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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/32
Addresses2^96
/64 networks2^32
Network
fcd5::/32
First address
fcd5::
Last address
fcd5:0:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
79,228,162,514,264,337,593,543,950,336 (2^96)
/64 networks (LANs)
4,294,967,296
Full form
fcd5:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
0.0.0.0.5.d.c.f.ip6.arpa
Split into smaller subnets/40
/33 (2)/34 (4)/35 (8)/36 (16)/40 (256)/44 (4,096)/48 (65,536)

fcd5::/32 makes 256 subnets of /40.

Subnets
#SubnetLast address
1fcd5::/40fcd5:0:ff:ffff:ffff:ffff:ffff:ffff
2fcd5:0:100::/40fcd5:0:1ff:ffff:ffff:ffff:ffff:ffff
3fcd5:0:200::/40fcd5:0:2ff:ffff:ffff:ffff:ffff:ffff
4fcd5:0:300::/40fcd5:0:3ff:ffff:ffff:ffff:ffff:ffff
5fcd5:0:400::/40fcd5:0:4ff:ffff:ffff:ffff:ffff:ffff
6fcd5:0:500::/40fcd5:0:5ff:ffff:ffff:ffff:ffff:ffff
7fcd5:0:600::/40fcd5:0:6ff:ffff:ffff:ffff:ffff:ffff
8fcd5:0:700::/40fcd5:0:7ff:ffff:ffff:ffff:ffff:ffff
9fcd5:0:800::/40fcd5:0:8ff:ffff:ffff:ffff:ffff:ffff
10fcd5:0:900::/40fcd5:0:9ff:ffff:ffff:ffff:ffff:ffff
11fcd5:0:a00::/40fcd5:0:aff:ffff:ffff:ffff:ffff:ffff
12fcd5:0:b00::/40fcd5:0:bff:ffff:ffff:ffff:ffff:ffff
13fcd5:0:c00::/40fcd5:0:cff:ffff:ffff:ffff:ffff:ffff
14fcd5:0:d00::/40fcd5:0:dff:ffff:ffff:ffff:ffff:ffff
15fcd5:0:e00::/40fcd5:0:eff:ffff:ffff:ffff:ffff:ffff
16fcd5:0:f00::/40fcd5:0:fff:ffff:ffff:ffff:ffff:ffff
17fcd5:0:1000::/40fcd5:0:10ff:ffff:ffff:ffff:ffff:ffff
18fcd5:0:1100::/40fcd5:0:11ff:ffff:ffff:ffff:ffff:ffff
19fcd5:0:1200::/40fcd5:0:12ff:ffff:ffff:ffff:ffff:ffff
20fcd5:0:1300::/40fcd5:0:13ff:ffff:ffff:ffff:ffff:ffff
21fcd5:0:1400::/40fcd5:0:14ff:ffff:ffff:ffff:ffff:ffff
22fcd5:0:1500::/40fcd5:0:15ff:ffff:ffff:ffff:ffff:ffff
23fcd5:0:1600::/40fcd5:0:16ff:ffff:ffff:ffff:ffff:ffff
24fcd5:0:1700::/40fcd5:0:17ff:ffff:ffff:ffff:ffff:ffff
25fcd5:0:1800::/40fcd5:0:18ff:ffff:ffff:ffff:ffff:ffff
26fcd5:0:1900::/40fcd5:0:19ff:ffff:ffff:ffff:ffff:ffff
27fcd5:0:1a00::/40fcd5:0:1aff:ffff:ffff:ffff:ffff:ffff
28fcd5:0:1b00::/40fcd5:0:1bff:ffff:ffff:ffff:ffff:ffff
29fcd5:0:1c00::/40fcd5:0:1cff:ffff:ffff:ffff:ffff:ffff
30fcd5:0:1d00::/40fcd5:0:1dff:ffff:ffff:ffff:ffff:ffff
31fcd5:0:1e00::/40fcd5:0:1eff:ffff:ffff:ffff:ffff:ffff
32fcd5:0:1f00::/40fcd5:0:1fff:ffff:ffff:ffff:ffff:ffff
33fcd5:0:2000::/40fcd5:0:20ff:ffff:ffff:ffff:ffff:ffff
34fcd5:0:2100::/40fcd5:0:21ff:ffff:ffff:ffff:ffff:ffff
35fcd5:0:2200::/40fcd5:0:22ff:ffff:ffff:ffff:ffff:ffff
36fcd5:0:2300::/40fcd5:0:23ff:ffff:ffff:ffff:ffff:ffff
37fcd5:0:2400::/40fcd5:0:24ff:ffff:ffff:ffff:ffff:ffff
38fcd5:0:2500::/40fcd5:0:25ff:ffff:ffff:ffff:ffff:ffff
39fcd5:0:2600::/40fcd5:0:26ff:ffff:ffff:ffff:ffff:ffff
40fcd5:0:2700::/40fcd5:0:27ff:ffff:ffff:ffff:ffff:ffff
41fcd5:0:2800::/40fcd5:0:28ff:ffff:ffff:ffff:ffff:ffff
42fcd5:0:2900::/40fcd5:0:29ff:ffff:ffff:ffff:ffff:ffff
43fcd5:0:2a00::/40fcd5:0:2aff:ffff:ffff:ffff:ffff:ffff
44fcd5:0:2b00::/40fcd5:0:2bff:ffff:ffff:ffff:ffff:ffff
45fcd5:0:2c00::/40fcd5:0:2cff:ffff:ffff:ffff:ffff:ffff
46fcd5:0:2d00::/40fcd5:0:2dff:ffff:ffff:ffff:ffff:ffff
47fcd5:0:2e00::/40fcd5:0:2eff:ffff:ffff:ffff:ffff:ffff
48fcd5:0:2f00::/40fcd5:0:2fff:ffff:ffff:ffff:ffff:ffff
49fcd5:0:3000::/40fcd5:0:30ff:ffff:ffff:ffff:ffff:ffff
50fcd5:0:3100::/40fcd5:0:31ff:ffff:ffff:ffff:ffff:ffff
51fcd5:0:3200::/40fcd5:0:32ff:ffff:ffff:ffff:ffff:ffff
52fcd5:0:3300::/40fcd5:0:33ff:ffff:ffff:ffff:ffff:ffff
53fcd5:0:3400::/40fcd5:0:34ff:ffff:ffff:ffff:ffff:ffff
54fcd5:0:3500::/40fcd5:0:35ff:ffff:ffff:ffff:ffff:ffff
55fcd5:0:3600::/40fcd5:0:36ff:ffff:ffff:ffff:ffff:ffff
56fcd5:0:3700::/40fcd5:0:37ff:ffff:ffff:ffff:ffff:ffff
57fcd5:0:3800::/40fcd5:0:38ff:ffff:ffff:ffff:ffff:ffff
58fcd5:0:3900::/40fcd5:0:39ff:ffff:ffff:ffff:ffff:ffff
59fcd5:0:3a00::/40fcd5:0:3aff:ffff:ffff:ffff:ffff:ffff
60fcd5:0:3b00::/40fcd5:0:3bff:ffff:ffff:ffff:ffff:ffff
61fcd5:0:3c00::/40fcd5:0:3cff:ffff:ffff:ffff:ffff:ffff
62fcd5:0:3d00::/40fcd5:0:3dff:ffff:ffff:ffff:ffff:ffff
63fcd5:0:3e00::/40fcd5:0:3eff:ffff:ffff:ffff:ffff:ffff
64fcd5:0:3f00::/40fcd5:0:3fff:ffff:ffff:ffff:ffff:ffff
65fcd5:0:4000::/40fcd5:0:40ff:ffff:ffff:ffff:ffff:ffff
66fcd5:0:4100::/40fcd5:0:41ff:ffff:ffff:ffff:ffff:ffff
67fcd5:0:4200::/40fcd5:0:42ff:ffff:ffff:ffff:ffff:ffff
68fcd5:0:4300::/40fcd5:0:43ff:ffff:ffff:ffff:ffff:ffff
69fcd5:0:4400::/40fcd5:0:44ff:ffff:ffff:ffff:ffff:ffff
70fcd5:0:4500::/40fcd5:0:45ff:ffff:ffff:ffff:ffff:ffff
71fcd5:0:4600::/40fcd5:0:46ff:ffff:ffff:ffff:ffff:ffff
72fcd5:0:4700::/40fcd5:0:47ff:ffff:ffff:ffff:ffff:ffff
73fcd5:0:4800::/40fcd5:0:48ff:ffff:ffff:ffff:ffff:ffff
74fcd5:0:4900::/40fcd5:0:49ff:ffff:ffff:ffff:ffff:ffff
75fcd5:0:4a00::/40fcd5:0:4aff:ffff:ffff:ffff:ffff:ffff
76fcd5:0:4b00::/40fcd5:0:4bff:ffff:ffff:ffff:ffff:ffff
77fcd5:0:4c00::/40fcd5:0:4cff:ffff:ffff:ffff:ffff:ffff
78fcd5:0:4d00::/40fcd5:0:4dff:ffff:ffff:ffff:ffff:ffff
79fcd5:0:4e00::/40fcd5:0:4eff:ffff:ffff:ffff:ffff:ffff
80fcd5:0:4f00::/40fcd5:0:4fff:ffff:ffff:ffff:ffff:ffff
81fcd5:0:5000::/40fcd5:0:50ff:ffff:ffff:ffff:ffff:ffff
82fcd5:0:5100::/40fcd5:0:51ff:ffff:ffff:ffff:ffff:ffff
83fcd5:0:5200::/40fcd5:0:52ff:ffff:ffff:ffff:ffff:ffff
84fcd5:0:5300::/40fcd5:0:53ff:ffff:ffff:ffff:ffff:ffff
85fcd5:0:5400::/40fcd5:0:54ff:ffff:ffff:ffff:ffff:ffff
86fcd5:0:5500::/40fcd5:0:55ff:ffff:ffff:ffff:ffff:ffff
87fcd5:0:5600::/40fcd5:0:56ff:ffff:ffff:ffff:ffff:ffff
88fcd5:0:5700::/40fcd5:0:57ff:ffff:ffff:ffff:ffff:ffff
89fcd5:0:5800::/40fcd5:0:58ff:ffff:ffff:ffff:ffff:ffff
90fcd5:0:5900::/40fcd5:0:59ff:ffff:ffff:ffff:ffff:ffff
91fcd5:0:5a00::/40fcd5:0:5aff:ffff:ffff:ffff:ffff:ffff
92fcd5:0:5b00::/40fcd5:0:5bff:ffff:ffff:ffff:ffff:ffff
93fcd5:0:5c00::/40fcd5:0:5cff:ffff:ffff:ffff:ffff:ffff
94fcd5:0:5d00::/40fcd5:0:5dff:ffff:ffff:ffff:ffff:ffff
95fcd5:0:5e00::/40fcd5:0:5eff:ffff:ffff:ffff:ffff:ffff
96fcd5:0:5f00::/40fcd5:0:5fff:ffff:ffff:ffff:ffff:ffff
97fcd5:0:6000::/40fcd5:0:60ff:ffff:ffff:ffff:ffff:ffff
98fcd5:0:6100::/40fcd5:0:61ff:ffff:ffff:ffff:ffff:ffff
99fcd5:0:6200::/40fcd5:0:62ff:ffff:ffff:ffff:ffff:ffff
100fcd5:0:6300::/40fcd5:0:63ff:ffff:ffff:ffff:ffff:ffff
101fcd5:0:6400::/40fcd5:0:64ff:ffff:ffff:ffff:ffff:ffff
102fcd5:0:6500::/40fcd5:0:65ff:ffff:ffff:ffff:ffff:ffff
103fcd5:0:6600::/40fcd5:0:66ff:ffff:ffff:ffff:ffff:ffff
104fcd5:0:6700::/40fcd5:0:67ff:ffff:ffff:ffff:ffff:ffff
105fcd5:0:6800::/40fcd5:0:68ff:ffff:ffff:ffff:ffff:ffff
106fcd5:0:6900::/40fcd5:0:69ff:ffff:ffff:ffff:ffff:ffff
107fcd5:0:6a00::/40fcd5:0:6aff:ffff:ffff:ffff:ffff:ffff
108fcd5:0:6b00::/40fcd5:0:6bff:ffff:ffff:ffff:ffff:ffff
109fcd5:0:6c00::/40fcd5:0:6cff:ffff:ffff:ffff:ffff:ffff
110fcd5:0:6d00::/40fcd5:0:6dff:ffff:ffff:ffff:ffff:ffff
111fcd5:0:6e00::/40fcd5:0:6eff:ffff:ffff:ffff:ffff:ffff
112fcd5:0:6f00::/40fcd5:0:6fff:ffff:ffff:ffff:ffff:ffff
113fcd5:0:7000::/40fcd5:0:70ff:ffff:ffff:ffff:ffff:ffff
114fcd5:0:7100::/40fcd5:0:71ff:ffff:ffff:ffff:ffff:ffff
115fcd5:0:7200::/40fcd5:0:72ff:ffff:ffff:ffff:ffff:ffff
116fcd5:0:7300::/40fcd5:0:73ff:ffff:ffff:ffff:ffff:ffff
117fcd5:0:7400::/40fcd5:0:74ff:ffff:ffff:ffff:ffff:ffff
118fcd5:0:7500::/40fcd5:0:75ff:ffff:ffff:ffff:ffff:ffff
119fcd5:0:7600::/40fcd5:0:76ff:ffff:ffff:ffff:ffff:ffff
120fcd5:0:7700::/40fcd5:0:77ff:ffff:ffff:ffff:ffff:ffff
121fcd5:0:7800::/40fcd5:0:78ff:ffff:ffff:ffff:ffff:ffff
122fcd5:0:7900::/40fcd5:0:79ff:ffff:ffff:ffff:ffff:ffff
123fcd5:0:7a00::/40fcd5:0:7aff:ffff:ffff:ffff:ffff:ffff
124fcd5:0:7b00::/40fcd5:0:7bff:ffff:ffff:ffff:ffff:ffff
125fcd5:0:7c00::/40fcd5:0:7cff:ffff:ffff:ffff:ffff:ffff
126fcd5:0:7d00::/40fcd5:0:7dff:ffff:ffff:ffff:ffff:ffff
127fcd5:0:7e00::/40fcd5:0:7eff:ffff:ffff:ffff:ffff:ffff
128fcd5:0:7f00::/40fcd5:0:7fff:ffff:ffff:ffff:ffff:ffff
129fcd5:0:8000::/40fcd5:0:80ff:ffff:ffff:ffff:ffff:ffff
130fcd5:0:8100::/40fcd5:0:81ff:ffff:ffff:ffff:ffff:ffff
131fcd5:0:8200::/40fcd5:0:82ff:ffff:ffff:ffff:ffff:ffff
132fcd5:0:8300::/40fcd5:0:83ff:ffff:ffff:ffff:ffff:ffff
133fcd5:0:8400::/40fcd5:0:84ff:ffff:ffff:ffff:ffff:ffff
134fcd5:0:8500::/40fcd5:0:85ff:ffff:ffff:ffff:ffff:ffff
135fcd5:0:8600::/40fcd5:0:86ff:ffff:ffff:ffff:ffff:ffff
136fcd5:0:8700::/40fcd5:0:87ff:ffff:ffff:ffff:ffff:ffff
137fcd5:0:8800::/40fcd5:0:88ff:ffff:ffff:ffff:ffff:ffff
138fcd5:0:8900::/40fcd5:0:89ff:ffff:ffff:ffff:ffff:ffff
139fcd5:0:8a00::/40fcd5:0:8aff:ffff:ffff:ffff:ffff:ffff
140fcd5:0:8b00::/40fcd5:0:8bff:ffff:ffff:ffff:ffff:ffff
141fcd5:0:8c00::/40fcd5:0:8cff:ffff:ffff:ffff:ffff:ffff
142fcd5:0:8d00::/40fcd5:0:8dff:ffff:ffff:ffff:ffff:ffff
143fcd5:0:8e00::/40fcd5:0:8eff:ffff:ffff:ffff:ffff:ffff
144fcd5:0:8f00::/40fcd5:0:8fff:ffff:ffff:ffff:ffff:ffff
145fcd5:0:9000::/40fcd5:0:90ff:ffff:ffff:ffff:ffff:ffff
146fcd5:0:9100::/40fcd5:0:91ff:ffff:ffff:ffff:ffff:ffff
147fcd5:0:9200::/40fcd5:0:92ff:ffff:ffff:ffff:ffff:ffff
148fcd5:0:9300::/40fcd5:0:93ff:ffff:ffff:ffff:ffff:ffff
149fcd5:0:9400::/40fcd5:0:94ff:ffff:ffff:ffff:ffff:ffff
150fcd5:0:9500::/40fcd5:0:95ff:ffff:ffff:ffff:ffff:ffff
151fcd5:0:9600::/40fcd5:0:96ff:ffff:ffff:ffff:ffff:ffff
152fcd5:0:9700::/40fcd5:0:97ff:ffff:ffff:ffff:ffff:ffff
153fcd5:0:9800::/40fcd5:0:98ff:ffff:ffff:ffff:ffff:ffff
154fcd5:0:9900::/40fcd5:0:99ff:ffff:ffff:ffff:ffff:ffff
155fcd5:0:9a00::/40fcd5:0:9aff:ffff:ffff:ffff:ffff:ffff
156fcd5:0:9b00::/40fcd5:0:9bff:ffff:ffff:ffff:ffff:ffff
157fcd5:0:9c00::/40fcd5:0:9cff:ffff:ffff:ffff:ffff:ffff
158fcd5:0:9d00::/40fcd5:0:9dff:ffff:ffff:ffff:ffff:ffff
159fcd5:0:9e00::/40fcd5:0:9eff:ffff:ffff:ffff:ffff:ffff
160fcd5:0:9f00::/40fcd5:0:9fff:ffff:ffff:ffff:ffff:ffff
161fcd5:0:a000::/40fcd5:0:a0ff:ffff:ffff:ffff:ffff:ffff
162fcd5:0:a100::/40fcd5:0:a1ff:ffff:ffff:ffff:ffff:ffff
163fcd5:0:a200::/40fcd5:0:a2ff:ffff:ffff:ffff:ffff:ffff
164fcd5:0:a300::/40fcd5:0:a3ff:ffff:ffff:ffff:ffff:ffff
165fcd5:0:a400::/40fcd5:0:a4ff:ffff:ffff:ffff:ffff:ffff
166fcd5:0:a500::/40fcd5:0:a5ff:ffff:ffff:ffff:ffff:ffff
167fcd5:0:a600::/40fcd5:0:a6ff:ffff:ffff:ffff:ffff:ffff
168fcd5:0:a700::/40fcd5:0:a7ff:ffff:ffff:ffff:ffff:ffff
169fcd5:0:a800::/40fcd5:0:a8ff:ffff:ffff:ffff:ffff:ffff
170fcd5:0:a900::/40fcd5:0:a9ff:ffff:ffff:ffff:ffff:ffff
171fcd5:0:aa00::/40fcd5:0:aaff:ffff:ffff:ffff:ffff:ffff
172fcd5:0:ab00::/40fcd5:0:abff:ffff:ffff:ffff:ffff:ffff
173fcd5:0:ac00::/40fcd5:0:acff:ffff:ffff:ffff:ffff:ffff
174fcd5:0:ad00::/40fcd5:0:adff:ffff:ffff:ffff:ffff:ffff
175fcd5:0:ae00::/40fcd5:0:aeff:ffff:ffff:ffff:ffff:ffff
176fcd5:0:af00::/40fcd5:0:afff:ffff:ffff:ffff:ffff:ffff
177fcd5:0:b000::/40fcd5:0:b0ff:ffff:ffff:ffff:ffff:ffff
178fcd5:0:b100::/40fcd5:0:b1ff:ffff:ffff:ffff:ffff:ffff
179fcd5:0:b200::/40fcd5:0:b2ff:ffff:ffff:ffff:ffff:ffff
180fcd5:0:b300::/40fcd5:0:b3ff:ffff:ffff:ffff:ffff:ffff
181fcd5:0:b400::/40fcd5:0:b4ff:ffff:ffff:ffff:ffff:ffff
182fcd5:0:b500::/40fcd5:0:b5ff:ffff:ffff:ffff:ffff:ffff
183fcd5:0:b600::/40fcd5:0:b6ff:ffff:ffff:ffff:ffff:ffff
184fcd5:0:b700::/40fcd5:0:b7ff:ffff:ffff:ffff:ffff:ffff
185fcd5:0:b800::/40fcd5:0:b8ff:ffff:ffff:ffff:ffff:ffff
186fcd5:0:b900::/40fcd5:0:b9ff:ffff:ffff:ffff:ffff:ffff
187fcd5:0:ba00::/40fcd5:0:baff:ffff:ffff:ffff:ffff:ffff
188fcd5:0:bb00::/40fcd5:0:bbff:ffff:ffff:ffff:ffff:ffff
189fcd5:0:bc00::/40fcd5:0:bcff:ffff:ffff:ffff:ffff:ffff
190fcd5:0:bd00::/40fcd5:0:bdff:ffff:ffff:ffff:ffff:ffff
191fcd5:0:be00::/40fcd5:0:beff:ffff:ffff:ffff:ffff:ffff
192fcd5:0:bf00::/40fcd5:0:bfff:ffff:ffff:ffff:ffff:ffff
193fcd5:0:c000::/40fcd5:0:c0ff:ffff:ffff:ffff:ffff:ffff
194fcd5:0:c100::/40fcd5:0:c1ff:ffff:ffff:ffff:ffff:ffff
195fcd5:0:c200::/40fcd5:0:c2ff:ffff:ffff:ffff:ffff:ffff
196fcd5:0:c300::/40fcd5:0:c3ff:ffff:ffff:ffff:ffff:ffff
197fcd5:0:c400::/40fcd5:0:c4ff:ffff:ffff:ffff:ffff:ffff
198fcd5:0:c500::/40fcd5:0:c5ff:ffff:ffff:ffff:ffff:ffff
199fcd5:0:c600::/40fcd5:0:c6ff:ffff:ffff:ffff:ffff:ffff
200fcd5:0:c700::/40fcd5:0:c7ff:ffff:ffff:ffff:ffff:ffff
201fcd5:0:c800::/40fcd5:0:c8ff:ffff:ffff:ffff:ffff:ffff
202fcd5:0:c900::/40fcd5:0:c9ff:ffff:ffff:ffff:ffff:ffff
203fcd5:0:ca00::/40fcd5:0:caff:ffff:ffff:ffff:ffff:ffff
204fcd5:0:cb00::/40fcd5:0:cbff:ffff:ffff:ffff:ffff:ffff
205fcd5:0:cc00::/40fcd5:0:ccff:ffff:ffff:ffff:ffff:ffff
206fcd5:0:cd00::/40fcd5:0:cdff:ffff:ffff:ffff:ffff:ffff
207fcd5:0:ce00::/40fcd5:0:ceff:ffff:ffff:ffff:ffff:ffff
208fcd5:0:cf00::/40fcd5:0:cfff:ffff:ffff:ffff:ffff:ffff
209fcd5:0:d000::/40fcd5:0:d0ff:ffff:ffff:ffff:ffff:ffff
210fcd5:0:d100::/40fcd5:0:d1ff:ffff:ffff:ffff:ffff:ffff
211fcd5:0:d200::/40fcd5:0:d2ff:ffff:ffff:ffff:ffff:ffff
212fcd5:0:d300::/40fcd5:0:d3ff:ffff:ffff:ffff:ffff:ffff
213fcd5:0:d400::/40fcd5:0:d4ff:ffff:ffff:ffff:ffff:ffff
214fcd5:0:d500::/40fcd5:0:d5ff:ffff:ffff:ffff:ffff:ffff
215fcd5:0:d600::/40fcd5:0:d6ff:ffff:ffff:ffff:ffff:ffff
216fcd5:0:d700::/40fcd5:0:d7ff:ffff:ffff:ffff:ffff:ffff
217fcd5:0:d800::/40fcd5:0:d8ff:ffff:ffff:ffff:ffff:ffff
218fcd5:0:d900::/40fcd5:0:d9ff:ffff:ffff:ffff:ffff:ffff
219fcd5:0:da00::/40fcd5:0:daff:ffff:ffff:ffff:ffff:ffff
220fcd5:0:db00::/40fcd5:0:dbff:ffff:ffff:ffff:ffff:ffff
221fcd5:0:dc00::/40fcd5:0:dcff:ffff:ffff:ffff:ffff:ffff
222fcd5:0:dd00::/40fcd5:0:ddff:ffff:ffff:ffff:ffff:ffff
223fcd5:0:de00::/40fcd5:0:deff:ffff:ffff:ffff:ffff:ffff
224fcd5:0:df00::/40fcd5:0:dfff:ffff:ffff:ffff:ffff:ffff
225fcd5:0:e000::/40fcd5:0:e0ff:ffff:ffff:ffff:ffff:ffff
226fcd5:0:e100::/40fcd5:0:e1ff:ffff:ffff:ffff:ffff:ffff
227fcd5:0:e200::/40fcd5:0:e2ff:ffff:ffff:ffff:ffff:ffff
228fcd5:0:e300::/40fcd5:0:e3ff:ffff:ffff:ffff:ffff:ffff
229fcd5:0:e400::/40fcd5:0:e4ff:ffff:ffff:ffff:ffff:ffff
230fcd5:0:e500::/40fcd5:0:e5ff:ffff:ffff:ffff:ffff:ffff
231fcd5:0:e600::/40fcd5:0:e6ff:ffff:ffff:ffff:ffff:ffff
232fcd5:0:e700::/40fcd5:0:e7ff:ffff:ffff:ffff:ffff:ffff
233fcd5:0:e800::/40fcd5:0:e8ff:ffff:ffff:ffff:ffff:ffff
234fcd5:0:e900::/40fcd5:0:e9ff:ffff:ffff:ffff:ffff:ffff
235fcd5:0:ea00::/40fcd5:0:eaff:ffff:ffff:ffff:ffff:ffff
236fcd5:0:eb00::/40fcd5:0:ebff:ffff:ffff:ffff:ffff:ffff
237fcd5:0:ec00::/40fcd5:0:ecff:ffff:ffff:ffff:ffff:ffff
238fcd5:0:ed00::/40fcd5:0:edff:ffff:ffff:ffff:ffff:ffff
239fcd5:0:ee00::/40fcd5:0:eeff:ffff:ffff:ffff:ffff:ffff
240fcd5:0:ef00::/40fcd5:0:efff:ffff:ffff:ffff:ffff:ffff
241fcd5:0:f000::/40fcd5:0:f0ff:ffff:ffff:ffff:ffff:ffff
242fcd5:0:f100::/40fcd5:0:f1ff:ffff:ffff:ffff:ffff:ffff
243fcd5:0:f200::/40fcd5:0:f2ff:ffff:ffff:ffff:ffff:ffff
244fcd5:0:f300::/40fcd5:0:f3ff:ffff:ffff:ffff:ffff:ffff
245fcd5:0:f400::/40fcd5:0:f4ff:ffff:ffff:ffff:ffff:ffff
246fcd5:0:f500::/40fcd5:0:f5ff:ffff:ffff:ffff:ffff:ffff
247fcd5:0:f600::/40fcd5:0:f6ff:ffff:ffff:ffff:ffff:ffff
248fcd5:0:f700::/40fcd5:0:f7ff:ffff:ffff:ffff:ffff:ffff
249fcd5:0:f800::/40fcd5:0:f8ff:ffff:ffff:ffff:ffff:ffff
250fcd5:0:f900::/40fcd5:0:f9ff:ffff:ffff:ffff:ffff:ffff
251fcd5:0:fa00::/40fcd5:0:faff:ffff:ffff:ffff:ffff:ffff
252fcd5:0:fb00::/40fcd5:0:fbff:ffff:ffff:ffff:ffff:ffff
253fcd5:0:fc00::/40fcd5:0:fcff:ffff:ffff:ffff:ffff:ffff
254fcd5:0:fd00::/40fcd5:0:fdff:ffff:ffff:ffff:ffff:ffff
255fcd5:0:fe00::/40fcd5:0:feff:ffff:ffff:ffff:ffff:ffff
256fcd5:0:ff00::/40fcd5:0: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.