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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
ff7f::/16
First address
ff7f::
Last address
ff7f: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
ff7f:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
f.7.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)

ff7f::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff7f::/24ff7f:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff7f:100::/24ff7f:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff7f:200::/24ff7f:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff7f:300::/24ff7f:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff7f:400::/24ff7f:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff7f:500::/24ff7f:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff7f:600::/24ff7f:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff7f:700::/24ff7f:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff7f:800::/24ff7f:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff7f:900::/24ff7f:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff7f:a00::/24ff7f:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff7f:b00::/24ff7f:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff7f:c00::/24ff7f:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff7f:d00::/24ff7f:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff7f:e00::/24ff7f:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff7f:f00::/24ff7f:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff7f:1000::/24ff7f:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff7f:1100::/24ff7f:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff7f:1200::/24ff7f:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff7f:1300::/24ff7f:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff7f:1400::/24ff7f:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff7f:1500::/24ff7f:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff7f:1600::/24ff7f:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff7f:1700::/24ff7f:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff7f:1800::/24ff7f:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff7f:1900::/24ff7f:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff7f:1a00::/24ff7f:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff7f:1b00::/24ff7f:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff7f:1c00::/24ff7f:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff7f:1d00::/24ff7f:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff7f:1e00::/24ff7f:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff7f:1f00::/24ff7f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff7f:2000::/24ff7f:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff7f:2100::/24ff7f:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff7f:2200::/24ff7f:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff7f:2300::/24ff7f:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff7f:2400::/24ff7f:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff7f:2500::/24ff7f:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff7f:2600::/24ff7f:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff7f:2700::/24ff7f:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff7f:2800::/24ff7f:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff7f:2900::/24ff7f:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff7f:2a00::/24ff7f:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff7f:2b00::/24ff7f:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff7f:2c00::/24ff7f:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff7f:2d00::/24ff7f:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff7f:2e00::/24ff7f:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff7f:2f00::/24ff7f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff7f:3000::/24ff7f:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff7f:3100::/24ff7f:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff7f:3200::/24ff7f:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff7f:3300::/24ff7f:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff7f:3400::/24ff7f:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff7f:3500::/24ff7f:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff7f:3600::/24ff7f:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff7f:3700::/24ff7f:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff7f:3800::/24ff7f:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff7f:3900::/24ff7f:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff7f:3a00::/24ff7f:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff7f:3b00::/24ff7f:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff7f:3c00::/24ff7f:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff7f:3d00::/24ff7f:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff7f:3e00::/24ff7f:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff7f:3f00::/24ff7f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff7f:4000::/24ff7f:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff7f:4100::/24ff7f:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff7f:4200::/24ff7f:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff7f:4300::/24ff7f:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff7f:4400::/24ff7f:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff7f:4500::/24ff7f:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff7f:4600::/24ff7f:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff7f:4700::/24ff7f:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff7f:4800::/24ff7f:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff7f:4900::/24ff7f:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff7f:4a00::/24ff7f:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff7f:4b00::/24ff7f:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff7f:4c00::/24ff7f:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff7f:4d00::/24ff7f:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff7f:4e00::/24ff7f:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff7f:4f00::/24ff7f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff7f:5000::/24ff7f:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff7f:5100::/24ff7f:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff7f:5200::/24ff7f:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff7f:5300::/24ff7f:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff7f:5400::/24ff7f:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff7f:5500::/24ff7f:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff7f:5600::/24ff7f:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff7f:5700::/24ff7f:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff7f:5800::/24ff7f:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff7f:5900::/24ff7f:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff7f:5a00::/24ff7f:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff7f:5b00::/24ff7f:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff7f:5c00::/24ff7f:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff7f:5d00::/24ff7f:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff7f:5e00::/24ff7f:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff7f:5f00::/24ff7f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff7f:6000::/24ff7f:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff7f:6100::/24ff7f:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff7f:6200::/24ff7f:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff7f:6300::/24ff7f:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff7f:6400::/24ff7f:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff7f:6500::/24ff7f:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff7f:6600::/24ff7f:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff7f:6700::/24ff7f:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff7f:6800::/24ff7f:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff7f:6900::/24ff7f:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff7f:6a00::/24ff7f:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff7f:6b00::/24ff7f:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff7f:6c00::/24ff7f:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff7f:6d00::/24ff7f:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff7f:6e00::/24ff7f:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff7f:6f00::/24ff7f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff7f:7000::/24ff7f:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff7f:7100::/24ff7f:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff7f:7200::/24ff7f:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff7f:7300::/24ff7f:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff7f:7400::/24ff7f:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff7f:7500::/24ff7f:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff7f:7600::/24ff7f:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff7f:7700::/24ff7f:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff7f:7800::/24ff7f:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff7f:7900::/24ff7f:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff7f:7a00::/24ff7f:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff7f:7b00::/24ff7f:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff7f:7c00::/24ff7f:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff7f:7d00::/24ff7f:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff7f:7e00::/24ff7f:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff7f:7f00::/24ff7f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff7f:8000::/24ff7f:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff7f:8100::/24ff7f:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff7f:8200::/24ff7f:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff7f:8300::/24ff7f:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff7f:8400::/24ff7f:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff7f:8500::/24ff7f:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff7f:8600::/24ff7f:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff7f:8700::/24ff7f:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff7f:8800::/24ff7f:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff7f:8900::/24ff7f:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff7f:8a00::/24ff7f:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff7f:8b00::/24ff7f:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff7f:8c00::/24ff7f:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff7f:8d00::/24ff7f:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff7f:8e00::/24ff7f:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff7f:8f00::/24ff7f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff7f:9000::/24ff7f:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff7f:9100::/24ff7f:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff7f:9200::/24ff7f:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff7f:9300::/24ff7f:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff7f:9400::/24ff7f:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff7f:9500::/24ff7f:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff7f:9600::/24ff7f:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff7f:9700::/24ff7f:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff7f:9800::/24ff7f:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff7f:9900::/24ff7f:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff7f:9a00::/24ff7f:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff7f:9b00::/24ff7f:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff7f:9c00::/24ff7f:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff7f:9d00::/24ff7f:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff7f:9e00::/24ff7f:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff7f:9f00::/24ff7f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff7f:a000::/24ff7f:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff7f:a100::/24ff7f:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff7f:a200::/24ff7f:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff7f:a300::/24ff7f:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff7f:a400::/24ff7f:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff7f:a500::/24ff7f:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff7f:a600::/24ff7f:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff7f:a700::/24ff7f:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff7f:a800::/24ff7f:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff7f:a900::/24ff7f:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff7f:aa00::/24ff7f:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff7f:ab00::/24ff7f:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff7f:ac00::/24ff7f:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff7f:ad00::/24ff7f:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff7f:ae00::/24ff7f:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff7f:af00::/24ff7f:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff7f:b000::/24ff7f:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff7f:b100::/24ff7f:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff7f:b200::/24ff7f:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff7f:b300::/24ff7f:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff7f:b400::/24ff7f:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff7f:b500::/24ff7f:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff7f:b600::/24ff7f:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff7f:b700::/24ff7f:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff7f:b800::/24ff7f:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff7f:b900::/24ff7f:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff7f:ba00::/24ff7f:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff7f:bb00::/24ff7f:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff7f:bc00::/24ff7f:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff7f:bd00::/24ff7f:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff7f:be00::/24ff7f:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff7f:bf00::/24ff7f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff7f:c000::/24ff7f:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff7f:c100::/24ff7f:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff7f:c200::/24ff7f:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff7f:c300::/24ff7f:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff7f:c400::/24ff7f:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff7f:c500::/24ff7f:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff7f:c600::/24ff7f:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff7f:c700::/24ff7f:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff7f:c800::/24ff7f:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff7f:c900::/24ff7f:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff7f:ca00::/24ff7f:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff7f:cb00::/24ff7f:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff7f:cc00::/24ff7f:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff7f:cd00::/24ff7f:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff7f:ce00::/24ff7f:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff7f:cf00::/24ff7f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff7f:d000::/24ff7f:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff7f:d100::/24ff7f:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff7f:d200::/24ff7f:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff7f:d300::/24ff7f:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff7f:d400::/24ff7f:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff7f:d500::/24ff7f:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff7f:d600::/24ff7f:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff7f:d700::/24ff7f:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff7f:d800::/24ff7f:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff7f:d900::/24ff7f:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff7f:da00::/24ff7f:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff7f:db00::/24ff7f:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff7f:dc00::/24ff7f:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff7f:dd00::/24ff7f:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff7f:de00::/24ff7f:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff7f:df00::/24ff7f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff7f:e000::/24ff7f:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff7f:e100::/24ff7f:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff7f:e200::/24ff7f:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff7f:e300::/24ff7f:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff7f:e400::/24ff7f:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff7f:e500::/24ff7f:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff7f:e600::/24ff7f:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff7f:e700::/24ff7f:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff7f:e800::/24ff7f:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff7f:e900::/24ff7f:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff7f:ea00::/24ff7f:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff7f:eb00::/24ff7f:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff7f:ec00::/24ff7f:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff7f:ed00::/24ff7f:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff7f:ee00::/24ff7f:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff7f:ef00::/24ff7f:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff7f:f000::/24ff7f:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff7f:f100::/24ff7f:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff7f:f200::/24ff7f:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff7f:f300::/24ff7f:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff7f:f400::/24ff7f:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff7f:f500::/24ff7f:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff7f:f600::/24ff7f:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff7f:f700::/24ff7f:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff7f:f800::/24ff7f:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff7f:f900::/24ff7f:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff7f:fa00::/24ff7f:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff7f:fb00::/24ff7f:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff7f:fc00::/24ff7f:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff7f:fd00::/24ff7f:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff7f:fe00::/24ff7f:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff7f:ff00::/24ff7f: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.