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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
ff72::/16
First address
ff72::
Last address
ff72: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
ff72:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
2.7.f.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ff72::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1ff72::/28ff72:f:ffff:ffff:ffff:ffff:ffff:ffff
2ff72:10::/28ff72:1f:ffff:ffff:ffff:ffff:ffff:ffff
3ff72:20::/28ff72:2f:ffff:ffff:ffff:ffff:ffff:ffff
4ff72:30::/28ff72:3f:ffff:ffff:ffff:ffff:ffff:ffff
5ff72:40::/28ff72:4f:ffff:ffff:ffff:ffff:ffff:ffff
6ff72:50::/28ff72:5f:ffff:ffff:ffff:ffff:ffff:ffff
7ff72:60::/28ff72:6f:ffff:ffff:ffff:ffff:ffff:ffff
8ff72:70::/28ff72:7f:ffff:ffff:ffff:ffff:ffff:ffff
9ff72:80::/28ff72:8f:ffff:ffff:ffff:ffff:ffff:ffff
10ff72:90::/28ff72:9f:ffff:ffff:ffff:ffff:ffff:ffff
11ff72:a0::/28ff72:af:ffff:ffff:ffff:ffff:ffff:ffff
12ff72:b0::/28ff72:bf:ffff:ffff:ffff:ffff:ffff:ffff
13ff72:c0::/28ff72:cf:ffff:ffff:ffff:ffff:ffff:ffff
14ff72:d0::/28ff72:df:ffff:ffff:ffff:ffff:ffff:ffff
15ff72:e0::/28ff72:ef:ffff:ffff:ffff:ffff:ffff:ffff
16ff72:f0::/28ff72:ff:ffff:ffff:ffff:ffff:ffff:ffff
17ff72:100::/28ff72:10f:ffff:ffff:ffff:ffff:ffff:ffff
18ff72:110::/28ff72:11f:ffff:ffff:ffff:ffff:ffff:ffff
19ff72:120::/28ff72:12f:ffff:ffff:ffff:ffff:ffff:ffff
20ff72:130::/28ff72:13f:ffff:ffff:ffff:ffff:ffff:ffff
21ff72:140::/28ff72:14f:ffff:ffff:ffff:ffff:ffff:ffff
22ff72:150::/28ff72:15f:ffff:ffff:ffff:ffff:ffff:ffff
23ff72:160::/28ff72:16f:ffff:ffff:ffff:ffff:ffff:ffff
24ff72:170::/28ff72:17f:ffff:ffff:ffff:ffff:ffff:ffff
25ff72:180::/28ff72:18f:ffff:ffff:ffff:ffff:ffff:ffff
26ff72:190::/28ff72:19f:ffff:ffff:ffff:ffff:ffff:ffff
27ff72:1a0::/28ff72:1af:ffff:ffff:ffff:ffff:ffff:ffff
28ff72:1b0::/28ff72:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29ff72:1c0::/28ff72:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30ff72:1d0::/28ff72:1df:ffff:ffff:ffff:ffff:ffff:ffff
31ff72:1e0::/28ff72:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32ff72:1f0::/28ff72:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33ff72:200::/28ff72:20f:ffff:ffff:ffff:ffff:ffff:ffff
34ff72:210::/28ff72:21f:ffff:ffff:ffff:ffff:ffff:ffff
35ff72:220::/28ff72:22f:ffff:ffff:ffff:ffff:ffff:ffff
36ff72:230::/28ff72:23f:ffff:ffff:ffff:ffff:ffff:ffff
37ff72:240::/28ff72:24f:ffff:ffff:ffff:ffff:ffff:ffff
38ff72:250::/28ff72:25f:ffff:ffff:ffff:ffff:ffff:ffff
39ff72:260::/28ff72:26f:ffff:ffff:ffff:ffff:ffff:ffff
40ff72:270::/28ff72:27f:ffff:ffff:ffff:ffff:ffff:ffff
41ff72:280::/28ff72:28f:ffff:ffff:ffff:ffff:ffff:ffff
42ff72:290::/28ff72:29f:ffff:ffff:ffff:ffff:ffff:ffff
43ff72:2a0::/28ff72:2af:ffff:ffff:ffff:ffff:ffff:ffff
44ff72:2b0::/28ff72:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45ff72:2c0::/28ff72:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46ff72:2d0::/28ff72:2df:ffff:ffff:ffff:ffff:ffff:ffff
47ff72:2e0::/28ff72:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48ff72:2f0::/28ff72:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49ff72:300::/28ff72:30f:ffff:ffff:ffff:ffff:ffff:ffff
50ff72:310::/28ff72:31f:ffff:ffff:ffff:ffff:ffff:ffff
51ff72:320::/28ff72:32f:ffff:ffff:ffff:ffff:ffff:ffff
52ff72:330::/28ff72:33f:ffff:ffff:ffff:ffff:ffff:ffff
53ff72:340::/28ff72:34f:ffff:ffff:ffff:ffff:ffff:ffff
54ff72:350::/28ff72:35f:ffff:ffff:ffff:ffff:ffff:ffff
55ff72:360::/28ff72:36f:ffff:ffff:ffff:ffff:ffff:ffff
56ff72:370::/28ff72:37f:ffff:ffff:ffff:ffff:ffff:ffff
57ff72:380::/28ff72:38f:ffff:ffff:ffff:ffff:ffff:ffff
58ff72:390::/28ff72:39f:ffff:ffff:ffff:ffff:ffff:ffff
59ff72:3a0::/28ff72:3af:ffff:ffff:ffff:ffff:ffff:ffff
60ff72:3b0::/28ff72:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61ff72:3c0::/28ff72:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62ff72:3d0::/28ff72:3df:ffff:ffff:ffff:ffff:ffff:ffff
63ff72:3e0::/28ff72:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64ff72:3f0::/28ff72:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65ff72:400::/28ff72:40f:ffff:ffff:ffff:ffff:ffff:ffff
66ff72:410::/28ff72:41f:ffff:ffff:ffff:ffff:ffff:ffff
67ff72:420::/28ff72:42f:ffff:ffff:ffff:ffff:ffff:ffff
68ff72:430::/28ff72:43f:ffff:ffff:ffff:ffff:ffff:ffff
69ff72:440::/28ff72:44f:ffff:ffff:ffff:ffff:ffff:ffff
70ff72:450::/28ff72:45f:ffff:ffff:ffff:ffff:ffff:ffff
71ff72:460::/28ff72:46f:ffff:ffff:ffff:ffff:ffff:ffff
72ff72:470::/28ff72:47f:ffff:ffff:ffff:ffff:ffff:ffff
73ff72:480::/28ff72:48f:ffff:ffff:ffff:ffff:ffff:ffff
74ff72:490::/28ff72:49f:ffff:ffff:ffff:ffff:ffff:ffff
75ff72:4a0::/28ff72:4af:ffff:ffff:ffff:ffff:ffff:ffff
76ff72:4b0::/28ff72:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77ff72:4c0::/28ff72:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78ff72:4d0::/28ff72:4df:ffff:ffff:ffff:ffff:ffff:ffff
79ff72:4e0::/28ff72:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80ff72:4f0::/28ff72:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81ff72:500::/28ff72:50f:ffff:ffff:ffff:ffff:ffff:ffff
82ff72:510::/28ff72:51f:ffff:ffff:ffff:ffff:ffff:ffff
83ff72:520::/28ff72:52f:ffff:ffff:ffff:ffff:ffff:ffff
84ff72:530::/28ff72:53f:ffff:ffff:ffff:ffff:ffff:ffff
85ff72:540::/28ff72:54f:ffff:ffff:ffff:ffff:ffff:ffff
86ff72:550::/28ff72:55f:ffff:ffff:ffff:ffff:ffff:ffff
87ff72:560::/28ff72:56f:ffff:ffff:ffff:ffff:ffff:ffff
88ff72:570::/28ff72:57f:ffff:ffff:ffff:ffff:ffff:ffff
89ff72:580::/28ff72:58f:ffff:ffff:ffff:ffff:ffff:ffff
90ff72:590::/28ff72:59f:ffff:ffff:ffff:ffff:ffff:ffff
91ff72:5a0::/28ff72:5af:ffff:ffff:ffff:ffff:ffff:ffff
92ff72:5b0::/28ff72:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93ff72:5c0::/28ff72:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94ff72:5d0::/28ff72:5df:ffff:ffff:ffff:ffff:ffff:ffff
95ff72:5e0::/28ff72:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96ff72:5f0::/28ff72:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97ff72:600::/28ff72:60f:ffff:ffff:ffff:ffff:ffff:ffff
98ff72:610::/28ff72:61f:ffff:ffff:ffff:ffff:ffff:ffff
99ff72:620::/28ff72:62f:ffff:ffff:ffff:ffff:ffff:ffff
100ff72:630::/28ff72:63f:ffff:ffff:ffff:ffff:ffff:ffff
101ff72:640::/28ff72:64f:ffff:ffff:ffff:ffff:ffff:ffff
102ff72:650::/28ff72:65f:ffff:ffff:ffff:ffff:ffff:ffff
103ff72:660::/28ff72:66f:ffff:ffff:ffff:ffff:ffff:ffff
104ff72:670::/28ff72:67f:ffff:ffff:ffff:ffff:ffff:ffff
105ff72:680::/28ff72:68f:ffff:ffff:ffff:ffff:ffff:ffff
106ff72:690::/28ff72:69f:ffff:ffff:ffff:ffff:ffff:ffff
107ff72:6a0::/28ff72:6af:ffff:ffff:ffff:ffff:ffff:ffff
108ff72:6b0::/28ff72:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109ff72:6c0::/28ff72:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110ff72:6d0::/28ff72:6df:ffff:ffff:ffff:ffff:ffff:ffff
111ff72:6e0::/28ff72:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112ff72:6f0::/28ff72:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113ff72:700::/28ff72:70f:ffff:ffff:ffff:ffff:ffff:ffff
114ff72:710::/28ff72:71f:ffff:ffff:ffff:ffff:ffff:ffff
115ff72:720::/28ff72:72f:ffff:ffff:ffff:ffff:ffff:ffff
116ff72:730::/28ff72:73f:ffff:ffff:ffff:ffff:ffff:ffff
117ff72:740::/28ff72:74f:ffff:ffff:ffff:ffff:ffff:ffff
118ff72:750::/28ff72:75f:ffff:ffff:ffff:ffff:ffff:ffff
119ff72:760::/28ff72:76f:ffff:ffff:ffff:ffff:ffff:ffff
120ff72:770::/28ff72:77f:ffff:ffff:ffff:ffff:ffff:ffff
121ff72:780::/28ff72:78f:ffff:ffff:ffff:ffff:ffff:ffff
122ff72:790::/28ff72:79f:ffff:ffff:ffff:ffff:ffff:ffff
123ff72:7a0::/28ff72:7af:ffff:ffff:ffff:ffff:ffff:ffff
124ff72:7b0::/28ff72:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125ff72:7c0::/28ff72:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126ff72:7d0::/28ff72:7df:ffff:ffff:ffff:ffff:ffff:ffff
127ff72:7e0::/28ff72:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128ff72:7f0::/28ff72:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129ff72:800::/28ff72:80f:ffff:ffff:ffff:ffff:ffff:ffff
130ff72:810::/28ff72:81f:ffff:ffff:ffff:ffff:ffff:ffff
131ff72:820::/28ff72:82f:ffff:ffff:ffff:ffff:ffff:ffff
132ff72:830::/28ff72:83f:ffff:ffff:ffff:ffff:ffff:ffff
133ff72:840::/28ff72:84f:ffff:ffff:ffff:ffff:ffff:ffff
134ff72:850::/28ff72:85f:ffff:ffff:ffff:ffff:ffff:ffff
135ff72:860::/28ff72:86f:ffff:ffff:ffff:ffff:ffff:ffff
136ff72:870::/28ff72:87f:ffff:ffff:ffff:ffff:ffff:ffff
137ff72:880::/28ff72:88f:ffff:ffff:ffff:ffff:ffff:ffff
138ff72:890::/28ff72:89f:ffff:ffff:ffff:ffff:ffff:ffff
139ff72:8a0::/28ff72:8af:ffff:ffff:ffff:ffff:ffff:ffff
140ff72:8b0::/28ff72:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141ff72:8c0::/28ff72:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142ff72:8d0::/28ff72:8df:ffff:ffff:ffff:ffff:ffff:ffff
143ff72:8e0::/28ff72:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144ff72:8f0::/28ff72:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145ff72:900::/28ff72:90f:ffff:ffff:ffff:ffff:ffff:ffff
146ff72:910::/28ff72:91f:ffff:ffff:ffff:ffff:ffff:ffff
147ff72:920::/28ff72:92f:ffff:ffff:ffff:ffff:ffff:ffff
148ff72:930::/28ff72:93f:ffff:ffff:ffff:ffff:ffff:ffff
149ff72:940::/28ff72:94f:ffff:ffff:ffff:ffff:ffff:ffff
150ff72:950::/28ff72:95f:ffff:ffff:ffff:ffff:ffff:ffff
151ff72:960::/28ff72:96f:ffff:ffff:ffff:ffff:ffff:ffff
152ff72:970::/28ff72:97f:ffff:ffff:ffff:ffff:ffff:ffff
153ff72:980::/28ff72:98f:ffff:ffff:ffff:ffff:ffff:ffff
154ff72:990::/28ff72:99f:ffff:ffff:ffff:ffff:ffff:ffff
155ff72:9a0::/28ff72:9af:ffff:ffff:ffff:ffff:ffff:ffff
156ff72:9b0::/28ff72:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157ff72:9c0::/28ff72:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158ff72:9d0::/28ff72:9df:ffff:ffff:ffff:ffff:ffff:ffff
159ff72:9e0::/28ff72:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160ff72:9f0::/28ff72:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161ff72:a00::/28ff72:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ff72:a10::/28ff72:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ff72:a20::/28ff72:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ff72:a30::/28ff72:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ff72:a40::/28ff72:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ff72:a50::/28ff72:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ff72:a60::/28ff72:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ff72:a70::/28ff72:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ff72:a80::/28ff72:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ff72:a90::/28ff72:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ff72:aa0::/28ff72:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ff72:ab0::/28ff72:abf:ffff:ffff:ffff:ffff:ffff:ffff
173ff72:ac0::/28ff72:acf:ffff:ffff:ffff:ffff:ffff:ffff
174ff72:ad0::/28ff72:adf:ffff:ffff:ffff:ffff:ffff:ffff
175ff72:ae0::/28ff72:aef:ffff:ffff:ffff:ffff:ffff:ffff
176ff72:af0::/28ff72:aff:ffff:ffff:ffff:ffff:ffff:ffff
177ff72:b00::/28ff72:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ff72:b10::/28ff72:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ff72:b20::/28ff72:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ff72:b30::/28ff72:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ff72:b40::/28ff72:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ff72:b50::/28ff72:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ff72:b60::/28ff72:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ff72:b70::/28ff72:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ff72:b80::/28ff72:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ff72:b90::/28ff72:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ff72:ba0::/28ff72:baf:ffff:ffff:ffff:ffff:ffff:ffff
188ff72:bb0::/28ff72:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ff72:bc0::/28ff72:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ff72:bd0::/28ff72:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ff72:be0::/28ff72:bef:ffff:ffff:ffff:ffff:ffff:ffff
192ff72:bf0::/28ff72:bff:ffff:ffff:ffff:ffff:ffff:ffff
193ff72:c00::/28ff72:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ff72:c10::/28ff72:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ff72:c20::/28ff72:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ff72:c30::/28ff72:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ff72:c40::/28ff72:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ff72:c50::/28ff72:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ff72:c60::/28ff72:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ff72:c70::/28ff72:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ff72:c80::/28ff72:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ff72:c90::/28ff72:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ff72:ca0::/28ff72:caf:ffff:ffff:ffff:ffff:ffff:ffff
204ff72:cb0::/28ff72:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ff72:cc0::/28ff72:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ff72:cd0::/28ff72:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ff72:ce0::/28ff72:cef:ffff:ffff:ffff:ffff:ffff:ffff
208ff72:cf0::/28ff72:cff:ffff:ffff:ffff:ffff:ffff:ffff
209ff72:d00::/28ff72:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ff72:d10::/28ff72:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ff72:d20::/28ff72:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ff72:d30::/28ff72:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ff72:d40::/28ff72:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ff72:d50::/28ff72:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ff72:d60::/28ff72:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ff72:d70::/28ff72:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ff72:d80::/28ff72:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ff72:d90::/28ff72:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ff72:da0::/28ff72:daf:ffff:ffff:ffff:ffff:ffff:ffff
220ff72:db0::/28ff72:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ff72:dc0::/28ff72:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ff72:dd0::/28ff72:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ff72:de0::/28ff72:def:ffff:ffff:ffff:ffff:ffff:ffff
224ff72:df0::/28ff72:dff:ffff:ffff:ffff:ffff:ffff:ffff
225ff72:e00::/28ff72:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ff72:e10::/28ff72:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ff72:e20::/28ff72:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ff72:e30::/28ff72:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ff72:e40::/28ff72:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ff72:e50::/28ff72:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ff72:e60::/28ff72:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ff72:e70::/28ff72:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ff72:e80::/28ff72:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ff72:e90::/28ff72:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ff72:ea0::/28ff72:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ff72:eb0::/28ff72:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ff72:ec0::/28ff72:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ff72:ed0::/28ff72:edf:ffff:ffff:ffff:ffff:ffff:ffff
239ff72:ee0::/28ff72:eef:ffff:ffff:ffff:ffff:ffff:ffff
240ff72:ef0::/28ff72:eff:ffff:ffff:ffff:ffff:ffff:ffff
241ff72:f00::/28ff72:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ff72:f10::/28ff72:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ff72:f20::/28ff72:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ff72:f30::/28ff72:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ff72:f40::/28ff72:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ff72:f50::/28ff72:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ff72:f60::/28ff72:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ff72:f70::/28ff72:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ff72:f80::/28ff72:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ff72:f90::/28ff72:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ff72:fa0::/28ff72:faf:ffff:ffff:ffff:ffff:ffff:ffff
252ff72:fb0::/28ff72:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ff72:fc0::/28ff72:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ff72:fd0::/28ff72:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ff72:fe0::/28ff72:fef:ffff:ffff:ffff:ffff:ffff:ffff
256ff72:ff0::/28ff72:fff: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.