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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
2cd9::/16
First address
2cd9::
Last address
2cd9: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
2cd9:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
9.d.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)

2cd9::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12cd9::/282cd9:f:ffff:ffff:ffff:ffff:ffff:ffff
22cd9:10::/282cd9:1f:ffff:ffff:ffff:ffff:ffff:ffff
32cd9:20::/282cd9:2f:ffff:ffff:ffff:ffff:ffff:ffff
42cd9:30::/282cd9:3f:ffff:ffff:ffff:ffff:ffff:ffff
52cd9:40::/282cd9:4f:ffff:ffff:ffff:ffff:ffff:ffff
62cd9:50::/282cd9:5f:ffff:ffff:ffff:ffff:ffff:ffff
72cd9:60::/282cd9:6f:ffff:ffff:ffff:ffff:ffff:ffff
82cd9:70::/282cd9:7f:ffff:ffff:ffff:ffff:ffff:ffff
92cd9:80::/282cd9:8f:ffff:ffff:ffff:ffff:ffff:ffff
102cd9:90::/282cd9:9f:ffff:ffff:ffff:ffff:ffff:ffff
112cd9:a0::/282cd9:af:ffff:ffff:ffff:ffff:ffff:ffff
122cd9:b0::/282cd9:bf:ffff:ffff:ffff:ffff:ffff:ffff
132cd9:c0::/282cd9:cf:ffff:ffff:ffff:ffff:ffff:ffff
142cd9:d0::/282cd9:df:ffff:ffff:ffff:ffff:ffff:ffff
152cd9:e0::/282cd9:ef:ffff:ffff:ffff:ffff:ffff:ffff
162cd9:f0::/282cd9:ff:ffff:ffff:ffff:ffff:ffff:ffff
172cd9:100::/282cd9:10f:ffff:ffff:ffff:ffff:ffff:ffff
182cd9:110::/282cd9:11f:ffff:ffff:ffff:ffff:ffff:ffff
192cd9:120::/282cd9:12f:ffff:ffff:ffff:ffff:ffff:ffff
202cd9:130::/282cd9:13f:ffff:ffff:ffff:ffff:ffff:ffff
212cd9:140::/282cd9:14f:ffff:ffff:ffff:ffff:ffff:ffff
222cd9:150::/282cd9:15f:ffff:ffff:ffff:ffff:ffff:ffff
232cd9:160::/282cd9:16f:ffff:ffff:ffff:ffff:ffff:ffff
242cd9:170::/282cd9:17f:ffff:ffff:ffff:ffff:ffff:ffff
252cd9:180::/282cd9:18f:ffff:ffff:ffff:ffff:ffff:ffff
262cd9:190::/282cd9:19f:ffff:ffff:ffff:ffff:ffff:ffff
272cd9:1a0::/282cd9:1af:ffff:ffff:ffff:ffff:ffff:ffff
282cd9:1b0::/282cd9:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292cd9:1c0::/282cd9:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302cd9:1d0::/282cd9:1df:ffff:ffff:ffff:ffff:ffff:ffff
312cd9:1e0::/282cd9:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322cd9:1f0::/282cd9:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332cd9:200::/282cd9:20f:ffff:ffff:ffff:ffff:ffff:ffff
342cd9:210::/282cd9:21f:ffff:ffff:ffff:ffff:ffff:ffff
352cd9:220::/282cd9:22f:ffff:ffff:ffff:ffff:ffff:ffff
362cd9:230::/282cd9:23f:ffff:ffff:ffff:ffff:ffff:ffff
372cd9:240::/282cd9:24f:ffff:ffff:ffff:ffff:ffff:ffff
382cd9:250::/282cd9:25f:ffff:ffff:ffff:ffff:ffff:ffff
392cd9:260::/282cd9:26f:ffff:ffff:ffff:ffff:ffff:ffff
402cd9:270::/282cd9:27f:ffff:ffff:ffff:ffff:ffff:ffff
412cd9:280::/282cd9:28f:ffff:ffff:ffff:ffff:ffff:ffff
422cd9:290::/282cd9:29f:ffff:ffff:ffff:ffff:ffff:ffff
432cd9:2a0::/282cd9:2af:ffff:ffff:ffff:ffff:ffff:ffff
442cd9:2b0::/282cd9:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452cd9:2c0::/282cd9:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462cd9:2d0::/282cd9:2df:ffff:ffff:ffff:ffff:ffff:ffff
472cd9:2e0::/282cd9:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482cd9:2f0::/282cd9:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492cd9:300::/282cd9:30f:ffff:ffff:ffff:ffff:ffff:ffff
502cd9:310::/282cd9:31f:ffff:ffff:ffff:ffff:ffff:ffff
512cd9:320::/282cd9:32f:ffff:ffff:ffff:ffff:ffff:ffff
522cd9:330::/282cd9:33f:ffff:ffff:ffff:ffff:ffff:ffff
532cd9:340::/282cd9:34f:ffff:ffff:ffff:ffff:ffff:ffff
542cd9:350::/282cd9:35f:ffff:ffff:ffff:ffff:ffff:ffff
552cd9:360::/282cd9:36f:ffff:ffff:ffff:ffff:ffff:ffff
562cd9:370::/282cd9:37f:ffff:ffff:ffff:ffff:ffff:ffff
572cd9:380::/282cd9:38f:ffff:ffff:ffff:ffff:ffff:ffff
582cd9:390::/282cd9:39f:ffff:ffff:ffff:ffff:ffff:ffff
592cd9:3a0::/282cd9:3af:ffff:ffff:ffff:ffff:ffff:ffff
602cd9:3b0::/282cd9:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612cd9:3c0::/282cd9:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622cd9:3d0::/282cd9:3df:ffff:ffff:ffff:ffff:ffff:ffff
632cd9:3e0::/282cd9:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642cd9:3f0::/282cd9:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652cd9:400::/282cd9:40f:ffff:ffff:ffff:ffff:ffff:ffff
662cd9:410::/282cd9:41f:ffff:ffff:ffff:ffff:ffff:ffff
672cd9:420::/282cd9:42f:ffff:ffff:ffff:ffff:ffff:ffff
682cd9:430::/282cd9:43f:ffff:ffff:ffff:ffff:ffff:ffff
692cd9:440::/282cd9:44f:ffff:ffff:ffff:ffff:ffff:ffff
702cd9:450::/282cd9:45f:ffff:ffff:ffff:ffff:ffff:ffff
712cd9:460::/282cd9:46f:ffff:ffff:ffff:ffff:ffff:ffff
722cd9:470::/282cd9:47f:ffff:ffff:ffff:ffff:ffff:ffff
732cd9:480::/282cd9:48f:ffff:ffff:ffff:ffff:ffff:ffff
742cd9:490::/282cd9:49f:ffff:ffff:ffff:ffff:ffff:ffff
752cd9:4a0::/282cd9:4af:ffff:ffff:ffff:ffff:ffff:ffff
762cd9:4b0::/282cd9:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772cd9:4c0::/282cd9:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782cd9:4d0::/282cd9:4df:ffff:ffff:ffff:ffff:ffff:ffff
792cd9:4e0::/282cd9:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802cd9:4f0::/282cd9:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812cd9:500::/282cd9:50f:ffff:ffff:ffff:ffff:ffff:ffff
822cd9:510::/282cd9:51f:ffff:ffff:ffff:ffff:ffff:ffff
832cd9:520::/282cd9:52f:ffff:ffff:ffff:ffff:ffff:ffff
842cd9:530::/282cd9:53f:ffff:ffff:ffff:ffff:ffff:ffff
852cd9:540::/282cd9:54f:ffff:ffff:ffff:ffff:ffff:ffff
862cd9:550::/282cd9:55f:ffff:ffff:ffff:ffff:ffff:ffff
872cd9:560::/282cd9:56f:ffff:ffff:ffff:ffff:ffff:ffff
882cd9:570::/282cd9:57f:ffff:ffff:ffff:ffff:ffff:ffff
892cd9:580::/282cd9:58f:ffff:ffff:ffff:ffff:ffff:ffff
902cd9:590::/282cd9:59f:ffff:ffff:ffff:ffff:ffff:ffff
912cd9:5a0::/282cd9:5af:ffff:ffff:ffff:ffff:ffff:ffff
922cd9:5b0::/282cd9:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932cd9:5c0::/282cd9:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942cd9:5d0::/282cd9:5df:ffff:ffff:ffff:ffff:ffff:ffff
952cd9:5e0::/282cd9:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962cd9:5f0::/282cd9:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972cd9:600::/282cd9:60f:ffff:ffff:ffff:ffff:ffff:ffff
982cd9:610::/282cd9:61f:ffff:ffff:ffff:ffff:ffff:ffff
992cd9:620::/282cd9:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002cd9:630::/282cd9:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012cd9:640::/282cd9:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022cd9:650::/282cd9:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032cd9:660::/282cd9:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042cd9:670::/282cd9:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052cd9:680::/282cd9:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062cd9:690::/282cd9:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072cd9:6a0::/282cd9:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082cd9:6b0::/282cd9:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092cd9:6c0::/282cd9:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102cd9:6d0::/282cd9:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112cd9:6e0::/282cd9:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122cd9:6f0::/282cd9:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132cd9:700::/282cd9:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142cd9:710::/282cd9:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152cd9:720::/282cd9:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162cd9:730::/282cd9:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172cd9:740::/282cd9:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182cd9:750::/282cd9:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192cd9:760::/282cd9:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202cd9:770::/282cd9:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212cd9:780::/282cd9:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222cd9:790::/282cd9:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232cd9:7a0::/282cd9:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242cd9:7b0::/282cd9:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252cd9:7c0::/282cd9:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262cd9:7d0::/282cd9:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272cd9:7e0::/282cd9:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282cd9:7f0::/282cd9:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292cd9:800::/282cd9:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302cd9:810::/282cd9:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312cd9:820::/282cd9:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322cd9:830::/282cd9:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332cd9:840::/282cd9:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342cd9:850::/282cd9:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352cd9:860::/282cd9:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362cd9:870::/282cd9:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372cd9:880::/282cd9:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382cd9:890::/282cd9:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392cd9:8a0::/282cd9:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402cd9:8b0::/282cd9:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412cd9:8c0::/282cd9:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422cd9:8d0::/282cd9:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432cd9:8e0::/282cd9:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442cd9:8f0::/282cd9:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452cd9:900::/282cd9:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462cd9:910::/282cd9:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472cd9:920::/282cd9:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482cd9:930::/282cd9:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492cd9:940::/282cd9:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502cd9:950::/282cd9:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512cd9:960::/282cd9:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522cd9:970::/282cd9:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532cd9:980::/282cd9:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542cd9:990::/282cd9:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552cd9:9a0::/282cd9:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562cd9:9b0::/282cd9:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572cd9:9c0::/282cd9:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582cd9:9d0::/282cd9:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592cd9:9e0::/282cd9:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602cd9:9f0::/282cd9:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612cd9:a00::/282cd9:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622cd9:a10::/282cd9:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632cd9:a20::/282cd9:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642cd9:a30::/282cd9:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652cd9:a40::/282cd9:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662cd9:a50::/282cd9:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672cd9:a60::/282cd9:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682cd9:a70::/282cd9:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692cd9:a80::/282cd9:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702cd9:a90::/282cd9:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712cd9:aa0::/282cd9:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722cd9:ab0::/282cd9:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732cd9:ac0::/282cd9:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742cd9:ad0::/282cd9:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752cd9:ae0::/282cd9:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762cd9:af0::/282cd9:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772cd9:b00::/282cd9:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782cd9:b10::/282cd9:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792cd9:b20::/282cd9:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802cd9:b30::/282cd9:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812cd9:b40::/282cd9:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822cd9:b50::/282cd9:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832cd9:b60::/282cd9:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842cd9:b70::/282cd9:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852cd9:b80::/282cd9:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862cd9:b90::/282cd9:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872cd9:ba0::/282cd9:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882cd9:bb0::/282cd9:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892cd9:bc0::/282cd9:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902cd9:bd0::/282cd9:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912cd9:be0::/282cd9:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922cd9:bf0::/282cd9:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932cd9:c00::/282cd9:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942cd9:c10::/282cd9:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952cd9:c20::/282cd9:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962cd9:c30::/282cd9:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972cd9:c40::/282cd9:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982cd9:c50::/282cd9:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992cd9:c60::/282cd9:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002cd9:c70::/282cd9:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012cd9:c80::/282cd9:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022cd9:c90::/282cd9:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032cd9:ca0::/282cd9:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042cd9:cb0::/282cd9:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052cd9:cc0::/282cd9:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062cd9:cd0::/282cd9:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072cd9:ce0::/282cd9:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082cd9:cf0::/282cd9:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092cd9:d00::/282cd9:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102cd9:d10::/282cd9:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112cd9:d20::/282cd9:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122cd9:d30::/282cd9:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132cd9:d40::/282cd9:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142cd9:d50::/282cd9:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152cd9:d60::/282cd9:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162cd9:d70::/282cd9:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172cd9:d80::/282cd9:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182cd9:d90::/282cd9:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192cd9:da0::/282cd9:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202cd9:db0::/282cd9:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212cd9:dc0::/282cd9:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222cd9:dd0::/282cd9:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232cd9:de0::/282cd9:def:ffff:ffff:ffff:ffff:ffff:ffff
2242cd9:df0::/282cd9:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252cd9:e00::/282cd9:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262cd9:e10::/282cd9:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272cd9:e20::/282cd9:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282cd9:e30::/282cd9:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292cd9:e40::/282cd9:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302cd9:e50::/282cd9:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312cd9:e60::/282cd9:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322cd9:e70::/282cd9:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332cd9:e80::/282cd9:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342cd9:e90::/282cd9:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352cd9:ea0::/282cd9:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362cd9:eb0::/282cd9:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372cd9:ec0::/282cd9:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382cd9:ed0::/282cd9:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392cd9:ee0::/282cd9:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402cd9:ef0::/282cd9:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412cd9:f00::/282cd9:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422cd9:f10::/282cd9:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432cd9:f20::/282cd9:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442cd9:f30::/282cd9:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452cd9:f40::/282cd9:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462cd9:f50::/282cd9:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472cd9:f60::/282cd9:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482cd9:f70::/282cd9:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492cd9:f80::/282cd9:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502cd9:f90::/282cd9:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512cd9:fa0::/282cd9:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522cd9:fb0::/282cd9:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532cd9:fc0::/282cd9:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542cd9:fd0::/282cd9:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552cd9:fe0::/282cd9:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562cd9:ff0::/282cd9: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.