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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/20
Addresses2^108
/64 networks2^44
Network
ff04::/20
First address
ff04::
Last address
ff04:fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
ff04:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
0.4.0.f.f.ip6.arpa
Split into smaller subnets/32
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

ff04::/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1ff04::/32ff04:0:ffff:ffff:ffff:ffff:ffff:ffff
2ff04:1::/32ff04:1:ffff:ffff:ffff:ffff:ffff:ffff
3ff04:2::/32ff04:2:ffff:ffff:ffff:ffff:ffff:ffff
4ff04:3::/32ff04:3:ffff:ffff:ffff:ffff:ffff:ffff
5ff04:4::/32ff04:4:ffff:ffff:ffff:ffff:ffff:ffff
6ff04:5::/32ff04:5:ffff:ffff:ffff:ffff:ffff:ffff
7ff04:6::/32ff04:6:ffff:ffff:ffff:ffff:ffff:ffff
8ff04:7::/32ff04:7:ffff:ffff:ffff:ffff:ffff:ffff
9ff04:8::/32ff04:8:ffff:ffff:ffff:ffff:ffff:ffff
10ff04:9::/32ff04:9:ffff:ffff:ffff:ffff:ffff:ffff
11ff04:a::/32ff04:a:ffff:ffff:ffff:ffff:ffff:ffff
12ff04:b::/32ff04:b:ffff:ffff:ffff:ffff:ffff:ffff
13ff04:c::/32ff04:c:ffff:ffff:ffff:ffff:ffff:ffff
14ff04:d::/32ff04:d:ffff:ffff:ffff:ffff:ffff:ffff
15ff04:e::/32ff04:e:ffff:ffff:ffff:ffff:ffff:ffff
16ff04:f::/32ff04:f:ffff:ffff:ffff:ffff:ffff:ffff
17ff04:10::/32ff04:10:ffff:ffff:ffff:ffff:ffff:ffff
18ff04:11::/32ff04:11:ffff:ffff:ffff:ffff:ffff:ffff
19ff04:12::/32ff04:12:ffff:ffff:ffff:ffff:ffff:ffff
20ff04:13::/32ff04:13:ffff:ffff:ffff:ffff:ffff:ffff
21ff04:14::/32ff04:14:ffff:ffff:ffff:ffff:ffff:ffff
22ff04:15::/32ff04:15:ffff:ffff:ffff:ffff:ffff:ffff
23ff04:16::/32ff04:16:ffff:ffff:ffff:ffff:ffff:ffff
24ff04:17::/32ff04:17:ffff:ffff:ffff:ffff:ffff:ffff
25ff04:18::/32ff04:18:ffff:ffff:ffff:ffff:ffff:ffff
26ff04:19::/32ff04:19:ffff:ffff:ffff:ffff:ffff:ffff
27ff04:1a::/32ff04:1a:ffff:ffff:ffff:ffff:ffff:ffff
28ff04:1b::/32ff04:1b:ffff:ffff:ffff:ffff:ffff:ffff
29ff04:1c::/32ff04:1c:ffff:ffff:ffff:ffff:ffff:ffff
30ff04:1d::/32ff04:1d:ffff:ffff:ffff:ffff:ffff:ffff
31ff04:1e::/32ff04:1e:ffff:ffff:ffff:ffff:ffff:ffff
32ff04:1f::/32ff04:1f:ffff:ffff:ffff:ffff:ffff:ffff
33ff04:20::/32ff04:20:ffff:ffff:ffff:ffff:ffff:ffff
34ff04:21::/32ff04:21:ffff:ffff:ffff:ffff:ffff:ffff
35ff04:22::/32ff04:22:ffff:ffff:ffff:ffff:ffff:ffff
36ff04:23::/32ff04:23:ffff:ffff:ffff:ffff:ffff:ffff
37ff04:24::/32ff04:24:ffff:ffff:ffff:ffff:ffff:ffff
38ff04:25::/32ff04:25:ffff:ffff:ffff:ffff:ffff:ffff
39ff04:26::/32ff04:26:ffff:ffff:ffff:ffff:ffff:ffff
40ff04:27::/32ff04:27:ffff:ffff:ffff:ffff:ffff:ffff
41ff04:28::/32ff04:28:ffff:ffff:ffff:ffff:ffff:ffff
42ff04:29::/32ff04:29:ffff:ffff:ffff:ffff:ffff:ffff
43ff04:2a::/32ff04:2a:ffff:ffff:ffff:ffff:ffff:ffff
44ff04:2b::/32ff04:2b:ffff:ffff:ffff:ffff:ffff:ffff
45ff04:2c::/32ff04:2c:ffff:ffff:ffff:ffff:ffff:ffff
46ff04:2d::/32ff04:2d:ffff:ffff:ffff:ffff:ffff:ffff
47ff04:2e::/32ff04:2e:ffff:ffff:ffff:ffff:ffff:ffff
48ff04:2f::/32ff04:2f:ffff:ffff:ffff:ffff:ffff:ffff
49ff04:30::/32ff04:30:ffff:ffff:ffff:ffff:ffff:ffff
50ff04:31::/32ff04:31:ffff:ffff:ffff:ffff:ffff:ffff
51ff04:32::/32ff04:32:ffff:ffff:ffff:ffff:ffff:ffff
52ff04:33::/32ff04:33:ffff:ffff:ffff:ffff:ffff:ffff
53ff04:34::/32ff04:34:ffff:ffff:ffff:ffff:ffff:ffff
54ff04:35::/32ff04:35:ffff:ffff:ffff:ffff:ffff:ffff
55ff04:36::/32ff04:36:ffff:ffff:ffff:ffff:ffff:ffff
56ff04:37::/32ff04:37:ffff:ffff:ffff:ffff:ffff:ffff
57ff04:38::/32ff04:38:ffff:ffff:ffff:ffff:ffff:ffff
58ff04:39::/32ff04:39:ffff:ffff:ffff:ffff:ffff:ffff
59ff04:3a::/32ff04:3a:ffff:ffff:ffff:ffff:ffff:ffff
60ff04:3b::/32ff04:3b:ffff:ffff:ffff:ffff:ffff:ffff
61ff04:3c::/32ff04:3c:ffff:ffff:ffff:ffff:ffff:ffff
62ff04:3d::/32ff04:3d:ffff:ffff:ffff:ffff:ffff:ffff
63ff04:3e::/32ff04:3e:ffff:ffff:ffff:ffff:ffff:ffff
64ff04:3f::/32ff04:3f:ffff:ffff:ffff:ffff:ffff:ffff
65ff04:40::/32ff04:40:ffff:ffff:ffff:ffff:ffff:ffff
66ff04:41::/32ff04:41:ffff:ffff:ffff:ffff:ffff:ffff
67ff04:42::/32ff04:42:ffff:ffff:ffff:ffff:ffff:ffff
68ff04:43::/32ff04:43:ffff:ffff:ffff:ffff:ffff:ffff
69ff04:44::/32ff04:44:ffff:ffff:ffff:ffff:ffff:ffff
70ff04:45::/32ff04:45:ffff:ffff:ffff:ffff:ffff:ffff
71ff04:46::/32ff04:46:ffff:ffff:ffff:ffff:ffff:ffff
72ff04:47::/32ff04:47:ffff:ffff:ffff:ffff:ffff:ffff
73ff04:48::/32ff04:48:ffff:ffff:ffff:ffff:ffff:ffff
74ff04:49::/32ff04:49:ffff:ffff:ffff:ffff:ffff:ffff
75ff04:4a::/32ff04:4a:ffff:ffff:ffff:ffff:ffff:ffff
76ff04:4b::/32ff04:4b:ffff:ffff:ffff:ffff:ffff:ffff
77ff04:4c::/32ff04:4c:ffff:ffff:ffff:ffff:ffff:ffff
78ff04:4d::/32ff04:4d:ffff:ffff:ffff:ffff:ffff:ffff
79ff04:4e::/32ff04:4e:ffff:ffff:ffff:ffff:ffff:ffff
80ff04:4f::/32ff04:4f:ffff:ffff:ffff:ffff:ffff:ffff
81ff04:50::/32ff04:50:ffff:ffff:ffff:ffff:ffff:ffff
82ff04:51::/32ff04:51:ffff:ffff:ffff:ffff:ffff:ffff
83ff04:52::/32ff04:52:ffff:ffff:ffff:ffff:ffff:ffff
84ff04:53::/32ff04:53:ffff:ffff:ffff:ffff:ffff:ffff
85ff04:54::/32ff04:54:ffff:ffff:ffff:ffff:ffff:ffff
86ff04:55::/32ff04:55:ffff:ffff:ffff:ffff:ffff:ffff
87ff04:56::/32ff04:56:ffff:ffff:ffff:ffff:ffff:ffff
88ff04:57::/32ff04:57:ffff:ffff:ffff:ffff:ffff:ffff
89ff04:58::/32ff04:58:ffff:ffff:ffff:ffff:ffff:ffff
90ff04:59::/32ff04:59:ffff:ffff:ffff:ffff:ffff:ffff
91ff04:5a::/32ff04:5a:ffff:ffff:ffff:ffff:ffff:ffff
92ff04:5b::/32ff04:5b:ffff:ffff:ffff:ffff:ffff:ffff
93ff04:5c::/32ff04:5c:ffff:ffff:ffff:ffff:ffff:ffff
94ff04:5d::/32ff04:5d:ffff:ffff:ffff:ffff:ffff:ffff
95ff04:5e::/32ff04:5e:ffff:ffff:ffff:ffff:ffff:ffff
96ff04:5f::/32ff04:5f:ffff:ffff:ffff:ffff:ffff:ffff
97ff04:60::/32ff04:60:ffff:ffff:ffff:ffff:ffff:ffff
98ff04:61::/32ff04:61:ffff:ffff:ffff:ffff:ffff:ffff
99ff04:62::/32ff04:62:ffff:ffff:ffff:ffff:ffff:ffff
100ff04:63::/32ff04:63:ffff:ffff:ffff:ffff:ffff:ffff
101ff04:64::/32ff04:64:ffff:ffff:ffff:ffff:ffff:ffff
102ff04:65::/32ff04:65:ffff:ffff:ffff:ffff:ffff:ffff
103ff04:66::/32ff04:66:ffff:ffff:ffff:ffff:ffff:ffff
104ff04:67::/32ff04:67:ffff:ffff:ffff:ffff:ffff:ffff
105ff04:68::/32ff04:68:ffff:ffff:ffff:ffff:ffff:ffff
106ff04:69::/32ff04:69:ffff:ffff:ffff:ffff:ffff:ffff
107ff04:6a::/32ff04:6a:ffff:ffff:ffff:ffff:ffff:ffff
108ff04:6b::/32ff04:6b:ffff:ffff:ffff:ffff:ffff:ffff
109ff04:6c::/32ff04:6c:ffff:ffff:ffff:ffff:ffff:ffff
110ff04:6d::/32ff04:6d:ffff:ffff:ffff:ffff:ffff:ffff
111ff04:6e::/32ff04:6e:ffff:ffff:ffff:ffff:ffff:ffff
112ff04:6f::/32ff04:6f:ffff:ffff:ffff:ffff:ffff:ffff
113ff04:70::/32ff04:70:ffff:ffff:ffff:ffff:ffff:ffff
114ff04:71::/32ff04:71:ffff:ffff:ffff:ffff:ffff:ffff
115ff04:72::/32ff04:72:ffff:ffff:ffff:ffff:ffff:ffff
116ff04:73::/32ff04:73:ffff:ffff:ffff:ffff:ffff:ffff
117ff04:74::/32ff04:74:ffff:ffff:ffff:ffff:ffff:ffff
118ff04:75::/32ff04:75:ffff:ffff:ffff:ffff:ffff:ffff
119ff04:76::/32ff04:76:ffff:ffff:ffff:ffff:ffff:ffff
120ff04:77::/32ff04:77:ffff:ffff:ffff:ffff:ffff:ffff
121ff04:78::/32ff04:78:ffff:ffff:ffff:ffff:ffff:ffff
122ff04:79::/32ff04:79:ffff:ffff:ffff:ffff:ffff:ffff
123ff04:7a::/32ff04:7a:ffff:ffff:ffff:ffff:ffff:ffff
124ff04:7b::/32ff04:7b:ffff:ffff:ffff:ffff:ffff:ffff
125ff04:7c::/32ff04:7c:ffff:ffff:ffff:ffff:ffff:ffff
126ff04:7d::/32ff04:7d:ffff:ffff:ffff:ffff:ffff:ffff
127ff04:7e::/32ff04:7e:ffff:ffff:ffff:ffff:ffff:ffff
128ff04:7f::/32ff04:7f:ffff:ffff:ffff:ffff:ffff:ffff
129ff04:80::/32ff04:80:ffff:ffff:ffff:ffff:ffff:ffff
130ff04:81::/32ff04:81:ffff:ffff:ffff:ffff:ffff:ffff
131ff04:82::/32ff04:82:ffff:ffff:ffff:ffff:ffff:ffff
132ff04:83::/32ff04:83:ffff:ffff:ffff:ffff:ffff:ffff
133ff04:84::/32ff04:84:ffff:ffff:ffff:ffff:ffff:ffff
134ff04:85::/32ff04:85:ffff:ffff:ffff:ffff:ffff:ffff
135ff04:86::/32ff04:86:ffff:ffff:ffff:ffff:ffff:ffff
136ff04:87::/32ff04:87:ffff:ffff:ffff:ffff:ffff:ffff
137ff04:88::/32ff04:88:ffff:ffff:ffff:ffff:ffff:ffff
138ff04:89::/32ff04:89:ffff:ffff:ffff:ffff:ffff:ffff
139ff04:8a::/32ff04:8a:ffff:ffff:ffff:ffff:ffff:ffff
140ff04:8b::/32ff04:8b:ffff:ffff:ffff:ffff:ffff:ffff
141ff04:8c::/32ff04:8c:ffff:ffff:ffff:ffff:ffff:ffff
142ff04:8d::/32ff04:8d:ffff:ffff:ffff:ffff:ffff:ffff
143ff04:8e::/32ff04:8e:ffff:ffff:ffff:ffff:ffff:ffff
144ff04:8f::/32ff04:8f:ffff:ffff:ffff:ffff:ffff:ffff
145ff04:90::/32ff04:90:ffff:ffff:ffff:ffff:ffff:ffff
146ff04:91::/32ff04:91:ffff:ffff:ffff:ffff:ffff:ffff
147ff04:92::/32ff04:92:ffff:ffff:ffff:ffff:ffff:ffff
148ff04:93::/32ff04:93:ffff:ffff:ffff:ffff:ffff:ffff
149ff04:94::/32ff04:94:ffff:ffff:ffff:ffff:ffff:ffff
150ff04:95::/32ff04:95:ffff:ffff:ffff:ffff:ffff:ffff
151ff04:96::/32ff04:96:ffff:ffff:ffff:ffff:ffff:ffff
152ff04:97::/32ff04:97:ffff:ffff:ffff:ffff:ffff:ffff
153ff04:98::/32ff04:98:ffff:ffff:ffff:ffff:ffff:ffff
154ff04:99::/32ff04:99:ffff:ffff:ffff:ffff:ffff:ffff
155ff04:9a::/32ff04:9a:ffff:ffff:ffff:ffff:ffff:ffff
156ff04:9b::/32ff04:9b:ffff:ffff:ffff:ffff:ffff:ffff
157ff04:9c::/32ff04:9c:ffff:ffff:ffff:ffff:ffff:ffff
158ff04:9d::/32ff04:9d:ffff:ffff:ffff:ffff:ffff:ffff
159ff04:9e::/32ff04:9e:ffff:ffff:ffff:ffff:ffff:ffff
160ff04:9f::/32ff04:9f:ffff:ffff:ffff:ffff:ffff:ffff
161ff04:a0::/32ff04:a0:ffff:ffff:ffff:ffff:ffff:ffff
162ff04:a1::/32ff04:a1:ffff:ffff:ffff:ffff:ffff:ffff
163ff04:a2::/32ff04:a2:ffff:ffff:ffff:ffff:ffff:ffff
164ff04:a3::/32ff04:a3:ffff:ffff:ffff:ffff:ffff:ffff
165ff04:a4::/32ff04:a4:ffff:ffff:ffff:ffff:ffff:ffff
166ff04:a5::/32ff04:a5:ffff:ffff:ffff:ffff:ffff:ffff
167ff04:a6::/32ff04:a6:ffff:ffff:ffff:ffff:ffff:ffff
168ff04:a7::/32ff04:a7:ffff:ffff:ffff:ffff:ffff:ffff
169ff04:a8::/32ff04:a8:ffff:ffff:ffff:ffff:ffff:ffff
170ff04:a9::/32ff04:a9:ffff:ffff:ffff:ffff:ffff:ffff
171ff04:aa::/32ff04:aa:ffff:ffff:ffff:ffff:ffff:ffff
172ff04:ab::/32ff04:ab:ffff:ffff:ffff:ffff:ffff:ffff
173ff04:ac::/32ff04:ac:ffff:ffff:ffff:ffff:ffff:ffff
174ff04:ad::/32ff04:ad:ffff:ffff:ffff:ffff:ffff:ffff
175ff04:ae::/32ff04:ae:ffff:ffff:ffff:ffff:ffff:ffff
176ff04:af::/32ff04:af:ffff:ffff:ffff:ffff:ffff:ffff
177ff04:b0::/32ff04:b0:ffff:ffff:ffff:ffff:ffff:ffff
178ff04:b1::/32ff04:b1:ffff:ffff:ffff:ffff:ffff:ffff
179ff04:b2::/32ff04:b2:ffff:ffff:ffff:ffff:ffff:ffff
180ff04:b3::/32ff04:b3:ffff:ffff:ffff:ffff:ffff:ffff
181ff04:b4::/32ff04:b4:ffff:ffff:ffff:ffff:ffff:ffff
182ff04:b5::/32ff04:b5:ffff:ffff:ffff:ffff:ffff:ffff
183ff04:b6::/32ff04:b6:ffff:ffff:ffff:ffff:ffff:ffff
184ff04:b7::/32ff04:b7:ffff:ffff:ffff:ffff:ffff:ffff
185ff04:b8::/32ff04:b8:ffff:ffff:ffff:ffff:ffff:ffff
186ff04:b9::/32ff04:b9:ffff:ffff:ffff:ffff:ffff:ffff
187ff04:ba::/32ff04:ba:ffff:ffff:ffff:ffff:ffff:ffff
188ff04:bb::/32ff04:bb:ffff:ffff:ffff:ffff:ffff:ffff
189ff04:bc::/32ff04:bc:ffff:ffff:ffff:ffff:ffff:ffff
190ff04:bd::/32ff04:bd:ffff:ffff:ffff:ffff:ffff:ffff
191ff04:be::/32ff04:be:ffff:ffff:ffff:ffff:ffff:ffff
192ff04:bf::/32ff04:bf:ffff:ffff:ffff:ffff:ffff:ffff
193ff04:c0::/32ff04:c0:ffff:ffff:ffff:ffff:ffff:ffff
194ff04:c1::/32ff04:c1:ffff:ffff:ffff:ffff:ffff:ffff
195ff04:c2::/32ff04:c2:ffff:ffff:ffff:ffff:ffff:ffff
196ff04:c3::/32ff04:c3:ffff:ffff:ffff:ffff:ffff:ffff
197ff04:c4::/32ff04:c4:ffff:ffff:ffff:ffff:ffff:ffff
198ff04:c5::/32ff04:c5:ffff:ffff:ffff:ffff:ffff:ffff
199ff04:c6::/32ff04:c6:ffff:ffff:ffff:ffff:ffff:ffff
200ff04:c7::/32ff04:c7:ffff:ffff:ffff:ffff:ffff:ffff
201ff04:c8::/32ff04:c8:ffff:ffff:ffff:ffff:ffff:ffff
202ff04:c9::/32ff04:c9:ffff:ffff:ffff:ffff:ffff:ffff
203ff04:ca::/32ff04:ca:ffff:ffff:ffff:ffff:ffff:ffff
204ff04:cb::/32ff04:cb:ffff:ffff:ffff:ffff:ffff:ffff
205ff04:cc::/32ff04:cc:ffff:ffff:ffff:ffff:ffff:ffff
206ff04:cd::/32ff04:cd:ffff:ffff:ffff:ffff:ffff:ffff
207ff04:ce::/32ff04:ce:ffff:ffff:ffff:ffff:ffff:ffff
208ff04:cf::/32ff04:cf:ffff:ffff:ffff:ffff:ffff:ffff
209ff04:d0::/32ff04:d0:ffff:ffff:ffff:ffff:ffff:ffff
210ff04:d1::/32ff04:d1:ffff:ffff:ffff:ffff:ffff:ffff
211ff04:d2::/32ff04:d2:ffff:ffff:ffff:ffff:ffff:ffff
212ff04:d3::/32ff04:d3:ffff:ffff:ffff:ffff:ffff:ffff
213ff04:d4::/32ff04:d4:ffff:ffff:ffff:ffff:ffff:ffff
214ff04:d5::/32ff04:d5:ffff:ffff:ffff:ffff:ffff:ffff
215ff04:d6::/32ff04:d6:ffff:ffff:ffff:ffff:ffff:ffff
216ff04:d7::/32ff04:d7:ffff:ffff:ffff:ffff:ffff:ffff
217ff04:d8::/32ff04:d8:ffff:ffff:ffff:ffff:ffff:ffff
218ff04:d9::/32ff04:d9:ffff:ffff:ffff:ffff:ffff:ffff
219ff04:da::/32ff04:da:ffff:ffff:ffff:ffff:ffff:ffff
220ff04:db::/32ff04:db:ffff:ffff:ffff:ffff:ffff:ffff
221ff04:dc::/32ff04:dc:ffff:ffff:ffff:ffff:ffff:ffff
222ff04:dd::/32ff04:dd:ffff:ffff:ffff:ffff:ffff:ffff
223ff04:de::/32ff04:de:ffff:ffff:ffff:ffff:ffff:ffff
224ff04:df::/32ff04:df:ffff:ffff:ffff:ffff:ffff:ffff
225ff04:e0::/32ff04:e0:ffff:ffff:ffff:ffff:ffff:ffff
226ff04:e1::/32ff04:e1:ffff:ffff:ffff:ffff:ffff:ffff
227ff04:e2::/32ff04:e2:ffff:ffff:ffff:ffff:ffff:ffff
228ff04:e3::/32ff04:e3:ffff:ffff:ffff:ffff:ffff:ffff
229ff04:e4::/32ff04:e4:ffff:ffff:ffff:ffff:ffff:ffff
230ff04:e5::/32ff04:e5:ffff:ffff:ffff:ffff:ffff:ffff
231ff04:e6::/32ff04:e6:ffff:ffff:ffff:ffff:ffff:ffff
232ff04:e7::/32ff04:e7:ffff:ffff:ffff:ffff:ffff:ffff
233ff04:e8::/32ff04:e8:ffff:ffff:ffff:ffff:ffff:ffff
234ff04:e9::/32ff04:e9:ffff:ffff:ffff:ffff:ffff:ffff
235ff04:ea::/32ff04:ea:ffff:ffff:ffff:ffff:ffff:ffff
236ff04:eb::/32ff04:eb:ffff:ffff:ffff:ffff:ffff:ffff
237ff04:ec::/32ff04:ec:ffff:ffff:ffff:ffff:ffff:ffff
238ff04:ed::/32ff04:ed:ffff:ffff:ffff:ffff:ffff:ffff
239ff04:ee::/32ff04:ee:ffff:ffff:ffff:ffff:ffff:ffff
240ff04:ef::/32ff04:ef:ffff:ffff:ffff:ffff:ffff:ffff
241ff04:f0::/32ff04:f0:ffff:ffff:ffff:ffff:ffff:ffff
242ff04:f1::/32ff04:f1:ffff:ffff:ffff:ffff:ffff:ffff
243ff04:f2::/32ff04:f2:ffff:ffff:ffff:ffff:ffff:ffff
244ff04:f3::/32ff04:f3:ffff:ffff:ffff:ffff:ffff:ffff
245ff04:f4::/32ff04:f4:ffff:ffff:ffff:ffff:ffff:ffff
246ff04:f5::/32ff04:f5:ffff:ffff:ffff:ffff:ffff:ffff
247ff04:f6::/32ff04:f6:ffff:ffff:ffff:ffff:ffff:ffff
248ff04:f7::/32ff04:f7:ffff:ffff:ffff:ffff:ffff:ffff
249ff04:f8::/32ff04:f8:ffff:ffff:ffff:ffff:ffff:ffff
250ff04:f9::/32ff04:f9:ffff:ffff:ffff:ffff:ffff:ffff
251ff04:fa::/32ff04:fa:ffff:ffff:ffff:ffff:ffff:ffff
252ff04:fb::/32ff04:fb:ffff:ffff:ffff:ffff:ffff:ffff
253ff04:fc::/32ff04:fc:ffff:ffff:ffff:ffff:ffff:ffff
254ff04:fd::/32ff04:fd:ffff:ffff:ffff:ffff:ffff:ffff
255ff04:fe::/32ff04:fe:ffff:ffff:ffff:ffff:ffff:ffff
256ff04:ff::/32ff04:ff: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.