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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
ff4d::/16
First address
ff4d::
Last address
ff4d: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
ff4d:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
d.4.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)

ff4d::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff4d::/24ff4d:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff4d:100::/24ff4d:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff4d:200::/24ff4d:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff4d:300::/24ff4d:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff4d:400::/24ff4d:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff4d:500::/24ff4d:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff4d:600::/24ff4d:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff4d:700::/24ff4d:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff4d:800::/24ff4d:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff4d:900::/24ff4d:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff4d:a00::/24ff4d:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff4d:b00::/24ff4d:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff4d:c00::/24ff4d:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff4d:d00::/24ff4d:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff4d:e00::/24ff4d:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff4d:f00::/24ff4d:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff4d:1000::/24ff4d:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff4d:1100::/24ff4d:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff4d:1200::/24ff4d:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff4d:1300::/24ff4d:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff4d:1400::/24ff4d:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff4d:1500::/24ff4d:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff4d:1600::/24ff4d:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff4d:1700::/24ff4d:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff4d:1800::/24ff4d:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff4d:1900::/24ff4d:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff4d:1a00::/24ff4d:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff4d:1b00::/24ff4d:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff4d:1c00::/24ff4d:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff4d:1d00::/24ff4d:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff4d:1e00::/24ff4d:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff4d:1f00::/24ff4d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff4d:2000::/24ff4d:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff4d:2100::/24ff4d:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff4d:2200::/24ff4d:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff4d:2300::/24ff4d:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff4d:2400::/24ff4d:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff4d:2500::/24ff4d:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff4d:2600::/24ff4d:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff4d:2700::/24ff4d:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff4d:2800::/24ff4d:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff4d:2900::/24ff4d:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff4d:2a00::/24ff4d:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff4d:2b00::/24ff4d:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff4d:2c00::/24ff4d:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff4d:2d00::/24ff4d:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff4d:2e00::/24ff4d:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff4d:2f00::/24ff4d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff4d:3000::/24ff4d:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff4d:3100::/24ff4d:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff4d:3200::/24ff4d:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff4d:3300::/24ff4d:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff4d:3400::/24ff4d:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff4d:3500::/24ff4d:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff4d:3600::/24ff4d:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff4d:3700::/24ff4d:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff4d:3800::/24ff4d:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff4d:3900::/24ff4d:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff4d:3a00::/24ff4d:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff4d:3b00::/24ff4d:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff4d:3c00::/24ff4d:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff4d:3d00::/24ff4d:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff4d:3e00::/24ff4d:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff4d:3f00::/24ff4d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff4d:4000::/24ff4d:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff4d:4100::/24ff4d:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff4d:4200::/24ff4d:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff4d:4300::/24ff4d:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff4d:4400::/24ff4d:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff4d:4500::/24ff4d:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff4d:4600::/24ff4d:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff4d:4700::/24ff4d:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff4d:4800::/24ff4d:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff4d:4900::/24ff4d:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff4d:4a00::/24ff4d:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff4d:4b00::/24ff4d:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff4d:4c00::/24ff4d:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff4d:4d00::/24ff4d:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff4d:4e00::/24ff4d:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff4d:4f00::/24ff4d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff4d:5000::/24ff4d:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff4d:5100::/24ff4d:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff4d:5200::/24ff4d:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff4d:5300::/24ff4d:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff4d:5400::/24ff4d:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff4d:5500::/24ff4d:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff4d:5600::/24ff4d:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff4d:5700::/24ff4d:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff4d:5800::/24ff4d:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff4d:5900::/24ff4d:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff4d:5a00::/24ff4d:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff4d:5b00::/24ff4d:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff4d:5c00::/24ff4d:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff4d:5d00::/24ff4d:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff4d:5e00::/24ff4d:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff4d:5f00::/24ff4d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff4d:6000::/24ff4d:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff4d:6100::/24ff4d:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff4d:6200::/24ff4d:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff4d:6300::/24ff4d:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff4d:6400::/24ff4d:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff4d:6500::/24ff4d:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff4d:6600::/24ff4d:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff4d:6700::/24ff4d:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff4d:6800::/24ff4d:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff4d:6900::/24ff4d:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff4d:6a00::/24ff4d:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff4d:6b00::/24ff4d:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff4d:6c00::/24ff4d:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff4d:6d00::/24ff4d:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff4d:6e00::/24ff4d:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff4d:6f00::/24ff4d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff4d:7000::/24ff4d:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff4d:7100::/24ff4d:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff4d:7200::/24ff4d:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff4d:7300::/24ff4d:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff4d:7400::/24ff4d:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff4d:7500::/24ff4d:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff4d:7600::/24ff4d:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff4d:7700::/24ff4d:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff4d:7800::/24ff4d:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff4d:7900::/24ff4d:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff4d:7a00::/24ff4d:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff4d:7b00::/24ff4d:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff4d:7c00::/24ff4d:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff4d:7d00::/24ff4d:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff4d:7e00::/24ff4d:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff4d:7f00::/24ff4d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff4d:8000::/24ff4d:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff4d:8100::/24ff4d:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff4d:8200::/24ff4d:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff4d:8300::/24ff4d:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff4d:8400::/24ff4d:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff4d:8500::/24ff4d:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff4d:8600::/24ff4d:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff4d:8700::/24ff4d:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff4d:8800::/24ff4d:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff4d:8900::/24ff4d:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff4d:8a00::/24ff4d:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff4d:8b00::/24ff4d:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff4d:8c00::/24ff4d:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff4d:8d00::/24ff4d:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff4d:8e00::/24ff4d:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff4d:8f00::/24ff4d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff4d:9000::/24ff4d:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff4d:9100::/24ff4d:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff4d:9200::/24ff4d:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff4d:9300::/24ff4d:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff4d:9400::/24ff4d:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff4d:9500::/24ff4d:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff4d:9600::/24ff4d:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff4d:9700::/24ff4d:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff4d:9800::/24ff4d:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff4d:9900::/24ff4d:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff4d:9a00::/24ff4d:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff4d:9b00::/24ff4d:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff4d:9c00::/24ff4d:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff4d:9d00::/24ff4d:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff4d:9e00::/24ff4d:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff4d:9f00::/24ff4d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff4d:a000::/24ff4d:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff4d:a100::/24ff4d:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff4d:a200::/24ff4d:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff4d:a300::/24ff4d:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff4d:a400::/24ff4d:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff4d:a500::/24ff4d:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff4d:a600::/24ff4d:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff4d:a700::/24ff4d:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff4d:a800::/24ff4d:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff4d:a900::/24ff4d:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff4d:aa00::/24ff4d:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff4d:ab00::/24ff4d:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff4d:ac00::/24ff4d:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff4d:ad00::/24ff4d:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff4d:ae00::/24ff4d:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff4d:af00::/24ff4d:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff4d:b000::/24ff4d:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff4d:b100::/24ff4d:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff4d:b200::/24ff4d:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff4d:b300::/24ff4d:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff4d:b400::/24ff4d:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff4d:b500::/24ff4d:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff4d:b600::/24ff4d:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff4d:b700::/24ff4d:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff4d:b800::/24ff4d:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff4d:b900::/24ff4d:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff4d:ba00::/24ff4d:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff4d:bb00::/24ff4d:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff4d:bc00::/24ff4d:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff4d:bd00::/24ff4d:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff4d:be00::/24ff4d:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff4d:bf00::/24ff4d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff4d:c000::/24ff4d:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff4d:c100::/24ff4d:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff4d:c200::/24ff4d:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff4d:c300::/24ff4d:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff4d:c400::/24ff4d:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff4d:c500::/24ff4d:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff4d:c600::/24ff4d:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff4d:c700::/24ff4d:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff4d:c800::/24ff4d:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff4d:c900::/24ff4d:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff4d:ca00::/24ff4d:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff4d:cb00::/24ff4d:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff4d:cc00::/24ff4d:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff4d:cd00::/24ff4d:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff4d:ce00::/24ff4d:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff4d:cf00::/24ff4d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff4d:d000::/24ff4d:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff4d:d100::/24ff4d:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff4d:d200::/24ff4d:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff4d:d300::/24ff4d:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff4d:d400::/24ff4d:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff4d:d500::/24ff4d:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff4d:d600::/24ff4d:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff4d:d700::/24ff4d:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff4d:d800::/24ff4d:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff4d:d900::/24ff4d:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff4d:da00::/24ff4d:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff4d:db00::/24ff4d:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff4d:dc00::/24ff4d:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff4d:dd00::/24ff4d:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff4d:de00::/24ff4d:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff4d:df00::/24ff4d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff4d:e000::/24ff4d:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff4d:e100::/24ff4d:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff4d:e200::/24ff4d:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff4d:e300::/24ff4d:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff4d:e400::/24ff4d:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff4d:e500::/24ff4d:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff4d:e600::/24ff4d:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff4d:e700::/24ff4d:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff4d:e800::/24ff4d:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff4d:e900::/24ff4d:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff4d:ea00::/24ff4d:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff4d:eb00::/24ff4d:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff4d:ec00::/24ff4d:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff4d:ed00::/24ff4d:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff4d:ee00::/24ff4d:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff4d:ef00::/24ff4d:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff4d:f000::/24ff4d:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff4d:f100::/24ff4d:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff4d:f200::/24ff4d:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff4d:f300::/24ff4d:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff4d:f400::/24ff4d:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff4d:f500::/24ff4d:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff4d:f600::/24ff4d:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff4d:f700::/24ff4d:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff4d:f800::/24ff4d:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff4d:f900::/24ff4d:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff4d:fa00::/24ff4d:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff4d:fb00::/24ff4d:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff4d:fc00::/24ff4d:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff4d:fd00::/24ff4d:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff4d:fe00::/24ff4d:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff4d:ff00::/24ff4d: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.