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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
ffb2::/16
First address
ffb2::
Last address
ffb2: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
ffb2:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
2.b.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)

ffb2::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ffb2::/24ffb2:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ffb2:100::/24ffb2:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ffb2:200::/24ffb2:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ffb2:300::/24ffb2:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ffb2:400::/24ffb2:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ffb2:500::/24ffb2:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ffb2:600::/24ffb2:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ffb2:700::/24ffb2:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ffb2:800::/24ffb2:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ffb2:900::/24ffb2:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ffb2:a00::/24ffb2:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ffb2:b00::/24ffb2:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ffb2:c00::/24ffb2:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ffb2:d00::/24ffb2:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ffb2:e00::/24ffb2:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ffb2:f00::/24ffb2:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ffb2:1000::/24ffb2:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ffb2:1100::/24ffb2:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ffb2:1200::/24ffb2:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ffb2:1300::/24ffb2:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ffb2:1400::/24ffb2:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ffb2:1500::/24ffb2:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ffb2:1600::/24ffb2:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ffb2:1700::/24ffb2:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ffb2:1800::/24ffb2:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ffb2:1900::/24ffb2:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ffb2:1a00::/24ffb2:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ffb2:1b00::/24ffb2:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ffb2:1c00::/24ffb2:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ffb2:1d00::/24ffb2:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ffb2:1e00::/24ffb2:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ffb2:1f00::/24ffb2:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ffb2:2000::/24ffb2:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ffb2:2100::/24ffb2:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ffb2:2200::/24ffb2:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ffb2:2300::/24ffb2:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ffb2:2400::/24ffb2:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ffb2:2500::/24ffb2:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ffb2:2600::/24ffb2:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ffb2:2700::/24ffb2:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ffb2:2800::/24ffb2:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ffb2:2900::/24ffb2:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ffb2:2a00::/24ffb2:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ffb2:2b00::/24ffb2:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ffb2:2c00::/24ffb2:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ffb2:2d00::/24ffb2:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ffb2:2e00::/24ffb2:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ffb2:2f00::/24ffb2:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ffb2:3000::/24ffb2:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ffb2:3100::/24ffb2:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ffb2:3200::/24ffb2:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ffb2:3300::/24ffb2:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ffb2:3400::/24ffb2:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ffb2:3500::/24ffb2:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ffb2:3600::/24ffb2:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ffb2:3700::/24ffb2:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ffb2:3800::/24ffb2:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ffb2:3900::/24ffb2:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ffb2:3a00::/24ffb2:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ffb2:3b00::/24ffb2:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ffb2:3c00::/24ffb2:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ffb2:3d00::/24ffb2:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ffb2:3e00::/24ffb2:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ffb2:3f00::/24ffb2:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ffb2:4000::/24ffb2:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ffb2:4100::/24ffb2:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ffb2:4200::/24ffb2:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ffb2:4300::/24ffb2:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ffb2:4400::/24ffb2:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ffb2:4500::/24ffb2:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ffb2:4600::/24ffb2:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ffb2:4700::/24ffb2:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ffb2:4800::/24ffb2:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ffb2:4900::/24ffb2:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ffb2:4a00::/24ffb2:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ffb2:4b00::/24ffb2:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ffb2:4c00::/24ffb2:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ffb2:4d00::/24ffb2:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ffb2:4e00::/24ffb2:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ffb2:4f00::/24ffb2:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ffb2:5000::/24ffb2:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ffb2:5100::/24ffb2:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ffb2:5200::/24ffb2:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ffb2:5300::/24ffb2:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ffb2:5400::/24ffb2:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ffb2:5500::/24ffb2:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ffb2:5600::/24ffb2:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ffb2:5700::/24ffb2:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ffb2:5800::/24ffb2:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ffb2:5900::/24ffb2:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ffb2:5a00::/24ffb2:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ffb2:5b00::/24ffb2:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ffb2:5c00::/24ffb2:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ffb2:5d00::/24ffb2:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ffb2:5e00::/24ffb2:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ffb2:5f00::/24ffb2:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ffb2:6000::/24ffb2:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ffb2:6100::/24ffb2:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ffb2:6200::/24ffb2:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ffb2:6300::/24ffb2:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ffb2:6400::/24ffb2:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ffb2:6500::/24ffb2:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ffb2:6600::/24ffb2:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ffb2:6700::/24ffb2:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ffb2:6800::/24ffb2:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ffb2:6900::/24ffb2:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ffb2:6a00::/24ffb2:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ffb2:6b00::/24ffb2:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ffb2:6c00::/24ffb2:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ffb2:6d00::/24ffb2:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ffb2:6e00::/24ffb2:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ffb2:6f00::/24ffb2:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ffb2:7000::/24ffb2:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ffb2:7100::/24ffb2:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ffb2:7200::/24ffb2:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ffb2:7300::/24ffb2:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ffb2:7400::/24ffb2:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ffb2:7500::/24ffb2:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ffb2:7600::/24ffb2:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ffb2:7700::/24ffb2:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ffb2:7800::/24ffb2:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ffb2:7900::/24ffb2:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ffb2:7a00::/24ffb2:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ffb2:7b00::/24ffb2:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ffb2:7c00::/24ffb2:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ffb2:7d00::/24ffb2:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ffb2:7e00::/24ffb2:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ffb2:7f00::/24ffb2:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ffb2:8000::/24ffb2:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ffb2:8100::/24ffb2:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ffb2:8200::/24ffb2:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ffb2:8300::/24ffb2:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ffb2:8400::/24ffb2:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ffb2:8500::/24ffb2:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ffb2:8600::/24ffb2:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ffb2:8700::/24ffb2:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ffb2:8800::/24ffb2:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ffb2:8900::/24ffb2:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ffb2:8a00::/24ffb2:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ffb2:8b00::/24ffb2:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ffb2:8c00::/24ffb2:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ffb2:8d00::/24ffb2:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ffb2:8e00::/24ffb2:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ffb2:8f00::/24ffb2:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ffb2:9000::/24ffb2:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ffb2:9100::/24ffb2:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ffb2:9200::/24ffb2:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ffb2:9300::/24ffb2:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ffb2:9400::/24ffb2:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ffb2:9500::/24ffb2:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ffb2:9600::/24ffb2:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ffb2:9700::/24ffb2:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ffb2:9800::/24ffb2:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ffb2:9900::/24ffb2:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ffb2:9a00::/24ffb2:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ffb2:9b00::/24ffb2:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ffb2:9c00::/24ffb2:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ffb2:9d00::/24ffb2:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ffb2:9e00::/24ffb2:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ffb2:9f00::/24ffb2:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ffb2:a000::/24ffb2:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ffb2:a100::/24ffb2:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ffb2:a200::/24ffb2:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ffb2:a300::/24ffb2:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ffb2:a400::/24ffb2:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ffb2:a500::/24ffb2:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ffb2:a600::/24ffb2:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ffb2:a700::/24ffb2:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ffb2:a800::/24ffb2:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ffb2:a900::/24ffb2:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ffb2:aa00::/24ffb2:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ffb2:ab00::/24ffb2:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ffb2:ac00::/24ffb2:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ffb2:ad00::/24ffb2:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ffb2:ae00::/24ffb2:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ffb2:af00::/24ffb2:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ffb2:b000::/24ffb2:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ffb2:b100::/24ffb2:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ffb2:b200::/24ffb2:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ffb2:b300::/24ffb2:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ffb2:b400::/24ffb2:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ffb2:b500::/24ffb2:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ffb2:b600::/24ffb2:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ffb2:b700::/24ffb2:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ffb2:b800::/24ffb2:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ffb2:b900::/24ffb2:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ffb2:ba00::/24ffb2:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ffb2:bb00::/24ffb2:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ffb2:bc00::/24ffb2:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ffb2:bd00::/24ffb2:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ffb2:be00::/24ffb2:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ffb2:bf00::/24ffb2:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ffb2:c000::/24ffb2:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ffb2:c100::/24ffb2:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ffb2:c200::/24ffb2:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ffb2:c300::/24ffb2:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ffb2:c400::/24ffb2:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ffb2:c500::/24ffb2:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ffb2:c600::/24ffb2:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ffb2:c700::/24ffb2:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ffb2:c800::/24ffb2:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ffb2:c900::/24ffb2:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ffb2:ca00::/24ffb2:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ffb2:cb00::/24ffb2:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ffb2:cc00::/24ffb2:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ffb2:cd00::/24ffb2:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ffb2:ce00::/24ffb2:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ffb2:cf00::/24ffb2:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ffb2:d000::/24ffb2:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ffb2:d100::/24ffb2:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ffb2:d200::/24ffb2:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ffb2:d300::/24ffb2:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ffb2:d400::/24ffb2:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ffb2:d500::/24ffb2:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ffb2:d600::/24ffb2:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ffb2:d700::/24ffb2:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ffb2:d800::/24ffb2:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ffb2:d900::/24ffb2:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ffb2:da00::/24ffb2:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ffb2:db00::/24ffb2:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ffb2:dc00::/24ffb2:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ffb2:dd00::/24ffb2:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ffb2:de00::/24ffb2:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ffb2:df00::/24ffb2:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ffb2:e000::/24ffb2:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ffb2:e100::/24ffb2:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ffb2:e200::/24ffb2:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ffb2:e300::/24ffb2:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ffb2:e400::/24ffb2:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ffb2:e500::/24ffb2:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ffb2:e600::/24ffb2:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ffb2:e700::/24ffb2:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ffb2:e800::/24ffb2:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ffb2:e900::/24ffb2:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ffb2:ea00::/24ffb2:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ffb2:eb00::/24ffb2:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ffb2:ec00::/24ffb2:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ffb2:ed00::/24ffb2:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ffb2:ee00::/24ffb2:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ffb2:ef00::/24ffb2:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ffb2:f000::/24ffb2:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ffb2:f100::/24ffb2:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ffb2:f200::/24ffb2:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ffb2:f300::/24ffb2:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ffb2:f400::/24ffb2:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ffb2:f500::/24ffb2:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ffb2:f600::/24ffb2:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ffb2:f700::/24ffb2:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ffb2:f800::/24ffb2:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ffb2:f900::/24ffb2:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ffb2:fa00::/24ffb2:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ffb2:fb00::/24ffb2:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ffb2:fc00::/24ffb2:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ffb2:fd00::/24ffb2:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ffb2:fe00::/24ffb2:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ffb2:ff00::/24ffb2: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.