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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
24c0::/12
First address
24c0::
Last address
24cf: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
24c0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
c.4.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

24c0::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
124c0::/2824c0:f:ffff:ffff:ffff:ffff:ffff:ffff
224c0:10::/2824c0:1f:ffff:ffff:ffff:ffff:ffff:ffff
324c0:20::/2824c0:2f:ffff:ffff:ffff:ffff:ffff:ffff
424c0:30::/2824c0:3f:ffff:ffff:ffff:ffff:ffff:ffff
524c0:40::/2824c0:4f:ffff:ffff:ffff:ffff:ffff:ffff
624c0:50::/2824c0:5f:ffff:ffff:ffff:ffff:ffff:ffff
724c0:60::/2824c0:6f:ffff:ffff:ffff:ffff:ffff:ffff
824c0:70::/2824c0:7f:ffff:ffff:ffff:ffff:ffff:ffff
924c0:80::/2824c0:8f:ffff:ffff:ffff:ffff:ffff:ffff
1024c0:90::/2824c0:9f:ffff:ffff:ffff:ffff:ffff:ffff
1124c0:a0::/2824c0:af:ffff:ffff:ffff:ffff:ffff:ffff
1224c0:b0::/2824c0:bf:ffff:ffff:ffff:ffff:ffff:ffff
1324c0:c0::/2824c0:cf:ffff:ffff:ffff:ffff:ffff:ffff
1424c0:d0::/2824c0:df:ffff:ffff:ffff:ffff:ffff:ffff
1524c0:e0::/2824c0:ef:ffff:ffff:ffff:ffff:ffff:ffff
1624c0:f0::/2824c0:ff:ffff:ffff:ffff:ffff:ffff:ffff
1724c0:100::/2824c0:10f:ffff:ffff:ffff:ffff:ffff:ffff
1824c0:110::/2824c0:11f:ffff:ffff:ffff:ffff:ffff:ffff
1924c0:120::/2824c0:12f:ffff:ffff:ffff:ffff:ffff:ffff
2024c0:130::/2824c0:13f:ffff:ffff:ffff:ffff:ffff:ffff
2124c0:140::/2824c0:14f:ffff:ffff:ffff:ffff:ffff:ffff
2224c0:150::/2824c0:15f:ffff:ffff:ffff:ffff:ffff:ffff
2324c0:160::/2824c0:16f:ffff:ffff:ffff:ffff:ffff:ffff
2424c0:170::/2824c0:17f:ffff:ffff:ffff:ffff:ffff:ffff
2524c0:180::/2824c0:18f:ffff:ffff:ffff:ffff:ffff:ffff
2624c0:190::/2824c0:19f:ffff:ffff:ffff:ffff:ffff:ffff
2724c0:1a0::/2824c0:1af:ffff:ffff:ffff:ffff:ffff:ffff
2824c0:1b0::/2824c0:1bf:ffff:ffff:ffff:ffff:ffff:ffff
2924c0:1c0::/2824c0:1cf:ffff:ffff:ffff:ffff:ffff:ffff
3024c0:1d0::/2824c0:1df:ffff:ffff:ffff:ffff:ffff:ffff
3124c0:1e0::/2824c0:1ef:ffff:ffff:ffff:ffff:ffff:ffff
3224c0:1f0::/2824c0:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3324c0:200::/2824c0:20f:ffff:ffff:ffff:ffff:ffff:ffff
3424c0:210::/2824c0:21f:ffff:ffff:ffff:ffff:ffff:ffff
3524c0:220::/2824c0:22f:ffff:ffff:ffff:ffff:ffff:ffff
3624c0:230::/2824c0:23f:ffff:ffff:ffff:ffff:ffff:ffff
3724c0:240::/2824c0:24f:ffff:ffff:ffff:ffff:ffff:ffff
3824c0:250::/2824c0:25f:ffff:ffff:ffff:ffff:ffff:ffff
3924c0:260::/2824c0:26f:ffff:ffff:ffff:ffff:ffff:ffff
4024c0:270::/2824c0:27f:ffff:ffff:ffff:ffff:ffff:ffff
4124c0:280::/2824c0:28f:ffff:ffff:ffff:ffff:ffff:ffff
4224c0:290::/2824c0:29f:ffff:ffff:ffff:ffff:ffff:ffff
4324c0:2a0::/2824c0:2af:ffff:ffff:ffff:ffff:ffff:ffff
4424c0:2b0::/2824c0:2bf:ffff:ffff:ffff:ffff:ffff:ffff
4524c0:2c0::/2824c0:2cf:ffff:ffff:ffff:ffff:ffff:ffff
4624c0:2d0::/2824c0:2df:ffff:ffff:ffff:ffff:ffff:ffff
4724c0:2e0::/2824c0:2ef:ffff:ffff:ffff:ffff:ffff:ffff
4824c0:2f0::/2824c0:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4924c0:300::/2824c0:30f:ffff:ffff:ffff:ffff:ffff:ffff
5024c0:310::/2824c0:31f:ffff:ffff:ffff:ffff:ffff:ffff
5124c0:320::/2824c0:32f:ffff:ffff:ffff:ffff:ffff:ffff
5224c0:330::/2824c0:33f:ffff:ffff:ffff:ffff:ffff:ffff
5324c0:340::/2824c0:34f:ffff:ffff:ffff:ffff:ffff:ffff
5424c0:350::/2824c0:35f:ffff:ffff:ffff:ffff:ffff:ffff
5524c0:360::/2824c0:36f:ffff:ffff:ffff:ffff:ffff:ffff
5624c0:370::/2824c0:37f:ffff:ffff:ffff:ffff:ffff:ffff
5724c0:380::/2824c0:38f:ffff:ffff:ffff:ffff:ffff:ffff
5824c0:390::/2824c0:39f:ffff:ffff:ffff:ffff:ffff:ffff
5924c0:3a0::/2824c0:3af:ffff:ffff:ffff:ffff:ffff:ffff
6024c0:3b0::/2824c0:3bf:ffff:ffff:ffff:ffff:ffff:ffff
6124c0:3c0::/2824c0:3cf:ffff:ffff:ffff:ffff:ffff:ffff
6224c0:3d0::/2824c0:3df:ffff:ffff:ffff:ffff:ffff:ffff
6324c0:3e0::/2824c0:3ef:ffff:ffff:ffff:ffff:ffff:ffff
6424c0:3f0::/2824c0:3ff:ffff:ffff:ffff:ffff:ffff:ffff
6524c0:400::/2824c0:40f:ffff:ffff:ffff:ffff:ffff:ffff
6624c0:410::/2824c0:41f:ffff:ffff:ffff:ffff:ffff:ffff
6724c0:420::/2824c0:42f:ffff:ffff:ffff:ffff:ffff:ffff
6824c0:430::/2824c0:43f:ffff:ffff:ffff:ffff:ffff:ffff
6924c0:440::/2824c0:44f:ffff:ffff:ffff:ffff:ffff:ffff
7024c0:450::/2824c0:45f:ffff:ffff:ffff:ffff:ffff:ffff
7124c0:460::/2824c0:46f:ffff:ffff:ffff:ffff:ffff:ffff
7224c0:470::/2824c0:47f:ffff:ffff:ffff:ffff:ffff:ffff
7324c0:480::/2824c0:48f:ffff:ffff:ffff:ffff:ffff:ffff
7424c0:490::/2824c0:49f:ffff:ffff:ffff:ffff:ffff:ffff
7524c0:4a0::/2824c0:4af:ffff:ffff:ffff:ffff:ffff:ffff
7624c0:4b0::/2824c0:4bf:ffff:ffff:ffff:ffff:ffff:ffff
7724c0:4c0::/2824c0:4cf:ffff:ffff:ffff:ffff:ffff:ffff
7824c0:4d0::/2824c0:4df:ffff:ffff:ffff:ffff:ffff:ffff
7924c0:4e0::/2824c0:4ef:ffff:ffff:ffff:ffff:ffff:ffff
8024c0:4f0::/2824c0:4ff:ffff:ffff:ffff:ffff:ffff:ffff
8124c0:500::/2824c0:50f:ffff:ffff:ffff:ffff:ffff:ffff
8224c0:510::/2824c0:51f:ffff:ffff:ffff:ffff:ffff:ffff
8324c0:520::/2824c0:52f:ffff:ffff:ffff:ffff:ffff:ffff
8424c0:530::/2824c0:53f:ffff:ffff:ffff:ffff:ffff:ffff
8524c0:540::/2824c0:54f:ffff:ffff:ffff:ffff:ffff:ffff
8624c0:550::/2824c0:55f:ffff:ffff:ffff:ffff:ffff:ffff
8724c0:560::/2824c0:56f:ffff:ffff:ffff:ffff:ffff:ffff
8824c0:570::/2824c0:57f:ffff:ffff:ffff:ffff:ffff:ffff
8924c0:580::/2824c0:58f:ffff:ffff:ffff:ffff:ffff:ffff
9024c0:590::/2824c0:59f:ffff:ffff:ffff:ffff:ffff:ffff
9124c0:5a0::/2824c0:5af:ffff:ffff:ffff:ffff:ffff:ffff
9224c0:5b0::/2824c0:5bf:ffff:ffff:ffff:ffff:ffff:ffff
9324c0:5c0::/2824c0:5cf:ffff:ffff:ffff:ffff:ffff:ffff
9424c0:5d0::/2824c0:5df:ffff:ffff:ffff:ffff:ffff:ffff
9524c0:5e0::/2824c0:5ef:ffff:ffff:ffff:ffff:ffff:ffff
9624c0:5f0::/2824c0:5ff:ffff:ffff:ffff:ffff:ffff:ffff
9724c0:600::/2824c0:60f:ffff:ffff:ffff:ffff:ffff:ffff
9824c0:610::/2824c0:61f:ffff:ffff:ffff:ffff:ffff:ffff
9924c0:620::/2824c0:62f:ffff:ffff:ffff:ffff:ffff:ffff
10024c0:630::/2824c0:63f:ffff:ffff:ffff:ffff:ffff:ffff
10124c0:640::/2824c0:64f:ffff:ffff:ffff:ffff:ffff:ffff
10224c0:650::/2824c0:65f:ffff:ffff:ffff:ffff:ffff:ffff
10324c0:660::/2824c0:66f:ffff:ffff:ffff:ffff:ffff:ffff
10424c0:670::/2824c0:67f:ffff:ffff:ffff:ffff:ffff:ffff
10524c0:680::/2824c0:68f:ffff:ffff:ffff:ffff:ffff:ffff
10624c0:690::/2824c0:69f:ffff:ffff:ffff:ffff:ffff:ffff
10724c0:6a0::/2824c0:6af:ffff:ffff:ffff:ffff:ffff:ffff
10824c0:6b0::/2824c0:6bf:ffff:ffff:ffff:ffff:ffff:ffff
10924c0:6c0::/2824c0:6cf:ffff:ffff:ffff:ffff:ffff:ffff
11024c0:6d0::/2824c0:6df:ffff:ffff:ffff:ffff:ffff:ffff
11124c0:6e0::/2824c0:6ef:ffff:ffff:ffff:ffff:ffff:ffff
11224c0:6f0::/2824c0:6ff:ffff:ffff:ffff:ffff:ffff:ffff
11324c0:700::/2824c0:70f:ffff:ffff:ffff:ffff:ffff:ffff
11424c0:710::/2824c0:71f:ffff:ffff:ffff:ffff:ffff:ffff
11524c0:720::/2824c0:72f:ffff:ffff:ffff:ffff:ffff:ffff
11624c0:730::/2824c0:73f:ffff:ffff:ffff:ffff:ffff:ffff
11724c0:740::/2824c0:74f:ffff:ffff:ffff:ffff:ffff:ffff
11824c0:750::/2824c0:75f:ffff:ffff:ffff:ffff:ffff:ffff
11924c0:760::/2824c0:76f:ffff:ffff:ffff:ffff:ffff:ffff
12024c0:770::/2824c0:77f:ffff:ffff:ffff:ffff:ffff:ffff
12124c0:780::/2824c0:78f:ffff:ffff:ffff:ffff:ffff:ffff
12224c0:790::/2824c0:79f:ffff:ffff:ffff:ffff:ffff:ffff
12324c0:7a0::/2824c0:7af:ffff:ffff:ffff:ffff:ffff:ffff
12424c0:7b0::/2824c0:7bf:ffff:ffff:ffff:ffff:ffff:ffff
12524c0:7c0::/2824c0:7cf:ffff:ffff:ffff:ffff:ffff:ffff
12624c0:7d0::/2824c0:7df:ffff:ffff:ffff:ffff:ffff:ffff
12724c0:7e0::/2824c0:7ef:ffff:ffff:ffff:ffff:ffff:ffff
12824c0:7f0::/2824c0:7ff:ffff:ffff:ffff:ffff:ffff:ffff
12924c0:800::/2824c0:80f:ffff:ffff:ffff:ffff:ffff:ffff
13024c0:810::/2824c0:81f:ffff:ffff:ffff:ffff:ffff:ffff
13124c0:820::/2824c0:82f:ffff:ffff:ffff:ffff:ffff:ffff
13224c0:830::/2824c0:83f:ffff:ffff:ffff:ffff:ffff:ffff
13324c0:840::/2824c0:84f:ffff:ffff:ffff:ffff:ffff:ffff
13424c0:850::/2824c0:85f:ffff:ffff:ffff:ffff:ffff:ffff
13524c0:860::/2824c0:86f:ffff:ffff:ffff:ffff:ffff:ffff
13624c0:870::/2824c0:87f:ffff:ffff:ffff:ffff:ffff:ffff
13724c0:880::/2824c0:88f:ffff:ffff:ffff:ffff:ffff:ffff
13824c0:890::/2824c0:89f:ffff:ffff:ffff:ffff:ffff:ffff
13924c0:8a0::/2824c0:8af:ffff:ffff:ffff:ffff:ffff:ffff
14024c0:8b0::/2824c0:8bf:ffff:ffff:ffff:ffff:ffff:ffff
14124c0:8c0::/2824c0:8cf:ffff:ffff:ffff:ffff:ffff:ffff
14224c0:8d0::/2824c0:8df:ffff:ffff:ffff:ffff:ffff:ffff
14324c0:8e0::/2824c0:8ef:ffff:ffff:ffff:ffff:ffff:ffff
14424c0:8f0::/2824c0:8ff:ffff:ffff:ffff:ffff:ffff:ffff
14524c0:900::/2824c0:90f:ffff:ffff:ffff:ffff:ffff:ffff
14624c0:910::/2824c0:91f:ffff:ffff:ffff:ffff:ffff:ffff
14724c0:920::/2824c0:92f:ffff:ffff:ffff:ffff:ffff:ffff
14824c0:930::/2824c0:93f:ffff:ffff:ffff:ffff:ffff:ffff
14924c0:940::/2824c0:94f:ffff:ffff:ffff:ffff:ffff:ffff
15024c0:950::/2824c0:95f:ffff:ffff:ffff:ffff:ffff:ffff
15124c0:960::/2824c0:96f:ffff:ffff:ffff:ffff:ffff:ffff
15224c0:970::/2824c0:97f:ffff:ffff:ffff:ffff:ffff:ffff
15324c0:980::/2824c0:98f:ffff:ffff:ffff:ffff:ffff:ffff
15424c0:990::/2824c0:99f:ffff:ffff:ffff:ffff:ffff:ffff
15524c0:9a0::/2824c0:9af:ffff:ffff:ffff:ffff:ffff:ffff
15624c0:9b0::/2824c0:9bf:ffff:ffff:ffff:ffff:ffff:ffff
15724c0:9c0::/2824c0:9cf:ffff:ffff:ffff:ffff:ffff:ffff
15824c0:9d0::/2824c0:9df:ffff:ffff:ffff:ffff:ffff:ffff
15924c0:9e0::/2824c0:9ef:ffff:ffff:ffff:ffff:ffff:ffff
16024c0:9f0::/2824c0:9ff:ffff:ffff:ffff:ffff:ffff:ffff
16124c0:a00::/2824c0:a0f:ffff:ffff:ffff:ffff:ffff:ffff
16224c0:a10::/2824c0:a1f:ffff:ffff:ffff:ffff:ffff:ffff
16324c0:a20::/2824c0:a2f:ffff:ffff:ffff:ffff:ffff:ffff
16424c0:a30::/2824c0:a3f:ffff:ffff:ffff:ffff:ffff:ffff
16524c0:a40::/2824c0:a4f:ffff:ffff:ffff:ffff:ffff:ffff
16624c0:a50::/2824c0:a5f:ffff:ffff:ffff:ffff:ffff:ffff
16724c0:a60::/2824c0:a6f:ffff:ffff:ffff:ffff:ffff:ffff
16824c0:a70::/2824c0:a7f:ffff:ffff:ffff:ffff:ffff:ffff
16924c0:a80::/2824c0:a8f:ffff:ffff:ffff:ffff:ffff:ffff
17024c0:a90::/2824c0:a9f:ffff:ffff:ffff:ffff:ffff:ffff
17124c0:aa0::/2824c0:aaf:ffff:ffff:ffff:ffff:ffff:ffff
17224c0:ab0::/2824c0:abf:ffff:ffff:ffff:ffff:ffff:ffff
17324c0:ac0::/2824c0:acf:ffff:ffff:ffff:ffff:ffff:ffff
17424c0:ad0::/2824c0:adf:ffff:ffff:ffff:ffff:ffff:ffff
17524c0:ae0::/2824c0:aef:ffff:ffff:ffff:ffff:ffff:ffff
17624c0:af0::/2824c0:aff:ffff:ffff:ffff:ffff:ffff:ffff
17724c0:b00::/2824c0:b0f:ffff:ffff:ffff:ffff:ffff:ffff
17824c0:b10::/2824c0:b1f:ffff:ffff:ffff:ffff:ffff:ffff
17924c0:b20::/2824c0:b2f:ffff:ffff:ffff:ffff:ffff:ffff
18024c0:b30::/2824c0:b3f:ffff:ffff:ffff:ffff:ffff:ffff
18124c0:b40::/2824c0:b4f:ffff:ffff:ffff:ffff:ffff:ffff
18224c0:b50::/2824c0:b5f:ffff:ffff:ffff:ffff:ffff:ffff
18324c0:b60::/2824c0:b6f:ffff:ffff:ffff:ffff:ffff:ffff
18424c0:b70::/2824c0:b7f:ffff:ffff:ffff:ffff:ffff:ffff
18524c0:b80::/2824c0:b8f:ffff:ffff:ffff:ffff:ffff:ffff
18624c0:b90::/2824c0:b9f:ffff:ffff:ffff:ffff:ffff:ffff
18724c0:ba0::/2824c0:baf:ffff:ffff:ffff:ffff:ffff:ffff
18824c0:bb0::/2824c0:bbf:ffff:ffff:ffff:ffff:ffff:ffff
18924c0:bc0::/2824c0:bcf:ffff:ffff:ffff:ffff:ffff:ffff
19024c0:bd0::/2824c0:bdf:ffff:ffff:ffff:ffff:ffff:ffff
19124c0:be0::/2824c0:bef:ffff:ffff:ffff:ffff:ffff:ffff
19224c0:bf0::/2824c0:bff:ffff:ffff:ffff:ffff:ffff:ffff
19324c0:c00::/2824c0:c0f:ffff:ffff:ffff:ffff:ffff:ffff
19424c0:c10::/2824c0:c1f:ffff:ffff:ffff:ffff:ffff:ffff
19524c0:c20::/2824c0:c2f:ffff:ffff:ffff:ffff:ffff:ffff
19624c0:c30::/2824c0:c3f:ffff:ffff:ffff:ffff:ffff:ffff
19724c0:c40::/2824c0:c4f:ffff:ffff:ffff:ffff:ffff:ffff
19824c0:c50::/2824c0:c5f:ffff:ffff:ffff:ffff:ffff:ffff
19924c0:c60::/2824c0:c6f:ffff:ffff:ffff:ffff:ffff:ffff
20024c0:c70::/2824c0:c7f:ffff:ffff:ffff:ffff:ffff:ffff
20124c0:c80::/2824c0:c8f:ffff:ffff:ffff:ffff:ffff:ffff
20224c0:c90::/2824c0:c9f:ffff:ffff:ffff:ffff:ffff:ffff
20324c0:ca0::/2824c0:caf:ffff:ffff:ffff:ffff:ffff:ffff
20424c0:cb0::/2824c0:cbf:ffff:ffff:ffff:ffff:ffff:ffff
20524c0:cc0::/2824c0:ccf:ffff:ffff:ffff:ffff:ffff:ffff
20624c0:cd0::/2824c0:cdf:ffff:ffff:ffff:ffff:ffff:ffff
20724c0:ce0::/2824c0:cef:ffff:ffff:ffff:ffff:ffff:ffff
20824c0:cf0::/2824c0:cff:ffff:ffff:ffff:ffff:ffff:ffff
20924c0:d00::/2824c0:d0f:ffff:ffff:ffff:ffff:ffff:ffff
21024c0:d10::/2824c0:d1f:ffff:ffff:ffff:ffff:ffff:ffff
21124c0:d20::/2824c0:d2f:ffff:ffff:ffff:ffff:ffff:ffff
21224c0:d30::/2824c0:d3f:ffff:ffff:ffff:ffff:ffff:ffff
21324c0:d40::/2824c0:d4f:ffff:ffff:ffff:ffff:ffff:ffff
21424c0:d50::/2824c0:d5f:ffff:ffff:ffff:ffff:ffff:ffff
21524c0:d60::/2824c0:d6f:ffff:ffff:ffff:ffff:ffff:ffff
21624c0:d70::/2824c0:d7f:ffff:ffff:ffff:ffff:ffff:ffff
21724c0:d80::/2824c0:d8f:ffff:ffff:ffff:ffff:ffff:ffff
21824c0:d90::/2824c0:d9f:ffff:ffff:ffff:ffff:ffff:ffff
21924c0:da0::/2824c0:daf:ffff:ffff:ffff:ffff:ffff:ffff
22024c0:db0::/2824c0:dbf:ffff:ffff:ffff:ffff:ffff:ffff
22124c0:dc0::/2824c0:dcf:ffff:ffff:ffff:ffff:ffff:ffff
22224c0:dd0::/2824c0:ddf:ffff:ffff:ffff:ffff:ffff:ffff
22324c0:de0::/2824c0:def:ffff:ffff:ffff:ffff:ffff:ffff
22424c0:df0::/2824c0:dff:ffff:ffff:ffff:ffff:ffff:ffff
22524c0:e00::/2824c0:e0f:ffff:ffff:ffff:ffff:ffff:ffff
22624c0:e10::/2824c0:e1f:ffff:ffff:ffff:ffff:ffff:ffff
22724c0:e20::/2824c0:e2f:ffff:ffff:ffff:ffff:ffff:ffff
22824c0:e30::/2824c0:e3f:ffff:ffff:ffff:ffff:ffff:ffff
22924c0:e40::/2824c0:e4f:ffff:ffff:ffff:ffff:ffff:ffff
23024c0:e50::/2824c0:e5f:ffff:ffff:ffff:ffff:ffff:ffff
23124c0:e60::/2824c0:e6f:ffff:ffff:ffff:ffff:ffff:ffff
23224c0:e70::/2824c0:e7f:ffff:ffff:ffff:ffff:ffff:ffff
23324c0:e80::/2824c0:e8f:ffff:ffff:ffff:ffff:ffff:ffff
23424c0:e90::/2824c0:e9f:ffff:ffff:ffff:ffff:ffff:ffff
23524c0:ea0::/2824c0:eaf:ffff:ffff:ffff:ffff:ffff:ffff
23624c0:eb0::/2824c0:ebf:ffff:ffff:ffff:ffff:ffff:ffff
23724c0:ec0::/2824c0:ecf:ffff:ffff:ffff:ffff:ffff:ffff
23824c0:ed0::/2824c0:edf:ffff:ffff:ffff:ffff:ffff:ffff
23924c0:ee0::/2824c0:eef:ffff:ffff:ffff:ffff:ffff:ffff
24024c0:ef0::/2824c0:eff:ffff:ffff:ffff:ffff:ffff:ffff
24124c0:f00::/2824c0:f0f:ffff:ffff:ffff:ffff:ffff:ffff
24224c0:f10::/2824c0:f1f:ffff:ffff:ffff:ffff:ffff:ffff
24324c0:f20::/2824c0:f2f:ffff:ffff:ffff:ffff:ffff:ffff
24424c0:f30::/2824c0:f3f:ffff:ffff:ffff:ffff:ffff:ffff
24524c0:f40::/2824c0:f4f:ffff:ffff:ffff:ffff:ffff:ffff
24624c0:f50::/2824c0:f5f:ffff:ffff:ffff:ffff:ffff:ffff
24724c0:f60::/2824c0:f6f:ffff:ffff:ffff:ffff:ffff:ffff
24824c0:f70::/2824c0:f7f:ffff:ffff:ffff:ffff:ffff:ffff
24924c0:f80::/2824c0:f8f:ffff:ffff:ffff:ffff:ffff:ffff
25024c0:f90::/2824c0:f9f:ffff:ffff:ffff:ffff:ffff:ffff
25124c0:fa0::/2824c0:faf:ffff:ffff:ffff:ffff:ffff:ffff
25224c0:fb0::/2824c0:fbf:ffff:ffff:ffff:ffff:ffff:ffff
25324c0:fc0::/2824c0:fcf:ffff:ffff:ffff:ffff:ffff:ffff
25424c0:fd0::/2824c0:fdf:ffff:ffff:ffff:ffff:ffff:ffff
25524c0:fe0::/2824c0:fef:ffff:ffff:ffff:ffff:ffff:ffff
25624c0:ff0::/2824c0: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.