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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/16
Addresses2^112
/64 networks2^48
Network
22bb::/16
First address
22bb::
Last address
22bb: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
22bb:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
b.b.2.2.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

22bb::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
122bb::/2822bb:f:ffff:ffff:ffff:ffff:ffff:ffff
222bb:10::/2822bb:1f:ffff:ffff:ffff:ffff:ffff:ffff
322bb:20::/2822bb:2f:ffff:ffff:ffff:ffff:ffff:ffff
422bb:30::/2822bb:3f:ffff:ffff:ffff:ffff:ffff:ffff
522bb:40::/2822bb:4f:ffff:ffff:ffff:ffff:ffff:ffff
622bb:50::/2822bb:5f:ffff:ffff:ffff:ffff:ffff:ffff
722bb:60::/2822bb:6f:ffff:ffff:ffff:ffff:ffff:ffff
822bb:70::/2822bb:7f:ffff:ffff:ffff:ffff:ffff:ffff
922bb:80::/2822bb:8f:ffff:ffff:ffff:ffff:ffff:ffff
1022bb:90::/2822bb:9f:ffff:ffff:ffff:ffff:ffff:ffff
1122bb:a0::/2822bb:af:ffff:ffff:ffff:ffff:ffff:ffff
1222bb:b0::/2822bb:bf:ffff:ffff:ffff:ffff:ffff:ffff
1322bb:c0::/2822bb:cf:ffff:ffff:ffff:ffff:ffff:ffff
1422bb:d0::/2822bb:df:ffff:ffff:ffff:ffff:ffff:ffff
1522bb:e0::/2822bb:ef:ffff:ffff:ffff:ffff:ffff:ffff
1622bb:f0::/2822bb:ff:ffff:ffff:ffff:ffff:ffff:ffff
1722bb:100::/2822bb:10f:ffff:ffff:ffff:ffff:ffff:ffff
1822bb:110::/2822bb:11f:ffff:ffff:ffff:ffff:ffff:ffff
1922bb:120::/2822bb:12f:ffff:ffff:ffff:ffff:ffff:ffff
2022bb:130::/2822bb:13f:ffff:ffff:ffff:ffff:ffff:ffff
2122bb:140::/2822bb:14f:ffff:ffff:ffff:ffff:ffff:ffff
2222bb:150::/2822bb:15f:ffff:ffff:ffff:ffff:ffff:ffff
2322bb:160::/2822bb:16f:ffff:ffff:ffff:ffff:ffff:ffff
2422bb:170::/2822bb:17f:ffff:ffff:ffff:ffff:ffff:ffff
2522bb:180::/2822bb:18f:ffff:ffff:ffff:ffff:ffff:ffff
2622bb:190::/2822bb:19f:ffff:ffff:ffff:ffff:ffff:ffff
2722bb:1a0::/2822bb:1af:ffff:ffff:ffff:ffff:ffff:ffff
2822bb:1b0::/2822bb:1bf:ffff:ffff:ffff:ffff:ffff:ffff
2922bb:1c0::/2822bb:1cf:ffff:ffff:ffff:ffff:ffff:ffff
3022bb:1d0::/2822bb:1df:ffff:ffff:ffff:ffff:ffff:ffff
3122bb:1e0::/2822bb:1ef:ffff:ffff:ffff:ffff:ffff:ffff
3222bb:1f0::/2822bb:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3322bb:200::/2822bb:20f:ffff:ffff:ffff:ffff:ffff:ffff
3422bb:210::/2822bb:21f:ffff:ffff:ffff:ffff:ffff:ffff
3522bb:220::/2822bb:22f:ffff:ffff:ffff:ffff:ffff:ffff
3622bb:230::/2822bb:23f:ffff:ffff:ffff:ffff:ffff:ffff
3722bb:240::/2822bb:24f:ffff:ffff:ffff:ffff:ffff:ffff
3822bb:250::/2822bb:25f:ffff:ffff:ffff:ffff:ffff:ffff
3922bb:260::/2822bb:26f:ffff:ffff:ffff:ffff:ffff:ffff
4022bb:270::/2822bb:27f:ffff:ffff:ffff:ffff:ffff:ffff
4122bb:280::/2822bb:28f:ffff:ffff:ffff:ffff:ffff:ffff
4222bb:290::/2822bb:29f:ffff:ffff:ffff:ffff:ffff:ffff
4322bb:2a0::/2822bb:2af:ffff:ffff:ffff:ffff:ffff:ffff
4422bb:2b0::/2822bb:2bf:ffff:ffff:ffff:ffff:ffff:ffff
4522bb:2c0::/2822bb:2cf:ffff:ffff:ffff:ffff:ffff:ffff
4622bb:2d0::/2822bb:2df:ffff:ffff:ffff:ffff:ffff:ffff
4722bb:2e0::/2822bb:2ef:ffff:ffff:ffff:ffff:ffff:ffff
4822bb:2f0::/2822bb:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4922bb:300::/2822bb:30f:ffff:ffff:ffff:ffff:ffff:ffff
5022bb:310::/2822bb:31f:ffff:ffff:ffff:ffff:ffff:ffff
5122bb:320::/2822bb:32f:ffff:ffff:ffff:ffff:ffff:ffff
5222bb:330::/2822bb:33f:ffff:ffff:ffff:ffff:ffff:ffff
5322bb:340::/2822bb:34f:ffff:ffff:ffff:ffff:ffff:ffff
5422bb:350::/2822bb:35f:ffff:ffff:ffff:ffff:ffff:ffff
5522bb:360::/2822bb:36f:ffff:ffff:ffff:ffff:ffff:ffff
5622bb:370::/2822bb:37f:ffff:ffff:ffff:ffff:ffff:ffff
5722bb:380::/2822bb:38f:ffff:ffff:ffff:ffff:ffff:ffff
5822bb:390::/2822bb:39f:ffff:ffff:ffff:ffff:ffff:ffff
5922bb:3a0::/2822bb:3af:ffff:ffff:ffff:ffff:ffff:ffff
6022bb:3b0::/2822bb:3bf:ffff:ffff:ffff:ffff:ffff:ffff
6122bb:3c0::/2822bb:3cf:ffff:ffff:ffff:ffff:ffff:ffff
6222bb:3d0::/2822bb:3df:ffff:ffff:ffff:ffff:ffff:ffff
6322bb:3e0::/2822bb:3ef:ffff:ffff:ffff:ffff:ffff:ffff
6422bb:3f0::/2822bb:3ff:ffff:ffff:ffff:ffff:ffff:ffff
6522bb:400::/2822bb:40f:ffff:ffff:ffff:ffff:ffff:ffff
6622bb:410::/2822bb:41f:ffff:ffff:ffff:ffff:ffff:ffff
6722bb:420::/2822bb:42f:ffff:ffff:ffff:ffff:ffff:ffff
6822bb:430::/2822bb:43f:ffff:ffff:ffff:ffff:ffff:ffff
6922bb:440::/2822bb:44f:ffff:ffff:ffff:ffff:ffff:ffff
7022bb:450::/2822bb:45f:ffff:ffff:ffff:ffff:ffff:ffff
7122bb:460::/2822bb:46f:ffff:ffff:ffff:ffff:ffff:ffff
7222bb:470::/2822bb:47f:ffff:ffff:ffff:ffff:ffff:ffff
7322bb:480::/2822bb:48f:ffff:ffff:ffff:ffff:ffff:ffff
7422bb:490::/2822bb:49f:ffff:ffff:ffff:ffff:ffff:ffff
7522bb:4a0::/2822bb:4af:ffff:ffff:ffff:ffff:ffff:ffff
7622bb:4b0::/2822bb:4bf:ffff:ffff:ffff:ffff:ffff:ffff
7722bb:4c0::/2822bb:4cf:ffff:ffff:ffff:ffff:ffff:ffff
7822bb:4d0::/2822bb:4df:ffff:ffff:ffff:ffff:ffff:ffff
7922bb:4e0::/2822bb:4ef:ffff:ffff:ffff:ffff:ffff:ffff
8022bb:4f0::/2822bb:4ff:ffff:ffff:ffff:ffff:ffff:ffff
8122bb:500::/2822bb:50f:ffff:ffff:ffff:ffff:ffff:ffff
8222bb:510::/2822bb:51f:ffff:ffff:ffff:ffff:ffff:ffff
8322bb:520::/2822bb:52f:ffff:ffff:ffff:ffff:ffff:ffff
8422bb:530::/2822bb:53f:ffff:ffff:ffff:ffff:ffff:ffff
8522bb:540::/2822bb:54f:ffff:ffff:ffff:ffff:ffff:ffff
8622bb:550::/2822bb:55f:ffff:ffff:ffff:ffff:ffff:ffff
8722bb:560::/2822bb:56f:ffff:ffff:ffff:ffff:ffff:ffff
8822bb:570::/2822bb:57f:ffff:ffff:ffff:ffff:ffff:ffff
8922bb:580::/2822bb:58f:ffff:ffff:ffff:ffff:ffff:ffff
9022bb:590::/2822bb:59f:ffff:ffff:ffff:ffff:ffff:ffff
9122bb:5a0::/2822bb:5af:ffff:ffff:ffff:ffff:ffff:ffff
9222bb:5b0::/2822bb:5bf:ffff:ffff:ffff:ffff:ffff:ffff
9322bb:5c0::/2822bb:5cf:ffff:ffff:ffff:ffff:ffff:ffff
9422bb:5d0::/2822bb:5df:ffff:ffff:ffff:ffff:ffff:ffff
9522bb:5e0::/2822bb:5ef:ffff:ffff:ffff:ffff:ffff:ffff
9622bb:5f0::/2822bb:5ff:ffff:ffff:ffff:ffff:ffff:ffff
9722bb:600::/2822bb:60f:ffff:ffff:ffff:ffff:ffff:ffff
9822bb:610::/2822bb:61f:ffff:ffff:ffff:ffff:ffff:ffff
9922bb:620::/2822bb:62f:ffff:ffff:ffff:ffff:ffff:ffff
10022bb:630::/2822bb:63f:ffff:ffff:ffff:ffff:ffff:ffff
10122bb:640::/2822bb:64f:ffff:ffff:ffff:ffff:ffff:ffff
10222bb:650::/2822bb:65f:ffff:ffff:ffff:ffff:ffff:ffff
10322bb:660::/2822bb:66f:ffff:ffff:ffff:ffff:ffff:ffff
10422bb:670::/2822bb:67f:ffff:ffff:ffff:ffff:ffff:ffff
10522bb:680::/2822bb:68f:ffff:ffff:ffff:ffff:ffff:ffff
10622bb:690::/2822bb:69f:ffff:ffff:ffff:ffff:ffff:ffff
10722bb:6a0::/2822bb:6af:ffff:ffff:ffff:ffff:ffff:ffff
10822bb:6b0::/2822bb:6bf:ffff:ffff:ffff:ffff:ffff:ffff
10922bb:6c0::/2822bb:6cf:ffff:ffff:ffff:ffff:ffff:ffff
11022bb:6d0::/2822bb:6df:ffff:ffff:ffff:ffff:ffff:ffff
11122bb:6e0::/2822bb:6ef:ffff:ffff:ffff:ffff:ffff:ffff
11222bb:6f0::/2822bb:6ff:ffff:ffff:ffff:ffff:ffff:ffff
11322bb:700::/2822bb:70f:ffff:ffff:ffff:ffff:ffff:ffff
11422bb:710::/2822bb:71f:ffff:ffff:ffff:ffff:ffff:ffff
11522bb:720::/2822bb:72f:ffff:ffff:ffff:ffff:ffff:ffff
11622bb:730::/2822bb:73f:ffff:ffff:ffff:ffff:ffff:ffff
11722bb:740::/2822bb:74f:ffff:ffff:ffff:ffff:ffff:ffff
11822bb:750::/2822bb:75f:ffff:ffff:ffff:ffff:ffff:ffff
11922bb:760::/2822bb:76f:ffff:ffff:ffff:ffff:ffff:ffff
12022bb:770::/2822bb:77f:ffff:ffff:ffff:ffff:ffff:ffff
12122bb:780::/2822bb:78f:ffff:ffff:ffff:ffff:ffff:ffff
12222bb:790::/2822bb:79f:ffff:ffff:ffff:ffff:ffff:ffff
12322bb:7a0::/2822bb:7af:ffff:ffff:ffff:ffff:ffff:ffff
12422bb:7b0::/2822bb:7bf:ffff:ffff:ffff:ffff:ffff:ffff
12522bb:7c0::/2822bb:7cf:ffff:ffff:ffff:ffff:ffff:ffff
12622bb:7d0::/2822bb:7df:ffff:ffff:ffff:ffff:ffff:ffff
12722bb:7e0::/2822bb:7ef:ffff:ffff:ffff:ffff:ffff:ffff
12822bb:7f0::/2822bb:7ff:ffff:ffff:ffff:ffff:ffff:ffff
12922bb:800::/2822bb:80f:ffff:ffff:ffff:ffff:ffff:ffff
13022bb:810::/2822bb:81f:ffff:ffff:ffff:ffff:ffff:ffff
13122bb:820::/2822bb:82f:ffff:ffff:ffff:ffff:ffff:ffff
13222bb:830::/2822bb:83f:ffff:ffff:ffff:ffff:ffff:ffff
13322bb:840::/2822bb:84f:ffff:ffff:ffff:ffff:ffff:ffff
13422bb:850::/2822bb:85f:ffff:ffff:ffff:ffff:ffff:ffff
13522bb:860::/2822bb:86f:ffff:ffff:ffff:ffff:ffff:ffff
13622bb:870::/2822bb:87f:ffff:ffff:ffff:ffff:ffff:ffff
13722bb:880::/2822bb:88f:ffff:ffff:ffff:ffff:ffff:ffff
13822bb:890::/2822bb:89f:ffff:ffff:ffff:ffff:ffff:ffff
13922bb:8a0::/2822bb:8af:ffff:ffff:ffff:ffff:ffff:ffff
14022bb:8b0::/2822bb:8bf:ffff:ffff:ffff:ffff:ffff:ffff
14122bb:8c0::/2822bb:8cf:ffff:ffff:ffff:ffff:ffff:ffff
14222bb:8d0::/2822bb:8df:ffff:ffff:ffff:ffff:ffff:ffff
14322bb:8e0::/2822bb:8ef:ffff:ffff:ffff:ffff:ffff:ffff
14422bb:8f0::/2822bb:8ff:ffff:ffff:ffff:ffff:ffff:ffff
14522bb:900::/2822bb:90f:ffff:ffff:ffff:ffff:ffff:ffff
14622bb:910::/2822bb:91f:ffff:ffff:ffff:ffff:ffff:ffff
14722bb:920::/2822bb:92f:ffff:ffff:ffff:ffff:ffff:ffff
14822bb:930::/2822bb:93f:ffff:ffff:ffff:ffff:ffff:ffff
14922bb:940::/2822bb:94f:ffff:ffff:ffff:ffff:ffff:ffff
15022bb:950::/2822bb:95f:ffff:ffff:ffff:ffff:ffff:ffff
15122bb:960::/2822bb:96f:ffff:ffff:ffff:ffff:ffff:ffff
15222bb:970::/2822bb:97f:ffff:ffff:ffff:ffff:ffff:ffff
15322bb:980::/2822bb:98f:ffff:ffff:ffff:ffff:ffff:ffff
15422bb:990::/2822bb:99f:ffff:ffff:ffff:ffff:ffff:ffff
15522bb:9a0::/2822bb:9af:ffff:ffff:ffff:ffff:ffff:ffff
15622bb:9b0::/2822bb:9bf:ffff:ffff:ffff:ffff:ffff:ffff
15722bb:9c0::/2822bb:9cf:ffff:ffff:ffff:ffff:ffff:ffff
15822bb:9d0::/2822bb:9df:ffff:ffff:ffff:ffff:ffff:ffff
15922bb:9e0::/2822bb:9ef:ffff:ffff:ffff:ffff:ffff:ffff
16022bb:9f0::/2822bb:9ff:ffff:ffff:ffff:ffff:ffff:ffff
16122bb:a00::/2822bb:a0f:ffff:ffff:ffff:ffff:ffff:ffff
16222bb:a10::/2822bb:a1f:ffff:ffff:ffff:ffff:ffff:ffff
16322bb:a20::/2822bb:a2f:ffff:ffff:ffff:ffff:ffff:ffff
16422bb:a30::/2822bb:a3f:ffff:ffff:ffff:ffff:ffff:ffff
16522bb:a40::/2822bb:a4f:ffff:ffff:ffff:ffff:ffff:ffff
16622bb:a50::/2822bb:a5f:ffff:ffff:ffff:ffff:ffff:ffff
16722bb:a60::/2822bb:a6f:ffff:ffff:ffff:ffff:ffff:ffff
16822bb:a70::/2822bb:a7f:ffff:ffff:ffff:ffff:ffff:ffff
16922bb:a80::/2822bb:a8f:ffff:ffff:ffff:ffff:ffff:ffff
17022bb:a90::/2822bb:a9f:ffff:ffff:ffff:ffff:ffff:ffff
17122bb:aa0::/2822bb:aaf:ffff:ffff:ffff:ffff:ffff:ffff
17222bb:ab0::/2822bb:abf:ffff:ffff:ffff:ffff:ffff:ffff
17322bb:ac0::/2822bb:acf:ffff:ffff:ffff:ffff:ffff:ffff
17422bb:ad0::/2822bb:adf:ffff:ffff:ffff:ffff:ffff:ffff
17522bb:ae0::/2822bb:aef:ffff:ffff:ffff:ffff:ffff:ffff
17622bb:af0::/2822bb:aff:ffff:ffff:ffff:ffff:ffff:ffff
17722bb:b00::/2822bb:b0f:ffff:ffff:ffff:ffff:ffff:ffff
17822bb:b10::/2822bb:b1f:ffff:ffff:ffff:ffff:ffff:ffff
17922bb:b20::/2822bb:b2f:ffff:ffff:ffff:ffff:ffff:ffff
18022bb:b30::/2822bb:b3f:ffff:ffff:ffff:ffff:ffff:ffff
18122bb:b40::/2822bb:b4f:ffff:ffff:ffff:ffff:ffff:ffff
18222bb:b50::/2822bb:b5f:ffff:ffff:ffff:ffff:ffff:ffff
18322bb:b60::/2822bb:b6f:ffff:ffff:ffff:ffff:ffff:ffff
18422bb:b70::/2822bb:b7f:ffff:ffff:ffff:ffff:ffff:ffff
18522bb:b80::/2822bb:b8f:ffff:ffff:ffff:ffff:ffff:ffff
18622bb:b90::/2822bb:b9f:ffff:ffff:ffff:ffff:ffff:ffff
18722bb:ba0::/2822bb:baf:ffff:ffff:ffff:ffff:ffff:ffff
18822bb:bb0::/2822bb:bbf:ffff:ffff:ffff:ffff:ffff:ffff
18922bb:bc0::/2822bb:bcf:ffff:ffff:ffff:ffff:ffff:ffff
19022bb:bd0::/2822bb:bdf:ffff:ffff:ffff:ffff:ffff:ffff
19122bb:be0::/2822bb:bef:ffff:ffff:ffff:ffff:ffff:ffff
19222bb:bf0::/2822bb:bff:ffff:ffff:ffff:ffff:ffff:ffff
19322bb:c00::/2822bb:c0f:ffff:ffff:ffff:ffff:ffff:ffff
19422bb:c10::/2822bb:c1f:ffff:ffff:ffff:ffff:ffff:ffff
19522bb:c20::/2822bb:c2f:ffff:ffff:ffff:ffff:ffff:ffff
19622bb:c30::/2822bb:c3f:ffff:ffff:ffff:ffff:ffff:ffff
19722bb:c40::/2822bb:c4f:ffff:ffff:ffff:ffff:ffff:ffff
19822bb:c50::/2822bb:c5f:ffff:ffff:ffff:ffff:ffff:ffff
19922bb:c60::/2822bb:c6f:ffff:ffff:ffff:ffff:ffff:ffff
20022bb:c70::/2822bb:c7f:ffff:ffff:ffff:ffff:ffff:ffff
20122bb:c80::/2822bb:c8f:ffff:ffff:ffff:ffff:ffff:ffff
20222bb:c90::/2822bb:c9f:ffff:ffff:ffff:ffff:ffff:ffff
20322bb:ca0::/2822bb:caf:ffff:ffff:ffff:ffff:ffff:ffff
20422bb:cb0::/2822bb:cbf:ffff:ffff:ffff:ffff:ffff:ffff
20522bb:cc0::/2822bb:ccf:ffff:ffff:ffff:ffff:ffff:ffff
20622bb:cd0::/2822bb:cdf:ffff:ffff:ffff:ffff:ffff:ffff
20722bb:ce0::/2822bb:cef:ffff:ffff:ffff:ffff:ffff:ffff
20822bb:cf0::/2822bb:cff:ffff:ffff:ffff:ffff:ffff:ffff
20922bb:d00::/2822bb:d0f:ffff:ffff:ffff:ffff:ffff:ffff
21022bb:d10::/2822bb:d1f:ffff:ffff:ffff:ffff:ffff:ffff
21122bb:d20::/2822bb:d2f:ffff:ffff:ffff:ffff:ffff:ffff
21222bb:d30::/2822bb:d3f:ffff:ffff:ffff:ffff:ffff:ffff
21322bb:d40::/2822bb:d4f:ffff:ffff:ffff:ffff:ffff:ffff
21422bb:d50::/2822bb:d5f:ffff:ffff:ffff:ffff:ffff:ffff
21522bb:d60::/2822bb:d6f:ffff:ffff:ffff:ffff:ffff:ffff
21622bb:d70::/2822bb:d7f:ffff:ffff:ffff:ffff:ffff:ffff
21722bb:d80::/2822bb:d8f:ffff:ffff:ffff:ffff:ffff:ffff
21822bb:d90::/2822bb:d9f:ffff:ffff:ffff:ffff:ffff:ffff
21922bb:da0::/2822bb:daf:ffff:ffff:ffff:ffff:ffff:ffff
22022bb:db0::/2822bb:dbf:ffff:ffff:ffff:ffff:ffff:ffff
22122bb:dc0::/2822bb:dcf:ffff:ffff:ffff:ffff:ffff:ffff
22222bb:dd0::/2822bb:ddf:ffff:ffff:ffff:ffff:ffff:ffff
22322bb:de0::/2822bb:def:ffff:ffff:ffff:ffff:ffff:ffff
22422bb:df0::/2822bb:dff:ffff:ffff:ffff:ffff:ffff:ffff
22522bb:e00::/2822bb:e0f:ffff:ffff:ffff:ffff:ffff:ffff
22622bb:e10::/2822bb:e1f:ffff:ffff:ffff:ffff:ffff:ffff
22722bb:e20::/2822bb:e2f:ffff:ffff:ffff:ffff:ffff:ffff
22822bb:e30::/2822bb:e3f:ffff:ffff:ffff:ffff:ffff:ffff
22922bb:e40::/2822bb:e4f:ffff:ffff:ffff:ffff:ffff:ffff
23022bb:e50::/2822bb:e5f:ffff:ffff:ffff:ffff:ffff:ffff
23122bb:e60::/2822bb:e6f:ffff:ffff:ffff:ffff:ffff:ffff
23222bb:e70::/2822bb:e7f:ffff:ffff:ffff:ffff:ffff:ffff
23322bb:e80::/2822bb:e8f:ffff:ffff:ffff:ffff:ffff:ffff
23422bb:e90::/2822bb:e9f:ffff:ffff:ffff:ffff:ffff:ffff
23522bb:ea0::/2822bb:eaf:ffff:ffff:ffff:ffff:ffff:ffff
23622bb:eb0::/2822bb:ebf:ffff:ffff:ffff:ffff:ffff:ffff
23722bb:ec0::/2822bb:ecf:ffff:ffff:ffff:ffff:ffff:ffff
23822bb:ed0::/2822bb:edf:ffff:ffff:ffff:ffff:ffff:ffff
23922bb:ee0::/2822bb:eef:ffff:ffff:ffff:ffff:ffff:ffff
24022bb:ef0::/2822bb:eff:ffff:ffff:ffff:ffff:ffff:ffff
24122bb:f00::/2822bb:f0f:ffff:ffff:ffff:ffff:ffff:ffff
24222bb:f10::/2822bb:f1f:ffff:ffff:ffff:ffff:ffff:ffff
24322bb:f20::/2822bb:f2f:ffff:ffff:ffff:ffff:ffff:ffff
24422bb:f30::/2822bb:f3f:ffff:ffff:ffff:ffff:ffff:ffff
24522bb:f40::/2822bb:f4f:ffff:ffff:ffff:ffff:ffff:ffff
24622bb:f50::/2822bb:f5f:ffff:ffff:ffff:ffff:ffff:ffff
24722bb:f60::/2822bb:f6f:ffff:ffff:ffff:ffff:ffff:ffff
24822bb:f70::/2822bb:f7f:ffff:ffff:ffff:ffff:ffff:ffff
24922bb:f80::/2822bb:f8f:ffff:ffff:ffff:ffff:ffff:ffff
25022bb:f90::/2822bb:f9f:ffff:ffff:ffff:ffff:ffff:ffff
25122bb:fa0::/2822bb:faf:ffff:ffff:ffff:ffff:ffff:ffff
25222bb:fb0::/2822bb:fbf:ffff:ffff:ffff:ffff:ffff:ffff
25322bb:fc0::/2822bb:fcf:ffff:ffff:ffff:ffff:ffff:ffff
25422bb:fd0::/2822bb:fdf:ffff:ffff:ffff:ffff:ffff:ffff
25522bb:fe0::/2822bb:fef:ffff:ffff:ffff:ffff:ffff:ffff
25622bb:ff0::/2822bb: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.