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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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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
21e0::/12
First address
21e0::
Last address
21ef: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
21e0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
e.1.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

21e0::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
121e0::/2821e0:f:ffff:ffff:ffff:ffff:ffff:ffff
221e0:10::/2821e0:1f:ffff:ffff:ffff:ffff:ffff:ffff
321e0:20::/2821e0:2f:ffff:ffff:ffff:ffff:ffff:ffff
421e0:30::/2821e0:3f:ffff:ffff:ffff:ffff:ffff:ffff
521e0:40::/2821e0:4f:ffff:ffff:ffff:ffff:ffff:ffff
621e0:50::/2821e0:5f:ffff:ffff:ffff:ffff:ffff:ffff
721e0:60::/2821e0:6f:ffff:ffff:ffff:ffff:ffff:ffff
821e0:70::/2821e0:7f:ffff:ffff:ffff:ffff:ffff:ffff
921e0:80::/2821e0:8f:ffff:ffff:ffff:ffff:ffff:ffff
1021e0:90::/2821e0:9f:ffff:ffff:ffff:ffff:ffff:ffff
1121e0:a0::/2821e0:af:ffff:ffff:ffff:ffff:ffff:ffff
1221e0:b0::/2821e0:bf:ffff:ffff:ffff:ffff:ffff:ffff
1321e0:c0::/2821e0:cf:ffff:ffff:ffff:ffff:ffff:ffff
1421e0:d0::/2821e0:df:ffff:ffff:ffff:ffff:ffff:ffff
1521e0:e0::/2821e0:ef:ffff:ffff:ffff:ffff:ffff:ffff
1621e0:f0::/2821e0:ff:ffff:ffff:ffff:ffff:ffff:ffff
1721e0:100::/2821e0:10f:ffff:ffff:ffff:ffff:ffff:ffff
1821e0:110::/2821e0:11f:ffff:ffff:ffff:ffff:ffff:ffff
1921e0:120::/2821e0:12f:ffff:ffff:ffff:ffff:ffff:ffff
2021e0:130::/2821e0:13f:ffff:ffff:ffff:ffff:ffff:ffff
2121e0:140::/2821e0:14f:ffff:ffff:ffff:ffff:ffff:ffff
2221e0:150::/2821e0:15f:ffff:ffff:ffff:ffff:ffff:ffff
2321e0:160::/2821e0:16f:ffff:ffff:ffff:ffff:ffff:ffff
2421e0:170::/2821e0:17f:ffff:ffff:ffff:ffff:ffff:ffff
2521e0:180::/2821e0:18f:ffff:ffff:ffff:ffff:ffff:ffff
2621e0:190::/2821e0:19f:ffff:ffff:ffff:ffff:ffff:ffff
2721e0:1a0::/2821e0:1af:ffff:ffff:ffff:ffff:ffff:ffff
2821e0:1b0::/2821e0:1bf:ffff:ffff:ffff:ffff:ffff:ffff
2921e0:1c0::/2821e0:1cf:ffff:ffff:ffff:ffff:ffff:ffff
3021e0:1d0::/2821e0:1df:ffff:ffff:ffff:ffff:ffff:ffff
3121e0:1e0::/2821e0:1ef:ffff:ffff:ffff:ffff:ffff:ffff
3221e0:1f0::/2821e0:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3321e0:200::/2821e0:20f:ffff:ffff:ffff:ffff:ffff:ffff
3421e0:210::/2821e0:21f:ffff:ffff:ffff:ffff:ffff:ffff
3521e0:220::/2821e0:22f:ffff:ffff:ffff:ffff:ffff:ffff
3621e0:230::/2821e0:23f:ffff:ffff:ffff:ffff:ffff:ffff
3721e0:240::/2821e0:24f:ffff:ffff:ffff:ffff:ffff:ffff
3821e0:250::/2821e0:25f:ffff:ffff:ffff:ffff:ffff:ffff
3921e0:260::/2821e0:26f:ffff:ffff:ffff:ffff:ffff:ffff
4021e0:270::/2821e0:27f:ffff:ffff:ffff:ffff:ffff:ffff
4121e0:280::/2821e0:28f:ffff:ffff:ffff:ffff:ffff:ffff
4221e0:290::/2821e0:29f:ffff:ffff:ffff:ffff:ffff:ffff
4321e0:2a0::/2821e0:2af:ffff:ffff:ffff:ffff:ffff:ffff
4421e0:2b0::/2821e0:2bf:ffff:ffff:ffff:ffff:ffff:ffff
4521e0:2c0::/2821e0:2cf:ffff:ffff:ffff:ffff:ffff:ffff
4621e0:2d0::/2821e0:2df:ffff:ffff:ffff:ffff:ffff:ffff
4721e0:2e0::/2821e0:2ef:ffff:ffff:ffff:ffff:ffff:ffff
4821e0:2f0::/2821e0:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4921e0:300::/2821e0:30f:ffff:ffff:ffff:ffff:ffff:ffff
5021e0:310::/2821e0:31f:ffff:ffff:ffff:ffff:ffff:ffff
5121e0:320::/2821e0:32f:ffff:ffff:ffff:ffff:ffff:ffff
5221e0:330::/2821e0:33f:ffff:ffff:ffff:ffff:ffff:ffff
5321e0:340::/2821e0:34f:ffff:ffff:ffff:ffff:ffff:ffff
5421e0:350::/2821e0:35f:ffff:ffff:ffff:ffff:ffff:ffff
5521e0:360::/2821e0:36f:ffff:ffff:ffff:ffff:ffff:ffff
5621e0:370::/2821e0:37f:ffff:ffff:ffff:ffff:ffff:ffff
5721e0:380::/2821e0:38f:ffff:ffff:ffff:ffff:ffff:ffff
5821e0:390::/2821e0:39f:ffff:ffff:ffff:ffff:ffff:ffff
5921e0:3a0::/2821e0:3af:ffff:ffff:ffff:ffff:ffff:ffff
6021e0:3b0::/2821e0:3bf:ffff:ffff:ffff:ffff:ffff:ffff
6121e0:3c0::/2821e0:3cf:ffff:ffff:ffff:ffff:ffff:ffff
6221e0:3d0::/2821e0:3df:ffff:ffff:ffff:ffff:ffff:ffff
6321e0:3e0::/2821e0:3ef:ffff:ffff:ffff:ffff:ffff:ffff
6421e0:3f0::/2821e0:3ff:ffff:ffff:ffff:ffff:ffff:ffff
6521e0:400::/2821e0:40f:ffff:ffff:ffff:ffff:ffff:ffff
6621e0:410::/2821e0:41f:ffff:ffff:ffff:ffff:ffff:ffff
6721e0:420::/2821e0:42f:ffff:ffff:ffff:ffff:ffff:ffff
6821e0:430::/2821e0:43f:ffff:ffff:ffff:ffff:ffff:ffff
6921e0:440::/2821e0:44f:ffff:ffff:ffff:ffff:ffff:ffff
7021e0:450::/2821e0:45f:ffff:ffff:ffff:ffff:ffff:ffff
7121e0:460::/2821e0:46f:ffff:ffff:ffff:ffff:ffff:ffff
7221e0:470::/2821e0:47f:ffff:ffff:ffff:ffff:ffff:ffff
7321e0:480::/2821e0:48f:ffff:ffff:ffff:ffff:ffff:ffff
7421e0:490::/2821e0:49f:ffff:ffff:ffff:ffff:ffff:ffff
7521e0:4a0::/2821e0:4af:ffff:ffff:ffff:ffff:ffff:ffff
7621e0:4b0::/2821e0:4bf:ffff:ffff:ffff:ffff:ffff:ffff
7721e0:4c0::/2821e0:4cf:ffff:ffff:ffff:ffff:ffff:ffff
7821e0:4d0::/2821e0:4df:ffff:ffff:ffff:ffff:ffff:ffff
7921e0:4e0::/2821e0:4ef:ffff:ffff:ffff:ffff:ffff:ffff
8021e0:4f0::/2821e0:4ff:ffff:ffff:ffff:ffff:ffff:ffff
8121e0:500::/2821e0:50f:ffff:ffff:ffff:ffff:ffff:ffff
8221e0:510::/2821e0:51f:ffff:ffff:ffff:ffff:ffff:ffff
8321e0:520::/2821e0:52f:ffff:ffff:ffff:ffff:ffff:ffff
8421e0:530::/2821e0:53f:ffff:ffff:ffff:ffff:ffff:ffff
8521e0:540::/2821e0:54f:ffff:ffff:ffff:ffff:ffff:ffff
8621e0:550::/2821e0:55f:ffff:ffff:ffff:ffff:ffff:ffff
8721e0:560::/2821e0:56f:ffff:ffff:ffff:ffff:ffff:ffff
8821e0:570::/2821e0:57f:ffff:ffff:ffff:ffff:ffff:ffff
8921e0:580::/2821e0:58f:ffff:ffff:ffff:ffff:ffff:ffff
9021e0:590::/2821e0:59f:ffff:ffff:ffff:ffff:ffff:ffff
9121e0:5a0::/2821e0:5af:ffff:ffff:ffff:ffff:ffff:ffff
9221e0:5b0::/2821e0:5bf:ffff:ffff:ffff:ffff:ffff:ffff
9321e0:5c0::/2821e0:5cf:ffff:ffff:ffff:ffff:ffff:ffff
9421e0:5d0::/2821e0:5df:ffff:ffff:ffff:ffff:ffff:ffff
9521e0:5e0::/2821e0:5ef:ffff:ffff:ffff:ffff:ffff:ffff
9621e0:5f0::/2821e0:5ff:ffff:ffff:ffff:ffff:ffff:ffff
9721e0:600::/2821e0:60f:ffff:ffff:ffff:ffff:ffff:ffff
9821e0:610::/2821e0:61f:ffff:ffff:ffff:ffff:ffff:ffff
9921e0:620::/2821e0:62f:ffff:ffff:ffff:ffff:ffff:ffff
10021e0:630::/2821e0:63f:ffff:ffff:ffff:ffff:ffff:ffff
10121e0:640::/2821e0:64f:ffff:ffff:ffff:ffff:ffff:ffff
10221e0:650::/2821e0:65f:ffff:ffff:ffff:ffff:ffff:ffff
10321e0:660::/2821e0:66f:ffff:ffff:ffff:ffff:ffff:ffff
10421e0:670::/2821e0:67f:ffff:ffff:ffff:ffff:ffff:ffff
10521e0:680::/2821e0:68f:ffff:ffff:ffff:ffff:ffff:ffff
10621e0:690::/2821e0:69f:ffff:ffff:ffff:ffff:ffff:ffff
10721e0:6a0::/2821e0:6af:ffff:ffff:ffff:ffff:ffff:ffff
10821e0:6b0::/2821e0:6bf:ffff:ffff:ffff:ffff:ffff:ffff
10921e0:6c0::/2821e0:6cf:ffff:ffff:ffff:ffff:ffff:ffff
11021e0:6d0::/2821e0:6df:ffff:ffff:ffff:ffff:ffff:ffff
11121e0:6e0::/2821e0:6ef:ffff:ffff:ffff:ffff:ffff:ffff
11221e0:6f0::/2821e0:6ff:ffff:ffff:ffff:ffff:ffff:ffff
11321e0:700::/2821e0:70f:ffff:ffff:ffff:ffff:ffff:ffff
11421e0:710::/2821e0:71f:ffff:ffff:ffff:ffff:ffff:ffff
11521e0:720::/2821e0:72f:ffff:ffff:ffff:ffff:ffff:ffff
11621e0:730::/2821e0:73f:ffff:ffff:ffff:ffff:ffff:ffff
11721e0:740::/2821e0:74f:ffff:ffff:ffff:ffff:ffff:ffff
11821e0:750::/2821e0:75f:ffff:ffff:ffff:ffff:ffff:ffff
11921e0:760::/2821e0:76f:ffff:ffff:ffff:ffff:ffff:ffff
12021e0:770::/2821e0:77f:ffff:ffff:ffff:ffff:ffff:ffff
12121e0:780::/2821e0:78f:ffff:ffff:ffff:ffff:ffff:ffff
12221e0:790::/2821e0:79f:ffff:ffff:ffff:ffff:ffff:ffff
12321e0:7a0::/2821e0:7af:ffff:ffff:ffff:ffff:ffff:ffff
12421e0:7b0::/2821e0:7bf:ffff:ffff:ffff:ffff:ffff:ffff
12521e0:7c0::/2821e0:7cf:ffff:ffff:ffff:ffff:ffff:ffff
12621e0:7d0::/2821e0:7df:ffff:ffff:ffff:ffff:ffff:ffff
12721e0:7e0::/2821e0:7ef:ffff:ffff:ffff:ffff:ffff:ffff
12821e0:7f0::/2821e0:7ff:ffff:ffff:ffff:ffff:ffff:ffff
12921e0:800::/2821e0:80f:ffff:ffff:ffff:ffff:ffff:ffff
13021e0:810::/2821e0:81f:ffff:ffff:ffff:ffff:ffff:ffff
13121e0:820::/2821e0:82f:ffff:ffff:ffff:ffff:ffff:ffff
13221e0:830::/2821e0:83f:ffff:ffff:ffff:ffff:ffff:ffff
13321e0:840::/2821e0:84f:ffff:ffff:ffff:ffff:ffff:ffff
13421e0:850::/2821e0:85f:ffff:ffff:ffff:ffff:ffff:ffff
13521e0:860::/2821e0:86f:ffff:ffff:ffff:ffff:ffff:ffff
13621e0:870::/2821e0:87f:ffff:ffff:ffff:ffff:ffff:ffff
13721e0:880::/2821e0:88f:ffff:ffff:ffff:ffff:ffff:ffff
13821e0:890::/2821e0:89f:ffff:ffff:ffff:ffff:ffff:ffff
13921e0:8a0::/2821e0:8af:ffff:ffff:ffff:ffff:ffff:ffff
14021e0:8b0::/2821e0:8bf:ffff:ffff:ffff:ffff:ffff:ffff
14121e0:8c0::/2821e0:8cf:ffff:ffff:ffff:ffff:ffff:ffff
14221e0:8d0::/2821e0:8df:ffff:ffff:ffff:ffff:ffff:ffff
14321e0:8e0::/2821e0:8ef:ffff:ffff:ffff:ffff:ffff:ffff
14421e0:8f0::/2821e0:8ff:ffff:ffff:ffff:ffff:ffff:ffff
14521e0:900::/2821e0:90f:ffff:ffff:ffff:ffff:ffff:ffff
14621e0:910::/2821e0:91f:ffff:ffff:ffff:ffff:ffff:ffff
14721e0:920::/2821e0:92f:ffff:ffff:ffff:ffff:ffff:ffff
14821e0:930::/2821e0:93f:ffff:ffff:ffff:ffff:ffff:ffff
14921e0:940::/2821e0:94f:ffff:ffff:ffff:ffff:ffff:ffff
15021e0:950::/2821e0:95f:ffff:ffff:ffff:ffff:ffff:ffff
15121e0:960::/2821e0:96f:ffff:ffff:ffff:ffff:ffff:ffff
15221e0:970::/2821e0:97f:ffff:ffff:ffff:ffff:ffff:ffff
15321e0:980::/2821e0:98f:ffff:ffff:ffff:ffff:ffff:ffff
15421e0:990::/2821e0:99f:ffff:ffff:ffff:ffff:ffff:ffff
15521e0:9a0::/2821e0:9af:ffff:ffff:ffff:ffff:ffff:ffff
15621e0:9b0::/2821e0:9bf:ffff:ffff:ffff:ffff:ffff:ffff
15721e0:9c0::/2821e0:9cf:ffff:ffff:ffff:ffff:ffff:ffff
15821e0:9d0::/2821e0:9df:ffff:ffff:ffff:ffff:ffff:ffff
15921e0:9e0::/2821e0:9ef:ffff:ffff:ffff:ffff:ffff:ffff
16021e0:9f0::/2821e0:9ff:ffff:ffff:ffff:ffff:ffff:ffff
16121e0:a00::/2821e0:a0f:ffff:ffff:ffff:ffff:ffff:ffff
16221e0:a10::/2821e0:a1f:ffff:ffff:ffff:ffff:ffff:ffff
16321e0:a20::/2821e0:a2f:ffff:ffff:ffff:ffff:ffff:ffff
16421e0:a30::/2821e0:a3f:ffff:ffff:ffff:ffff:ffff:ffff
16521e0:a40::/2821e0:a4f:ffff:ffff:ffff:ffff:ffff:ffff
16621e0:a50::/2821e0:a5f:ffff:ffff:ffff:ffff:ffff:ffff
16721e0:a60::/2821e0:a6f:ffff:ffff:ffff:ffff:ffff:ffff
16821e0:a70::/2821e0:a7f:ffff:ffff:ffff:ffff:ffff:ffff
16921e0:a80::/2821e0:a8f:ffff:ffff:ffff:ffff:ffff:ffff
17021e0:a90::/2821e0:a9f:ffff:ffff:ffff:ffff:ffff:ffff
17121e0:aa0::/2821e0:aaf:ffff:ffff:ffff:ffff:ffff:ffff
17221e0:ab0::/2821e0:abf:ffff:ffff:ffff:ffff:ffff:ffff
17321e0:ac0::/2821e0:acf:ffff:ffff:ffff:ffff:ffff:ffff
17421e0:ad0::/2821e0:adf:ffff:ffff:ffff:ffff:ffff:ffff
17521e0:ae0::/2821e0:aef:ffff:ffff:ffff:ffff:ffff:ffff
17621e0:af0::/2821e0:aff:ffff:ffff:ffff:ffff:ffff:ffff
17721e0:b00::/2821e0:b0f:ffff:ffff:ffff:ffff:ffff:ffff
17821e0:b10::/2821e0:b1f:ffff:ffff:ffff:ffff:ffff:ffff
17921e0:b20::/2821e0:b2f:ffff:ffff:ffff:ffff:ffff:ffff
18021e0:b30::/2821e0:b3f:ffff:ffff:ffff:ffff:ffff:ffff
18121e0:b40::/2821e0:b4f:ffff:ffff:ffff:ffff:ffff:ffff
18221e0:b50::/2821e0:b5f:ffff:ffff:ffff:ffff:ffff:ffff
18321e0:b60::/2821e0:b6f:ffff:ffff:ffff:ffff:ffff:ffff
18421e0:b70::/2821e0:b7f:ffff:ffff:ffff:ffff:ffff:ffff
18521e0:b80::/2821e0:b8f:ffff:ffff:ffff:ffff:ffff:ffff
18621e0:b90::/2821e0:b9f:ffff:ffff:ffff:ffff:ffff:ffff
18721e0:ba0::/2821e0:baf:ffff:ffff:ffff:ffff:ffff:ffff
18821e0:bb0::/2821e0:bbf:ffff:ffff:ffff:ffff:ffff:ffff
18921e0:bc0::/2821e0:bcf:ffff:ffff:ffff:ffff:ffff:ffff
19021e0:bd0::/2821e0:bdf:ffff:ffff:ffff:ffff:ffff:ffff
19121e0:be0::/2821e0:bef:ffff:ffff:ffff:ffff:ffff:ffff
19221e0:bf0::/2821e0:bff:ffff:ffff:ffff:ffff:ffff:ffff
19321e0:c00::/2821e0:c0f:ffff:ffff:ffff:ffff:ffff:ffff
19421e0:c10::/2821e0:c1f:ffff:ffff:ffff:ffff:ffff:ffff
19521e0:c20::/2821e0:c2f:ffff:ffff:ffff:ffff:ffff:ffff
19621e0:c30::/2821e0:c3f:ffff:ffff:ffff:ffff:ffff:ffff
19721e0:c40::/2821e0:c4f:ffff:ffff:ffff:ffff:ffff:ffff
19821e0:c50::/2821e0:c5f:ffff:ffff:ffff:ffff:ffff:ffff
19921e0:c60::/2821e0:c6f:ffff:ffff:ffff:ffff:ffff:ffff
20021e0:c70::/2821e0:c7f:ffff:ffff:ffff:ffff:ffff:ffff
20121e0:c80::/2821e0:c8f:ffff:ffff:ffff:ffff:ffff:ffff
20221e0:c90::/2821e0:c9f:ffff:ffff:ffff:ffff:ffff:ffff
20321e0:ca0::/2821e0:caf:ffff:ffff:ffff:ffff:ffff:ffff
20421e0:cb0::/2821e0:cbf:ffff:ffff:ffff:ffff:ffff:ffff
20521e0:cc0::/2821e0:ccf:ffff:ffff:ffff:ffff:ffff:ffff
20621e0:cd0::/2821e0:cdf:ffff:ffff:ffff:ffff:ffff:ffff
20721e0:ce0::/2821e0:cef:ffff:ffff:ffff:ffff:ffff:ffff
20821e0:cf0::/2821e0:cff:ffff:ffff:ffff:ffff:ffff:ffff
20921e0:d00::/2821e0:d0f:ffff:ffff:ffff:ffff:ffff:ffff
21021e0:d10::/2821e0:d1f:ffff:ffff:ffff:ffff:ffff:ffff
21121e0:d20::/2821e0:d2f:ffff:ffff:ffff:ffff:ffff:ffff
21221e0:d30::/2821e0:d3f:ffff:ffff:ffff:ffff:ffff:ffff
21321e0:d40::/2821e0:d4f:ffff:ffff:ffff:ffff:ffff:ffff
21421e0:d50::/2821e0:d5f:ffff:ffff:ffff:ffff:ffff:ffff
21521e0:d60::/2821e0:d6f:ffff:ffff:ffff:ffff:ffff:ffff
21621e0:d70::/2821e0:d7f:ffff:ffff:ffff:ffff:ffff:ffff
21721e0:d80::/2821e0:d8f:ffff:ffff:ffff:ffff:ffff:ffff
21821e0:d90::/2821e0:d9f:ffff:ffff:ffff:ffff:ffff:ffff
21921e0:da0::/2821e0:daf:ffff:ffff:ffff:ffff:ffff:ffff
22021e0:db0::/2821e0:dbf:ffff:ffff:ffff:ffff:ffff:ffff
22121e0:dc0::/2821e0:dcf:ffff:ffff:ffff:ffff:ffff:ffff
22221e0:dd0::/2821e0:ddf:ffff:ffff:ffff:ffff:ffff:ffff
22321e0:de0::/2821e0:def:ffff:ffff:ffff:ffff:ffff:ffff
22421e0:df0::/2821e0:dff:ffff:ffff:ffff:ffff:ffff:ffff
22521e0:e00::/2821e0:e0f:ffff:ffff:ffff:ffff:ffff:ffff
22621e0:e10::/2821e0:e1f:ffff:ffff:ffff:ffff:ffff:ffff
22721e0:e20::/2821e0:e2f:ffff:ffff:ffff:ffff:ffff:ffff
22821e0:e30::/2821e0:e3f:ffff:ffff:ffff:ffff:ffff:ffff
22921e0:e40::/2821e0:e4f:ffff:ffff:ffff:ffff:ffff:ffff
23021e0:e50::/2821e0:e5f:ffff:ffff:ffff:ffff:ffff:ffff
23121e0:e60::/2821e0:e6f:ffff:ffff:ffff:ffff:ffff:ffff
23221e0:e70::/2821e0:e7f:ffff:ffff:ffff:ffff:ffff:ffff
23321e0:e80::/2821e0:e8f:ffff:ffff:ffff:ffff:ffff:ffff
23421e0:e90::/2821e0:e9f:ffff:ffff:ffff:ffff:ffff:ffff
23521e0:ea0::/2821e0:eaf:ffff:ffff:ffff:ffff:ffff:ffff
23621e0:eb0::/2821e0:ebf:ffff:ffff:ffff:ffff:ffff:ffff
23721e0:ec0::/2821e0:ecf:ffff:ffff:ffff:ffff:ffff:ffff
23821e0:ed0::/2821e0:edf:ffff:ffff:ffff:ffff:ffff:ffff
23921e0:ee0::/2821e0:eef:ffff:ffff:ffff:ffff:ffff:ffff
24021e0:ef0::/2821e0:eff:ffff:ffff:ffff:ffff:ffff:ffff
24121e0:f00::/2821e0:f0f:ffff:ffff:ffff:ffff:ffff:ffff
24221e0:f10::/2821e0:f1f:ffff:ffff:ffff:ffff:ffff:ffff
24321e0:f20::/2821e0:f2f:ffff:ffff:ffff:ffff:ffff:ffff
24421e0:f30::/2821e0:f3f:ffff:ffff:ffff:ffff:ffff:ffff
24521e0:f40::/2821e0:f4f:ffff:ffff:ffff:ffff:ffff:ffff
24621e0:f50::/2821e0:f5f:ffff:ffff:ffff:ffff:ffff:ffff
24721e0:f60::/2821e0:f6f:ffff:ffff:ffff:ffff:ffff:ffff
24821e0:f70::/2821e0:f7f:ffff:ffff:ffff:ffff:ffff:ffff
24921e0:f80::/2821e0:f8f:ffff:ffff:ffff:ffff:ffff:ffff
25021e0:f90::/2821e0:f9f:ffff:ffff:ffff:ffff:ffff:ffff
25121e0:fa0::/2821e0:faf:ffff:ffff:ffff:ffff:ffff:ffff
25221e0:fb0::/2821e0:fbf:ffff:ffff:ffff:ffff:ffff:ffff
25321e0:fc0::/2821e0:fcf:ffff:ffff:ffff:ffff:ffff:ffff
25421e0:fd0::/2821e0:fdf:ffff:ffff:ffff:ffff:ffff:ffff
25521e0:fe0::/2821e0:fef:ffff:ffff:ffff:ffff:ffff:ffff
25621e0:ff0::/2821e0: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.