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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
2fa0::/12
First address
2fa0::
Last address
2faf: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
2fa0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.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)

2fa0::/12 makes 65,536 subnets of /28; the first 256 are listed.

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