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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
ff7a::/16
First address
ff7a::
Last address
ff7a: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
ff7a:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
a.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)

ff7a::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff7a::/24ff7a:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff7a:100::/24ff7a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff7a:200::/24ff7a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff7a:300::/24ff7a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff7a:400::/24ff7a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff7a:500::/24ff7a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff7a:600::/24ff7a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff7a:700::/24ff7a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff7a:800::/24ff7a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff7a:900::/24ff7a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff7a:a00::/24ff7a:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff7a:b00::/24ff7a:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff7a:c00::/24ff7a:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff7a:d00::/24ff7a:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff7a:e00::/24ff7a:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff7a:f00::/24ff7a:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff7a:1000::/24ff7a:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff7a:1100::/24ff7a:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff7a:1200::/24ff7a:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff7a:1300::/24ff7a:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff7a:1400::/24ff7a:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff7a:1500::/24ff7a:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff7a:1600::/24ff7a:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff7a:1700::/24ff7a:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff7a:1800::/24ff7a:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff7a:1900::/24ff7a:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff7a:1a00::/24ff7a:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff7a:1b00::/24ff7a:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff7a:1c00::/24ff7a:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff7a:1d00::/24ff7a:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff7a:1e00::/24ff7a:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff7a:1f00::/24ff7a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff7a:2000::/24ff7a:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff7a:2100::/24ff7a:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff7a:2200::/24ff7a:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff7a:2300::/24ff7a:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff7a:2400::/24ff7a:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff7a:2500::/24ff7a:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff7a:2600::/24ff7a:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff7a:2700::/24ff7a:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff7a:2800::/24ff7a:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff7a:2900::/24ff7a:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff7a:2a00::/24ff7a:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff7a:2b00::/24ff7a:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff7a:2c00::/24ff7a:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff7a:2d00::/24ff7a:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff7a:2e00::/24ff7a:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff7a:2f00::/24ff7a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff7a:3000::/24ff7a:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff7a:3100::/24ff7a:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff7a:3200::/24ff7a:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff7a:3300::/24ff7a:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff7a:3400::/24ff7a:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff7a:3500::/24ff7a:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff7a:3600::/24ff7a:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff7a:3700::/24ff7a:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff7a:3800::/24ff7a:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff7a:3900::/24ff7a:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff7a:3a00::/24ff7a:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff7a:3b00::/24ff7a:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff7a:3c00::/24ff7a:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff7a:3d00::/24ff7a:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff7a:3e00::/24ff7a:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff7a:3f00::/24ff7a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff7a:4000::/24ff7a:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff7a:4100::/24ff7a:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff7a:4200::/24ff7a:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff7a:4300::/24ff7a:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff7a:4400::/24ff7a:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff7a:4500::/24ff7a:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff7a:4600::/24ff7a:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff7a:4700::/24ff7a:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff7a:4800::/24ff7a:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff7a:4900::/24ff7a:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff7a:4a00::/24ff7a:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff7a:4b00::/24ff7a:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff7a:4c00::/24ff7a:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff7a:4d00::/24ff7a:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff7a:4e00::/24ff7a:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff7a:4f00::/24ff7a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff7a:5000::/24ff7a:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff7a:5100::/24ff7a:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff7a:5200::/24ff7a:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff7a:5300::/24ff7a:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff7a:5400::/24ff7a:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff7a:5500::/24ff7a:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff7a:5600::/24ff7a:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff7a:5700::/24ff7a:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff7a:5800::/24ff7a:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff7a:5900::/24ff7a:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff7a:5a00::/24ff7a:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff7a:5b00::/24ff7a:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff7a:5c00::/24ff7a:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff7a:5d00::/24ff7a:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff7a:5e00::/24ff7a:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff7a:5f00::/24ff7a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff7a:6000::/24ff7a:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff7a:6100::/24ff7a:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff7a:6200::/24ff7a:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff7a:6300::/24ff7a:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff7a:6400::/24ff7a:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff7a:6500::/24ff7a:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff7a:6600::/24ff7a:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff7a:6700::/24ff7a:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff7a:6800::/24ff7a:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff7a:6900::/24ff7a:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff7a:6a00::/24ff7a:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff7a:6b00::/24ff7a:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff7a:6c00::/24ff7a:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff7a:6d00::/24ff7a:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff7a:6e00::/24ff7a:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff7a:6f00::/24ff7a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff7a:7000::/24ff7a:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff7a:7100::/24ff7a:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff7a:7200::/24ff7a:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff7a:7300::/24ff7a:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff7a:7400::/24ff7a:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff7a:7500::/24ff7a:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff7a:7600::/24ff7a:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff7a:7700::/24ff7a:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff7a:7800::/24ff7a:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff7a:7900::/24ff7a:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff7a:7a00::/24ff7a:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff7a:7b00::/24ff7a:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff7a:7c00::/24ff7a:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff7a:7d00::/24ff7a:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff7a:7e00::/24ff7a:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff7a:7f00::/24ff7a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff7a:8000::/24ff7a:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff7a:8100::/24ff7a:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff7a:8200::/24ff7a:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff7a:8300::/24ff7a:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff7a:8400::/24ff7a:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff7a:8500::/24ff7a:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff7a:8600::/24ff7a:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff7a:8700::/24ff7a:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff7a:8800::/24ff7a:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff7a:8900::/24ff7a:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff7a:8a00::/24ff7a:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff7a:8b00::/24ff7a:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff7a:8c00::/24ff7a:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff7a:8d00::/24ff7a:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff7a:8e00::/24ff7a:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff7a:8f00::/24ff7a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff7a:9000::/24ff7a:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff7a:9100::/24ff7a:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff7a:9200::/24ff7a:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff7a:9300::/24ff7a:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff7a:9400::/24ff7a:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff7a:9500::/24ff7a:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff7a:9600::/24ff7a:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff7a:9700::/24ff7a:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff7a:9800::/24ff7a:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff7a:9900::/24ff7a:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff7a:9a00::/24ff7a:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff7a:9b00::/24ff7a:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff7a:9c00::/24ff7a:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff7a:9d00::/24ff7a:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff7a:9e00::/24ff7a:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff7a:9f00::/24ff7a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff7a:a000::/24ff7a:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff7a:a100::/24ff7a:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff7a:a200::/24ff7a:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff7a:a300::/24ff7a:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff7a:a400::/24ff7a:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff7a:a500::/24ff7a:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff7a:a600::/24ff7a:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff7a:a700::/24ff7a:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff7a:a800::/24ff7a:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff7a:a900::/24ff7a:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff7a:aa00::/24ff7a:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff7a:ab00::/24ff7a:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff7a:ac00::/24ff7a:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff7a:ad00::/24ff7a:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff7a:ae00::/24ff7a:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff7a:af00::/24ff7a:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff7a:b000::/24ff7a:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff7a:b100::/24ff7a:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff7a:b200::/24ff7a:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff7a:b300::/24ff7a:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff7a:b400::/24ff7a:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff7a:b500::/24ff7a:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff7a:b600::/24ff7a:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff7a:b700::/24ff7a:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff7a:b800::/24ff7a:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff7a:b900::/24ff7a:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff7a:ba00::/24ff7a:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff7a:bb00::/24ff7a:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff7a:bc00::/24ff7a:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff7a:bd00::/24ff7a:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff7a:be00::/24ff7a:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff7a:bf00::/24ff7a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff7a:c000::/24ff7a:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff7a:c100::/24ff7a:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff7a:c200::/24ff7a:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff7a:c300::/24ff7a:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff7a:c400::/24ff7a:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff7a:c500::/24ff7a:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff7a:c600::/24ff7a:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff7a:c700::/24ff7a:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff7a:c800::/24ff7a:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff7a:c900::/24ff7a:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff7a:ca00::/24ff7a:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff7a:cb00::/24ff7a:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff7a:cc00::/24ff7a:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff7a:cd00::/24ff7a:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff7a:ce00::/24ff7a:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff7a:cf00::/24ff7a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff7a:d000::/24ff7a:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff7a:d100::/24ff7a:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff7a:d200::/24ff7a:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff7a:d300::/24ff7a:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff7a:d400::/24ff7a:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff7a:d500::/24ff7a:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff7a:d600::/24ff7a:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff7a:d700::/24ff7a:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff7a:d800::/24ff7a:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff7a:d900::/24ff7a:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff7a:da00::/24ff7a:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff7a:db00::/24ff7a:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff7a:dc00::/24ff7a:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff7a:dd00::/24ff7a:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff7a:de00::/24ff7a:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff7a:df00::/24ff7a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff7a:e000::/24ff7a:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff7a:e100::/24ff7a:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff7a:e200::/24ff7a:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff7a:e300::/24ff7a:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff7a:e400::/24ff7a:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff7a:e500::/24ff7a:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff7a:e600::/24ff7a:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff7a:e700::/24ff7a:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff7a:e800::/24ff7a:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff7a:e900::/24ff7a:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff7a:ea00::/24ff7a:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff7a:eb00::/24ff7a:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff7a:ec00::/24ff7a:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff7a:ed00::/24ff7a:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff7a:ee00::/24ff7a:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff7a:ef00::/24ff7a:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff7a:f000::/24ff7a:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff7a:f100::/24ff7a:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff7a:f200::/24ff7a:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff7a:f300::/24ff7a:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff7a:f400::/24ff7a:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff7a:f500::/24ff7a:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff7a:f600::/24ff7a:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff7a:f700::/24ff7a:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff7a:f800::/24ff7a:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff7a:f900::/24ff7a:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff7a:fa00::/24ff7a:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff7a:fb00::/24ff7a:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff7a:fc00::/24ff7a:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff7a:fd00::/24ff7a:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff7a:fe00::/24ff7a:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff7a:ff00::/24ff7a: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.