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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/18
Addresses2^110
/64 networks2^46
Network
2abc::/18
First address
2abc::
Last address
2abc:3fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
1,298,074,214,633,706,907,132,624,082,305,024 (2^110)
/64 networks (LANs)
70,368,744,177,664 (2^46)
Full form
2abc:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
0.c.b.a.2.ip6.arpa
1.c.b.a.2.ip6.arpa
2.c.b.a.2.ip6.arpa
3.c.b.a.2.ip6.arpa
/18 is not on a 4-bit boundary, so it takes 4 /20 zones.
Split into smaller subnets/28
/19 (2)/20 (4)/21 (8)/22 (16)/24 (64)/28 (1,024)/32 (16,384)

2abc::/18 makes 1,024 subnets of /28; the first 256 are listed.

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