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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/8
Addresses2^120
/64 networks2^56
Network
ff00::/8
First address
ff00::
Last address
ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
1,329,227,995,784,915,872,903,807,060,280,344,576 (2^120)
/64 networks (LANs)
72,057,594,037,927,936 (2^56)
Full form
ff00:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
f.f.ip6.arpa
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/16 (256)/20 (4,096)/24 (65,536)

ff00::/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
1ff00::/20ff00:fff:ffff:ffff:ffff:ffff:ffff:ffff
2ff00:1000::/20ff00:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3ff00:2000::/20ff00:2fff:ffff:ffff:ffff:ffff:ffff:ffff
4ff00:3000::/20ff00:3fff:ffff:ffff:ffff:ffff:ffff:ffff
5ff00:4000::/20ff00:4fff:ffff:ffff:ffff:ffff:ffff:ffff
6ff00:5000::/20ff00:5fff:ffff:ffff:ffff:ffff:ffff:ffff
7ff00:6000::/20ff00:6fff:ffff:ffff:ffff:ffff:ffff:ffff
8ff00:7000::/20ff00:7fff:ffff:ffff:ffff:ffff:ffff:ffff
9ff00:8000::/20ff00:8fff:ffff:ffff:ffff:ffff:ffff:ffff
10ff00:9000::/20ff00:9fff:ffff:ffff:ffff:ffff:ffff:ffff
11ff00:a000::/20ff00:afff:ffff:ffff:ffff:ffff:ffff:ffff
12ff00:b000::/20ff00:bfff:ffff:ffff:ffff:ffff:ffff:ffff
13ff00:c000::/20ff00:cfff:ffff:ffff:ffff:ffff:ffff:ffff
14ff00:d000::/20ff00:dfff:ffff:ffff:ffff:ffff:ffff:ffff
15ff00:e000::/20ff00:efff:ffff:ffff:ffff:ffff:ffff:ffff
16ff00:f000::/20ff00:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17ff01::/20ff01:fff:ffff:ffff:ffff:ffff:ffff:ffff
18ff01:1000::/20ff01:1fff:ffff:ffff:ffff:ffff:ffff:ffff
19ff01:2000::/20ff01:2fff:ffff:ffff:ffff:ffff:ffff:ffff
20ff01:3000::/20ff01:3fff:ffff:ffff:ffff:ffff:ffff:ffff
21ff01:4000::/20ff01:4fff:ffff:ffff:ffff:ffff:ffff:ffff
22ff01:5000::/20ff01:5fff:ffff:ffff:ffff:ffff:ffff:ffff
23ff01:6000::/20ff01:6fff:ffff:ffff:ffff:ffff:ffff:ffff
24ff01:7000::/20ff01:7fff:ffff:ffff:ffff:ffff:ffff:ffff
25ff01:8000::/20ff01:8fff:ffff:ffff:ffff:ffff:ffff:ffff
26ff01:9000::/20ff01:9fff:ffff:ffff:ffff:ffff:ffff:ffff
27ff01:a000::/20ff01:afff:ffff:ffff:ffff:ffff:ffff:ffff
28ff01:b000::/20ff01:bfff:ffff:ffff:ffff:ffff:ffff:ffff
29ff01:c000::/20ff01:cfff:ffff:ffff:ffff:ffff:ffff:ffff
30ff01:d000::/20ff01:dfff:ffff:ffff:ffff:ffff:ffff:ffff
31ff01:e000::/20ff01:efff:ffff:ffff:ffff:ffff:ffff:ffff
32ff01:f000::/20ff01:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33ff02::/20ff02:fff:ffff:ffff:ffff:ffff:ffff:ffff
34ff02:1000::/20ff02:1fff:ffff:ffff:ffff:ffff:ffff:ffff
35ff02:2000::/20ff02:2fff:ffff:ffff:ffff:ffff:ffff:ffff
36ff02:3000::/20ff02:3fff:ffff:ffff:ffff:ffff:ffff:ffff
37ff02:4000::/20ff02:4fff:ffff:ffff:ffff:ffff:ffff:ffff
38ff02:5000::/20ff02:5fff:ffff:ffff:ffff:ffff:ffff:ffff
39ff02:6000::/20ff02:6fff:ffff:ffff:ffff:ffff:ffff:ffff
40ff02:7000::/20ff02:7fff:ffff:ffff:ffff:ffff:ffff:ffff
41ff02:8000::/20ff02:8fff:ffff:ffff:ffff:ffff:ffff:ffff
42ff02:9000::/20ff02:9fff:ffff:ffff:ffff:ffff:ffff:ffff
43ff02:a000::/20ff02:afff:ffff:ffff:ffff:ffff:ffff:ffff
44ff02:b000::/20ff02:bfff:ffff:ffff:ffff:ffff:ffff:ffff
45ff02:c000::/20ff02:cfff:ffff:ffff:ffff:ffff:ffff:ffff
46ff02:d000::/20ff02:dfff:ffff:ffff:ffff:ffff:ffff:ffff
47ff02:e000::/20ff02:efff:ffff:ffff:ffff:ffff:ffff:ffff
48ff02:f000::/20ff02:ffff:ffff:ffff:ffff:ffff:ffff:ffff
49ff03::/20ff03:fff:ffff:ffff:ffff:ffff:ffff:ffff
50ff03:1000::/20ff03:1fff:ffff:ffff:ffff:ffff:ffff:ffff
51ff03:2000::/20ff03:2fff:ffff:ffff:ffff:ffff:ffff:ffff
52ff03:3000::/20ff03:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53ff03:4000::/20ff03:4fff:ffff:ffff:ffff:ffff:ffff:ffff
54ff03:5000::/20ff03:5fff:ffff:ffff:ffff:ffff:ffff:ffff
55ff03:6000::/20ff03:6fff:ffff:ffff:ffff:ffff:ffff:ffff
56ff03:7000::/20ff03:7fff:ffff:ffff:ffff:ffff:ffff:ffff
57ff03:8000::/20ff03:8fff:ffff:ffff:ffff:ffff:ffff:ffff
58ff03:9000::/20ff03:9fff:ffff:ffff:ffff:ffff:ffff:ffff
59ff03:a000::/20ff03:afff:ffff:ffff:ffff:ffff:ffff:ffff
60ff03:b000::/20ff03:bfff:ffff:ffff:ffff:ffff:ffff:ffff
61ff03:c000::/20ff03:cfff:ffff:ffff:ffff:ffff:ffff:ffff
62ff03:d000::/20ff03:dfff:ffff:ffff:ffff:ffff:ffff:ffff
63ff03:e000::/20ff03:efff:ffff:ffff:ffff:ffff:ffff:ffff
64ff03:f000::/20ff03:ffff:ffff:ffff:ffff:ffff:ffff:ffff
65ff04::/20ff04:fff:ffff:ffff:ffff:ffff:ffff:ffff
66ff04:1000::/20ff04:1fff:ffff:ffff:ffff:ffff:ffff:ffff
67ff04:2000::/20ff04:2fff:ffff:ffff:ffff:ffff:ffff:ffff
68ff04:3000::/20ff04:3fff:ffff:ffff:ffff:ffff:ffff:ffff
69ff04:4000::/20ff04:4fff:ffff:ffff:ffff:ffff:ffff:ffff
70ff04:5000::/20ff04:5fff:ffff:ffff:ffff:ffff:ffff:ffff
71ff04:6000::/20ff04:6fff:ffff:ffff:ffff:ffff:ffff:ffff
72ff04:7000::/20ff04:7fff:ffff:ffff:ffff:ffff:ffff:ffff
73ff04:8000::/20ff04:8fff:ffff:ffff:ffff:ffff:ffff:ffff
74ff04:9000::/20ff04:9fff:ffff:ffff:ffff:ffff:ffff:ffff
75ff04:a000::/20ff04:afff:ffff:ffff:ffff:ffff:ffff:ffff
76ff04:b000::/20ff04:bfff:ffff:ffff:ffff:ffff:ffff:ffff
77ff04:c000::/20ff04:cfff:ffff:ffff:ffff:ffff:ffff:ffff
78ff04:d000::/20ff04:dfff:ffff:ffff:ffff:ffff:ffff:ffff
79ff04:e000::/20ff04:efff:ffff:ffff:ffff:ffff:ffff:ffff
80ff04:f000::/20ff04:ffff:ffff:ffff:ffff:ffff:ffff:ffff
81ff05::/20ff05:fff:ffff:ffff:ffff:ffff:ffff:ffff
82ff05:1000::/20ff05:1fff:ffff:ffff:ffff:ffff:ffff:ffff
83ff05:2000::/20ff05:2fff:ffff:ffff:ffff:ffff:ffff:ffff
84ff05:3000::/20ff05:3fff:ffff:ffff:ffff:ffff:ffff:ffff
85ff05:4000::/20ff05:4fff:ffff:ffff:ffff:ffff:ffff:ffff
86ff05:5000::/20ff05:5fff:ffff:ffff:ffff:ffff:ffff:ffff
87ff05:6000::/20ff05:6fff:ffff:ffff:ffff:ffff:ffff:ffff
88ff05:7000::/20ff05:7fff:ffff:ffff:ffff:ffff:ffff:ffff
89ff05:8000::/20ff05:8fff:ffff:ffff:ffff:ffff:ffff:ffff
90ff05:9000::/20ff05:9fff:ffff:ffff:ffff:ffff:ffff:ffff
91ff05:a000::/20ff05:afff:ffff:ffff:ffff:ffff:ffff:ffff
92ff05:b000::/20ff05:bfff:ffff:ffff:ffff:ffff:ffff:ffff
93ff05:c000::/20ff05:cfff:ffff:ffff:ffff:ffff:ffff:ffff
94ff05:d000::/20ff05:dfff:ffff:ffff:ffff:ffff:ffff:ffff
95ff05:e000::/20ff05:efff:ffff:ffff:ffff:ffff:ffff:ffff
96ff05:f000::/20ff05:ffff:ffff:ffff:ffff:ffff:ffff:ffff
97ff06::/20ff06:fff:ffff:ffff:ffff:ffff:ffff:ffff
98ff06:1000::/20ff06:1fff:ffff:ffff:ffff:ffff:ffff:ffff
99ff06:2000::/20ff06:2fff:ffff:ffff:ffff:ffff:ffff:ffff
100ff06:3000::/20ff06:3fff:ffff:ffff:ffff:ffff:ffff:ffff
101ff06:4000::/20ff06:4fff:ffff:ffff:ffff:ffff:ffff:ffff
102ff06:5000::/20ff06:5fff:ffff:ffff:ffff:ffff:ffff:ffff
103ff06:6000::/20ff06:6fff:ffff:ffff:ffff:ffff:ffff:ffff
104ff06:7000::/20ff06:7fff:ffff:ffff:ffff:ffff:ffff:ffff
105ff06:8000::/20ff06:8fff:ffff:ffff:ffff:ffff:ffff:ffff
106ff06:9000::/20ff06:9fff:ffff:ffff:ffff:ffff:ffff:ffff
107ff06:a000::/20ff06:afff:ffff:ffff:ffff:ffff:ffff:ffff
108ff06:b000::/20ff06:bfff:ffff:ffff:ffff:ffff:ffff:ffff
109ff06:c000::/20ff06:cfff:ffff:ffff:ffff:ffff:ffff:ffff
110ff06:d000::/20ff06:dfff:ffff:ffff:ffff:ffff:ffff:ffff
111ff06:e000::/20ff06:efff:ffff:ffff:ffff:ffff:ffff:ffff
112ff06:f000::/20ff06:ffff:ffff:ffff:ffff:ffff:ffff:ffff
113ff07::/20ff07:fff:ffff:ffff:ffff:ffff:ffff:ffff
114ff07:1000::/20ff07:1fff:ffff:ffff:ffff:ffff:ffff:ffff
115ff07:2000::/20ff07:2fff:ffff:ffff:ffff:ffff:ffff:ffff
116ff07:3000::/20ff07:3fff:ffff:ffff:ffff:ffff:ffff:ffff
117ff07:4000::/20ff07:4fff:ffff:ffff:ffff:ffff:ffff:ffff
118ff07:5000::/20ff07:5fff:ffff:ffff:ffff:ffff:ffff:ffff
119ff07:6000::/20ff07:6fff:ffff:ffff:ffff:ffff:ffff:ffff
120ff07:7000::/20ff07:7fff:ffff:ffff:ffff:ffff:ffff:ffff
121ff07:8000::/20ff07:8fff:ffff:ffff:ffff:ffff:ffff:ffff
122ff07:9000::/20ff07:9fff:ffff:ffff:ffff:ffff:ffff:ffff
123ff07:a000::/20ff07:afff:ffff:ffff:ffff:ffff:ffff:ffff
124ff07:b000::/20ff07:bfff:ffff:ffff:ffff:ffff:ffff:ffff
125ff07:c000::/20ff07:cfff:ffff:ffff:ffff:ffff:ffff:ffff
126ff07:d000::/20ff07:dfff:ffff:ffff:ffff:ffff:ffff:ffff
127ff07:e000::/20ff07:efff:ffff:ffff:ffff:ffff:ffff:ffff
128ff07:f000::/20ff07:ffff:ffff:ffff:ffff:ffff:ffff:ffff
129ff08::/20ff08:fff:ffff:ffff:ffff:ffff:ffff:ffff
130ff08:1000::/20ff08:1fff:ffff:ffff:ffff:ffff:ffff:ffff
131ff08:2000::/20ff08:2fff:ffff:ffff:ffff:ffff:ffff:ffff
132ff08:3000::/20ff08:3fff:ffff:ffff:ffff:ffff:ffff:ffff
133ff08:4000::/20ff08:4fff:ffff:ffff:ffff:ffff:ffff:ffff
134ff08:5000::/20ff08:5fff:ffff:ffff:ffff:ffff:ffff:ffff
135ff08:6000::/20ff08:6fff:ffff:ffff:ffff:ffff:ffff:ffff
136ff08:7000::/20ff08:7fff:ffff:ffff:ffff:ffff:ffff:ffff
137ff08:8000::/20ff08:8fff:ffff:ffff:ffff:ffff:ffff:ffff
138ff08:9000::/20ff08:9fff:ffff:ffff:ffff:ffff:ffff:ffff
139ff08:a000::/20ff08:afff:ffff:ffff:ffff:ffff:ffff:ffff
140ff08:b000::/20ff08:bfff:ffff:ffff:ffff:ffff:ffff:ffff
141ff08:c000::/20ff08:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142ff08:d000::/20ff08:dfff:ffff:ffff:ffff:ffff:ffff:ffff
143ff08:e000::/20ff08:efff:ffff:ffff:ffff:ffff:ffff:ffff
144ff08:f000::/20ff08:ffff:ffff:ffff:ffff:ffff:ffff:ffff
145ff09::/20ff09:fff:ffff:ffff:ffff:ffff:ffff:ffff
146ff09:1000::/20ff09:1fff:ffff:ffff:ffff:ffff:ffff:ffff
147ff09:2000::/20ff09:2fff:ffff:ffff:ffff:ffff:ffff:ffff
148ff09:3000::/20ff09:3fff:ffff:ffff:ffff:ffff:ffff:ffff
149ff09:4000::/20ff09:4fff:ffff:ffff:ffff:ffff:ffff:ffff
150ff09:5000::/20ff09:5fff:ffff:ffff:ffff:ffff:ffff:ffff
151ff09:6000::/20ff09:6fff:ffff:ffff:ffff:ffff:ffff:ffff
152ff09:7000::/20ff09:7fff:ffff:ffff:ffff:ffff:ffff:ffff
153ff09:8000::/20ff09:8fff:ffff:ffff:ffff:ffff:ffff:ffff
154ff09:9000::/20ff09:9fff:ffff:ffff:ffff:ffff:ffff:ffff
155ff09:a000::/20ff09:afff:ffff:ffff:ffff:ffff:ffff:ffff
156ff09:b000::/20ff09:bfff:ffff:ffff:ffff:ffff:ffff:ffff
157ff09:c000::/20ff09:cfff:ffff:ffff:ffff:ffff:ffff:ffff
158ff09:d000::/20ff09:dfff:ffff:ffff:ffff:ffff:ffff:ffff
159ff09:e000::/20ff09:efff:ffff:ffff:ffff:ffff:ffff:ffff
160ff09:f000::/20ff09:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161ff0a::/20ff0a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162ff0a:1000::/20ff0a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163ff0a:2000::/20ff0a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164ff0a:3000::/20ff0a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165ff0a:4000::/20ff0a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166ff0a:5000::/20ff0a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167ff0a:6000::/20ff0a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168ff0a:7000::/20ff0a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169ff0a:8000::/20ff0a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170ff0a:9000::/20ff0a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171ff0a:a000::/20ff0a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172ff0a:b000::/20ff0a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173ff0a:c000::/20ff0a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174ff0a:d000::/20ff0a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175ff0a:e000::/20ff0a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176ff0a:f000::/20ff0a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177ff0b::/20ff0b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178ff0b:1000::/20ff0b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179ff0b:2000::/20ff0b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180ff0b:3000::/20ff0b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181ff0b:4000::/20ff0b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182ff0b:5000::/20ff0b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183ff0b:6000::/20ff0b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184ff0b:7000::/20ff0b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185ff0b:8000::/20ff0b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186ff0b:9000::/20ff0b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187ff0b:a000::/20ff0b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188ff0b:b000::/20ff0b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189ff0b:c000::/20ff0b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190ff0b:d000::/20ff0b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191ff0b:e000::/20ff0b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192ff0b:f000::/20ff0b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193ff0c::/20ff0c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194ff0c:1000::/20ff0c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195ff0c:2000::/20ff0c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196ff0c:3000::/20ff0c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197ff0c:4000::/20ff0c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198ff0c:5000::/20ff0c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199ff0c:6000::/20ff0c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200ff0c:7000::/20ff0c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201ff0c:8000::/20ff0c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202ff0c:9000::/20ff0c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203ff0c:a000::/20ff0c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204ff0c:b000::/20ff0c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205ff0c:c000::/20ff0c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206ff0c:d000::/20ff0c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207ff0c:e000::/20ff0c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208ff0c:f000::/20ff0c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209ff0d::/20ff0d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210ff0d:1000::/20ff0d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211ff0d:2000::/20ff0d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212ff0d:3000::/20ff0d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213ff0d:4000::/20ff0d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214ff0d:5000::/20ff0d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215ff0d:6000::/20ff0d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216ff0d:7000::/20ff0d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217ff0d:8000::/20ff0d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218ff0d:9000::/20ff0d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219ff0d:a000::/20ff0d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220ff0d:b000::/20ff0d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221ff0d:c000::/20ff0d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222ff0d:d000::/20ff0d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223ff0d:e000::/20ff0d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224ff0d:f000::/20ff0d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225ff0e::/20ff0e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226ff0e:1000::/20ff0e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227ff0e:2000::/20ff0e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228ff0e:3000::/20ff0e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229ff0e:4000::/20ff0e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230ff0e:5000::/20ff0e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231ff0e:6000::/20ff0e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232ff0e:7000::/20ff0e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233ff0e:8000::/20ff0e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234ff0e:9000::/20ff0e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235ff0e:a000::/20ff0e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236ff0e:b000::/20ff0e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237ff0e:c000::/20ff0e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238ff0e:d000::/20ff0e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239ff0e:e000::/20ff0e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240ff0e:f000::/20ff0e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241ff0f::/20ff0f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242ff0f:1000::/20ff0f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243ff0f:2000::/20ff0f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244ff0f:3000::/20ff0f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245ff0f:4000::/20ff0f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246ff0f:5000::/20ff0f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247ff0f:6000::/20ff0f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248ff0f:7000::/20ff0f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249ff0f:8000::/20ff0f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250ff0f:9000::/20ff0f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251ff0f:a000::/20ff0f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252ff0f:b000::/20ff0f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253ff0f:c000::/20ff0f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254ff0f:d000::/20ff0f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255ff0f:e000::/20ff0f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256ff0f:f000::/20ff0f: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.