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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
ff73::/16
First address
ff73::
Last address
ff73: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
ff73:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
3.7.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)

ff73::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff73::/24ff73:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff73:100::/24ff73:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff73:200::/24ff73:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff73:300::/24ff73:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff73:400::/24ff73:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff73:500::/24ff73:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff73:600::/24ff73:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff73:700::/24ff73:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff73:800::/24ff73:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff73:900::/24ff73:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff73:a00::/24ff73:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff73:b00::/24ff73:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff73:c00::/24ff73:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff73:d00::/24ff73:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff73:e00::/24ff73:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff73:f00::/24ff73:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff73:1000::/24ff73:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff73:1100::/24ff73:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff73:1200::/24ff73:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff73:1300::/24ff73:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff73:1400::/24ff73:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff73:1500::/24ff73:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff73:1600::/24ff73:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff73:1700::/24ff73:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff73:1800::/24ff73:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff73:1900::/24ff73:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff73:1a00::/24ff73:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff73:1b00::/24ff73:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff73:1c00::/24ff73:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff73:1d00::/24ff73:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff73:1e00::/24ff73:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff73:1f00::/24ff73:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff73:2000::/24ff73:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff73:2100::/24ff73:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff73:2200::/24ff73:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff73:2300::/24ff73:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff73:2400::/24ff73:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff73:2500::/24ff73:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff73:2600::/24ff73:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff73:2700::/24ff73:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff73:2800::/24ff73:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff73:2900::/24ff73:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff73:2a00::/24ff73:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff73:2b00::/24ff73:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff73:2c00::/24ff73:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff73:2d00::/24ff73:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff73:2e00::/24ff73:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff73:2f00::/24ff73:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff73:3000::/24ff73:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff73:3100::/24ff73:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff73:3200::/24ff73:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff73:3300::/24ff73:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff73:3400::/24ff73:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff73:3500::/24ff73:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff73:3600::/24ff73:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff73:3700::/24ff73:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff73:3800::/24ff73:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff73:3900::/24ff73:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff73:3a00::/24ff73:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff73:3b00::/24ff73:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff73:3c00::/24ff73:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff73:3d00::/24ff73:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff73:3e00::/24ff73:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff73:3f00::/24ff73:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff73:4000::/24ff73:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff73:4100::/24ff73:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff73:4200::/24ff73:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff73:4300::/24ff73:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff73:4400::/24ff73:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff73:4500::/24ff73:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff73:4600::/24ff73:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff73:4700::/24ff73:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff73:4800::/24ff73:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff73:4900::/24ff73:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff73:4a00::/24ff73:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff73:4b00::/24ff73:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff73:4c00::/24ff73:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff73:4d00::/24ff73:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff73:4e00::/24ff73:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff73:4f00::/24ff73:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff73:5000::/24ff73:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff73:5100::/24ff73:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff73:5200::/24ff73:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff73:5300::/24ff73:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff73:5400::/24ff73:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff73:5500::/24ff73:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff73:5600::/24ff73:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff73:5700::/24ff73:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff73:5800::/24ff73:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff73:5900::/24ff73:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff73:5a00::/24ff73:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff73:5b00::/24ff73:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff73:5c00::/24ff73:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff73:5d00::/24ff73:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff73:5e00::/24ff73:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff73:5f00::/24ff73:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff73:6000::/24ff73:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff73:6100::/24ff73:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff73:6200::/24ff73:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff73:6300::/24ff73:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff73:6400::/24ff73:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff73:6500::/24ff73:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff73:6600::/24ff73:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff73:6700::/24ff73:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff73:6800::/24ff73:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff73:6900::/24ff73:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff73:6a00::/24ff73:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff73:6b00::/24ff73:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff73:6c00::/24ff73:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff73:6d00::/24ff73:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff73:6e00::/24ff73:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff73:6f00::/24ff73:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff73:7000::/24ff73:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff73:7100::/24ff73:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff73:7200::/24ff73:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff73:7300::/24ff73:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff73:7400::/24ff73:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff73:7500::/24ff73:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff73:7600::/24ff73:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff73:7700::/24ff73:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff73:7800::/24ff73:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff73:7900::/24ff73:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff73:7a00::/24ff73:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff73:7b00::/24ff73:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff73:7c00::/24ff73:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff73:7d00::/24ff73:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff73:7e00::/24ff73:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff73:7f00::/24ff73:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff73:8000::/24ff73:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff73:8100::/24ff73:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff73:8200::/24ff73:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff73:8300::/24ff73:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff73:8400::/24ff73:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff73:8500::/24ff73:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff73:8600::/24ff73:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff73:8700::/24ff73:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff73:8800::/24ff73:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff73:8900::/24ff73:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff73:8a00::/24ff73:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff73:8b00::/24ff73:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff73:8c00::/24ff73:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff73:8d00::/24ff73:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff73:8e00::/24ff73:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff73:8f00::/24ff73:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff73:9000::/24ff73:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff73:9100::/24ff73:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff73:9200::/24ff73:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff73:9300::/24ff73:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff73:9400::/24ff73:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff73:9500::/24ff73:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff73:9600::/24ff73:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff73:9700::/24ff73:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff73:9800::/24ff73:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff73:9900::/24ff73:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff73:9a00::/24ff73:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff73:9b00::/24ff73:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff73:9c00::/24ff73:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff73:9d00::/24ff73:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff73:9e00::/24ff73:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff73:9f00::/24ff73:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff73:a000::/24ff73:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff73:a100::/24ff73:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff73:a200::/24ff73:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff73:a300::/24ff73:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff73:a400::/24ff73:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff73:a500::/24ff73:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff73:a600::/24ff73:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff73:a700::/24ff73:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff73:a800::/24ff73:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff73:a900::/24ff73:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff73:aa00::/24ff73:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff73:ab00::/24ff73:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff73:ac00::/24ff73:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff73:ad00::/24ff73:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff73:ae00::/24ff73:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff73:af00::/24ff73:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff73:b000::/24ff73:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff73:b100::/24ff73:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff73:b200::/24ff73:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff73:b300::/24ff73:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff73:b400::/24ff73:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff73:b500::/24ff73:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff73:b600::/24ff73:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff73:b700::/24ff73:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff73:b800::/24ff73:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff73:b900::/24ff73:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff73:ba00::/24ff73:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff73:bb00::/24ff73:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff73:bc00::/24ff73:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff73:bd00::/24ff73:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff73:be00::/24ff73:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff73:bf00::/24ff73:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff73:c000::/24ff73:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff73:c100::/24ff73:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff73:c200::/24ff73:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff73:c300::/24ff73:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff73:c400::/24ff73:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff73:c500::/24ff73:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff73:c600::/24ff73:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff73:c700::/24ff73:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff73:c800::/24ff73:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff73:c900::/24ff73:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff73:ca00::/24ff73:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff73:cb00::/24ff73:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff73:cc00::/24ff73:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff73:cd00::/24ff73:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff73:ce00::/24ff73:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff73:cf00::/24ff73:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff73:d000::/24ff73:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff73:d100::/24ff73:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff73:d200::/24ff73:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff73:d300::/24ff73:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff73:d400::/24ff73:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff73:d500::/24ff73:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff73:d600::/24ff73:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff73:d700::/24ff73:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff73:d800::/24ff73:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff73:d900::/24ff73:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff73:da00::/24ff73:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff73:db00::/24ff73:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff73:dc00::/24ff73:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff73:dd00::/24ff73:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff73:de00::/24ff73:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff73:df00::/24ff73:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff73:e000::/24ff73:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff73:e100::/24ff73:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff73:e200::/24ff73:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff73:e300::/24ff73:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff73:e400::/24ff73:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff73:e500::/24ff73:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff73:e600::/24ff73:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff73:e700::/24ff73:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff73:e800::/24ff73:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff73:e900::/24ff73:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff73:ea00::/24ff73:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff73:eb00::/24ff73:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff73:ec00::/24ff73:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff73:ed00::/24ff73:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff73:ee00::/24ff73:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff73:ef00::/24ff73:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff73:f000::/24ff73:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff73:f100::/24ff73:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff73:f200::/24ff73:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff73:f300::/24ff73:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff73:f400::/24ff73:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff73:f500::/24ff73:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff73:f600::/24ff73:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff73:f700::/24ff73:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff73:f800::/24ff73:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff73:f900::/24ff73:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff73:fa00::/24ff73:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff73:fb00::/24ff73:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff73:fc00::/24ff73:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff73:fd00::/24ff73:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff73:fe00::/24ff73:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff73:ff00::/24ff73: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.