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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
ffd6::/16
First address
ffd6::
Last address
ffd6: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
ffd6:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
6.d.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)

ffd6::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ffd6::/24ffd6:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ffd6:100::/24ffd6:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ffd6:200::/24ffd6:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ffd6:300::/24ffd6:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ffd6:400::/24ffd6:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ffd6:500::/24ffd6:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ffd6:600::/24ffd6:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ffd6:700::/24ffd6:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ffd6:800::/24ffd6:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ffd6:900::/24ffd6:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ffd6:a00::/24ffd6:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ffd6:b00::/24ffd6:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ffd6:c00::/24ffd6:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ffd6:d00::/24ffd6:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ffd6:e00::/24ffd6:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ffd6:f00::/24ffd6:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ffd6:1000::/24ffd6:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ffd6:1100::/24ffd6:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ffd6:1200::/24ffd6:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ffd6:1300::/24ffd6:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ffd6:1400::/24ffd6:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ffd6:1500::/24ffd6:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ffd6:1600::/24ffd6:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ffd6:1700::/24ffd6:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ffd6:1800::/24ffd6:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ffd6:1900::/24ffd6:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ffd6:1a00::/24ffd6:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ffd6:1b00::/24ffd6:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ffd6:1c00::/24ffd6:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ffd6:1d00::/24ffd6:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ffd6:1e00::/24ffd6:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ffd6:1f00::/24ffd6:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ffd6:2000::/24ffd6:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ffd6:2100::/24ffd6:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ffd6:2200::/24ffd6:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ffd6:2300::/24ffd6:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ffd6:2400::/24ffd6:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ffd6:2500::/24ffd6:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ffd6:2600::/24ffd6:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ffd6:2700::/24ffd6:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ffd6:2800::/24ffd6:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ffd6:2900::/24ffd6:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ffd6:2a00::/24ffd6:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ffd6:2b00::/24ffd6:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ffd6:2c00::/24ffd6:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ffd6:2d00::/24ffd6:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ffd6:2e00::/24ffd6:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ffd6:2f00::/24ffd6:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ffd6:3000::/24ffd6:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ffd6:3100::/24ffd6:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ffd6:3200::/24ffd6:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ffd6:3300::/24ffd6:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ffd6:3400::/24ffd6:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ffd6:3500::/24ffd6:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ffd6:3600::/24ffd6:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ffd6:3700::/24ffd6:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ffd6:3800::/24ffd6:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ffd6:3900::/24ffd6:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ffd6:3a00::/24ffd6:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ffd6:3b00::/24ffd6:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ffd6:3c00::/24ffd6:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ffd6:3d00::/24ffd6:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ffd6:3e00::/24ffd6:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ffd6:3f00::/24ffd6:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ffd6:4000::/24ffd6:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ffd6:4100::/24ffd6:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ffd6:4200::/24ffd6:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ffd6:4300::/24ffd6:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ffd6:4400::/24ffd6:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ffd6:4500::/24ffd6:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ffd6:4600::/24ffd6:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ffd6:4700::/24ffd6:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ffd6:4800::/24ffd6:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ffd6:4900::/24ffd6:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ffd6:4a00::/24ffd6:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ffd6:4b00::/24ffd6:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ffd6:4c00::/24ffd6:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ffd6:4d00::/24ffd6:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ffd6:4e00::/24ffd6:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ffd6:4f00::/24ffd6:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ffd6:5000::/24ffd6:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ffd6:5100::/24ffd6:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ffd6:5200::/24ffd6:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ffd6:5300::/24ffd6:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ffd6:5400::/24ffd6:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ffd6:5500::/24ffd6:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ffd6:5600::/24ffd6:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ffd6:5700::/24ffd6:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ffd6:5800::/24ffd6:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ffd6:5900::/24ffd6:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ffd6:5a00::/24ffd6:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ffd6:5b00::/24ffd6:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ffd6:5c00::/24ffd6:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ffd6:5d00::/24ffd6:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ffd6:5e00::/24ffd6:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ffd6:5f00::/24ffd6:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ffd6:6000::/24ffd6:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ffd6:6100::/24ffd6:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ffd6:6200::/24ffd6:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ffd6:6300::/24ffd6:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ffd6:6400::/24ffd6:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ffd6:6500::/24ffd6:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ffd6:6600::/24ffd6:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ffd6:6700::/24ffd6:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ffd6:6800::/24ffd6:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ffd6:6900::/24ffd6:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ffd6:6a00::/24ffd6:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ffd6:6b00::/24ffd6:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ffd6:6c00::/24ffd6:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ffd6:6d00::/24ffd6:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ffd6:6e00::/24ffd6:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ffd6:6f00::/24ffd6:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ffd6:7000::/24ffd6:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ffd6:7100::/24ffd6:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ffd6:7200::/24ffd6:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ffd6:7300::/24ffd6:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ffd6:7400::/24ffd6:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ffd6:7500::/24ffd6:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ffd6:7600::/24ffd6:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ffd6:7700::/24ffd6:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ffd6:7800::/24ffd6:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ffd6:7900::/24ffd6:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ffd6:7a00::/24ffd6:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ffd6:7b00::/24ffd6:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ffd6:7c00::/24ffd6:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ffd6:7d00::/24ffd6:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ffd6:7e00::/24ffd6:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ffd6:7f00::/24ffd6:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ffd6:8000::/24ffd6:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ffd6:8100::/24ffd6:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ffd6:8200::/24ffd6:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ffd6:8300::/24ffd6:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ffd6:8400::/24ffd6:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ffd6:8500::/24ffd6:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ffd6:8600::/24ffd6:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ffd6:8700::/24ffd6:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ffd6:8800::/24ffd6:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ffd6:8900::/24ffd6:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ffd6:8a00::/24ffd6:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ffd6:8b00::/24ffd6:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ffd6:8c00::/24ffd6:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ffd6:8d00::/24ffd6:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ffd6:8e00::/24ffd6:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ffd6:8f00::/24ffd6:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ffd6:9000::/24ffd6:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ffd6:9100::/24ffd6:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ffd6:9200::/24ffd6:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ffd6:9300::/24ffd6:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ffd6:9400::/24ffd6:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ffd6:9500::/24ffd6:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ffd6:9600::/24ffd6:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ffd6:9700::/24ffd6:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ffd6:9800::/24ffd6:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ffd6:9900::/24ffd6:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ffd6:9a00::/24ffd6:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ffd6:9b00::/24ffd6:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ffd6:9c00::/24ffd6:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ffd6:9d00::/24ffd6:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ffd6:9e00::/24ffd6:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ffd6:9f00::/24ffd6:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ffd6:a000::/24ffd6:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ffd6:a100::/24ffd6:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ffd6:a200::/24ffd6:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ffd6:a300::/24ffd6:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ffd6:a400::/24ffd6:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ffd6:a500::/24ffd6:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ffd6:a600::/24ffd6:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ffd6:a700::/24ffd6:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ffd6:a800::/24ffd6:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ffd6:a900::/24ffd6:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ffd6:aa00::/24ffd6:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ffd6:ab00::/24ffd6:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ffd6:ac00::/24ffd6:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ffd6:ad00::/24ffd6:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ffd6:ae00::/24ffd6:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ffd6:af00::/24ffd6:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ffd6:b000::/24ffd6:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ffd6:b100::/24ffd6:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ffd6:b200::/24ffd6:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ffd6:b300::/24ffd6:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ffd6:b400::/24ffd6:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ffd6:b500::/24ffd6:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ffd6:b600::/24ffd6:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ffd6:b700::/24ffd6:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ffd6:b800::/24ffd6:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ffd6:b900::/24ffd6:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ffd6:ba00::/24ffd6:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ffd6:bb00::/24ffd6:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ffd6:bc00::/24ffd6:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ffd6:bd00::/24ffd6:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ffd6:be00::/24ffd6:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ffd6:bf00::/24ffd6:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ffd6:c000::/24ffd6:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ffd6:c100::/24ffd6:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ffd6:c200::/24ffd6:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ffd6:c300::/24ffd6:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ffd6:c400::/24ffd6:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ffd6:c500::/24ffd6:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ffd6:c600::/24ffd6:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ffd6:c700::/24ffd6:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ffd6:c800::/24ffd6:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ffd6:c900::/24ffd6:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ffd6:ca00::/24ffd6:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ffd6:cb00::/24ffd6:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ffd6:cc00::/24ffd6:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ffd6:cd00::/24ffd6:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ffd6:ce00::/24ffd6:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ffd6:cf00::/24ffd6:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ffd6:d000::/24ffd6:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ffd6:d100::/24ffd6:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ffd6:d200::/24ffd6:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ffd6:d300::/24ffd6:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ffd6:d400::/24ffd6:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ffd6:d500::/24ffd6:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ffd6:d600::/24ffd6:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ffd6:d700::/24ffd6:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ffd6:d800::/24ffd6:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ffd6:d900::/24ffd6:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ffd6:da00::/24ffd6:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ffd6:db00::/24ffd6:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ffd6:dc00::/24ffd6:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ffd6:dd00::/24ffd6:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ffd6:de00::/24ffd6:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ffd6:df00::/24ffd6:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ffd6:e000::/24ffd6:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ffd6:e100::/24ffd6:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ffd6:e200::/24ffd6:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ffd6:e300::/24ffd6:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ffd6:e400::/24ffd6:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ffd6:e500::/24ffd6:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ffd6:e600::/24ffd6:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ffd6:e700::/24ffd6:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ffd6:e800::/24ffd6:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ffd6:e900::/24ffd6:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ffd6:ea00::/24ffd6:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ffd6:eb00::/24ffd6:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ffd6:ec00::/24ffd6:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ffd6:ed00::/24ffd6:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ffd6:ee00::/24ffd6:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ffd6:ef00::/24ffd6:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ffd6:f000::/24ffd6:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ffd6:f100::/24ffd6:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ffd6:f200::/24ffd6:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ffd6:f300::/24ffd6:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ffd6:f400::/24ffd6:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ffd6:f500::/24ffd6:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ffd6:f600::/24ffd6:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ffd6:f700::/24ffd6:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ffd6:f800::/24ffd6:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ffd6:f900::/24ffd6:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ffd6:fa00::/24ffd6:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ffd6:fb00::/24ffd6:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ffd6:fc00::/24ffd6:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ffd6:fd00::/24ffd6:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ffd6:fe00::/24ffd6:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ffd6:ff00::/24ffd6: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.