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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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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
fcea::/16
First address
fcea::
Last address
fcea: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
fcea:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
a.e.c.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

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

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