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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/12
Addresses2^116
/64 networks2^52
Network
2ff0::/12
First address
2ff0::
Last address
2fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
83,076,749,736,557,242,056,487,941,267,521,536 (2^116)
/64 networks (LANs)
4,503,599,627,370,496 (2^52)
Full form
2ff0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
f.f.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

2ff0::/12 makes 65,536 subnets of /28; the first 256 are listed.

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