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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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Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

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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
ffc2::/16
First address
ffc2::
Last address
ffc2: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
ffc2:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
2.c.f.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ffc2::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ffc2::/24ffc2:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ffc2:100::/24ffc2:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ffc2:200::/24ffc2:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ffc2:300::/24ffc2:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ffc2:400::/24ffc2:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ffc2:500::/24ffc2:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ffc2:600::/24ffc2:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ffc2:700::/24ffc2:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ffc2:800::/24ffc2:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ffc2:900::/24ffc2:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ffc2:a00::/24ffc2:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ffc2:b00::/24ffc2:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ffc2:c00::/24ffc2:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ffc2:d00::/24ffc2:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ffc2:e00::/24ffc2:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ffc2:f00::/24ffc2:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ffc2:1000::/24ffc2:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ffc2:1100::/24ffc2:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ffc2:1200::/24ffc2:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ffc2:1300::/24ffc2:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ffc2:1400::/24ffc2:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ffc2:1500::/24ffc2:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ffc2:1600::/24ffc2:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ffc2:1700::/24ffc2:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ffc2:1800::/24ffc2:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ffc2:1900::/24ffc2:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ffc2:1a00::/24ffc2:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ffc2:1b00::/24ffc2:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ffc2:1c00::/24ffc2:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ffc2:1d00::/24ffc2:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ffc2:1e00::/24ffc2:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ffc2:1f00::/24ffc2:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ffc2:2000::/24ffc2:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ffc2:2100::/24ffc2:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ffc2:2200::/24ffc2:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ffc2:2300::/24ffc2:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ffc2:2400::/24ffc2:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ffc2:2500::/24ffc2:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ffc2:2600::/24ffc2:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ffc2:2700::/24ffc2:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ffc2:2800::/24ffc2:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ffc2:2900::/24ffc2:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ffc2:2a00::/24ffc2:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ffc2:2b00::/24ffc2:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ffc2:2c00::/24ffc2:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ffc2:2d00::/24ffc2:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ffc2:2e00::/24ffc2:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ffc2:2f00::/24ffc2:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ffc2:3000::/24ffc2:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ffc2:3100::/24ffc2:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ffc2:3200::/24ffc2:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ffc2:3300::/24ffc2:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ffc2:3400::/24ffc2:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ffc2:3500::/24ffc2:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ffc2:3600::/24ffc2:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ffc2:3700::/24ffc2:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ffc2:3800::/24ffc2:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ffc2:3900::/24ffc2:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ffc2:3a00::/24ffc2:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ffc2:3b00::/24ffc2:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ffc2:3c00::/24ffc2:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ffc2:3d00::/24ffc2:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ffc2:3e00::/24ffc2:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ffc2:3f00::/24ffc2:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ffc2:4000::/24ffc2:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ffc2:4100::/24ffc2:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ffc2:4200::/24ffc2:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ffc2:4300::/24ffc2:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ffc2:4400::/24ffc2:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ffc2:4500::/24ffc2:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ffc2:4600::/24ffc2:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ffc2:4700::/24ffc2:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ffc2:4800::/24ffc2:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ffc2:4900::/24ffc2:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ffc2:4a00::/24ffc2:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ffc2:4b00::/24ffc2:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ffc2:4c00::/24ffc2:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ffc2:4d00::/24ffc2:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ffc2:4e00::/24ffc2:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ffc2:4f00::/24ffc2:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ffc2:5000::/24ffc2:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ffc2:5100::/24ffc2:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ffc2:5200::/24ffc2:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ffc2:5300::/24ffc2:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ffc2:5400::/24ffc2:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ffc2:5500::/24ffc2:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ffc2:5600::/24ffc2:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ffc2:5700::/24ffc2:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ffc2:5800::/24ffc2:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ffc2:5900::/24ffc2:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ffc2:5a00::/24ffc2:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ffc2:5b00::/24ffc2:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ffc2:5c00::/24ffc2:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ffc2:5d00::/24ffc2:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ffc2:5e00::/24ffc2:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ffc2:5f00::/24ffc2:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ffc2:6000::/24ffc2:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ffc2:6100::/24ffc2:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ffc2:6200::/24ffc2:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ffc2:6300::/24ffc2:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ffc2:6400::/24ffc2:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ffc2:6500::/24ffc2:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ffc2:6600::/24ffc2:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ffc2:6700::/24ffc2:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ffc2:6800::/24ffc2:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ffc2:6900::/24ffc2:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ffc2:6a00::/24ffc2:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ffc2:6b00::/24ffc2:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ffc2:6c00::/24ffc2:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ffc2:6d00::/24ffc2:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ffc2:6e00::/24ffc2:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ffc2:6f00::/24ffc2:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ffc2:7000::/24ffc2:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ffc2:7100::/24ffc2:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ffc2:7200::/24ffc2:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ffc2:7300::/24ffc2:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ffc2:7400::/24ffc2:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ffc2:7500::/24ffc2:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ffc2:7600::/24ffc2:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ffc2:7700::/24ffc2:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ffc2:7800::/24ffc2:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ffc2:7900::/24ffc2:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ffc2:7a00::/24ffc2:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ffc2:7b00::/24ffc2:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ffc2:7c00::/24ffc2:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ffc2:7d00::/24ffc2:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ffc2:7e00::/24ffc2:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ffc2:7f00::/24ffc2:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ffc2:8000::/24ffc2:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ffc2:8100::/24ffc2:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ffc2:8200::/24ffc2:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ffc2:8300::/24ffc2:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ffc2:8400::/24ffc2:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ffc2:8500::/24ffc2:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ffc2:8600::/24ffc2:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ffc2:8700::/24ffc2:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ffc2:8800::/24ffc2:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ffc2:8900::/24ffc2:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ffc2:8a00::/24ffc2:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ffc2:8b00::/24ffc2:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ffc2:8c00::/24ffc2:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ffc2:8d00::/24ffc2:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ffc2:8e00::/24ffc2:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ffc2:8f00::/24ffc2:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ffc2:9000::/24ffc2:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ffc2:9100::/24ffc2:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ffc2:9200::/24ffc2:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ffc2:9300::/24ffc2:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ffc2:9400::/24ffc2:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ffc2:9500::/24ffc2:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ffc2:9600::/24ffc2:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ffc2:9700::/24ffc2:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ffc2:9800::/24ffc2:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ffc2:9900::/24ffc2:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ffc2:9a00::/24ffc2:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ffc2:9b00::/24ffc2:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ffc2:9c00::/24ffc2:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ffc2:9d00::/24ffc2:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ffc2:9e00::/24ffc2:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ffc2:9f00::/24ffc2:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ffc2:a000::/24ffc2:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ffc2:a100::/24ffc2:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ffc2:a200::/24ffc2:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ffc2:a300::/24ffc2:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ffc2:a400::/24ffc2:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ffc2:a500::/24ffc2:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ffc2:a600::/24ffc2:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ffc2:a700::/24ffc2:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ffc2:a800::/24ffc2:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ffc2:a900::/24ffc2:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ffc2:aa00::/24ffc2:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ffc2:ab00::/24ffc2:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ffc2:ac00::/24ffc2:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ffc2:ad00::/24ffc2:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ffc2:ae00::/24ffc2:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ffc2:af00::/24ffc2:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ffc2:b000::/24ffc2:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ffc2:b100::/24ffc2:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ffc2:b200::/24ffc2:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ffc2:b300::/24ffc2:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ffc2:b400::/24ffc2:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ffc2:b500::/24ffc2:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ffc2:b600::/24ffc2:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ffc2:b700::/24ffc2:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ffc2:b800::/24ffc2:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ffc2:b900::/24ffc2:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ffc2:ba00::/24ffc2:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ffc2:bb00::/24ffc2:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ffc2:bc00::/24ffc2:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ffc2:bd00::/24ffc2:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ffc2:be00::/24ffc2:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ffc2:bf00::/24ffc2:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ffc2:c000::/24ffc2:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ffc2:c100::/24ffc2:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ffc2:c200::/24ffc2:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ffc2:c300::/24ffc2:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ffc2:c400::/24ffc2:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ffc2:c500::/24ffc2:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ffc2:c600::/24ffc2:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ffc2:c700::/24ffc2:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ffc2:c800::/24ffc2:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ffc2:c900::/24ffc2:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ffc2:ca00::/24ffc2:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ffc2:cb00::/24ffc2:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ffc2:cc00::/24ffc2:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ffc2:cd00::/24ffc2:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ffc2:ce00::/24ffc2:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ffc2:cf00::/24ffc2:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ffc2:d000::/24ffc2:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ffc2:d100::/24ffc2:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ffc2:d200::/24ffc2:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ffc2:d300::/24ffc2:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ffc2:d400::/24ffc2:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ffc2:d500::/24ffc2:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ffc2:d600::/24ffc2:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ffc2:d700::/24ffc2:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ffc2:d800::/24ffc2:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ffc2:d900::/24ffc2:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ffc2:da00::/24ffc2:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ffc2:db00::/24ffc2:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ffc2:dc00::/24ffc2:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ffc2:dd00::/24ffc2:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ffc2:de00::/24ffc2:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ffc2:df00::/24ffc2:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ffc2:e000::/24ffc2:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ffc2:e100::/24ffc2:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ffc2:e200::/24ffc2:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ffc2:e300::/24ffc2:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ffc2:e400::/24ffc2:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ffc2:e500::/24ffc2:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ffc2:e600::/24ffc2:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ffc2:e700::/24ffc2:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ffc2:e800::/24ffc2:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ffc2:e900::/24ffc2:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ffc2:ea00::/24ffc2:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ffc2:eb00::/24ffc2:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ffc2:ec00::/24ffc2:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ffc2:ed00::/24ffc2:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ffc2:ee00::/24ffc2:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ffc2:ef00::/24ffc2:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ffc2:f000::/24ffc2:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ffc2:f100::/24ffc2:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ffc2:f200::/24ffc2:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ffc2:f300::/24ffc2:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ffc2:f400::/24ffc2:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ffc2:f500::/24ffc2:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ffc2:f600::/24ffc2:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ffc2:f700::/24ffc2:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ffc2:f800::/24ffc2:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ffc2:f900::/24ffc2:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ffc2:fa00::/24ffc2:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ffc2:fb00::/24ffc2:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ffc2:fc00::/24ffc2:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ffc2:fd00::/24ffc2:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ffc2:fe00::/24ffc2:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ffc2:ff00::/24ffc2: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.