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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/11
Addresses2^117
/64 networks2^53
Network
ff40::/11
First address
ff40::
Last address
ff5f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
166,153,499,473,114,484,112,975,882,535,043,072 (2^117)
/64 networks (LANs)
9,007,199,254,740,992 (2^53)
Full form
ff40:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zones
4.f.f.ip6.arpa
5.f.f.ip6.arpa
/11 is not on a 4-bit boundary, so it takes 2 /12 zones.
Split into smaller subnets/24
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/20 (512)/24 (8,192)

ff40::/11 makes 8,192 subnets of /24; the first 256 are listed.

Subnets
#SubnetLast address
1ff40::/24ff40:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff40:100::/24ff40:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff40:200::/24ff40:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff40:300::/24ff40:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff40:400::/24ff40:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff40:500::/24ff40:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff40:600::/24ff40:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff40:700::/24ff40:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff40:800::/24ff40:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff40:900::/24ff40:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff40:a00::/24ff40:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff40:b00::/24ff40:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff40:c00::/24ff40:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff40:d00::/24ff40:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff40:e00::/24ff40:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff40:f00::/24ff40:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff40:1000::/24ff40:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff40:1100::/24ff40:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff40:1200::/24ff40:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff40:1300::/24ff40:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff40:1400::/24ff40:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff40:1500::/24ff40:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff40:1600::/24ff40:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff40:1700::/24ff40:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff40:1800::/24ff40:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff40:1900::/24ff40:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff40:1a00::/24ff40:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff40:1b00::/24ff40:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff40:1c00::/24ff40:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff40:1d00::/24ff40:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff40:1e00::/24ff40:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff40:1f00::/24ff40:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff40:2000::/24ff40:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff40:2100::/24ff40:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff40:2200::/24ff40:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff40:2300::/24ff40:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff40:2400::/24ff40:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff40:2500::/24ff40:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff40:2600::/24ff40:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff40:2700::/24ff40:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff40:2800::/24ff40:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff40:2900::/24ff40:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff40:2a00::/24ff40:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff40:2b00::/24ff40:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff40:2c00::/24ff40:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff40:2d00::/24ff40:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff40:2e00::/24ff40:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff40:2f00::/24ff40:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff40:3000::/24ff40:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff40:3100::/24ff40:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff40:3200::/24ff40:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff40:3300::/24ff40:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff40:3400::/24ff40:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff40:3500::/24ff40:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff40:3600::/24ff40:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff40:3700::/24ff40:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff40:3800::/24ff40:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff40:3900::/24ff40:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff40:3a00::/24ff40:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff40:3b00::/24ff40:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff40:3c00::/24ff40:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff40:3d00::/24ff40:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff40:3e00::/24ff40:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff40:3f00::/24ff40:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff40:4000::/24ff40:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff40:4100::/24ff40:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff40:4200::/24ff40:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff40:4300::/24ff40:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff40:4400::/24ff40:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff40:4500::/24ff40:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff40:4600::/24ff40:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff40:4700::/24ff40:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff40:4800::/24ff40:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff40:4900::/24ff40:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff40:4a00::/24ff40:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff40:4b00::/24ff40:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff40:4c00::/24ff40:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff40:4d00::/24ff40:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff40:4e00::/24ff40:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff40:4f00::/24ff40:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff40:5000::/24ff40:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff40:5100::/24ff40:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff40:5200::/24ff40:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff40:5300::/24ff40:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff40:5400::/24ff40:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff40:5500::/24ff40:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff40:5600::/24ff40:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff40:5700::/24ff40:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff40:5800::/24ff40:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff40:5900::/24ff40:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff40:5a00::/24ff40:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff40:5b00::/24ff40:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff40:5c00::/24ff40:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff40:5d00::/24ff40:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff40:5e00::/24ff40:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff40:5f00::/24ff40:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff40:6000::/24ff40:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff40:6100::/24ff40:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff40:6200::/24ff40:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff40:6300::/24ff40:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff40:6400::/24ff40:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff40:6500::/24ff40:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff40:6600::/24ff40:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff40:6700::/24ff40:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff40:6800::/24ff40:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff40:6900::/24ff40:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff40:6a00::/24ff40:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff40:6b00::/24ff40:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff40:6c00::/24ff40:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff40:6d00::/24ff40:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff40:6e00::/24ff40:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff40:6f00::/24ff40:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff40:7000::/24ff40:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff40:7100::/24ff40:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff40:7200::/24ff40:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff40:7300::/24ff40:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff40:7400::/24ff40:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff40:7500::/24ff40:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff40:7600::/24ff40:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff40:7700::/24ff40:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff40:7800::/24ff40:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff40:7900::/24ff40:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff40:7a00::/24ff40:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff40:7b00::/24ff40:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff40:7c00::/24ff40:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff40:7d00::/24ff40:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff40:7e00::/24ff40:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff40:7f00::/24ff40:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff40:8000::/24ff40:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff40:8100::/24ff40:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff40:8200::/24ff40:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff40:8300::/24ff40:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff40:8400::/24ff40:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff40:8500::/24ff40:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff40:8600::/24ff40:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff40:8700::/24ff40:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff40:8800::/24ff40:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff40:8900::/24ff40:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff40:8a00::/24ff40:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff40:8b00::/24ff40:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff40:8c00::/24ff40:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff40:8d00::/24ff40:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff40:8e00::/24ff40:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff40:8f00::/24ff40:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff40:9000::/24ff40:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff40:9100::/24ff40:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff40:9200::/24ff40:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff40:9300::/24ff40:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff40:9400::/24ff40:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff40:9500::/24ff40:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff40:9600::/24ff40:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff40:9700::/24ff40:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff40:9800::/24ff40:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff40:9900::/24ff40:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff40:9a00::/24ff40:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff40:9b00::/24ff40:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff40:9c00::/24ff40:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff40:9d00::/24ff40:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff40:9e00::/24ff40:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff40:9f00::/24ff40:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff40:a000::/24ff40:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff40:a100::/24ff40:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff40:a200::/24ff40:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff40:a300::/24ff40:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff40:a400::/24ff40:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff40:a500::/24ff40:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff40:a600::/24ff40:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff40:a700::/24ff40:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff40:a800::/24ff40:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff40:a900::/24ff40:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff40:aa00::/24ff40:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff40:ab00::/24ff40:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff40:ac00::/24ff40:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff40:ad00::/24ff40:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff40:ae00::/24ff40:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff40:af00::/24ff40:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff40:b000::/24ff40:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff40:b100::/24ff40:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff40:b200::/24ff40:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff40:b300::/24ff40:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff40:b400::/24ff40:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff40:b500::/24ff40:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff40:b600::/24ff40:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff40:b700::/24ff40:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff40:b800::/24ff40:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff40:b900::/24ff40:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff40:ba00::/24ff40:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff40:bb00::/24ff40:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff40:bc00::/24ff40:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff40:bd00::/24ff40:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff40:be00::/24ff40:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff40:bf00::/24ff40:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff40:c000::/24ff40:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff40:c100::/24ff40:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff40:c200::/24ff40:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff40:c300::/24ff40:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff40:c400::/24ff40:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff40:c500::/24ff40:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff40:c600::/24ff40:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff40:c700::/24ff40:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff40:c800::/24ff40:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff40:c900::/24ff40:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff40:ca00::/24ff40:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff40:cb00::/24ff40:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff40:cc00::/24ff40:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff40:cd00::/24ff40:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff40:ce00::/24ff40:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff40:cf00::/24ff40:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff40:d000::/24ff40:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff40:d100::/24ff40:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff40:d200::/24ff40:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff40:d300::/24ff40:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff40:d400::/24ff40:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff40:d500::/24ff40:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff40:d600::/24ff40:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff40:d700::/24ff40:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff40:d800::/24ff40:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff40:d900::/24ff40:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff40:da00::/24ff40:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff40:db00::/24ff40:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff40:dc00::/24ff40:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff40:dd00::/24ff40:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff40:de00::/24ff40:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff40:df00::/24ff40:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff40:e000::/24ff40:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff40:e100::/24ff40:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff40:e200::/24ff40:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff40:e300::/24ff40:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff40:e400::/24ff40:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff40:e500::/24ff40:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff40:e600::/24ff40:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff40:e700::/24ff40:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff40:e800::/24ff40:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff40:e900::/24ff40:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff40:ea00::/24ff40:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff40:eb00::/24ff40:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff40:ec00::/24ff40:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff40:ed00::/24ff40:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff40:ee00::/24ff40:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff40:ef00::/24ff40:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff40:f000::/24ff40:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff40:f100::/24ff40:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff40:f200::/24ff40:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff40:f300::/24ff40:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff40:f400::/24ff40:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff40:f500::/24ff40:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff40:f600::/24ff40:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff40:f700::/24ff40:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff40:f800::/24ff40:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff40:f900::/24ff40:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff40:fa00::/24ff40:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff40:fb00::/24ff40:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff40:fc00::/24ff40:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff40:fd00::/24ff40:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff40:fe00::/24ff40:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff40:ff00::/24ff40: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.