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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
2fc0::/12
First address
2fc0::
Last address
2fcf: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
2fc0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
c.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)

2fc0::/12 makes 65,536 subnets of /28; the first 256 are listed.

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