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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
ff9d::/16
First address
ff9d::
Last address
ff9d: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
ff9d:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
d.9.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)

ff9d::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff9d::/24ff9d:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff9d:100::/24ff9d:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff9d:200::/24ff9d:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff9d:300::/24ff9d:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff9d:400::/24ff9d:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff9d:500::/24ff9d:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff9d:600::/24ff9d:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff9d:700::/24ff9d:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff9d:800::/24ff9d:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff9d:900::/24ff9d:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff9d:a00::/24ff9d:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff9d:b00::/24ff9d:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff9d:c00::/24ff9d:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff9d:d00::/24ff9d:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff9d:e00::/24ff9d:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff9d:f00::/24ff9d:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff9d:1000::/24ff9d:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff9d:1100::/24ff9d:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff9d:1200::/24ff9d:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff9d:1300::/24ff9d:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff9d:1400::/24ff9d:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff9d:1500::/24ff9d:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff9d:1600::/24ff9d:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff9d:1700::/24ff9d:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff9d:1800::/24ff9d:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff9d:1900::/24ff9d:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff9d:1a00::/24ff9d:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff9d:1b00::/24ff9d:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff9d:1c00::/24ff9d:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff9d:1d00::/24ff9d:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff9d:1e00::/24ff9d:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff9d:1f00::/24ff9d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff9d:2000::/24ff9d:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff9d:2100::/24ff9d:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff9d:2200::/24ff9d:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff9d:2300::/24ff9d:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff9d:2400::/24ff9d:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff9d:2500::/24ff9d:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff9d:2600::/24ff9d:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff9d:2700::/24ff9d:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff9d:2800::/24ff9d:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff9d:2900::/24ff9d:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff9d:2a00::/24ff9d:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff9d:2b00::/24ff9d:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff9d:2c00::/24ff9d:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff9d:2d00::/24ff9d:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff9d:2e00::/24ff9d:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff9d:2f00::/24ff9d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff9d:3000::/24ff9d:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff9d:3100::/24ff9d:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff9d:3200::/24ff9d:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff9d:3300::/24ff9d:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff9d:3400::/24ff9d:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff9d:3500::/24ff9d:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff9d:3600::/24ff9d:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff9d:3700::/24ff9d:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff9d:3800::/24ff9d:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff9d:3900::/24ff9d:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff9d:3a00::/24ff9d:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff9d:3b00::/24ff9d:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff9d:3c00::/24ff9d:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff9d:3d00::/24ff9d:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff9d:3e00::/24ff9d:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff9d:3f00::/24ff9d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff9d:4000::/24ff9d:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff9d:4100::/24ff9d:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff9d:4200::/24ff9d:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff9d:4300::/24ff9d:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff9d:4400::/24ff9d:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff9d:4500::/24ff9d:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff9d:4600::/24ff9d:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff9d:4700::/24ff9d:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff9d:4800::/24ff9d:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff9d:4900::/24ff9d:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff9d:4a00::/24ff9d:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff9d:4b00::/24ff9d:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff9d:4c00::/24ff9d:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff9d:4d00::/24ff9d:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff9d:4e00::/24ff9d:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff9d:4f00::/24ff9d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff9d:5000::/24ff9d:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff9d:5100::/24ff9d:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff9d:5200::/24ff9d:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff9d:5300::/24ff9d:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff9d:5400::/24ff9d:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff9d:5500::/24ff9d:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff9d:5600::/24ff9d:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff9d:5700::/24ff9d:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff9d:5800::/24ff9d:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff9d:5900::/24ff9d:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff9d:5a00::/24ff9d:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff9d:5b00::/24ff9d:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff9d:5c00::/24ff9d:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff9d:5d00::/24ff9d:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff9d:5e00::/24ff9d:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff9d:5f00::/24ff9d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff9d:6000::/24ff9d:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff9d:6100::/24ff9d:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff9d:6200::/24ff9d:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff9d:6300::/24ff9d:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff9d:6400::/24ff9d:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff9d:6500::/24ff9d:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff9d:6600::/24ff9d:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff9d:6700::/24ff9d:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff9d:6800::/24ff9d:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff9d:6900::/24ff9d:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff9d:6a00::/24ff9d:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff9d:6b00::/24ff9d:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff9d:6c00::/24ff9d:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff9d:6d00::/24ff9d:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff9d:6e00::/24ff9d:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff9d:6f00::/24ff9d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff9d:7000::/24ff9d:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff9d:7100::/24ff9d:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff9d:7200::/24ff9d:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff9d:7300::/24ff9d:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff9d:7400::/24ff9d:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff9d:7500::/24ff9d:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff9d:7600::/24ff9d:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff9d:7700::/24ff9d:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff9d:7800::/24ff9d:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff9d:7900::/24ff9d:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff9d:7a00::/24ff9d:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff9d:7b00::/24ff9d:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff9d:7c00::/24ff9d:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff9d:7d00::/24ff9d:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff9d:7e00::/24ff9d:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff9d:7f00::/24ff9d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff9d:8000::/24ff9d:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff9d:8100::/24ff9d:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff9d:8200::/24ff9d:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff9d:8300::/24ff9d:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff9d:8400::/24ff9d:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff9d:8500::/24ff9d:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff9d:8600::/24ff9d:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff9d:8700::/24ff9d:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff9d:8800::/24ff9d:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff9d:8900::/24ff9d:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff9d:8a00::/24ff9d:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff9d:8b00::/24ff9d:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff9d:8c00::/24ff9d:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff9d:8d00::/24ff9d:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff9d:8e00::/24ff9d:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff9d:8f00::/24ff9d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff9d:9000::/24ff9d:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff9d:9100::/24ff9d:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff9d:9200::/24ff9d:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff9d:9300::/24ff9d:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff9d:9400::/24ff9d:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff9d:9500::/24ff9d:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff9d:9600::/24ff9d:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff9d:9700::/24ff9d:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff9d:9800::/24ff9d:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff9d:9900::/24ff9d:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff9d:9a00::/24ff9d:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff9d:9b00::/24ff9d:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff9d:9c00::/24ff9d:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff9d:9d00::/24ff9d:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff9d:9e00::/24ff9d:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff9d:9f00::/24ff9d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff9d:a000::/24ff9d:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff9d:a100::/24ff9d:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff9d:a200::/24ff9d:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff9d:a300::/24ff9d:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff9d:a400::/24ff9d:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff9d:a500::/24ff9d:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff9d:a600::/24ff9d:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff9d:a700::/24ff9d:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff9d:a800::/24ff9d:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff9d:a900::/24ff9d:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff9d:aa00::/24ff9d:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff9d:ab00::/24ff9d:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff9d:ac00::/24ff9d:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff9d:ad00::/24ff9d:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff9d:ae00::/24ff9d:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff9d:af00::/24ff9d:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff9d:b000::/24ff9d:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff9d:b100::/24ff9d:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff9d:b200::/24ff9d:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff9d:b300::/24ff9d:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff9d:b400::/24ff9d:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff9d:b500::/24ff9d:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff9d:b600::/24ff9d:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff9d:b700::/24ff9d:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff9d:b800::/24ff9d:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff9d:b900::/24ff9d:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff9d:ba00::/24ff9d:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff9d:bb00::/24ff9d:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff9d:bc00::/24ff9d:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff9d:bd00::/24ff9d:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff9d:be00::/24ff9d:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff9d:bf00::/24ff9d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff9d:c000::/24ff9d:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff9d:c100::/24ff9d:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff9d:c200::/24ff9d:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff9d:c300::/24ff9d:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff9d:c400::/24ff9d:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff9d:c500::/24ff9d:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff9d:c600::/24ff9d:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff9d:c700::/24ff9d:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff9d:c800::/24ff9d:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff9d:c900::/24ff9d:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff9d:ca00::/24ff9d:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff9d:cb00::/24ff9d:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff9d:cc00::/24ff9d:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff9d:cd00::/24ff9d:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff9d:ce00::/24ff9d:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff9d:cf00::/24ff9d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff9d:d000::/24ff9d:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff9d:d100::/24ff9d:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff9d:d200::/24ff9d:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff9d:d300::/24ff9d:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff9d:d400::/24ff9d:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff9d:d500::/24ff9d:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff9d:d600::/24ff9d:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff9d:d700::/24ff9d:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff9d:d800::/24ff9d:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff9d:d900::/24ff9d:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff9d:da00::/24ff9d:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff9d:db00::/24ff9d:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff9d:dc00::/24ff9d:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff9d:dd00::/24ff9d:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff9d:de00::/24ff9d:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff9d:df00::/24ff9d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff9d:e000::/24ff9d:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff9d:e100::/24ff9d:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff9d:e200::/24ff9d:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff9d:e300::/24ff9d:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff9d:e400::/24ff9d:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff9d:e500::/24ff9d:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff9d:e600::/24ff9d:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff9d:e700::/24ff9d:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff9d:e800::/24ff9d:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff9d:e900::/24ff9d:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff9d:ea00::/24ff9d:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff9d:eb00::/24ff9d:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff9d:ec00::/24ff9d:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff9d:ed00::/24ff9d:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff9d:ee00::/24ff9d:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff9d:ef00::/24ff9d:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff9d:f000::/24ff9d:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff9d:f100::/24ff9d:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff9d:f200::/24ff9d:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff9d:f300::/24ff9d:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff9d:f400::/24ff9d:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff9d:f500::/24ff9d:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff9d:f600::/24ff9d:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff9d:f700::/24ff9d:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff9d:f800::/24ff9d:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff9d:f900::/24ff9d:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff9d:fa00::/24ff9d:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff9d:fb00::/24ff9d:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff9d:fc00::/24ff9d:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff9d:fd00::/24ff9d:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff9d:fe00::/24ff9d:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff9d:ff00::/24ff9d: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.