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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
2040::/12
First address
2040::
Last address
204f: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
2040:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
4.0.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

2040::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12040::/282040:f:ffff:ffff:ffff:ffff:ffff:ffff
22040:10::/282040:1f:ffff:ffff:ffff:ffff:ffff:ffff
32040:20::/282040:2f:ffff:ffff:ffff:ffff:ffff:ffff
42040:30::/282040:3f:ffff:ffff:ffff:ffff:ffff:ffff
52040:40::/282040:4f:ffff:ffff:ffff:ffff:ffff:ffff
62040:50::/282040:5f:ffff:ffff:ffff:ffff:ffff:ffff
72040:60::/282040:6f:ffff:ffff:ffff:ffff:ffff:ffff
82040:70::/282040:7f:ffff:ffff:ffff:ffff:ffff:ffff
92040:80::/282040:8f:ffff:ffff:ffff:ffff:ffff:ffff
102040:90::/282040:9f:ffff:ffff:ffff:ffff:ffff:ffff
112040:a0::/282040:af:ffff:ffff:ffff:ffff:ffff:ffff
122040:b0::/282040:bf:ffff:ffff:ffff:ffff:ffff:ffff
132040:c0::/282040:cf:ffff:ffff:ffff:ffff:ffff:ffff
142040:d0::/282040:df:ffff:ffff:ffff:ffff:ffff:ffff
152040:e0::/282040:ef:ffff:ffff:ffff:ffff:ffff:ffff
162040:f0::/282040:ff:ffff:ffff:ffff:ffff:ffff:ffff
172040:100::/282040:10f:ffff:ffff:ffff:ffff:ffff:ffff
182040:110::/282040:11f:ffff:ffff:ffff:ffff:ffff:ffff
192040:120::/282040:12f:ffff:ffff:ffff:ffff:ffff:ffff
202040:130::/282040:13f:ffff:ffff:ffff:ffff:ffff:ffff
212040:140::/282040:14f:ffff:ffff:ffff:ffff:ffff:ffff
222040:150::/282040:15f:ffff:ffff:ffff:ffff:ffff:ffff
232040:160::/282040:16f:ffff:ffff:ffff:ffff:ffff:ffff
242040:170::/282040:17f:ffff:ffff:ffff:ffff:ffff:ffff
252040:180::/282040:18f:ffff:ffff:ffff:ffff:ffff:ffff
262040:190::/282040:19f:ffff:ffff:ffff:ffff:ffff:ffff
272040:1a0::/282040:1af:ffff:ffff:ffff:ffff:ffff:ffff
282040:1b0::/282040:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292040:1c0::/282040:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302040:1d0::/282040:1df:ffff:ffff:ffff:ffff:ffff:ffff
312040:1e0::/282040:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322040:1f0::/282040:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332040:200::/282040:20f:ffff:ffff:ffff:ffff:ffff:ffff
342040:210::/282040:21f:ffff:ffff:ffff:ffff:ffff:ffff
352040:220::/282040:22f:ffff:ffff:ffff:ffff:ffff:ffff
362040:230::/282040:23f:ffff:ffff:ffff:ffff:ffff:ffff
372040:240::/282040:24f:ffff:ffff:ffff:ffff:ffff:ffff
382040:250::/282040:25f:ffff:ffff:ffff:ffff:ffff:ffff
392040:260::/282040:26f:ffff:ffff:ffff:ffff:ffff:ffff
402040:270::/282040:27f:ffff:ffff:ffff:ffff:ffff:ffff
412040:280::/282040:28f:ffff:ffff:ffff:ffff:ffff:ffff
422040:290::/282040:29f:ffff:ffff:ffff:ffff:ffff:ffff
432040:2a0::/282040:2af:ffff:ffff:ffff:ffff:ffff:ffff
442040:2b0::/282040:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452040:2c0::/282040:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462040:2d0::/282040:2df:ffff:ffff:ffff:ffff:ffff:ffff
472040:2e0::/282040:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482040:2f0::/282040:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492040:300::/282040:30f:ffff:ffff:ffff:ffff:ffff:ffff
502040:310::/282040:31f:ffff:ffff:ffff:ffff:ffff:ffff
512040:320::/282040:32f:ffff:ffff:ffff:ffff:ffff:ffff
522040:330::/282040:33f:ffff:ffff:ffff:ffff:ffff:ffff
532040:340::/282040:34f:ffff:ffff:ffff:ffff:ffff:ffff
542040:350::/282040:35f:ffff:ffff:ffff:ffff:ffff:ffff
552040:360::/282040:36f:ffff:ffff:ffff:ffff:ffff:ffff
562040:370::/282040:37f:ffff:ffff:ffff:ffff:ffff:ffff
572040:380::/282040:38f:ffff:ffff:ffff:ffff:ffff:ffff
582040:390::/282040:39f:ffff:ffff:ffff:ffff:ffff:ffff
592040:3a0::/282040:3af:ffff:ffff:ffff:ffff:ffff:ffff
602040:3b0::/282040:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612040:3c0::/282040:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622040:3d0::/282040:3df:ffff:ffff:ffff:ffff:ffff:ffff
632040:3e0::/282040:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642040:3f0::/282040:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652040:400::/282040:40f:ffff:ffff:ffff:ffff:ffff:ffff
662040:410::/282040:41f:ffff:ffff:ffff:ffff:ffff:ffff
672040:420::/282040:42f:ffff:ffff:ffff:ffff:ffff:ffff
682040:430::/282040:43f:ffff:ffff:ffff:ffff:ffff:ffff
692040:440::/282040:44f:ffff:ffff:ffff:ffff:ffff:ffff
702040:450::/282040:45f:ffff:ffff:ffff:ffff:ffff:ffff
712040:460::/282040:46f:ffff:ffff:ffff:ffff:ffff:ffff
722040:470::/282040:47f:ffff:ffff:ffff:ffff:ffff:ffff
732040:480::/282040:48f:ffff:ffff:ffff:ffff:ffff:ffff
742040:490::/282040:49f:ffff:ffff:ffff:ffff:ffff:ffff
752040:4a0::/282040:4af:ffff:ffff:ffff:ffff:ffff:ffff
762040:4b0::/282040:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772040:4c0::/282040:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782040:4d0::/282040:4df:ffff:ffff:ffff:ffff:ffff:ffff
792040:4e0::/282040:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802040:4f0::/282040:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812040:500::/282040:50f:ffff:ffff:ffff:ffff:ffff:ffff
822040:510::/282040:51f:ffff:ffff:ffff:ffff:ffff:ffff
832040:520::/282040:52f:ffff:ffff:ffff:ffff:ffff:ffff
842040:530::/282040:53f:ffff:ffff:ffff:ffff:ffff:ffff
852040:540::/282040:54f:ffff:ffff:ffff:ffff:ffff:ffff
862040:550::/282040:55f:ffff:ffff:ffff:ffff:ffff:ffff
872040:560::/282040:56f:ffff:ffff:ffff:ffff:ffff:ffff
882040:570::/282040:57f:ffff:ffff:ffff:ffff:ffff:ffff
892040:580::/282040:58f:ffff:ffff:ffff:ffff:ffff:ffff
902040:590::/282040:59f:ffff:ffff:ffff:ffff:ffff:ffff
912040:5a0::/282040:5af:ffff:ffff:ffff:ffff:ffff:ffff
922040:5b0::/282040:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932040:5c0::/282040:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942040:5d0::/282040:5df:ffff:ffff:ffff:ffff:ffff:ffff
952040:5e0::/282040:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962040:5f0::/282040:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972040:600::/282040:60f:ffff:ffff:ffff:ffff:ffff:ffff
982040:610::/282040:61f:ffff:ffff:ffff:ffff:ffff:ffff
992040:620::/282040:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002040:630::/282040:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012040:640::/282040:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022040:650::/282040:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032040:660::/282040:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042040:670::/282040:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052040:680::/282040:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062040:690::/282040:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072040:6a0::/282040:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082040:6b0::/282040:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092040:6c0::/282040:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102040:6d0::/282040:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112040:6e0::/282040:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122040:6f0::/282040:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132040:700::/282040:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142040:710::/282040:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152040:720::/282040:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162040:730::/282040:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172040:740::/282040:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182040:750::/282040:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192040:760::/282040:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202040:770::/282040:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212040:780::/282040:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222040:790::/282040:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232040:7a0::/282040:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242040:7b0::/282040:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252040:7c0::/282040:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262040:7d0::/282040:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272040:7e0::/282040:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282040:7f0::/282040:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292040:800::/282040:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302040:810::/282040:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312040:820::/282040:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322040:830::/282040:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332040:840::/282040:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342040:850::/282040:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352040:860::/282040:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362040:870::/282040:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372040:880::/282040:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382040:890::/282040:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392040:8a0::/282040:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402040:8b0::/282040:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412040:8c0::/282040:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422040:8d0::/282040:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432040:8e0::/282040:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442040:8f0::/282040:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452040:900::/282040:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462040:910::/282040:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472040:920::/282040:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482040:930::/282040:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492040:940::/282040:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502040:950::/282040:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512040:960::/282040:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522040:970::/282040:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532040:980::/282040:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542040:990::/282040:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552040:9a0::/282040:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562040:9b0::/282040:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572040:9c0::/282040:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582040:9d0::/282040:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592040:9e0::/282040:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602040:9f0::/282040:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612040:a00::/282040:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622040:a10::/282040:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632040:a20::/282040:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642040:a30::/282040:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652040:a40::/282040:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662040:a50::/282040:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672040:a60::/282040:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682040:a70::/282040:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692040:a80::/282040:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702040:a90::/282040:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712040:aa0::/282040:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722040:ab0::/282040:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732040:ac0::/282040:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742040:ad0::/282040:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752040:ae0::/282040:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762040:af0::/282040:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772040:b00::/282040:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782040:b10::/282040:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792040:b20::/282040:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802040:b30::/282040:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812040:b40::/282040:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822040:b50::/282040:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832040:b60::/282040:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842040:b70::/282040:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852040:b80::/282040:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862040:b90::/282040:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872040:ba0::/282040:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882040:bb0::/282040:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892040:bc0::/282040:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902040:bd0::/282040:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912040:be0::/282040:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922040:bf0::/282040:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932040:c00::/282040:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942040:c10::/282040:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952040:c20::/282040:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962040:c30::/282040:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972040:c40::/282040:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982040:c50::/282040:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992040:c60::/282040:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002040:c70::/282040:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012040:c80::/282040:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022040:c90::/282040:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032040:ca0::/282040:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042040:cb0::/282040:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052040:cc0::/282040:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062040:cd0::/282040:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072040:ce0::/282040:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082040:cf0::/282040:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092040:d00::/282040:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102040:d10::/282040:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112040:d20::/282040:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122040:d30::/282040:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132040:d40::/282040:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142040:d50::/282040:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152040:d60::/282040:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162040:d70::/282040:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172040:d80::/282040:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182040:d90::/282040:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192040:da0::/282040:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202040:db0::/282040:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212040:dc0::/282040:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222040:dd0::/282040:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232040:de0::/282040:def:ffff:ffff:ffff:ffff:ffff:ffff
2242040:df0::/282040:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252040:e00::/282040:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262040:e10::/282040:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272040:e20::/282040:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282040:e30::/282040:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292040:e40::/282040:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302040:e50::/282040:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312040:e60::/282040:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322040:e70::/282040:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332040:e80::/282040:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342040:e90::/282040:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352040:ea0::/282040:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362040:eb0::/282040:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372040:ec0::/282040:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382040:ed0::/282040:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392040:ee0::/282040:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402040:ef0::/282040:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412040:f00::/282040:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422040:f10::/282040:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432040:f20::/282040:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442040:f30::/282040:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452040:f40::/282040:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462040:f50::/282040:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472040:f60::/282040:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482040:f70::/282040:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492040:f80::/282040:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502040:f90::/282040:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512040:fa0::/282040:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522040:fb0::/282040:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532040:fc0::/282040:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542040:fd0::/282040:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552040:fe0::/282040:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562040:ff0::/282040: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.