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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
fcd3::/16
First address
fcd3::
Last address
fcd3: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
fcd3:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
3.d.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)

fcd3::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fcd3::/24fcd3:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fcd3:100::/24fcd3:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fcd3:200::/24fcd3:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fcd3:300::/24fcd3:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fcd3:400::/24fcd3:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fcd3:500::/24fcd3:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fcd3:600::/24fcd3:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fcd3:700::/24fcd3:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fcd3:800::/24fcd3:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fcd3:900::/24fcd3:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fcd3:a00::/24fcd3:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fcd3:b00::/24fcd3:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fcd3:c00::/24fcd3:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fcd3:d00::/24fcd3:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fcd3:e00::/24fcd3:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fcd3:f00::/24fcd3:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fcd3:1000::/24fcd3:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fcd3:1100::/24fcd3:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fcd3:1200::/24fcd3:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fcd3:1300::/24fcd3:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fcd3:1400::/24fcd3:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fcd3:1500::/24fcd3:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fcd3:1600::/24fcd3:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fcd3:1700::/24fcd3:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fcd3:1800::/24fcd3:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fcd3:1900::/24fcd3:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fcd3:1a00::/24fcd3:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fcd3:1b00::/24fcd3:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fcd3:1c00::/24fcd3:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fcd3:1d00::/24fcd3:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fcd3:1e00::/24fcd3:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fcd3:1f00::/24fcd3:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fcd3:2000::/24fcd3:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fcd3:2100::/24fcd3:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fcd3:2200::/24fcd3:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fcd3:2300::/24fcd3:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fcd3:2400::/24fcd3:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fcd3:2500::/24fcd3:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fcd3:2600::/24fcd3:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fcd3:2700::/24fcd3:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fcd3:2800::/24fcd3:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fcd3:2900::/24fcd3:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fcd3:2a00::/24fcd3:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fcd3:2b00::/24fcd3:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fcd3:2c00::/24fcd3:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fcd3:2d00::/24fcd3:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fcd3:2e00::/24fcd3:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fcd3:2f00::/24fcd3:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fcd3:3000::/24fcd3:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fcd3:3100::/24fcd3:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fcd3:3200::/24fcd3:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fcd3:3300::/24fcd3:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fcd3:3400::/24fcd3:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fcd3:3500::/24fcd3:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fcd3:3600::/24fcd3:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fcd3:3700::/24fcd3:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fcd3:3800::/24fcd3:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fcd3:3900::/24fcd3:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fcd3:3a00::/24fcd3:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fcd3:3b00::/24fcd3:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fcd3:3c00::/24fcd3:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fcd3:3d00::/24fcd3:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fcd3:3e00::/24fcd3:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fcd3:3f00::/24fcd3:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fcd3:4000::/24fcd3:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fcd3:4100::/24fcd3:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fcd3:4200::/24fcd3:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fcd3:4300::/24fcd3:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fcd3:4400::/24fcd3:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fcd3:4500::/24fcd3:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fcd3:4600::/24fcd3:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fcd3:4700::/24fcd3:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fcd3:4800::/24fcd3:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fcd3:4900::/24fcd3:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fcd3:4a00::/24fcd3:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fcd3:4b00::/24fcd3:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fcd3:4c00::/24fcd3:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fcd3:4d00::/24fcd3:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fcd3:4e00::/24fcd3:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fcd3:4f00::/24fcd3:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fcd3:5000::/24fcd3:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fcd3:5100::/24fcd3:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fcd3:5200::/24fcd3:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fcd3:5300::/24fcd3:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fcd3:5400::/24fcd3:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fcd3:5500::/24fcd3:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fcd3:5600::/24fcd3:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fcd3:5700::/24fcd3:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fcd3:5800::/24fcd3:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fcd3:5900::/24fcd3:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fcd3:5a00::/24fcd3:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fcd3:5b00::/24fcd3:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fcd3:5c00::/24fcd3:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fcd3:5d00::/24fcd3:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fcd3:5e00::/24fcd3:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fcd3:5f00::/24fcd3:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fcd3:6000::/24fcd3:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fcd3:6100::/24fcd3:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fcd3:6200::/24fcd3:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fcd3:6300::/24fcd3:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fcd3:6400::/24fcd3:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fcd3:6500::/24fcd3:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fcd3:6600::/24fcd3:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fcd3:6700::/24fcd3:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fcd3:6800::/24fcd3:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fcd3:6900::/24fcd3:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fcd3:6a00::/24fcd3:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fcd3:6b00::/24fcd3:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fcd3:6c00::/24fcd3:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fcd3:6d00::/24fcd3:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fcd3:6e00::/24fcd3:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fcd3:6f00::/24fcd3:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fcd3:7000::/24fcd3:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fcd3:7100::/24fcd3:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fcd3:7200::/24fcd3:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fcd3:7300::/24fcd3:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fcd3:7400::/24fcd3:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fcd3:7500::/24fcd3:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fcd3:7600::/24fcd3:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fcd3:7700::/24fcd3:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fcd3:7800::/24fcd3:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fcd3:7900::/24fcd3:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fcd3:7a00::/24fcd3:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fcd3:7b00::/24fcd3:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fcd3:7c00::/24fcd3:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fcd3:7d00::/24fcd3:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fcd3:7e00::/24fcd3:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fcd3:7f00::/24fcd3:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fcd3:8000::/24fcd3:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fcd3:8100::/24fcd3:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fcd3:8200::/24fcd3:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fcd3:8300::/24fcd3:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fcd3:8400::/24fcd3:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fcd3:8500::/24fcd3:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fcd3:8600::/24fcd3:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fcd3:8700::/24fcd3:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fcd3:8800::/24fcd3:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fcd3:8900::/24fcd3:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fcd3:8a00::/24fcd3:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fcd3:8b00::/24fcd3:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fcd3:8c00::/24fcd3:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fcd3:8d00::/24fcd3:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fcd3:8e00::/24fcd3:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fcd3:8f00::/24fcd3:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fcd3:9000::/24fcd3:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fcd3:9100::/24fcd3:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fcd3:9200::/24fcd3:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fcd3:9300::/24fcd3:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fcd3:9400::/24fcd3:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fcd3:9500::/24fcd3:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fcd3:9600::/24fcd3:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fcd3:9700::/24fcd3:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fcd3:9800::/24fcd3:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fcd3:9900::/24fcd3:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fcd3:9a00::/24fcd3:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fcd3:9b00::/24fcd3:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fcd3:9c00::/24fcd3:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fcd3:9d00::/24fcd3:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fcd3:9e00::/24fcd3:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fcd3:9f00::/24fcd3:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fcd3:a000::/24fcd3:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fcd3:a100::/24fcd3:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fcd3:a200::/24fcd3:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fcd3:a300::/24fcd3:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fcd3:a400::/24fcd3:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fcd3:a500::/24fcd3:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fcd3:a600::/24fcd3:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fcd3:a700::/24fcd3:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fcd3:a800::/24fcd3:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fcd3:a900::/24fcd3:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fcd3:aa00::/24fcd3:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fcd3:ab00::/24fcd3:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fcd3:ac00::/24fcd3:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fcd3:ad00::/24fcd3:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fcd3:ae00::/24fcd3:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fcd3:af00::/24fcd3:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fcd3:b000::/24fcd3:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fcd3:b100::/24fcd3:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fcd3:b200::/24fcd3:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fcd3:b300::/24fcd3:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fcd3:b400::/24fcd3:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fcd3:b500::/24fcd3:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fcd3:b600::/24fcd3:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fcd3:b700::/24fcd3:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fcd3:b800::/24fcd3:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fcd3:b900::/24fcd3:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fcd3:ba00::/24fcd3:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fcd3:bb00::/24fcd3:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fcd3:bc00::/24fcd3:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fcd3:bd00::/24fcd3:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fcd3:be00::/24fcd3:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fcd3:bf00::/24fcd3:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fcd3:c000::/24fcd3:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fcd3:c100::/24fcd3:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fcd3:c200::/24fcd3:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fcd3:c300::/24fcd3:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fcd3:c400::/24fcd3:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fcd3:c500::/24fcd3:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fcd3:c600::/24fcd3:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fcd3:c700::/24fcd3:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fcd3:c800::/24fcd3:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fcd3:c900::/24fcd3:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fcd3:ca00::/24fcd3:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fcd3:cb00::/24fcd3:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fcd3:cc00::/24fcd3:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fcd3:cd00::/24fcd3:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fcd3:ce00::/24fcd3:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fcd3:cf00::/24fcd3:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fcd3:d000::/24fcd3:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fcd3:d100::/24fcd3:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fcd3:d200::/24fcd3:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fcd3:d300::/24fcd3:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fcd3:d400::/24fcd3:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fcd3:d500::/24fcd3:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fcd3:d600::/24fcd3:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fcd3:d700::/24fcd3:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fcd3:d800::/24fcd3:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fcd3:d900::/24fcd3:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fcd3:da00::/24fcd3:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fcd3:db00::/24fcd3:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fcd3:dc00::/24fcd3:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fcd3:dd00::/24fcd3:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fcd3:de00::/24fcd3:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fcd3:df00::/24fcd3:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fcd3:e000::/24fcd3:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fcd3:e100::/24fcd3:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fcd3:e200::/24fcd3:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fcd3:e300::/24fcd3:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fcd3:e400::/24fcd3:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fcd3:e500::/24fcd3:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fcd3:e600::/24fcd3:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fcd3:e700::/24fcd3:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fcd3:e800::/24fcd3:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fcd3:e900::/24fcd3:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fcd3:ea00::/24fcd3:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fcd3:eb00::/24fcd3:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fcd3:ec00::/24fcd3:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fcd3:ed00::/24fcd3:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fcd3:ee00::/24fcd3:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fcd3:ef00::/24fcd3:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fcd3:f000::/24fcd3:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fcd3:f100::/24fcd3:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fcd3:f200::/24fcd3:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fcd3:f300::/24fcd3:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fcd3:f400::/24fcd3:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fcd3:f500::/24fcd3:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fcd3:f600::/24fcd3:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fcd3:f700::/24fcd3:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fcd3:f800::/24fcd3:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fcd3:f900::/24fcd3:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fcd3:fa00::/24fcd3:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fcd3:fb00::/24fcd3:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fcd3:fc00::/24fcd3:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fcd3:fd00::/24fcd3:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fcd3:fe00::/24fcd3:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fcd3:ff00::/24fcd3: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.