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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
2520::/12
First address
2520::
Last address
252f: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
2520:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
2.5.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

2520::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12520::/282520:f:ffff:ffff:ffff:ffff:ffff:ffff
22520:10::/282520:1f:ffff:ffff:ffff:ffff:ffff:ffff
32520:20::/282520:2f:ffff:ffff:ffff:ffff:ffff:ffff
42520:30::/282520:3f:ffff:ffff:ffff:ffff:ffff:ffff
52520:40::/282520:4f:ffff:ffff:ffff:ffff:ffff:ffff
62520:50::/282520:5f:ffff:ffff:ffff:ffff:ffff:ffff
72520:60::/282520:6f:ffff:ffff:ffff:ffff:ffff:ffff
82520:70::/282520:7f:ffff:ffff:ffff:ffff:ffff:ffff
92520:80::/282520:8f:ffff:ffff:ffff:ffff:ffff:ffff
102520:90::/282520:9f:ffff:ffff:ffff:ffff:ffff:ffff
112520:a0::/282520:af:ffff:ffff:ffff:ffff:ffff:ffff
122520:b0::/282520:bf:ffff:ffff:ffff:ffff:ffff:ffff
132520:c0::/282520:cf:ffff:ffff:ffff:ffff:ffff:ffff
142520:d0::/282520:df:ffff:ffff:ffff:ffff:ffff:ffff
152520:e0::/282520:ef:ffff:ffff:ffff:ffff:ffff:ffff
162520:f0::/282520:ff:ffff:ffff:ffff:ffff:ffff:ffff
172520:100::/282520:10f:ffff:ffff:ffff:ffff:ffff:ffff
182520:110::/282520:11f:ffff:ffff:ffff:ffff:ffff:ffff
192520:120::/282520:12f:ffff:ffff:ffff:ffff:ffff:ffff
202520:130::/282520:13f:ffff:ffff:ffff:ffff:ffff:ffff
212520:140::/282520:14f:ffff:ffff:ffff:ffff:ffff:ffff
222520:150::/282520:15f:ffff:ffff:ffff:ffff:ffff:ffff
232520:160::/282520:16f:ffff:ffff:ffff:ffff:ffff:ffff
242520:170::/282520:17f:ffff:ffff:ffff:ffff:ffff:ffff
252520:180::/282520:18f:ffff:ffff:ffff:ffff:ffff:ffff
262520:190::/282520:19f:ffff:ffff:ffff:ffff:ffff:ffff
272520:1a0::/282520:1af:ffff:ffff:ffff:ffff:ffff:ffff
282520:1b0::/282520:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292520:1c0::/282520:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302520:1d0::/282520:1df:ffff:ffff:ffff:ffff:ffff:ffff
312520:1e0::/282520:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322520:1f0::/282520:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332520:200::/282520:20f:ffff:ffff:ffff:ffff:ffff:ffff
342520:210::/282520:21f:ffff:ffff:ffff:ffff:ffff:ffff
352520:220::/282520:22f:ffff:ffff:ffff:ffff:ffff:ffff
362520:230::/282520:23f:ffff:ffff:ffff:ffff:ffff:ffff
372520:240::/282520:24f:ffff:ffff:ffff:ffff:ffff:ffff
382520:250::/282520:25f:ffff:ffff:ffff:ffff:ffff:ffff
392520:260::/282520:26f:ffff:ffff:ffff:ffff:ffff:ffff
402520:270::/282520:27f:ffff:ffff:ffff:ffff:ffff:ffff
412520:280::/282520:28f:ffff:ffff:ffff:ffff:ffff:ffff
422520:290::/282520:29f:ffff:ffff:ffff:ffff:ffff:ffff
432520:2a0::/282520:2af:ffff:ffff:ffff:ffff:ffff:ffff
442520:2b0::/282520:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452520:2c0::/282520:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462520:2d0::/282520:2df:ffff:ffff:ffff:ffff:ffff:ffff
472520:2e0::/282520:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482520:2f0::/282520:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492520:300::/282520:30f:ffff:ffff:ffff:ffff:ffff:ffff
502520:310::/282520:31f:ffff:ffff:ffff:ffff:ffff:ffff
512520:320::/282520:32f:ffff:ffff:ffff:ffff:ffff:ffff
522520:330::/282520:33f:ffff:ffff:ffff:ffff:ffff:ffff
532520:340::/282520:34f:ffff:ffff:ffff:ffff:ffff:ffff
542520:350::/282520:35f:ffff:ffff:ffff:ffff:ffff:ffff
552520:360::/282520:36f:ffff:ffff:ffff:ffff:ffff:ffff
562520:370::/282520:37f:ffff:ffff:ffff:ffff:ffff:ffff
572520:380::/282520:38f:ffff:ffff:ffff:ffff:ffff:ffff
582520:390::/282520:39f:ffff:ffff:ffff:ffff:ffff:ffff
592520:3a0::/282520:3af:ffff:ffff:ffff:ffff:ffff:ffff
602520:3b0::/282520:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612520:3c0::/282520:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622520:3d0::/282520:3df:ffff:ffff:ffff:ffff:ffff:ffff
632520:3e0::/282520:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642520:3f0::/282520:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652520:400::/282520:40f:ffff:ffff:ffff:ffff:ffff:ffff
662520:410::/282520:41f:ffff:ffff:ffff:ffff:ffff:ffff
672520:420::/282520:42f:ffff:ffff:ffff:ffff:ffff:ffff
682520:430::/282520:43f:ffff:ffff:ffff:ffff:ffff:ffff
692520:440::/282520:44f:ffff:ffff:ffff:ffff:ffff:ffff
702520:450::/282520:45f:ffff:ffff:ffff:ffff:ffff:ffff
712520:460::/282520:46f:ffff:ffff:ffff:ffff:ffff:ffff
722520:470::/282520:47f:ffff:ffff:ffff:ffff:ffff:ffff
732520:480::/282520:48f:ffff:ffff:ffff:ffff:ffff:ffff
742520:490::/282520:49f:ffff:ffff:ffff:ffff:ffff:ffff
752520:4a0::/282520:4af:ffff:ffff:ffff:ffff:ffff:ffff
762520:4b0::/282520:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772520:4c0::/282520:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782520:4d0::/282520:4df:ffff:ffff:ffff:ffff:ffff:ffff
792520:4e0::/282520:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802520:4f0::/282520:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812520:500::/282520:50f:ffff:ffff:ffff:ffff:ffff:ffff
822520:510::/282520:51f:ffff:ffff:ffff:ffff:ffff:ffff
832520:520::/282520:52f:ffff:ffff:ffff:ffff:ffff:ffff
842520:530::/282520:53f:ffff:ffff:ffff:ffff:ffff:ffff
852520:540::/282520:54f:ffff:ffff:ffff:ffff:ffff:ffff
862520:550::/282520:55f:ffff:ffff:ffff:ffff:ffff:ffff
872520:560::/282520:56f:ffff:ffff:ffff:ffff:ffff:ffff
882520:570::/282520:57f:ffff:ffff:ffff:ffff:ffff:ffff
892520:580::/282520:58f:ffff:ffff:ffff:ffff:ffff:ffff
902520:590::/282520:59f:ffff:ffff:ffff:ffff:ffff:ffff
912520:5a0::/282520:5af:ffff:ffff:ffff:ffff:ffff:ffff
922520:5b0::/282520:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932520:5c0::/282520:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942520:5d0::/282520:5df:ffff:ffff:ffff:ffff:ffff:ffff
952520:5e0::/282520:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962520:5f0::/282520:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972520:600::/282520:60f:ffff:ffff:ffff:ffff:ffff:ffff
982520:610::/282520:61f:ffff:ffff:ffff:ffff:ffff:ffff
992520:620::/282520:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002520:630::/282520:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012520:640::/282520:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022520:650::/282520:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032520:660::/282520:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042520:670::/282520:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052520:680::/282520:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062520:690::/282520:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072520:6a0::/282520:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082520:6b0::/282520:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092520:6c0::/282520:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102520:6d0::/282520:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112520:6e0::/282520:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122520:6f0::/282520:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132520:700::/282520:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142520:710::/282520:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152520:720::/282520:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162520:730::/282520:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172520:740::/282520:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182520:750::/282520:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192520:760::/282520:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202520:770::/282520:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212520:780::/282520:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222520:790::/282520:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232520:7a0::/282520:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242520:7b0::/282520:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252520:7c0::/282520:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262520:7d0::/282520:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272520:7e0::/282520:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282520:7f0::/282520:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292520:800::/282520:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302520:810::/282520:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312520:820::/282520:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322520:830::/282520:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332520:840::/282520:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342520:850::/282520:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352520:860::/282520:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362520:870::/282520:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372520:880::/282520:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382520:890::/282520:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392520:8a0::/282520:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402520:8b0::/282520:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412520:8c0::/282520:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422520:8d0::/282520:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432520:8e0::/282520:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442520:8f0::/282520:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452520:900::/282520:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462520:910::/282520:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472520:920::/282520:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482520:930::/282520:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492520:940::/282520:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502520:950::/282520:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512520:960::/282520:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522520:970::/282520:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532520:980::/282520:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542520:990::/282520:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552520:9a0::/282520:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562520:9b0::/282520:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572520:9c0::/282520:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582520:9d0::/282520:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592520:9e0::/282520:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602520:9f0::/282520:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612520:a00::/282520:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622520:a10::/282520:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632520:a20::/282520:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642520:a30::/282520:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652520:a40::/282520:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662520:a50::/282520:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672520:a60::/282520:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682520:a70::/282520:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692520:a80::/282520:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702520:a90::/282520:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712520:aa0::/282520:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722520:ab0::/282520:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732520:ac0::/282520:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742520:ad0::/282520:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752520:ae0::/282520:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762520:af0::/282520:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772520:b00::/282520:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782520:b10::/282520:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792520:b20::/282520:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802520:b30::/282520:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812520:b40::/282520:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822520:b50::/282520:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832520:b60::/282520:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842520:b70::/282520:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852520:b80::/282520:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862520:b90::/282520:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872520:ba0::/282520:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882520:bb0::/282520:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892520:bc0::/282520:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902520:bd0::/282520:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912520:be0::/282520:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922520:bf0::/282520:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932520:c00::/282520:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942520:c10::/282520:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952520:c20::/282520:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962520:c30::/282520:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972520:c40::/282520:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982520:c50::/282520:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992520:c60::/282520:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002520:c70::/282520:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012520:c80::/282520:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022520:c90::/282520:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032520:ca0::/282520:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042520:cb0::/282520:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052520:cc0::/282520:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062520:cd0::/282520:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072520:ce0::/282520:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082520:cf0::/282520:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092520:d00::/282520:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102520:d10::/282520:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112520:d20::/282520:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122520:d30::/282520:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132520:d40::/282520:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142520:d50::/282520:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152520:d60::/282520:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162520:d70::/282520:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172520:d80::/282520:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182520:d90::/282520:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192520:da0::/282520:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202520:db0::/282520:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212520:dc0::/282520:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222520:dd0::/282520:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232520:de0::/282520:def:ffff:ffff:ffff:ffff:ffff:ffff
2242520:df0::/282520:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252520:e00::/282520:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262520:e10::/282520:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272520:e20::/282520:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282520:e30::/282520:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292520:e40::/282520:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302520:e50::/282520:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312520:e60::/282520:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322520:e70::/282520:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332520:e80::/282520:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342520:e90::/282520:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352520:ea0::/282520:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362520:eb0::/282520:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372520:ec0::/282520:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382520:ed0::/282520:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392520:ee0::/282520:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402520:ef0::/282520:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412520:f00::/282520:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422520:f10::/282520:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432520:f20::/282520:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442520:f30::/282520:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452520:f40::/282520:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462520:f50::/282520:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472520:f60::/282520:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482520:f70::/282520:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492520:f80::/282520:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502520:f90::/282520:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512520:fa0::/282520:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522520:fb0::/282520:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532520:fc0::/282520:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542520:fd0::/282520:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552520:fe0::/282520:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562520:ff0::/282520: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.