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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/20
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/20 (512)/24 (8,192)

ff40::/11 makes 512 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
1ff40::/20ff40:fff:ffff:ffff:ffff:ffff:ffff:ffff
2ff40:1000::/20ff40:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3ff40:2000::/20ff40:2fff:ffff:ffff:ffff:ffff:ffff:ffff
4ff40:3000::/20ff40:3fff:ffff:ffff:ffff:ffff:ffff:ffff
5ff40:4000::/20ff40:4fff:ffff:ffff:ffff:ffff:ffff:ffff
6ff40:5000::/20ff40:5fff:ffff:ffff:ffff:ffff:ffff:ffff
7ff40:6000::/20ff40:6fff:ffff:ffff:ffff:ffff:ffff:ffff
8ff40:7000::/20ff40:7fff:ffff:ffff:ffff:ffff:ffff:ffff
9ff40:8000::/20ff40:8fff:ffff:ffff:ffff:ffff:ffff:ffff
10ff40:9000::/20ff40:9fff:ffff:ffff:ffff:ffff:ffff:ffff
11ff40:a000::/20ff40:afff:ffff:ffff:ffff:ffff:ffff:ffff
12ff40:b000::/20ff40:bfff:ffff:ffff:ffff:ffff:ffff:ffff
13ff40:c000::/20ff40:cfff:ffff:ffff:ffff:ffff:ffff:ffff
14ff40:d000::/20ff40:dfff:ffff:ffff:ffff:ffff:ffff:ffff
15ff40:e000::/20ff40:efff:ffff:ffff:ffff:ffff:ffff:ffff
16ff40:f000::/20ff40:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17ff41::/20ff41:fff:ffff:ffff:ffff:ffff:ffff:ffff
18ff41:1000::/20ff41:1fff:ffff:ffff:ffff:ffff:ffff:ffff
19ff41:2000::/20ff41:2fff:ffff:ffff:ffff:ffff:ffff:ffff
20ff41:3000::/20ff41:3fff:ffff:ffff:ffff:ffff:ffff:ffff
21ff41:4000::/20ff41:4fff:ffff:ffff:ffff:ffff:ffff:ffff
22ff41:5000::/20ff41:5fff:ffff:ffff:ffff:ffff:ffff:ffff
23ff41:6000::/20ff41:6fff:ffff:ffff:ffff:ffff:ffff:ffff
24ff41:7000::/20ff41:7fff:ffff:ffff:ffff:ffff:ffff:ffff
25ff41:8000::/20ff41:8fff:ffff:ffff:ffff:ffff:ffff:ffff
26ff41:9000::/20ff41:9fff:ffff:ffff:ffff:ffff:ffff:ffff
27ff41:a000::/20ff41:afff:ffff:ffff:ffff:ffff:ffff:ffff
28ff41:b000::/20ff41:bfff:ffff:ffff:ffff:ffff:ffff:ffff
29ff41:c000::/20ff41:cfff:ffff:ffff:ffff:ffff:ffff:ffff
30ff41:d000::/20ff41:dfff:ffff:ffff:ffff:ffff:ffff:ffff
31ff41:e000::/20ff41:efff:ffff:ffff:ffff:ffff:ffff:ffff
32ff41:f000::/20ff41:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33ff42::/20ff42:fff:ffff:ffff:ffff:ffff:ffff:ffff
34ff42:1000::/20ff42:1fff:ffff:ffff:ffff:ffff:ffff:ffff
35ff42:2000::/20ff42:2fff:ffff:ffff:ffff:ffff:ffff:ffff
36ff42:3000::/20ff42:3fff:ffff:ffff:ffff:ffff:ffff:ffff
37ff42:4000::/20ff42:4fff:ffff:ffff:ffff:ffff:ffff:ffff
38ff42:5000::/20ff42:5fff:ffff:ffff:ffff:ffff:ffff:ffff
39ff42:6000::/20ff42:6fff:ffff:ffff:ffff:ffff:ffff:ffff
40ff42:7000::/20ff42:7fff:ffff:ffff:ffff:ffff:ffff:ffff
41ff42:8000::/20ff42:8fff:ffff:ffff:ffff:ffff:ffff:ffff
42ff42:9000::/20ff42:9fff:ffff:ffff:ffff:ffff:ffff:ffff
43ff42:a000::/20ff42:afff:ffff:ffff:ffff:ffff:ffff:ffff
44ff42:b000::/20ff42:bfff:ffff:ffff:ffff:ffff:ffff:ffff
45ff42:c000::/20ff42:cfff:ffff:ffff:ffff:ffff:ffff:ffff
46ff42:d000::/20ff42:dfff:ffff:ffff:ffff:ffff:ffff:ffff
47ff42:e000::/20ff42:efff:ffff:ffff:ffff:ffff:ffff:ffff
48ff42:f000::/20ff42:ffff:ffff:ffff:ffff:ffff:ffff:ffff
49ff43::/20ff43:fff:ffff:ffff:ffff:ffff:ffff:ffff
50ff43:1000::/20ff43:1fff:ffff:ffff:ffff:ffff:ffff:ffff
51ff43:2000::/20ff43:2fff:ffff:ffff:ffff:ffff:ffff:ffff
52ff43:3000::/20ff43:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53ff43:4000::/20ff43:4fff:ffff:ffff:ffff:ffff:ffff:ffff
54ff43:5000::/20ff43:5fff:ffff:ffff:ffff:ffff:ffff:ffff
55ff43:6000::/20ff43:6fff:ffff:ffff:ffff:ffff:ffff:ffff
56ff43:7000::/20ff43:7fff:ffff:ffff:ffff:ffff:ffff:ffff
57ff43:8000::/20ff43:8fff:ffff:ffff:ffff:ffff:ffff:ffff
58ff43:9000::/20ff43:9fff:ffff:ffff:ffff:ffff:ffff:ffff
59ff43:a000::/20ff43:afff:ffff:ffff:ffff:ffff:ffff:ffff
60ff43:b000::/20ff43:bfff:ffff:ffff:ffff:ffff:ffff:ffff
61ff43:c000::/20ff43:cfff:ffff:ffff:ffff:ffff:ffff:ffff
62ff43:d000::/20ff43:dfff:ffff:ffff:ffff:ffff:ffff:ffff
63ff43:e000::/20ff43:efff:ffff:ffff:ffff:ffff:ffff:ffff
64ff43:f000::/20ff43:ffff:ffff:ffff:ffff:ffff:ffff:ffff
65ff44::/20ff44:fff:ffff:ffff:ffff:ffff:ffff:ffff
66ff44:1000::/20ff44:1fff:ffff:ffff:ffff:ffff:ffff:ffff
67ff44:2000::/20ff44:2fff:ffff:ffff:ffff:ffff:ffff:ffff
68ff44:3000::/20ff44:3fff:ffff:ffff:ffff:ffff:ffff:ffff
69ff44:4000::/20ff44:4fff:ffff:ffff:ffff:ffff:ffff:ffff
70ff44:5000::/20ff44:5fff:ffff:ffff:ffff:ffff:ffff:ffff
71ff44:6000::/20ff44:6fff:ffff:ffff:ffff:ffff:ffff:ffff
72ff44:7000::/20ff44:7fff:ffff:ffff:ffff:ffff:ffff:ffff
73ff44:8000::/20ff44:8fff:ffff:ffff:ffff:ffff:ffff:ffff
74ff44:9000::/20ff44:9fff:ffff:ffff:ffff:ffff:ffff:ffff
75ff44:a000::/20ff44:afff:ffff:ffff:ffff:ffff:ffff:ffff
76ff44:b000::/20ff44:bfff:ffff:ffff:ffff:ffff:ffff:ffff
77ff44:c000::/20ff44:cfff:ffff:ffff:ffff:ffff:ffff:ffff
78ff44:d000::/20ff44:dfff:ffff:ffff:ffff:ffff:ffff:ffff
79ff44:e000::/20ff44:efff:ffff:ffff:ffff:ffff:ffff:ffff
80ff44:f000::/20ff44:ffff:ffff:ffff:ffff:ffff:ffff:ffff
81ff45::/20ff45:fff:ffff:ffff:ffff:ffff:ffff:ffff
82ff45:1000::/20ff45:1fff:ffff:ffff:ffff:ffff:ffff:ffff
83ff45:2000::/20ff45:2fff:ffff:ffff:ffff:ffff:ffff:ffff
84ff45:3000::/20ff45:3fff:ffff:ffff:ffff:ffff:ffff:ffff
85ff45:4000::/20ff45:4fff:ffff:ffff:ffff:ffff:ffff:ffff
86ff45:5000::/20ff45:5fff:ffff:ffff:ffff:ffff:ffff:ffff
87ff45:6000::/20ff45:6fff:ffff:ffff:ffff:ffff:ffff:ffff
88ff45:7000::/20ff45:7fff:ffff:ffff:ffff:ffff:ffff:ffff
89ff45:8000::/20ff45:8fff:ffff:ffff:ffff:ffff:ffff:ffff
90ff45:9000::/20ff45:9fff:ffff:ffff:ffff:ffff:ffff:ffff
91ff45:a000::/20ff45:afff:ffff:ffff:ffff:ffff:ffff:ffff
92ff45:b000::/20ff45:bfff:ffff:ffff:ffff:ffff:ffff:ffff
93ff45:c000::/20ff45:cfff:ffff:ffff:ffff:ffff:ffff:ffff
94ff45:d000::/20ff45:dfff:ffff:ffff:ffff:ffff:ffff:ffff
95ff45:e000::/20ff45:efff:ffff:ffff:ffff:ffff:ffff:ffff
96ff45:f000::/20ff45:ffff:ffff:ffff:ffff:ffff:ffff:ffff
97ff46::/20ff46:fff:ffff:ffff:ffff:ffff:ffff:ffff
98ff46:1000::/20ff46:1fff:ffff:ffff:ffff:ffff:ffff:ffff
99ff46:2000::/20ff46:2fff:ffff:ffff:ffff:ffff:ffff:ffff
100ff46:3000::/20ff46:3fff:ffff:ffff:ffff:ffff:ffff:ffff
101ff46:4000::/20ff46:4fff:ffff:ffff:ffff:ffff:ffff:ffff
102ff46:5000::/20ff46:5fff:ffff:ffff:ffff:ffff:ffff:ffff
103ff46:6000::/20ff46:6fff:ffff:ffff:ffff:ffff:ffff:ffff
104ff46:7000::/20ff46:7fff:ffff:ffff:ffff:ffff:ffff:ffff
105ff46:8000::/20ff46:8fff:ffff:ffff:ffff:ffff:ffff:ffff
106ff46:9000::/20ff46:9fff:ffff:ffff:ffff:ffff:ffff:ffff
107ff46:a000::/20ff46:afff:ffff:ffff:ffff:ffff:ffff:ffff
108ff46:b000::/20ff46:bfff:ffff:ffff:ffff:ffff:ffff:ffff
109ff46:c000::/20ff46:cfff:ffff:ffff:ffff:ffff:ffff:ffff
110ff46:d000::/20ff46:dfff:ffff:ffff:ffff:ffff:ffff:ffff
111ff46:e000::/20ff46:efff:ffff:ffff:ffff:ffff:ffff:ffff
112ff46:f000::/20ff46:ffff:ffff:ffff:ffff:ffff:ffff:ffff
113ff47::/20ff47:fff:ffff:ffff:ffff:ffff:ffff:ffff
114ff47:1000::/20ff47:1fff:ffff:ffff:ffff:ffff:ffff:ffff
115ff47:2000::/20ff47:2fff:ffff:ffff:ffff:ffff:ffff:ffff
116ff47:3000::/20ff47:3fff:ffff:ffff:ffff:ffff:ffff:ffff
117ff47:4000::/20ff47:4fff:ffff:ffff:ffff:ffff:ffff:ffff
118ff47:5000::/20ff47:5fff:ffff:ffff:ffff:ffff:ffff:ffff
119ff47:6000::/20ff47:6fff:ffff:ffff:ffff:ffff:ffff:ffff
120ff47:7000::/20ff47:7fff:ffff:ffff:ffff:ffff:ffff:ffff
121ff47:8000::/20ff47:8fff:ffff:ffff:ffff:ffff:ffff:ffff
122ff47:9000::/20ff47:9fff:ffff:ffff:ffff:ffff:ffff:ffff
123ff47:a000::/20ff47:afff:ffff:ffff:ffff:ffff:ffff:ffff
124ff47:b000::/20ff47:bfff:ffff:ffff:ffff:ffff:ffff:ffff
125ff47:c000::/20ff47:cfff:ffff:ffff:ffff:ffff:ffff:ffff
126ff47:d000::/20ff47:dfff:ffff:ffff:ffff:ffff:ffff:ffff
127ff47:e000::/20ff47:efff:ffff:ffff:ffff:ffff:ffff:ffff
128ff47:f000::/20ff47:ffff:ffff:ffff:ffff:ffff:ffff:ffff
129ff48::/20ff48:fff:ffff:ffff:ffff:ffff:ffff:ffff
130ff48:1000::/20ff48:1fff:ffff:ffff:ffff:ffff:ffff:ffff
131ff48:2000::/20ff48:2fff:ffff:ffff:ffff:ffff:ffff:ffff
132ff48:3000::/20ff48:3fff:ffff:ffff:ffff:ffff:ffff:ffff
133ff48:4000::/20ff48:4fff:ffff:ffff:ffff:ffff:ffff:ffff
134ff48:5000::/20ff48:5fff:ffff:ffff:ffff:ffff:ffff:ffff
135ff48:6000::/20ff48:6fff:ffff:ffff:ffff:ffff:ffff:ffff
136ff48:7000::/20ff48:7fff:ffff:ffff:ffff:ffff:ffff:ffff
137ff48:8000::/20ff48:8fff:ffff:ffff:ffff:ffff:ffff:ffff
138ff48:9000::/20ff48:9fff:ffff:ffff:ffff:ffff:ffff:ffff
139ff48:a000::/20ff48:afff:ffff:ffff:ffff:ffff:ffff:ffff
140ff48:b000::/20ff48:bfff:ffff:ffff:ffff:ffff:ffff:ffff
141ff48:c000::/20ff48:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142ff48:d000::/20ff48:dfff:ffff:ffff:ffff:ffff:ffff:ffff
143ff48:e000::/20ff48:efff:ffff:ffff:ffff:ffff:ffff:ffff
144ff48:f000::/20ff48:ffff:ffff:ffff:ffff:ffff:ffff:ffff
145ff49::/20ff49:fff:ffff:ffff:ffff:ffff:ffff:ffff
146ff49:1000::/20ff49:1fff:ffff:ffff:ffff:ffff:ffff:ffff
147ff49:2000::/20ff49:2fff:ffff:ffff:ffff:ffff:ffff:ffff
148ff49:3000::/20ff49:3fff:ffff:ffff:ffff:ffff:ffff:ffff
149ff49:4000::/20ff49:4fff:ffff:ffff:ffff:ffff:ffff:ffff
150ff49:5000::/20ff49:5fff:ffff:ffff:ffff:ffff:ffff:ffff
151ff49:6000::/20ff49:6fff:ffff:ffff:ffff:ffff:ffff:ffff
152ff49:7000::/20ff49:7fff:ffff:ffff:ffff:ffff:ffff:ffff
153ff49:8000::/20ff49:8fff:ffff:ffff:ffff:ffff:ffff:ffff
154ff49:9000::/20ff49:9fff:ffff:ffff:ffff:ffff:ffff:ffff
155ff49:a000::/20ff49:afff:ffff:ffff:ffff:ffff:ffff:ffff
156ff49:b000::/20ff49:bfff:ffff:ffff:ffff:ffff:ffff:ffff
157ff49:c000::/20ff49:cfff:ffff:ffff:ffff:ffff:ffff:ffff
158ff49:d000::/20ff49:dfff:ffff:ffff:ffff:ffff:ffff:ffff
159ff49:e000::/20ff49:efff:ffff:ffff:ffff:ffff:ffff:ffff
160ff49:f000::/20ff49:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161ff4a::/20ff4a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162ff4a:1000::/20ff4a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163ff4a:2000::/20ff4a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164ff4a:3000::/20ff4a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165ff4a:4000::/20ff4a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166ff4a:5000::/20ff4a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167ff4a:6000::/20ff4a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168ff4a:7000::/20ff4a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169ff4a:8000::/20ff4a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170ff4a:9000::/20ff4a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171ff4a:a000::/20ff4a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172ff4a:b000::/20ff4a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173ff4a:c000::/20ff4a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174ff4a:d000::/20ff4a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175ff4a:e000::/20ff4a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176ff4a:f000::/20ff4a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177ff4b::/20ff4b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178ff4b:1000::/20ff4b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179ff4b:2000::/20ff4b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180ff4b:3000::/20ff4b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181ff4b:4000::/20ff4b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182ff4b:5000::/20ff4b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183ff4b:6000::/20ff4b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184ff4b:7000::/20ff4b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185ff4b:8000::/20ff4b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186ff4b:9000::/20ff4b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187ff4b:a000::/20ff4b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188ff4b:b000::/20ff4b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189ff4b:c000::/20ff4b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190ff4b:d000::/20ff4b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191ff4b:e000::/20ff4b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192ff4b:f000::/20ff4b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193ff4c::/20ff4c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194ff4c:1000::/20ff4c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195ff4c:2000::/20ff4c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196ff4c:3000::/20ff4c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197ff4c:4000::/20ff4c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198ff4c:5000::/20ff4c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199ff4c:6000::/20ff4c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200ff4c:7000::/20ff4c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201ff4c:8000::/20ff4c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202ff4c:9000::/20ff4c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203ff4c:a000::/20ff4c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204ff4c:b000::/20ff4c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205ff4c:c000::/20ff4c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206ff4c:d000::/20ff4c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207ff4c:e000::/20ff4c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208ff4c:f000::/20ff4c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209ff4d::/20ff4d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210ff4d:1000::/20ff4d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211ff4d:2000::/20ff4d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212ff4d:3000::/20ff4d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213ff4d:4000::/20ff4d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214ff4d:5000::/20ff4d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215ff4d:6000::/20ff4d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216ff4d:7000::/20ff4d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217ff4d:8000::/20ff4d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218ff4d:9000::/20ff4d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219ff4d:a000::/20ff4d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220ff4d:b000::/20ff4d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221ff4d:c000::/20ff4d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222ff4d:d000::/20ff4d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223ff4d:e000::/20ff4d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224ff4d:f000::/20ff4d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225ff4e::/20ff4e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226ff4e:1000::/20ff4e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227ff4e:2000::/20ff4e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228ff4e:3000::/20ff4e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229ff4e:4000::/20ff4e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230ff4e:5000::/20ff4e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231ff4e:6000::/20ff4e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232ff4e:7000::/20ff4e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233ff4e:8000::/20ff4e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234ff4e:9000::/20ff4e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235ff4e:a000::/20ff4e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236ff4e:b000::/20ff4e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237ff4e:c000::/20ff4e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238ff4e:d000::/20ff4e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239ff4e:e000::/20ff4e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240ff4e:f000::/20ff4e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241ff4f::/20ff4f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242ff4f:1000::/20ff4f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243ff4f:2000::/20ff4f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244ff4f:3000::/20ff4f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245ff4f:4000::/20ff4f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246ff4f:5000::/20ff4f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247ff4f:6000::/20ff4f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248ff4f:7000::/20ff4f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249ff4f:8000::/20ff4f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250ff4f:9000::/20ff4f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251ff4f:a000::/20ff4f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252ff4f:b000::/20ff4f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253ff4f:c000::/20ff4f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254ff4f:d000::/20ff4f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255ff4f:e000::/20ff4f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256ff4f:f000::/20ff4f: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.