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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
febb::/16
First address
febb::
Last address
febb: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
febb:0000:0000:0000:0000:0000:0000:0000
Type
Link-local fe80::/10
Every IPv6 interface has one; not routed
Reverse DNS zone
b.b.e.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

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

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