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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
ff65::/16
First address
ff65::
Last address
ff65: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
ff65:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.6.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)

ff65::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff65::/24ff65:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff65:100::/24ff65:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff65:200::/24ff65:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff65:300::/24ff65:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff65:400::/24ff65:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff65:500::/24ff65:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff65:600::/24ff65:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff65:700::/24ff65:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff65:800::/24ff65:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff65:900::/24ff65:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff65:a00::/24ff65:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff65:b00::/24ff65:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff65:c00::/24ff65:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff65:d00::/24ff65:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff65:e00::/24ff65:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff65:f00::/24ff65:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff65:1000::/24ff65:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff65:1100::/24ff65:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff65:1200::/24ff65:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff65:1300::/24ff65:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff65:1400::/24ff65:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff65:1500::/24ff65:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff65:1600::/24ff65:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff65:1700::/24ff65:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff65:1800::/24ff65:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff65:1900::/24ff65:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff65:1a00::/24ff65:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff65:1b00::/24ff65:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff65:1c00::/24ff65:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff65:1d00::/24ff65:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff65:1e00::/24ff65:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff65:1f00::/24ff65:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff65:2000::/24ff65:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff65:2100::/24ff65:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff65:2200::/24ff65:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff65:2300::/24ff65:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff65:2400::/24ff65:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff65:2500::/24ff65:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff65:2600::/24ff65:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff65:2700::/24ff65:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff65:2800::/24ff65:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff65:2900::/24ff65:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff65:2a00::/24ff65:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff65:2b00::/24ff65:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff65:2c00::/24ff65:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff65:2d00::/24ff65:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff65:2e00::/24ff65:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff65:2f00::/24ff65:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff65:3000::/24ff65:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff65:3100::/24ff65:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff65:3200::/24ff65:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff65:3300::/24ff65:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff65:3400::/24ff65:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff65:3500::/24ff65:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff65:3600::/24ff65:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff65:3700::/24ff65:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff65:3800::/24ff65:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff65:3900::/24ff65:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff65:3a00::/24ff65:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff65:3b00::/24ff65:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff65:3c00::/24ff65:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff65:3d00::/24ff65:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff65:3e00::/24ff65:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff65:3f00::/24ff65:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff65:4000::/24ff65:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff65:4100::/24ff65:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff65:4200::/24ff65:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff65:4300::/24ff65:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff65:4400::/24ff65:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff65:4500::/24ff65:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff65:4600::/24ff65:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff65:4700::/24ff65:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff65:4800::/24ff65:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff65:4900::/24ff65:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff65:4a00::/24ff65:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff65:4b00::/24ff65:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff65:4c00::/24ff65:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff65:4d00::/24ff65:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff65:4e00::/24ff65:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff65:4f00::/24ff65:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff65:5000::/24ff65:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff65:5100::/24ff65:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff65:5200::/24ff65:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff65:5300::/24ff65:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff65:5400::/24ff65:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff65:5500::/24ff65:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff65:5600::/24ff65:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff65:5700::/24ff65:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff65:5800::/24ff65:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff65:5900::/24ff65:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff65:5a00::/24ff65:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff65:5b00::/24ff65:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff65:5c00::/24ff65:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff65:5d00::/24ff65:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff65:5e00::/24ff65:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff65:5f00::/24ff65:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff65:6000::/24ff65:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff65:6100::/24ff65:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff65:6200::/24ff65:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff65:6300::/24ff65:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff65:6400::/24ff65:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff65:6500::/24ff65:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff65:6600::/24ff65:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff65:6700::/24ff65:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff65:6800::/24ff65:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff65:6900::/24ff65:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff65:6a00::/24ff65:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff65:6b00::/24ff65:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff65:6c00::/24ff65:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff65:6d00::/24ff65:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff65:6e00::/24ff65:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff65:6f00::/24ff65:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff65:7000::/24ff65:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff65:7100::/24ff65:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff65:7200::/24ff65:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff65:7300::/24ff65:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff65:7400::/24ff65:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff65:7500::/24ff65:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff65:7600::/24ff65:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff65:7700::/24ff65:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff65:7800::/24ff65:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff65:7900::/24ff65:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff65:7a00::/24ff65:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff65:7b00::/24ff65:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff65:7c00::/24ff65:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff65:7d00::/24ff65:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff65:7e00::/24ff65:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff65:7f00::/24ff65:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff65:8000::/24ff65:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff65:8100::/24ff65:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff65:8200::/24ff65:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff65:8300::/24ff65:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff65:8400::/24ff65:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff65:8500::/24ff65:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff65:8600::/24ff65:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff65:8700::/24ff65:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff65:8800::/24ff65:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff65:8900::/24ff65:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff65:8a00::/24ff65:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff65:8b00::/24ff65:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff65:8c00::/24ff65:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff65:8d00::/24ff65:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff65:8e00::/24ff65:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff65:8f00::/24ff65:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff65:9000::/24ff65:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff65:9100::/24ff65:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff65:9200::/24ff65:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff65:9300::/24ff65:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff65:9400::/24ff65:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff65:9500::/24ff65:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff65:9600::/24ff65:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff65:9700::/24ff65:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff65:9800::/24ff65:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff65:9900::/24ff65:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff65:9a00::/24ff65:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff65:9b00::/24ff65:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff65:9c00::/24ff65:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff65:9d00::/24ff65:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff65:9e00::/24ff65:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff65:9f00::/24ff65:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff65:a000::/24ff65:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff65:a100::/24ff65:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff65:a200::/24ff65:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff65:a300::/24ff65:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff65:a400::/24ff65:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff65:a500::/24ff65:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff65:a600::/24ff65:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff65:a700::/24ff65:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff65:a800::/24ff65:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff65:a900::/24ff65:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff65:aa00::/24ff65:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff65:ab00::/24ff65:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff65:ac00::/24ff65:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff65:ad00::/24ff65:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff65:ae00::/24ff65:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff65:af00::/24ff65:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff65:b000::/24ff65:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff65:b100::/24ff65:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff65:b200::/24ff65:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff65:b300::/24ff65:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff65:b400::/24ff65:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff65:b500::/24ff65:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff65:b600::/24ff65:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff65:b700::/24ff65:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff65:b800::/24ff65:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff65:b900::/24ff65:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff65:ba00::/24ff65:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff65:bb00::/24ff65:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff65:bc00::/24ff65:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff65:bd00::/24ff65:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff65:be00::/24ff65:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff65:bf00::/24ff65:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff65:c000::/24ff65:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff65:c100::/24ff65:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff65:c200::/24ff65:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff65:c300::/24ff65:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff65:c400::/24ff65:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff65:c500::/24ff65:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff65:c600::/24ff65:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff65:c700::/24ff65:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff65:c800::/24ff65:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff65:c900::/24ff65:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff65:ca00::/24ff65:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff65:cb00::/24ff65:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff65:cc00::/24ff65:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff65:cd00::/24ff65:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff65:ce00::/24ff65:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff65:cf00::/24ff65:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff65:d000::/24ff65:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff65:d100::/24ff65:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff65:d200::/24ff65:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff65:d300::/24ff65:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff65:d400::/24ff65:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff65:d500::/24ff65:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff65:d600::/24ff65:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff65:d700::/24ff65:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff65:d800::/24ff65:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff65:d900::/24ff65:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff65:da00::/24ff65:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff65:db00::/24ff65:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff65:dc00::/24ff65:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff65:dd00::/24ff65:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff65:de00::/24ff65:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff65:df00::/24ff65:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff65:e000::/24ff65:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff65:e100::/24ff65:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff65:e200::/24ff65:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff65:e300::/24ff65:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff65:e400::/24ff65:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff65:e500::/24ff65:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff65:e600::/24ff65:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff65:e700::/24ff65:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff65:e800::/24ff65:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff65:e900::/24ff65:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff65:ea00::/24ff65:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff65:eb00::/24ff65:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff65:ec00::/24ff65:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff65:ed00::/24ff65:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff65:ee00::/24ff65:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff65:ef00::/24ff65:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff65:f000::/24ff65:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff65:f100::/24ff65:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff65:f200::/24ff65:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff65:f300::/24ff65:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff65:f400::/24ff65:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff65:f500::/24ff65:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff65:f600::/24ff65:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff65:f700::/24ff65:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff65:f800::/24ff65:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff65:f900::/24ff65:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff65:fa00::/24ff65:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff65:fb00::/24ff65:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff65:fc00::/24ff65:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff65:fd00::/24ff65:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff65:fe00::/24ff65:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff65:ff00::/24ff65: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.