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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
ff45::/16
First address
ff45::
Last address
ff45: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
ff45:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.4.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)

ff45::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff45::/24ff45:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff45:100::/24ff45:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff45:200::/24ff45:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff45:300::/24ff45:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff45:400::/24ff45:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff45:500::/24ff45:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff45:600::/24ff45:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff45:700::/24ff45:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff45:800::/24ff45:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff45:900::/24ff45:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff45:a00::/24ff45:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff45:b00::/24ff45:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff45:c00::/24ff45:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff45:d00::/24ff45:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff45:e00::/24ff45:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff45:f00::/24ff45:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff45:1000::/24ff45:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff45:1100::/24ff45:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff45:1200::/24ff45:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff45:1300::/24ff45:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff45:1400::/24ff45:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff45:1500::/24ff45:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff45:1600::/24ff45:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff45:1700::/24ff45:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff45:1800::/24ff45:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff45:1900::/24ff45:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff45:1a00::/24ff45:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff45:1b00::/24ff45:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff45:1c00::/24ff45:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff45:1d00::/24ff45:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff45:1e00::/24ff45:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff45:1f00::/24ff45:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff45:2000::/24ff45:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff45:2100::/24ff45:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff45:2200::/24ff45:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff45:2300::/24ff45:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff45:2400::/24ff45:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff45:2500::/24ff45:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff45:2600::/24ff45:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff45:2700::/24ff45:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff45:2800::/24ff45:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff45:2900::/24ff45:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff45:2a00::/24ff45:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff45:2b00::/24ff45:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff45:2c00::/24ff45:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff45:2d00::/24ff45:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff45:2e00::/24ff45:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff45:2f00::/24ff45:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff45:3000::/24ff45:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff45:3100::/24ff45:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff45:3200::/24ff45:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff45:3300::/24ff45:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff45:3400::/24ff45:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff45:3500::/24ff45:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff45:3600::/24ff45:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff45:3700::/24ff45:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff45:3800::/24ff45:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff45:3900::/24ff45:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff45:3a00::/24ff45:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff45:3b00::/24ff45:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff45:3c00::/24ff45:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff45:3d00::/24ff45:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff45:3e00::/24ff45:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff45:3f00::/24ff45:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff45:4000::/24ff45:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff45:4100::/24ff45:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff45:4200::/24ff45:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff45:4300::/24ff45:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff45:4400::/24ff45:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff45:4500::/24ff45:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff45:4600::/24ff45:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff45:4700::/24ff45:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff45:4800::/24ff45:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff45:4900::/24ff45:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff45:4a00::/24ff45:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff45:4b00::/24ff45:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff45:4c00::/24ff45:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff45:4d00::/24ff45:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff45:4e00::/24ff45:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff45:4f00::/24ff45:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff45:5000::/24ff45:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff45:5100::/24ff45:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff45:5200::/24ff45:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff45:5300::/24ff45:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff45:5400::/24ff45:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff45:5500::/24ff45:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff45:5600::/24ff45:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff45:5700::/24ff45:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff45:5800::/24ff45:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff45:5900::/24ff45:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff45:5a00::/24ff45:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff45:5b00::/24ff45:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff45:5c00::/24ff45:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff45:5d00::/24ff45:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff45:5e00::/24ff45:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff45:5f00::/24ff45:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff45:6000::/24ff45:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff45:6100::/24ff45:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff45:6200::/24ff45:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff45:6300::/24ff45:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff45:6400::/24ff45:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff45:6500::/24ff45:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff45:6600::/24ff45:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff45:6700::/24ff45:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff45:6800::/24ff45:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff45:6900::/24ff45:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff45:6a00::/24ff45:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff45:6b00::/24ff45:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff45:6c00::/24ff45:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff45:6d00::/24ff45:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff45:6e00::/24ff45:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff45:6f00::/24ff45:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff45:7000::/24ff45:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff45:7100::/24ff45:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff45:7200::/24ff45:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff45:7300::/24ff45:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff45:7400::/24ff45:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff45:7500::/24ff45:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff45:7600::/24ff45:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff45:7700::/24ff45:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff45:7800::/24ff45:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff45:7900::/24ff45:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff45:7a00::/24ff45:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff45:7b00::/24ff45:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff45:7c00::/24ff45:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff45:7d00::/24ff45:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff45:7e00::/24ff45:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff45:7f00::/24ff45:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff45:8000::/24ff45:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff45:8100::/24ff45:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff45:8200::/24ff45:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff45:8300::/24ff45:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff45:8400::/24ff45:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff45:8500::/24ff45:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff45:8600::/24ff45:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff45:8700::/24ff45:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff45:8800::/24ff45:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff45:8900::/24ff45:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff45:8a00::/24ff45:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff45:8b00::/24ff45:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff45:8c00::/24ff45:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff45:8d00::/24ff45:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff45:8e00::/24ff45:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff45:8f00::/24ff45:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff45:9000::/24ff45:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff45:9100::/24ff45:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff45:9200::/24ff45:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff45:9300::/24ff45:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff45:9400::/24ff45:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff45:9500::/24ff45:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff45:9600::/24ff45:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff45:9700::/24ff45:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff45:9800::/24ff45:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff45:9900::/24ff45:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff45:9a00::/24ff45:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff45:9b00::/24ff45:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff45:9c00::/24ff45:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff45:9d00::/24ff45:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff45:9e00::/24ff45:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff45:9f00::/24ff45:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff45:a000::/24ff45:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff45:a100::/24ff45:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff45:a200::/24ff45:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff45:a300::/24ff45:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff45:a400::/24ff45:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff45:a500::/24ff45:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff45:a600::/24ff45:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff45:a700::/24ff45:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff45:a800::/24ff45:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff45:a900::/24ff45:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff45:aa00::/24ff45:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff45:ab00::/24ff45:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff45:ac00::/24ff45:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff45:ad00::/24ff45:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff45:ae00::/24ff45:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff45:af00::/24ff45:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff45:b000::/24ff45:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff45:b100::/24ff45:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff45:b200::/24ff45:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff45:b300::/24ff45:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff45:b400::/24ff45:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff45:b500::/24ff45:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff45:b600::/24ff45:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff45:b700::/24ff45:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff45:b800::/24ff45:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff45:b900::/24ff45:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff45:ba00::/24ff45:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff45:bb00::/24ff45:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff45:bc00::/24ff45:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff45:bd00::/24ff45:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff45:be00::/24ff45:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff45:bf00::/24ff45:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff45:c000::/24ff45:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff45:c100::/24ff45:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff45:c200::/24ff45:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff45:c300::/24ff45:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff45:c400::/24ff45:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff45:c500::/24ff45:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff45:c600::/24ff45:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff45:c700::/24ff45:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff45:c800::/24ff45:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff45:c900::/24ff45:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff45:ca00::/24ff45:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff45:cb00::/24ff45:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff45:cc00::/24ff45:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff45:cd00::/24ff45:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff45:ce00::/24ff45:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff45:cf00::/24ff45:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff45:d000::/24ff45:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff45:d100::/24ff45:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff45:d200::/24ff45:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff45:d300::/24ff45:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff45:d400::/24ff45:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff45:d500::/24ff45:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff45:d600::/24ff45:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff45:d700::/24ff45:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff45:d800::/24ff45:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff45:d900::/24ff45:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff45:da00::/24ff45:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff45:db00::/24ff45:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff45:dc00::/24ff45:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff45:dd00::/24ff45:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff45:de00::/24ff45:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff45:df00::/24ff45:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff45:e000::/24ff45:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff45:e100::/24ff45:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff45:e200::/24ff45:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff45:e300::/24ff45:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff45:e400::/24ff45:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff45:e500::/24ff45:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff45:e600::/24ff45:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff45:e700::/24ff45:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff45:e800::/24ff45:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff45:e900::/24ff45:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff45:ea00::/24ff45:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff45:eb00::/24ff45:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff45:ec00::/24ff45:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff45:ed00::/24ff45:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff45:ee00::/24ff45:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff45:ef00::/24ff45:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff45:f000::/24ff45:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff45:f100::/24ff45:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff45:f200::/24ff45:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff45:f300::/24ff45:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff45:f400::/24ff45:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff45:f500::/24ff45:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff45:f600::/24ff45:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff45:f700::/24ff45:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff45:f800::/24ff45:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff45:f900::/24ff45:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff45:fa00::/24ff45:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff45:fb00::/24ff45:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff45:fc00::/24ff45:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff45:fd00::/24ff45:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff45:fe00::/24ff45:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff45:ff00::/24ff45: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.