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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
20a0::/16
First address
20a0::
Last address
20a0: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
20a0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
0.a.0.2.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

20a0::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
120a0::/2420a0:ff:ffff:ffff:ffff:ffff:ffff:ffff
220a0:100::/2420a0:1ff:ffff:ffff:ffff:ffff:ffff:ffff
320a0:200::/2420a0:2ff:ffff:ffff:ffff:ffff:ffff:ffff
420a0:300::/2420a0:3ff:ffff:ffff:ffff:ffff:ffff:ffff
520a0:400::/2420a0:4ff:ffff:ffff:ffff:ffff:ffff:ffff
620a0:500::/2420a0:5ff:ffff:ffff:ffff:ffff:ffff:ffff
720a0:600::/2420a0:6ff:ffff:ffff:ffff:ffff:ffff:ffff
820a0:700::/2420a0:7ff:ffff:ffff:ffff:ffff:ffff:ffff
920a0:800::/2420a0:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1020a0:900::/2420a0:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1120a0:a00::/2420a0:aff:ffff:ffff:ffff:ffff:ffff:ffff
1220a0:b00::/2420a0:bff:ffff:ffff:ffff:ffff:ffff:ffff
1320a0:c00::/2420a0:cff:ffff:ffff:ffff:ffff:ffff:ffff
1420a0:d00::/2420a0:dff:ffff:ffff:ffff:ffff:ffff:ffff
1520a0:e00::/2420a0:eff:ffff:ffff:ffff:ffff:ffff:ffff
1620a0:f00::/2420a0:fff:ffff:ffff:ffff:ffff:ffff:ffff
1720a0:1000::/2420a0:10ff:ffff:ffff:ffff:ffff:ffff:ffff
1820a0:1100::/2420a0:11ff:ffff:ffff:ffff:ffff:ffff:ffff
1920a0:1200::/2420a0:12ff:ffff:ffff:ffff:ffff:ffff:ffff
2020a0:1300::/2420a0:13ff:ffff:ffff:ffff:ffff:ffff:ffff
2120a0:1400::/2420a0:14ff:ffff:ffff:ffff:ffff:ffff:ffff
2220a0:1500::/2420a0:15ff:ffff:ffff:ffff:ffff:ffff:ffff
2320a0:1600::/2420a0:16ff:ffff:ffff:ffff:ffff:ffff:ffff
2420a0:1700::/2420a0:17ff:ffff:ffff:ffff:ffff:ffff:ffff
2520a0:1800::/2420a0:18ff:ffff:ffff:ffff:ffff:ffff:ffff
2620a0:1900::/2420a0:19ff:ffff:ffff:ffff:ffff:ffff:ffff
2720a0:1a00::/2420a0:1aff:ffff:ffff:ffff:ffff:ffff:ffff
2820a0:1b00::/2420a0:1bff:ffff:ffff:ffff:ffff:ffff:ffff
2920a0:1c00::/2420a0:1cff:ffff:ffff:ffff:ffff:ffff:ffff
3020a0:1d00::/2420a0:1dff:ffff:ffff:ffff:ffff:ffff:ffff
3120a0:1e00::/2420a0:1eff:ffff:ffff:ffff:ffff:ffff:ffff
3220a0:1f00::/2420a0:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3320a0:2000::/2420a0:20ff:ffff:ffff:ffff:ffff:ffff:ffff
3420a0:2100::/2420a0:21ff:ffff:ffff:ffff:ffff:ffff:ffff
3520a0:2200::/2420a0:22ff:ffff:ffff:ffff:ffff:ffff:ffff
3620a0:2300::/2420a0:23ff:ffff:ffff:ffff:ffff:ffff:ffff
3720a0:2400::/2420a0:24ff:ffff:ffff:ffff:ffff:ffff:ffff
3820a0:2500::/2420a0:25ff:ffff:ffff:ffff:ffff:ffff:ffff
3920a0:2600::/2420a0:26ff:ffff:ffff:ffff:ffff:ffff:ffff
4020a0:2700::/2420a0:27ff:ffff:ffff:ffff:ffff:ffff:ffff
4120a0:2800::/2420a0:28ff:ffff:ffff:ffff:ffff:ffff:ffff
4220a0:2900::/2420a0:29ff:ffff:ffff:ffff:ffff:ffff:ffff
4320a0:2a00::/2420a0:2aff:ffff:ffff:ffff:ffff:ffff:ffff
4420a0:2b00::/2420a0:2bff:ffff:ffff:ffff:ffff:ffff:ffff
4520a0:2c00::/2420a0:2cff:ffff:ffff:ffff:ffff:ffff:ffff
4620a0:2d00::/2420a0:2dff:ffff:ffff:ffff:ffff:ffff:ffff
4720a0:2e00::/2420a0:2eff:ffff:ffff:ffff:ffff:ffff:ffff
4820a0:2f00::/2420a0:2fff:ffff:ffff:ffff:ffff:ffff:ffff
4920a0:3000::/2420a0:30ff:ffff:ffff:ffff:ffff:ffff:ffff
5020a0:3100::/2420a0:31ff:ffff:ffff:ffff:ffff:ffff:ffff
5120a0:3200::/2420a0:32ff:ffff:ffff:ffff:ffff:ffff:ffff
5220a0:3300::/2420a0:33ff:ffff:ffff:ffff:ffff:ffff:ffff
5320a0:3400::/2420a0:34ff:ffff:ffff:ffff:ffff:ffff:ffff
5420a0:3500::/2420a0:35ff:ffff:ffff:ffff:ffff:ffff:ffff
5520a0:3600::/2420a0:36ff:ffff:ffff:ffff:ffff:ffff:ffff
5620a0:3700::/2420a0:37ff:ffff:ffff:ffff:ffff:ffff:ffff
5720a0:3800::/2420a0:38ff:ffff:ffff:ffff:ffff:ffff:ffff
5820a0:3900::/2420a0:39ff:ffff:ffff:ffff:ffff:ffff:ffff
5920a0:3a00::/2420a0:3aff:ffff:ffff:ffff:ffff:ffff:ffff
6020a0:3b00::/2420a0:3bff:ffff:ffff:ffff:ffff:ffff:ffff
6120a0:3c00::/2420a0:3cff:ffff:ffff:ffff:ffff:ffff:ffff
6220a0:3d00::/2420a0:3dff:ffff:ffff:ffff:ffff:ffff:ffff
6320a0:3e00::/2420a0:3eff:ffff:ffff:ffff:ffff:ffff:ffff
6420a0:3f00::/2420a0:3fff:ffff:ffff:ffff:ffff:ffff:ffff
6520a0:4000::/2420a0:40ff:ffff:ffff:ffff:ffff:ffff:ffff
6620a0:4100::/2420a0:41ff:ffff:ffff:ffff:ffff:ffff:ffff
6720a0:4200::/2420a0:42ff:ffff:ffff:ffff:ffff:ffff:ffff
6820a0:4300::/2420a0:43ff:ffff:ffff:ffff:ffff:ffff:ffff
6920a0:4400::/2420a0:44ff:ffff:ffff:ffff:ffff:ffff:ffff
7020a0:4500::/2420a0:45ff:ffff:ffff:ffff:ffff:ffff:ffff
7120a0:4600::/2420a0:46ff:ffff:ffff:ffff:ffff:ffff:ffff
7220a0:4700::/2420a0:47ff:ffff:ffff:ffff:ffff:ffff:ffff
7320a0:4800::/2420a0:48ff:ffff:ffff:ffff:ffff:ffff:ffff
7420a0:4900::/2420a0:49ff:ffff:ffff:ffff:ffff:ffff:ffff
7520a0:4a00::/2420a0:4aff:ffff:ffff:ffff:ffff:ffff:ffff
7620a0:4b00::/2420a0:4bff:ffff:ffff:ffff:ffff:ffff:ffff
7720a0:4c00::/2420a0:4cff:ffff:ffff:ffff:ffff:ffff:ffff
7820a0:4d00::/2420a0:4dff:ffff:ffff:ffff:ffff:ffff:ffff
7920a0:4e00::/2420a0:4eff:ffff:ffff:ffff:ffff:ffff:ffff
8020a0:4f00::/2420a0:4fff:ffff:ffff:ffff:ffff:ffff:ffff
8120a0:5000::/2420a0:50ff:ffff:ffff:ffff:ffff:ffff:ffff
8220a0:5100::/2420a0:51ff:ffff:ffff:ffff:ffff:ffff:ffff
8320a0:5200::/2420a0:52ff:ffff:ffff:ffff:ffff:ffff:ffff
8420a0:5300::/2420a0:53ff:ffff:ffff:ffff:ffff:ffff:ffff
8520a0:5400::/2420a0:54ff:ffff:ffff:ffff:ffff:ffff:ffff
8620a0:5500::/2420a0:55ff:ffff:ffff:ffff:ffff:ffff:ffff
8720a0:5600::/2420a0:56ff:ffff:ffff:ffff:ffff:ffff:ffff
8820a0:5700::/2420a0:57ff:ffff:ffff:ffff:ffff:ffff:ffff
8920a0:5800::/2420a0:58ff:ffff:ffff:ffff:ffff:ffff:ffff
9020a0:5900::/2420a0:59ff:ffff:ffff:ffff:ffff:ffff:ffff
9120a0:5a00::/2420a0:5aff:ffff:ffff:ffff:ffff:ffff:ffff
9220a0:5b00::/2420a0:5bff:ffff:ffff:ffff:ffff:ffff:ffff
9320a0:5c00::/2420a0:5cff:ffff:ffff:ffff:ffff:ffff:ffff
9420a0:5d00::/2420a0:5dff:ffff:ffff:ffff:ffff:ffff:ffff
9520a0:5e00::/2420a0:5eff:ffff:ffff:ffff:ffff:ffff:ffff
9620a0:5f00::/2420a0:5fff:ffff:ffff:ffff:ffff:ffff:ffff
9720a0:6000::/2420a0:60ff:ffff:ffff:ffff:ffff:ffff:ffff
9820a0:6100::/2420a0:61ff:ffff:ffff:ffff:ffff:ffff:ffff
9920a0:6200::/2420a0:62ff:ffff:ffff:ffff:ffff:ffff:ffff
10020a0:6300::/2420a0:63ff:ffff:ffff:ffff:ffff:ffff:ffff
10120a0:6400::/2420a0:64ff:ffff:ffff:ffff:ffff:ffff:ffff
10220a0:6500::/2420a0:65ff:ffff:ffff:ffff:ffff:ffff:ffff
10320a0:6600::/2420a0:66ff:ffff:ffff:ffff:ffff:ffff:ffff
10420a0:6700::/2420a0:67ff:ffff:ffff:ffff:ffff:ffff:ffff
10520a0:6800::/2420a0:68ff:ffff:ffff:ffff:ffff:ffff:ffff
10620a0:6900::/2420a0:69ff:ffff:ffff:ffff:ffff:ffff:ffff
10720a0:6a00::/2420a0:6aff:ffff:ffff:ffff:ffff:ffff:ffff
10820a0:6b00::/2420a0:6bff:ffff:ffff:ffff:ffff:ffff:ffff
10920a0:6c00::/2420a0:6cff:ffff:ffff:ffff:ffff:ffff:ffff
11020a0:6d00::/2420a0:6dff:ffff:ffff:ffff:ffff:ffff:ffff
11120a0:6e00::/2420a0:6eff:ffff:ffff:ffff:ffff:ffff:ffff
11220a0:6f00::/2420a0:6fff:ffff:ffff:ffff:ffff:ffff:ffff
11320a0:7000::/2420a0:70ff:ffff:ffff:ffff:ffff:ffff:ffff
11420a0:7100::/2420a0:71ff:ffff:ffff:ffff:ffff:ffff:ffff
11520a0:7200::/2420a0:72ff:ffff:ffff:ffff:ffff:ffff:ffff
11620a0:7300::/2420a0:73ff:ffff:ffff:ffff:ffff:ffff:ffff
11720a0:7400::/2420a0:74ff:ffff:ffff:ffff:ffff:ffff:ffff
11820a0:7500::/2420a0:75ff:ffff:ffff:ffff:ffff:ffff:ffff
11920a0:7600::/2420a0:76ff:ffff:ffff:ffff:ffff:ffff:ffff
12020a0:7700::/2420a0:77ff:ffff:ffff:ffff:ffff:ffff:ffff
12120a0:7800::/2420a0:78ff:ffff:ffff:ffff:ffff:ffff:ffff
12220a0:7900::/2420a0:79ff:ffff:ffff:ffff:ffff:ffff:ffff
12320a0:7a00::/2420a0:7aff:ffff:ffff:ffff:ffff:ffff:ffff
12420a0:7b00::/2420a0:7bff:ffff:ffff:ffff:ffff:ffff:ffff
12520a0:7c00::/2420a0:7cff:ffff:ffff:ffff:ffff:ffff:ffff
12620a0:7d00::/2420a0:7dff:ffff:ffff:ffff:ffff:ffff:ffff
12720a0:7e00::/2420a0:7eff:ffff:ffff:ffff:ffff:ffff:ffff
12820a0:7f00::/2420a0:7fff:ffff:ffff:ffff:ffff:ffff:ffff
12920a0:8000::/2420a0:80ff:ffff:ffff:ffff:ffff:ffff:ffff
13020a0:8100::/2420a0:81ff:ffff:ffff:ffff:ffff:ffff:ffff
13120a0:8200::/2420a0:82ff:ffff:ffff:ffff:ffff:ffff:ffff
13220a0:8300::/2420a0:83ff:ffff:ffff:ffff:ffff:ffff:ffff
13320a0:8400::/2420a0:84ff:ffff:ffff:ffff:ffff:ffff:ffff
13420a0:8500::/2420a0:85ff:ffff:ffff:ffff:ffff:ffff:ffff
13520a0:8600::/2420a0:86ff:ffff:ffff:ffff:ffff:ffff:ffff
13620a0:8700::/2420a0:87ff:ffff:ffff:ffff:ffff:ffff:ffff
13720a0:8800::/2420a0:88ff:ffff:ffff:ffff:ffff:ffff:ffff
13820a0:8900::/2420a0:89ff:ffff:ffff:ffff:ffff:ffff:ffff
13920a0:8a00::/2420a0:8aff:ffff:ffff:ffff:ffff:ffff:ffff
14020a0:8b00::/2420a0:8bff:ffff:ffff:ffff:ffff:ffff:ffff
14120a0:8c00::/2420a0:8cff:ffff:ffff:ffff:ffff:ffff:ffff
14220a0:8d00::/2420a0:8dff:ffff:ffff:ffff:ffff:ffff:ffff
14320a0:8e00::/2420a0:8eff:ffff:ffff:ffff:ffff:ffff:ffff
14420a0:8f00::/2420a0:8fff:ffff:ffff:ffff:ffff:ffff:ffff
14520a0:9000::/2420a0:90ff:ffff:ffff:ffff:ffff:ffff:ffff
14620a0:9100::/2420a0:91ff:ffff:ffff:ffff:ffff:ffff:ffff
14720a0:9200::/2420a0:92ff:ffff:ffff:ffff:ffff:ffff:ffff
14820a0:9300::/2420a0:93ff:ffff:ffff:ffff:ffff:ffff:ffff
14920a0:9400::/2420a0:94ff:ffff:ffff:ffff:ffff:ffff:ffff
15020a0:9500::/2420a0:95ff:ffff:ffff:ffff:ffff:ffff:ffff
15120a0:9600::/2420a0:96ff:ffff:ffff:ffff:ffff:ffff:ffff
15220a0:9700::/2420a0:97ff:ffff:ffff:ffff:ffff:ffff:ffff
15320a0:9800::/2420a0:98ff:ffff:ffff:ffff:ffff:ffff:ffff
15420a0:9900::/2420a0:99ff:ffff:ffff:ffff:ffff:ffff:ffff
15520a0:9a00::/2420a0:9aff:ffff:ffff:ffff:ffff:ffff:ffff
15620a0:9b00::/2420a0:9bff:ffff:ffff:ffff:ffff:ffff:ffff
15720a0:9c00::/2420a0:9cff:ffff:ffff:ffff:ffff:ffff:ffff
15820a0:9d00::/2420a0:9dff:ffff:ffff:ffff:ffff:ffff:ffff
15920a0:9e00::/2420a0:9eff:ffff:ffff:ffff:ffff:ffff:ffff
16020a0:9f00::/2420a0:9fff:ffff:ffff:ffff:ffff:ffff:ffff
16120a0:a000::/2420a0:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
16220a0:a100::/2420a0:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
16320a0:a200::/2420a0:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
16420a0:a300::/2420a0:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
16520a0:a400::/2420a0:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
16620a0:a500::/2420a0:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
16720a0:a600::/2420a0:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
16820a0:a700::/2420a0:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
16920a0:a800::/2420a0:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
17020a0:a900::/2420a0:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
17120a0:aa00::/2420a0:aaff:ffff:ffff:ffff:ffff:ffff:ffff
17220a0:ab00::/2420a0:abff:ffff:ffff:ffff:ffff:ffff:ffff
17320a0:ac00::/2420a0:acff:ffff:ffff:ffff:ffff:ffff:ffff
17420a0:ad00::/2420a0:adff:ffff:ffff:ffff:ffff:ffff:ffff
17520a0:ae00::/2420a0:aeff:ffff:ffff:ffff:ffff:ffff:ffff
17620a0:af00::/2420a0:afff:ffff:ffff:ffff:ffff:ffff:ffff
17720a0:b000::/2420a0:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
17820a0:b100::/2420a0:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
17920a0:b200::/2420a0:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
18020a0:b300::/2420a0:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
18120a0:b400::/2420a0:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
18220a0:b500::/2420a0:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
18320a0:b600::/2420a0:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
18420a0:b700::/2420a0:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
18520a0:b800::/2420a0:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
18620a0:b900::/2420a0:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
18720a0:ba00::/2420a0:baff:ffff:ffff:ffff:ffff:ffff:ffff
18820a0:bb00::/2420a0:bbff:ffff:ffff:ffff:ffff:ffff:ffff
18920a0:bc00::/2420a0:bcff:ffff:ffff:ffff:ffff:ffff:ffff
19020a0:bd00::/2420a0:bdff:ffff:ffff:ffff:ffff:ffff:ffff
19120a0:be00::/2420a0:beff:ffff:ffff:ffff:ffff:ffff:ffff
19220a0:bf00::/2420a0:bfff:ffff:ffff:ffff:ffff:ffff:ffff
19320a0:c000::/2420a0:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
19420a0:c100::/2420a0:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
19520a0:c200::/2420a0:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
19620a0:c300::/2420a0:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
19720a0:c400::/2420a0:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
19820a0:c500::/2420a0:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
19920a0:c600::/2420a0:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
20020a0:c700::/2420a0:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
20120a0:c800::/2420a0:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
20220a0:c900::/2420a0:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
20320a0:ca00::/2420a0:caff:ffff:ffff:ffff:ffff:ffff:ffff
20420a0:cb00::/2420a0:cbff:ffff:ffff:ffff:ffff:ffff:ffff
20520a0:cc00::/2420a0:ccff:ffff:ffff:ffff:ffff:ffff:ffff
20620a0:cd00::/2420a0:cdff:ffff:ffff:ffff:ffff:ffff:ffff
20720a0:ce00::/2420a0:ceff:ffff:ffff:ffff:ffff:ffff:ffff
20820a0:cf00::/2420a0:cfff:ffff:ffff:ffff:ffff:ffff:ffff
20920a0:d000::/2420a0:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
21020a0:d100::/2420a0:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
21120a0:d200::/2420a0:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
21220a0:d300::/2420a0:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
21320a0:d400::/2420a0:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
21420a0:d500::/2420a0:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
21520a0:d600::/2420a0:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
21620a0:d700::/2420a0:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
21720a0:d800::/2420a0:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
21820a0:d900::/2420a0:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
21920a0:da00::/2420a0:daff:ffff:ffff:ffff:ffff:ffff:ffff
22020a0:db00::/2420a0:dbff:ffff:ffff:ffff:ffff:ffff:ffff
22120a0:dc00::/2420a0:dcff:ffff:ffff:ffff:ffff:ffff:ffff
22220a0:dd00::/2420a0:ddff:ffff:ffff:ffff:ffff:ffff:ffff
22320a0:de00::/2420a0:deff:ffff:ffff:ffff:ffff:ffff:ffff
22420a0:df00::/2420a0:dfff:ffff:ffff:ffff:ffff:ffff:ffff
22520a0:e000::/2420a0:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
22620a0:e100::/2420a0:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
22720a0:e200::/2420a0:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
22820a0:e300::/2420a0:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
22920a0:e400::/2420a0:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
23020a0:e500::/2420a0:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
23120a0:e600::/2420a0:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
23220a0:e700::/2420a0:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
23320a0:e800::/2420a0:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
23420a0:e900::/2420a0:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
23520a0:ea00::/2420a0:eaff:ffff:ffff:ffff:ffff:ffff:ffff
23620a0:eb00::/2420a0:ebff:ffff:ffff:ffff:ffff:ffff:ffff
23720a0:ec00::/2420a0:ecff:ffff:ffff:ffff:ffff:ffff:ffff
23820a0:ed00::/2420a0:edff:ffff:ffff:ffff:ffff:ffff:ffff
23920a0:ee00::/2420a0:eeff:ffff:ffff:ffff:ffff:ffff:ffff
24020a0:ef00::/2420a0:efff:ffff:ffff:ffff:ffff:ffff:ffff
24120a0:f000::/2420a0:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
24220a0:f100::/2420a0:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
24320a0:f200::/2420a0:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
24420a0:f300::/2420a0:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
24520a0:f400::/2420a0:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
24620a0:f500::/2420a0:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
24720a0:f600::/2420a0:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
24820a0:f700::/2420a0:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
24920a0:f800::/2420a0:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
25020a0:f900::/2420a0:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
25120a0:fa00::/2420a0:faff:ffff:ffff:ffff:ffff:ffff:ffff
25220a0:fb00::/2420a0:fbff:ffff:ffff:ffff:ffff:ffff:ffff
25320a0:fc00::/2420a0:fcff:ffff:ffff:ffff:ffff:ffff:ffff
25420a0:fd00::/2420a0:fdff:ffff:ffff:ffff:ffff:ffff:ffff
25520a0:fe00::/2420a0:feff:ffff:ffff:ffff:ffff:ffff:ffff
25620a0:ff00::/2420a0:ffff: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.