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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
2037::/16
First address
2037::
Last address
2037: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
2037:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
7.3.0.2.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

2037::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12037::/282037:f:ffff:ffff:ffff:ffff:ffff:ffff
22037:10::/282037:1f:ffff:ffff:ffff:ffff:ffff:ffff
32037:20::/282037:2f:ffff:ffff:ffff:ffff:ffff:ffff
42037:30::/282037:3f:ffff:ffff:ffff:ffff:ffff:ffff
52037:40::/282037:4f:ffff:ffff:ffff:ffff:ffff:ffff
62037:50::/282037:5f:ffff:ffff:ffff:ffff:ffff:ffff
72037:60::/282037:6f:ffff:ffff:ffff:ffff:ffff:ffff
82037:70::/282037:7f:ffff:ffff:ffff:ffff:ffff:ffff
92037:80::/282037:8f:ffff:ffff:ffff:ffff:ffff:ffff
102037:90::/282037:9f:ffff:ffff:ffff:ffff:ffff:ffff
112037:a0::/282037:af:ffff:ffff:ffff:ffff:ffff:ffff
122037:b0::/282037:bf:ffff:ffff:ffff:ffff:ffff:ffff
132037:c0::/282037:cf:ffff:ffff:ffff:ffff:ffff:ffff
142037:d0::/282037:df:ffff:ffff:ffff:ffff:ffff:ffff
152037:e0::/282037:ef:ffff:ffff:ffff:ffff:ffff:ffff
162037:f0::/282037:ff:ffff:ffff:ffff:ffff:ffff:ffff
172037:100::/282037:10f:ffff:ffff:ffff:ffff:ffff:ffff
182037:110::/282037:11f:ffff:ffff:ffff:ffff:ffff:ffff
192037:120::/282037:12f:ffff:ffff:ffff:ffff:ffff:ffff
202037:130::/282037:13f:ffff:ffff:ffff:ffff:ffff:ffff
212037:140::/282037:14f:ffff:ffff:ffff:ffff:ffff:ffff
222037:150::/282037:15f:ffff:ffff:ffff:ffff:ffff:ffff
232037:160::/282037:16f:ffff:ffff:ffff:ffff:ffff:ffff
242037:170::/282037:17f:ffff:ffff:ffff:ffff:ffff:ffff
252037:180::/282037:18f:ffff:ffff:ffff:ffff:ffff:ffff
262037:190::/282037:19f:ffff:ffff:ffff:ffff:ffff:ffff
272037:1a0::/282037:1af:ffff:ffff:ffff:ffff:ffff:ffff
282037:1b0::/282037:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292037:1c0::/282037:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302037:1d0::/282037:1df:ffff:ffff:ffff:ffff:ffff:ffff
312037:1e0::/282037:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322037:1f0::/282037:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332037:200::/282037:20f:ffff:ffff:ffff:ffff:ffff:ffff
342037:210::/282037:21f:ffff:ffff:ffff:ffff:ffff:ffff
352037:220::/282037:22f:ffff:ffff:ffff:ffff:ffff:ffff
362037:230::/282037:23f:ffff:ffff:ffff:ffff:ffff:ffff
372037:240::/282037:24f:ffff:ffff:ffff:ffff:ffff:ffff
382037:250::/282037:25f:ffff:ffff:ffff:ffff:ffff:ffff
392037:260::/282037:26f:ffff:ffff:ffff:ffff:ffff:ffff
402037:270::/282037:27f:ffff:ffff:ffff:ffff:ffff:ffff
412037:280::/282037:28f:ffff:ffff:ffff:ffff:ffff:ffff
422037:290::/282037:29f:ffff:ffff:ffff:ffff:ffff:ffff
432037:2a0::/282037:2af:ffff:ffff:ffff:ffff:ffff:ffff
442037:2b0::/282037:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452037:2c0::/282037:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462037:2d0::/282037:2df:ffff:ffff:ffff:ffff:ffff:ffff
472037:2e0::/282037:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482037:2f0::/282037:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492037:300::/282037:30f:ffff:ffff:ffff:ffff:ffff:ffff
502037:310::/282037:31f:ffff:ffff:ffff:ffff:ffff:ffff
512037:320::/282037:32f:ffff:ffff:ffff:ffff:ffff:ffff
522037:330::/282037:33f:ffff:ffff:ffff:ffff:ffff:ffff
532037:340::/282037:34f:ffff:ffff:ffff:ffff:ffff:ffff
542037:350::/282037:35f:ffff:ffff:ffff:ffff:ffff:ffff
552037:360::/282037:36f:ffff:ffff:ffff:ffff:ffff:ffff
562037:370::/282037:37f:ffff:ffff:ffff:ffff:ffff:ffff
572037:380::/282037:38f:ffff:ffff:ffff:ffff:ffff:ffff
582037:390::/282037:39f:ffff:ffff:ffff:ffff:ffff:ffff
592037:3a0::/282037:3af:ffff:ffff:ffff:ffff:ffff:ffff
602037:3b0::/282037:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612037:3c0::/282037:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622037:3d0::/282037:3df:ffff:ffff:ffff:ffff:ffff:ffff
632037:3e0::/282037:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642037:3f0::/282037:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652037:400::/282037:40f:ffff:ffff:ffff:ffff:ffff:ffff
662037:410::/282037:41f:ffff:ffff:ffff:ffff:ffff:ffff
672037:420::/282037:42f:ffff:ffff:ffff:ffff:ffff:ffff
682037:430::/282037:43f:ffff:ffff:ffff:ffff:ffff:ffff
692037:440::/282037:44f:ffff:ffff:ffff:ffff:ffff:ffff
702037:450::/282037:45f:ffff:ffff:ffff:ffff:ffff:ffff
712037:460::/282037:46f:ffff:ffff:ffff:ffff:ffff:ffff
722037:470::/282037:47f:ffff:ffff:ffff:ffff:ffff:ffff
732037:480::/282037:48f:ffff:ffff:ffff:ffff:ffff:ffff
742037:490::/282037:49f:ffff:ffff:ffff:ffff:ffff:ffff
752037:4a0::/282037:4af:ffff:ffff:ffff:ffff:ffff:ffff
762037:4b0::/282037:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772037:4c0::/282037:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782037:4d0::/282037:4df:ffff:ffff:ffff:ffff:ffff:ffff
792037:4e0::/282037:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802037:4f0::/282037:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812037:500::/282037:50f:ffff:ffff:ffff:ffff:ffff:ffff
822037:510::/282037:51f:ffff:ffff:ffff:ffff:ffff:ffff
832037:520::/282037:52f:ffff:ffff:ffff:ffff:ffff:ffff
842037:530::/282037:53f:ffff:ffff:ffff:ffff:ffff:ffff
852037:540::/282037:54f:ffff:ffff:ffff:ffff:ffff:ffff
862037:550::/282037:55f:ffff:ffff:ffff:ffff:ffff:ffff
872037:560::/282037:56f:ffff:ffff:ffff:ffff:ffff:ffff
882037:570::/282037:57f:ffff:ffff:ffff:ffff:ffff:ffff
892037:580::/282037:58f:ffff:ffff:ffff:ffff:ffff:ffff
902037:590::/282037:59f:ffff:ffff:ffff:ffff:ffff:ffff
912037:5a0::/282037:5af:ffff:ffff:ffff:ffff:ffff:ffff
922037:5b0::/282037:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932037:5c0::/282037:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942037:5d0::/282037:5df:ffff:ffff:ffff:ffff:ffff:ffff
952037:5e0::/282037:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962037:5f0::/282037:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972037:600::/282037:60f:ffff:ffff:ffff:ffff:ffff:ffff
982037:610::/282037:61f:ffff:ffff:ffff:ffff:ffff:ffff
992037:620::/282037:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002037:630::/282037:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012037:640::/282037:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022037:650::/282037:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032037:660::/282037:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042037:670::/282037:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052037:680::/282037:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062037:690::/282037:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072037:6a0::/282037:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082037:6b0::/282037:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092037:6c0::/282037:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102037:6d0::/282037:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112037:6e0::/282037:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122037:6f0::/282037:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132037:700::/282037:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142037:710::/282037:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152037:720::/282037:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162037:730::/282037:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172037:740::/282037:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182037:750::/282037:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192037:760::/282037:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202037:770::/282037:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212037:780::/282037:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222037:790::/282037:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232037:7a0::/282037:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242037:7b0::/282037:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252037:7c0::/282037:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262037:7d0::/282037:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272037:7e0::/282037:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282037:7f0::/282037:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292037:800::/282037:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302037:810::/282037:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312037:820::/282037:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322037:830::/282037:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332037:840::/282037:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342037:850::/282037:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352037:860::/282037:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362037:870::/282037:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372037:880::/282037:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382037:890::/282037:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392037:8a0::/282037:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402037:8b0::/282037:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412037:8c0::/282037:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422037:8d0::/282037:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432037:8e0::/282037:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442037:8f0::/282037:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452037:900::/282037:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462037:910::/282037:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472037:920::/282037:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482037:930::/282037:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492037:940::/282037:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502037:950::/282037:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512037:960::/282037:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522037:970::/282037:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532037:980::/282037:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542037:990::/282037:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552037:9a0::/282037:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562037:9b0::/282037:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572037:9c0::/282037:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582037:9d0::/282037:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592037:9e0::/282037:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602037:9f0::/282037:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612037:a00::/282037:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622037:a10::/282037:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632037:a20::/282037:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642037:a30::/282037:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652037:a40::/282037:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662037:a50::/282037:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672037:a60::/282037:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682037:a70::/282037:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692037:a80::/282037:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702037:a90::/282037:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712037:aa0::/282037:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722037:ab0::/282037:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732037:ac0::/282037:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742037:ad0::/282037:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752037:ae0::/282037:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762037:af0::/282037:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772037:b00::/282037:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782037:b10::/282037:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792037:b20::/282037:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802037:b30::/282037:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812037:b40::/282037:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822037:b50::/282037:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832037:b60::/282037:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842037:b70::/282037:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852037:b80::/282037:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862037:b90::/282037:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872037:ba0::/282037:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882037:bb0::/282037:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892037:bc0::/282037:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902037:bd0::/282037:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912037:be0::/282037:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922037:bf0::/282037:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932037:c00::/282037:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942037:c10::/282037:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952037:c20::/282037:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962037:c30::/282037:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972037:c40::/282037:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982037:c50::/282037:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992037:c60::/282037:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002037:c70::/282037:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012037:c80::/282037:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022037:c90::/282037:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032037:ca0::/282037:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042037:cb0::/282037:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052037:cc0::/282037:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062037:cd0::/282037:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072037:ce0::/282037:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082037:cf0::/282037:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092037:d00::/282037:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102037:d10::/282037:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112037:d20::/282037:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122037:d30::/282037:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132037:d40::/282037:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142037:d50::/282037:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152037:d60::/282037:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162037:d70::/282037:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172037:d80::/282037:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182037:d90::/282037:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192037:da0::/282037:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202037:db0::/282037:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212037:dc0::/282037:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222037:dd0::/282037:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232037:de0::/282037:def:ffff:ffff:ffff:ffff:ffff:ffff
2242037:df0::/282037:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252037:e00::/282037:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262037:e10::/282037:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272037:e20::/282037:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282037:e30::/282037:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292037:e40::/282037:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302037:e50::/282037:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312037:e60::/282037:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322037:e70::/282037:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332037:e80::/282037:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342037:e90::/282037:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352037:ea0::/282037:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362037:eb0::/282037:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372037:ec0::/282037:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382037:ed0::/282037:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392037:ee0::/282037:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402037:ef0::/282037:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412037:f00::/282037:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422037:f10::/282037:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432037:f20::/282037:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442037:f30::/282037:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452037:f40::/282037:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462037:f50::/282037:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472037:f60::/282037:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482037:f70::/282037:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492037:f80::/282037:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502037:f90::/282037:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512037:fa0::/282037:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522037:fb0::/282037:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532037:fc0::/282037:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542037:fd0::/282037:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552037:fe0::/282037:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562037:ff0::/282037: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.