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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
ff16::/16
First address
ff16::
Last address
ff16: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
ff16:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
6.1.f.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ff16::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1ff16::/32ff16:0:ffff:ffff:ffff:ffff:ffff:ffff
2ff16:1::/32ff16:1:ffff:ffff:ffff:ffff:ffff:ffff
3ff16:2::/32ff16:2:ffff:ffff:ffff:ffff:ffff:ffff
4ff16:3::/32ff16:3:ffff:ffff:ffff:ffff:ffff:ffff
5ff16:4::/32ff16:4:ffff:ffff:ffff:ffff:ffff:ffff
6ff16:5::/32ff16:5:ffff:ffff:ffff:ffff:ffff:ffff
7ff16:6::/32ff16:6:ffff:ffff:ffff:ffff:ffff:ffff
8ff16:7::/32ff16:7:ffff:ffff:ffff:ffff:ffff:ffff
9ff16:8::/32ff16:8:ffff:ffff:ffff:ffff:ffff:ffff
10ff16:9::/32ff16:9:ffff:ffff:ffff:ffff:ffff:ffff
11ff16:a::/32ff16:a:ffff:ffff:ffff:ffff:ffff:ffff
12ff16:b::/32ff16:b:ffff:ffff:ffff:ffff:ffff:ffff
13ff16:c::/32ff16:c:ffff:ffff:ffff:ffff:ffff:ffff
14ff16:d::/32ff16:d:ffff:ffff:ffff:ffff:ffff:ffff
15ff16:e::/32ff16:e:ffff:ffff:ffff:ffff:ffff:ffff
16ff16:f::/32ff16:f:ffff:ffff:ffff:ffff:ffff:ffff
17ff16:10::/32ff16:10:ffff:ffff:ffff:ffff:ffff:ffff
18ff16:11::/32ff16:11:ffff:ffff:ffff:ffff:ffff:ffff
19ff16:12::/32ff16:12:ffff:ffff:ffff:ffff:ffff:ffff
20ff16:13::/32ff16:13:ffff:ffff:ffff:ffff:ffff:ffff
21ff16:14::/32ff16:14:ffff:ffff:ffff:ffff:ffff:ffff
22ff16:15::/32ff16:15:ffff:ffff:ffff:ffff:ffff:ffff
23ff16:16::/32ff16:16:ffff:ffff:ffff:ffff:ffff:ffff
24ff16:17::/32ff16:17:ffff:ffff:ffff:ffff:ffff:ffff
25ff16:18::/32ff16:18:ffff:ffff:ffff:ffff:ffff:ffff
26ff16:19::/32ff16:19:ffff:ffff:ffff:ffff:ffff:ffff
27ff16:1a::/32ff16:1a:ffff:ffff:ffff:ffff:ffff:ffff
28ff16:1b::/32ff16:1b:ffff:ffff:ffff:ffff:ffff:ffff
29ff16:1c::/32ff16:1c:ffff:ffff:ffff:ffff:ffff:ffff
30ff16:1d::/32ff16:1d:ffff:ffff:ffff:ffff:ffff:ffff
31ff16:1e::/32ff16:1e:ffff:ffff:ffff:ffff:ffff:ffff
32ff16:1f::/32ff16:1f:ffff:ffff:ffff:ffff:ffff:ffff
33ff16:20::/32ff16:20:ffff:ffff:ffff:ffff:ffff:ffff
34ff16:21::/32ff16:21:ffff:ffff:ffff:ffff:ffff:ffff
35ff16:22::/32ff16:22:ffff:ffff:ffff:ffff:ffff:ffff
36ff16:23::/32ff16:23:ffff:ffff:ffff:ffff:ffff:ffff
37ff16:24::/32ff16:24:ffff:ffff:ffff:ffff:ffff:ffff
38ff16:25::/32ff16:25:ffff:ffff:ffff:ffff:ffff:ffff
39ff16:26::/32ff16:26:ffff:ffff:ffff:ffff:ffff:ffff
40ff16:27::/32ff16:27:ffff:ffff:ffff:ffff:ffff:ffff
41ff16:28::/32ff16:28:ffff:ffff:ffff:ffff:ffff:ffff
42ff16:29::/32ff16:29:ffff:ffff:ffff:ffff:ffff:ffff
43ff16:2a::/32ff16:2a:ffff:ffff:ffff:ffff:ffff:ffff
44ff16:2b::/32ff16:2b:ffff:ffff:ffff:ffff:ffff:ffff
45ff16:2c::/32ff16:2c:ffff:ffff:ffff:ffff:ffff:ffff
46ff16:2d::/32ff16:2d:ffff:ffff:ffff:ffff:ffff:ffff
47ff16:2e::/32ff16:2e:ffff:ffff:ffff:ffff:ffff:ffff
48ff16:2f::/32ff16:2f:ffff:ffff:ffff:ffff:ffff:ffff
49ff16:30::/32ff16:30:ffff:ffff:ffff:ffff:ffff:ffff
50ff16:31::/32ff16:31:ffff:ffff:ffff:ffff:ffff:ffff
51ff16:32::/32ff16:32:ffff:ffff:ffff:ffff:ffff:ffff
52ff16:33::/32ff16:33:ffff:ffff:ffff:ffff:ffff:ffff
53ff16:34::/32ff16:34:ffff:ffff:ffff:ffff:ffff:ffff
54ff16:35::/32ff16:35:ffff:ffff:ffff:ffff:ffff:ffff
55ff16:36::/32ff16:36:ffff:ffff:ffff:ffff:ffff:ffff
56ff16:37::/32ff16:37:ffff:ffff:ffff:ffff:ffff:ffff
57ff16:38::/32ff16:38:ffff:ffff:ffff:ffff:ffff:ffff
58ff16:39::/32ff16:39:ffff:ffff:ffff:ffff:ffff:ffff
59ff16:3a::/32ff16:3a:ffff:ffff:ffff:ffff:ffff:ffff
60ff16:3b::/32ff16:3b:ffff:ffff:ffff:ffff:ffff:ffff
61ff16:3c::/32ff16:3c:ffff:ffff:ffff:ffff:ffff:ffff
62ff16:3d::/32ff16:3d:ffff:ffff:ffff:ffff:ffff:ffff
63ff16:3e::/32ff16:3e:ffff:ffff:ffff:ffff:ffff:ffff
64ff16:3f::/32ff16:3f:ffff:ffff:ffff:ffff:ffff:ffff
65ff16:40::/32ff16:40:ffff:ffff:ffff:ffff:ffff:ffff
66ff16:41::/32ff16:41:ffff:ffff:ffff:ffff:ffff:ffff
67ff16:42::/32ff16:42:ffff:ffff:ffff:ffff:ffff:ffff
68ff16:43::/32ff16:43:ffff:ffff:ffff:ffff:ffff:ffff
69ff16:44::/32ff16:44:ffff:ffff:ffff:ffff:ffff:ffff
70ff16:45::/32ff16:45:ffff:ffff:ffff:ffff:ffff:ffff
71ff16:46::/32ff16:46:ffff:ffff:ffff:ffff:ffff:ffff
72ff16:47::/32ff16:47:ffff:ffff:ffff:ffff:ffff:ffff
73ff16:48::/32ff16:48:ffff:ffff:ffff:ffff:ffff:ffff
74ff16:49::/32ff16:49:ffff:ffff:ffff:ffff:ffff:ffff
75ff16:4a::/32ff16:4a:ffff:ffff:ffff:ffff:ffff:ffff
76ff16:4b::/32ff16:4b:ffff:ffff:ffff:ffff:ffff:ffff
77ff16:4c::/32ff16:4c:ffff:ffff:ffff:ffff:ffff:ffff
78ff16:4d::/32ff16:4d:ffff:ffff:ffff:ffff:ffff:ffff
79ff16:4e::/32ff16:4e:ffff:ffff:ffff:ffff:ffff:ffff
80ff16:4f::/32ff16:4f:ffff:ffff:ffff:ffff:ffff:ffff
81ff16:50::/32ff16:50:ffff:ffff:ffff:ffff:ffff:ffff
82ff16:51::/32ff16:51:ffff:ffff:ffff:ffff:ffff:ffff
83ff16:52::/32ff16:52:ffff:ffff:ffff:ffff:ffff:ffff
84ff16:53::/32ff16:53:ffff:ffff:ffff:ffff:ffff:ffff
85ff16:54::/32ff16:54:ffff:ffff:ffff:ffff:ffff:ffff
86ff16:55::/32ff16:55:ffff:ffff:ffff:ffff:ffff:ffff
87ff16:56::/32ff16:56:ffff:ffff:ffff:ffff:ffff:ffff
88ff16:57::/32ff16:57:ffff:ffff:ffff:ffff:ffff:ffff
89ff16:58::/32ff16:58:ffff:ffff:ffff:ffff:ffff:ffff
90ff16:59::/32ff16:59:ffff:ffff:ffff:ffff:ffff:ffff
91ff16:5a::/32ff16:5a:ffff:ffff:ffff:ffff:ffff:ffff
92ff16:5b::/32ff16:5b:ffff:ffff:ffff:ffff:ffff:ffff
93ff16:5c::/32ff16:5c:ffff:ffff:ffff:ffff:ffff:ffff
94ff16:5d::/32ff16:5d:ffff:ffff:ffff:ffff:ffff:ffff
95ff16:5e::/32ff16:5e:ffff:ffff:ffff:ffff:ffff:ffff
96ff16:5f::/32ff16:5f:ffff:ffff:ffff:ffff:ffff:ffff
97ff16:60::/32ff16:60:ffff:ffff:ffff:ffff:ffff:ffff
98ff16:61::/32ff16:61:ffff:ffff:ffff:ffff:ffff:ffff
99ff16:62::/32ff16:62:ffff:ffff:ffff:ffff:ffff:ffff
100ff16:63::/32ff16:63:ffff:ffff:ffff:ffff:ffff:ffff
101ff16:64::/32ff16:64:ffff:ffff:ffff:ffff:ffff:ffff
102ff16:65::/32ff16:65:ffff:ffff:ffff:ffff:ffff:ffff
103ff16:66::/32ff16:66:ffff:ffff:ffff:ffff:ffff:ffff
104ff16:67::/32ff16:67:ffff:ffff:ffff:ffff:ffff:ffff
105ff16:68::/32ff16:68:ffff:ffff:ffff:ffff:ffff:ffff
106ff16:69::/32ff16:69:ffff:ffff:ffff:ffff:ffff:ffff
107ff16:6a::/32ff16:6a:ffff:ffff:ffff:ffff:ffff:ffff
108ff16:6b::/32ff16:6b:ffff:ffff:ffff:ffff:ffff:ffff
109ff16:6c::/32ff16:6c:ffff:ffff:ffff:ffff:ffff:ffff
110ff16:6d::/32ff16:6d:ffff:ffff:ffff:ffff:ffff:ffff
111ff16:6e::/32ff16:6e:ffff:ffff:ffff:ffff:ffff:ffff
112ff16:6f::/32ff16:6f:ffff:ffff:ffff:ffff:ffff:ffff
113ff16:70::/32ff16:70:ffff:ffff:ffff:ffff:ffff:ffff
114ff16:71::/32ff16:71:ffff:ffff:ffff:ffff:ffff:ffff
115ff16:72::/32ff16:72:ffff:ffff:ffff:ffff:ffff:ffff
116ff16:73::/32ff16:73:ffff:ffff:ffff:ffff:ffff:ffff
117ff16:74::/32ff16:74:ffff:ffff:ffff:ffff:ffff:ffff
118ff16:75::/32ff16:75:ffff:ffff:ffff:ffff:ffff:ffff
119ff16:76::/32ff16:76:ffff:ffff:ffff:ffff:ffff:ffff
120ff16:77::/32ff16:77:ffff:ffff:ffff:ffff:ffff:ffff
121ff16:78::/32ff16:78:ffff:ffff:ffff:ffff:ffff:ffff
122ff16:79::/32ff16:79:ffff:ffff:ffff:ffff:ffff:ffff
123ff16:7a::/32ff16:7a:ffff:ffff:ffff:ffff:ffff:ffff
124ff16:7b::/32ff16:7b:ffff:ffff:ffff:ffff:ffff:ffff
125ff16:7c::/32ff16:7c:ffff:ffff:ffff:ffff:ffff:ffff
126ff16:7d::/32ff16:7d:ffff:ffff:ffff:ffff:ffff:ffff
127ff16:7e::/32ff16:7e:ffff:ffff:ffff:ffff:ffff:ffff
128ff16:7f::/32ff16:7f:ffff:ffff:ffff:ffff:ffff:ffff
129ff16:80::/32ff16:80:ffff:ffff:ffff:ffff:ffff:ffff
130ff16:81::/32ff16:81:ffff:ffff:ffff:ffff:ffff:ffff
131ff16:82::/32ff16:82:ffff:ffff:ffff:ffff:ffff:ffff
132ff16:83::/32ff16:83:ffff:ffff:ffff:ffff:ffff:ffff
133ff16:84::/32ff16:84:ffff:ffff:ffff:ffff:ffff:ffff
134ff16:85::/32ff16:85:ffff:ffff:ffff:ffff:ffff:ffff
135ff16:86::/32ff16:86:ffff:ffff:ffff:ffff:ffff:ffff
136ff16:87::/32ff16:87:ffff:ffff:ffff:ffff:ffff:ffff
137ff16:88::/32ff16:88:ffff:ffff:ffff:ffff:ffff:ffff
138ff16:89::/32ff16:89:ffff:ffff:ffff:ffff:ffff:ffff
139ff16:8a::/32ff16:8a:ffff:ffff:ffff:ffff:ffff:ffff
140ff16:8b::/32ff16:8b:ffff:ffff:ffff:ffff:ffff:ffff
141ff16:8c::/32ff16:8c:ffff:ffff:ffff:ffff:ffff:ffff
142ff16:8d::/32ff16:8d:ffff:ffff:ffff:ffff:ffff:ffff
143ff16:8e::/32ff16:8e:ffff:ffff:ffff:ffff:ffff:ffff
144ff16:8f::/32ff16:8f:ffff:ffff:ffff:ffff:ffff:ffff
145ff16:90::/32ff16:90:ffff:ffff:ffff:ffff:ffff:ffff
146ff16:91::/32ff16:91:ffff:ffff:ffff:ffff:ffff:ffff
147ff16:92::/32ff16:92:ffff:ffff:ffff:ffff:ffff:ffff
148ff16:93::/32ff16:93:ffff:ffff:ffff:ffff:ffff:ffff
149ff16:94::/32ff16:94:ffff:ffff:ffff:ffff:ffff:ffff
150ff16:95::/32ff16:95:ffff:ffff:ffff:ffff:ffff:ffff
151ff16:96::/32ff16:96:ffff:ffff:ffff:ffff:ffff:ffff
152ff16:97::/32ff16:97:ffff:ffff:ffff:ffff:ffff:ffff
153ff16:98::/32ff16:98:ffff:ffff:ffff:ffff:ffff:ffff
154ff16:99::/32ff16:99:ffff:ffff:ffff:ffff:ffff:ffff
155ff16:9a::/32ff16:9a:ffff:ffff:ffff:ffff:ffff:ffff
156ff16:9b::/32ff16:9b:ffff:ffff:ffff:ffff:ffff:ffff
157ff16:9c::/32ff16:9c:ffff:ffff:ffff:ffff:ffff:ffff
158ff16:9d::/32ff16:9d:ffff:ffff:ffff:ffff:ffff:ffff
159ff16:9e::/32ff16:9e:ffff:ffff:ffff:ffff:ffff:ffff
160ff16:9f::/32ff16:9f:ffff:ffff:ffff:ffff:ffff:ffff
161ff16:a0::/32ff16:a0:ffff:ffff:ffff:ffff:ffff:ffff
162ff16:a1::/32ff16:a1:ffff:ffff:ffff:ffff:ffff:ffff
163ff16:a2::/32ff16:a2:ffff:ffff:ffff:ffff:ffff:ffff
164ff16:a3::/32ff16:a3:ffff:ffff:ffff:ffff:ffff:ffff
165ff16:a4::/32ff16:a4:ffff:ffff:ffff:ffff:ffff:ffff
166ff16:a5::/32ff16:a5:ffff:ffff:ffff:ffff:ffff:ffff
167ff16:a6::/32ff16:a6:ffff:ffff:ffff:ffff:ffff:ffff
168ff16:a7::/32ff16:a7:ffff:ffff:ffff:ffff:ffff:ffff
169ff16:a8::/32ff16:a8:ffff:ffff:ffff:ffff:ffff:ffff
170ff16:a9::/32ff16:a9:ffff:ffff:ffff:ffff:ffff:ffff
171ff16:aa::/32ff16:aa:ffff:ffff:ffff:ffff:ffff:ffff
172ff16:ab::/32ff16:ab:ffff:ffff:ffff:ffff:ffff:ffff
173ff16:ac::/32ff16:ac:ffff:ffff:ffff:ffff:ffff:ffff
174ff16:ad::/32ff16:ad:ffff:ffff:ffff:ffff:ffff:ffff
175ff16:ae::/32ff16:ae:ffff:ffff:ffff:ffff:ffff:ffff
176ff16:af::/32ff16:af:ffff:ffff:ffff:ffff:ffff:ffff
177ff16:b0::/32ff16:b0:ffff:ffff:ffff:ffff:ffff:ffff
178ff16:b1::/32ff16:b1:ffff:ffff:ffff:ffff:ffff:ffff
179ff16:b2::/32ff16:b2:ffff:ffff:ffff:ffff:ffff:ffff
180ff16:b3::/32ff16:b3:ffff:ffff:ffff:ffff:ffff:ffff
181ff16:b4::/32ff16:b4:ffff:ffff:ffff:ffff:ffff:ffff
182ff16:b5::/32ff16:b5:ffff:ffff:ffff:ffff:ffff:ffff
183ff16:b6::/32ff16:b6:ffff:ffff:ffff:ffff:ffff:ffff
184ff16:b7::/32ff16:b7:ffff:ffff:ffff:ffff:ffff:ffff
185ff16:b8::/32ff16:b8:ffff:ffff:ffff:ffff:ffff:ffff
186ff16:b9::/32ff16:b9:ffff:ffff:ffff:ffff:ffff:ffff
187ff16:ba::/32ff16:ba:ffff:ffff:ffff:ffff:ffff:ffff
188ff16:bb::/32ff16:bb:ffff:ffff:ffff:ffff:ffff:ffff
189ff16:bc::/32ff16:bc:ffff:ffff:ffff:ffff:ffff:ffff
190ff16:bd::/32ff16:bd:ffff:ffff:ffff:ffff:ffff:ffff
191ff16:be::/32ff16:be:ffff:ffff:ffff:ffff:ffff:ffff
192ff16:bf::/32ff16:bf:ffff:ffff:ffff:ffff:ffff:ffff
193ff16:c0::/32ff16:c0:ffff:ffff:ffff:ffff:ffff:ffff
194ff16:c1::/32ff16:c1:ffff:ffff:ffff:ffff:ffff:ffff
195ff16:c2::/32ff16:c2:ffff:ffff:ffff:ffff:ffff:ffff
196ff16:c3::/32ff16:c3:ffff:ffff:ffff:ffff:ffff:ffff
197ff16:c4::/32ff16:c4:ffff:ffff:ffff:ffff:ffff:ffff
198ff16:c5::/32ff16:c5:ffff:ffff:ffff:ffff:ffff:ffff
199ff16:c6::/32ff16:c6:ffff:ffff:ffff:ffff:ffff:ffff
200ff16:c7::/32ff16:c7:ffff:ffff:ffff:ffff:ffff:ffff
201ff16:c8::/32ff16:c8:ffff:ffff:ffff:ffff:ffff:ffff
202ff16:c9::/32ff16:c9:ffff:ffff:ffff:ffff:ffff:ffff
203ff16:ca::/32ff16:ca:ffff:ffff:ffff:ffff:ffff:ffff
204ff16:cb::/32ff16:cb:ffff:ffff:ffff:ffff:ffff:ffff
205ff16:cc::/32ff16:cc:ffff:ffff:ffff:ffff:ffff:ffff
206ff16:cd::/32ff16:cd:ffff:ffff:ffff:ffff:ffff:ffff
207ff16:ce::/32ff16:ce:ffff:ffff:ffff:ffff:ffff:ffff
208ff16:cf::/32ff16:cf:ffff:ffff:ffff:ffff:ffff:ffff
209ff16:d0::/32ff16:d0:ffff:ffff:ffff:ffff:ffff:ffff
210ff16:d1::/32ff16:d1:ffff:ffff:ffff:ffff:ffff:ffff
211ff16:d2::/32ff16:d2:ffff:ffff:ffff:ffff:ffff:ffff
212ff16:d3::/32ff16:d3:ffff:ffff:ffff:ffff:ffff:ffff
213ff16:d4::/32ff16:d4:ffff:ffff:ffff:ffff:ffff:ffff
214ff16:d5::/32ff16:d5:ffff:ffff:ffff:ffff:ffff:ffff
215ff16:d6::/32ff16:d6:ffff:ffff:ffff:ffff:ffff:ffff
216ff16:d7::/32ff16:d7:ffff:ffff:ffff:ffff:ffff:ffff
217ff16:d8::/32ff16:d8:ffff:ffff:ffff:ffff:ffff:ffff
218ff16:d9::/32ff16:d9:ffff:ffff:ffff:ffff:ffff:ffff
219ff16:da::/32ff16:da:ffff:ffff:ffff:ffff:ffff:ffff
220ff16:db::/32ff16:db:ffff:ffff:ffff:ffff:ffff:ffff
221ff16:dc::/32ff16:dc:ffff:ffff:ffff:ffff:ffff:ffff
222ff16:dd::/32ff16:dd:ffff:ffff:ffff:ffff:ffff:ffff
223ff16:de::/32ff16:de:ffff:ffff:ffff:ffff:ffff:ffff
224ff16:df::/32ff16:df:ffff:ffff:ffff:ffff:ffff:ffff
225ff16:e0::/32ff16:e0:ffff:ffff:ffff:ffff:ffff:ffff
226ff16:e1::/32ff16:e1:ffff:ffff:ffff:ffff:ffff:ffff
227ff16:e2::/32ff16:e2:ffff:ffff:ffff:ffff:ffff:ffff
228ff16:e3::/32ff16:e3:ffff:ffff:ffff:ffff:ffff:ffff
229ff16:e4::/32ff16:e4:ffff:ffff:ffff:ffff:ffff:ffff
230ff16:e5::/32ff16:e5:ffff:ffff:ffff:ffff:ffff:ffff
231ff16:e6::/32ff16:e6:ffff:ffff:ffff:ffff:ffff:ffff
232ff16:e7::/32ff16:e7:ffff:ffff:ffff:ffff:ffff:ffff
233ff16:e8::/32ff16:e8:ffff:ffff:ffff:ffff:ffff:ffff
234ff16:e9::/32ff16:e9:ffff:ffff:ffff:ffff:ffff:ffff
235ff16:ea::/32ff16:ea:ffff:ffff:ffff:ffff:ffff:ffff
236ff16:eb::/32ff16:eb:ffff:ffff:ffff:ffff:ffff:ffff
237ff16:ec::/32ff16:ec:ffff:ffff:ffff:ffff:ffff:ffff
238ff16:ed::/32ff16:ed:ffff:ffff:ffff:ffff:ffff:ffff
239ff16:ee::/32ff16:ee:ffff:ffff:ffff:ffff:ffff:ffff
240ff16:ef::/32ff16:ef:ffff:ffff:ffff:ffff:ffff:ffff
241ff16:f0::/32ff16:f0:ffff:ffff:ffff:ffff:ffff:ffff
242ff16:f1::/32ff16:f1:ffff:ffff:ffff:ffff:ffff:ffff
243ff16:f2::/32ff16:f2:ffff:ffff:ffff:ffff:ffff:ffff
244ff16:f3::/32ff16:f3:ffff:ffff:ffff:ffff:ffff:ffff
245ff16:f4::/32ff16:f4:ffff:ffff:ffff:ffff:ffff:ffff
246ff16:f5::/32ff16:f5:ffff:ffff:ffff:ffff:ffff:ffff
247ff16:f6::/32ff16:f6:ffff:ffff:ffff:ffff:ffff:ffff
248ff16:f7::/32ff16:f7:ffff:ffff:ffff:ffff:ffff:ffff
249ff16:f8::/32ff16:f8:ffff:ffff:ffff:ffff:ffff:ffff
250ff16:f9::/32ff16:f9:ffff:ffff:ffff:ffff:ffff:ffff
251ff16:fa::/32ff16:fa:ffff:ffff:ffff:ffff:ffff:ffff
252ff16:fb::/32ff16:fb:ffff:ffff:ffff:ffff:ffff:ffff
253ff16:fc::/32ff16:fc:ffff:ffff:ffff:ffff:ffff:ffff
254ff16:fd::/32ff16:fd:ffff:ffff:ffff:ffff:ffff:ffff
255ff16:fe::/32ff16:fe:ffff:ffff:ffff:ffff:ffff:ffff
256ff16:ff::/32ff16: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.