff:ffff:ffff
912c8b:5a0::/282c8b:5af:ffff:ffff:ffff:ffff:ffff:ffff
922c8b:5b0::/282c8b:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932c8b:5c0::/282c8b:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942c8b:5d0::/282c8b:5df:ffff:ffff:ffff:ffff:ffff:ffff
952c8b:5e0::/282c8b:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962c8b:5f0::/282c8b:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972c8b:600::/282c8b:60f:ffff:ffff:ffff:ffff:ffff:ffff
982c8b:610::/282c8b:61f:ffff:ffff:ffff:ffff:ffff:ffff
992c8b:620::/282c8b:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002c8b:630::/282c8b:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012c8b:640::/282c8b:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022c8b:650::/282c8b:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032c8b:660::/282c8b:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042c8b:670::/282c8b:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052c8b:680::/282c8b:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062c8b:690::/282c8b:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072c8b:6a0::/282c8b:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082c8b:6b0::/282c8b:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092c8b:6c0::/282c8b:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102c8b:6d0::/282c8b:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112c8b:6e0::/282c8b:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122c8b:6f0::/282c8b:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132c8b:700::/282c8b:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142c8b:710::/282c8b:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152c8b:720::/282c8b:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162c8b:730::/282c8b:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172c8b:740::/282c8b:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182c8b:750::/282c8b:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192c8b:760::/282c8b:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202c8b:770::/282c8b:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212c8b:780::/282c8b:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222c8b:790::/282c8b:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232c8b:7a0::/282c8b:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242c8b:7b0::/282c8b:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252c8b:7c0::/282c8b:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262c8b:7d0::/282c8b:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272c8b:7e0::/282c8b:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282c8b:7f0::/282c8b:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292c8b:800::/282c8b:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302c8b:810::/282c8b:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312c8b:820::/282c8b:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322c8b:830::/282c8b:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332c8b:840::/282c8b:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342c8b:850::/282c8b:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352c8b:860::/282c8b:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362c8b:870::/282c8b:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372c8b:880::/282c8b:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382c8b:890::/282c8b:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392c8b:8a0::/282c8b:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402c8b:8b0::/282c8b:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412c8b:8c0::/282c8b:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422c8b:8d0::/282c8b:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432c8b:8e0::/282c8b:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442c8b:8f0::/282c8b:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452c8b:900::/282c8b:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462c8b:910::/282c8b:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472c8b:920::/282c8b:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482c8b:930::/282c8b:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492c8b:940::/282c8b:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502c8b:950::/282c8b:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512c8b:960::/282c8b:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522c8b:970::/282c8b:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532c8b:980::/282c8b:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542c8b:990::/282c8b:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552c8b:9a0::/282c8b:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562c8b:9b0::/282c8b:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572c8b:9c0::/282c8b:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582c8b:9d0::/282c8b:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592c8b:9e0::/282c8b:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602c8b:9f0::/282c8b:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612c8b:a00::/282c8b:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622c8b:a10::/282c8b:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632c8b:a20::/282c8b:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642c8b:a30::/282c8b:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652c8b:a40::/282c8b:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662c8b:a50::/282c8b:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672c8b:a60::/282c8b:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682c8b:a70::/282c8b:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692c8b:a80::/282c8b:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702c8b:a90::/282c8b:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712c8b:aa0::/282c8b:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722c8b:ab0::/282c8b:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732c8b:ac0::/282c8b:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742c8b:ad0::/282c8b:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752c8b:ae0::/282c8b:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762c8b:af0::/282c8b:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772c8b:b00::/282c8b:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782c8b:b10::/282c8b:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792c8b:b20::/282c8b:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802c8b:b30::/282c8b:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812c8b:b40::/282c8b:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822c8b:b50::/282c8b:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832c8b:b60::/282c8b:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842c8b:b70::/282c8b:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852c8b:b80::/282c8b:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862c8b:b90::/282c8b:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872c8b:ba0::/282c8b:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882c8b:bb0::/282c8b:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892c8b:bc0::/282c8b:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902c8b:bd0::/282c8b:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912c8b:be0::/282c8b:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922c8b:bf0::/282c8b:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932c8b:c00::/282c8b:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942c8b:c10::/282c8b:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952c8b:c20::/282c8b:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962c8b:c30::/282c8b:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972c8b:c40::/282c8b:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982c8b:c50::/282c8b:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992c8b:c60::/282c8b:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002c8b:c70::/282c8b:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012c8b:c80::/282c8b:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022c8b:c90::/282c8b:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032c8b:ca0::/282c8b:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042c8b:cb0::/282c8b:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052c8b:cc0::/282c8b:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062c8b:cd0::/282c8b:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072c8b:ce0::/282c8b:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082c8b:cf0::/282c8b:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092c8b:d00::/282c8b:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102c8b:d10::/282c8b:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112c8b:d20::/282c8b:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122c8b:d30::/282c8b:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132c8b:d40::/282c8b:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142c8b:d50::/282c8b:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152c8b:d60::/282c8b:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162c8b:d70::/282c8b:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172c8b:d80::/282c8b:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182c8b:d90::/282c8b:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192c8b:da0::/282c8b:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202c8b:db0::/282c8b:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212c8b:dc0::/282c8b:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222c8b:dd0::/282c8b:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232c8b:de0::/282c8b:def:ffff:ffff:ffff:ffff:ffff:ffff
2242c8b:df0::/282c8b:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252c8b:e00::/282c8b:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262c8b:e10::/282c8b:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272c8b:e20::/282c8b:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282c8b:e30::/282c8b:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292c8b:e40::/282c8b:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302c8b:e50::/282c8b:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312c8b:e60::/282c8b:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322c8b:e70::/282c8b:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332c8b:e80::/282c8b:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342c8b:e90::/282c8b:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352c8b:ea0::/282c8b:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362c8b:eb0::/282c8b:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372c8b:ec0::/282c8b:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382c8b:ed0::/282c8b:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392c8b:ee0::/282c8b:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402c8b:ef0::/282c8b:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412c8b:f00::/282c8b:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422c8b:f10::/282c8b:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432c8b:f20::/282c8b:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442c8b:f30::/282c8b:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452c8b:f40::/282c8b:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462c8b:f50::/282c8b:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472c8b:f60::/282c8b:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482c8b:f70::/282c8b:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492c8b:f80::/282c8b:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502c8b:f90::/282c8b:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512c8b:fa0::/282c8b:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522c8b:fb0::/282c8b:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532c8b:fc0::/282c8b:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542c8b:fd0::/282c8b:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552c8b:fe0::/282c8b:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562c8b:ff0::/282c8b: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.