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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
ff3a::/16
First address
ff3a::
Last address
ff3a: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
ff3a:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
a.3.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)

ff3a::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1ff3a::/28ff3a:f:ffff:ffff:ffff:ffff:ffff:ffff
2ff3a:10::/28ff3a:1f:ffff:ffff:ffff:ffff:ffff:ffff
3ff3a:20::/28ff3a:2f:ffff:ffff:ffff:ffff:ffff:ffff
4ff3a:30::/28ff3a:3f:ffff:ffff:ffff:ffff:ffff:ffff
5ff3a:40::/28ff3a:4f:ffff:ffff:ffff:ffff:ffff:ffff
6ff3a:50::/28ff3a:5f:ffff:ffff:ffff:ffff:ffff:ffff
7ff3a:60::/28ff3a:6f:ffff:ffff:ffff:ffff:ffff:ffff
8ff3a:70::/28ff3a:7f:ffff:ffff:ffff:ffff:ffff:ffff
9ff3a:80::/28ff3a:8f:ffff:ffff:ffff:ffff:ffff:ffff
10ff3a:90::/28ff3a:9f:ffff:ffff:ffff:ffff:ffff:ffff
11ff3a:a0::/28ff3a:af:ffff:ffff:ffff:ffff:ffff:ffff
12ff3a:b0::/28ff3a:bf:ffff:ffff:ffff:ffff:ffff:ffff
13ff3a:c0::/28ff3a:cf:ffff:ffff:ffff:ffff:ffff:ffff
14ff3a:d0::/28ff3a:df:ffff:ffff:ffff:ffff:ffff:ffff
15ff3a:e0::/28ff3a:ef:ffff:ffff:ffff:ffff:ffff:ffff
16ff3a:f0::/28ff3a:ff:ffff:ffff:ffff:ffff:ffff:ffff
17ff3a:100::/28ff3a:10f:ffff:ffff:ffff:ffff:ffff:ffff
18ff3a:110::/28ff3a:11f:ffff:ffff:ffff:ffff:ffff:ffff
19ff3a:120::/28ff3a:12f:ffff:ffff:ffff:ffff:ffff:ffff
20ff3a:130::/28ff3a:13f:ffff:ffff:ffff:ffff:ffff:ffff
21ff3a:140::/28ff3a:14f:ffff:ffff:ffff:ffff:ffff:ffff
22ff3a:150::/28ff3a:15f:ffff:ffff:ffff:ffff:ffff:ffff
23ff3a:160::/28ff3a:16f:ffff:ffff:ffff:ffff:ffff:ffff
24ff3a:170::/28ff3a:17f:ffff:ffff:ffff:ffff:ffff:ffff
25ff3a:180::/28ff3a:18f:ffff:ffff:ffff:ffff:ffff:ffff
26ff3a:190::/28ff3a:19f:ffff:ffff:ffff:ffff:ffff:ffff
27ff3a:1a0::/28ff3a:1af:ffff:ffff:ffff:ffff:ffff:ffff
28ff3a:1b0::/28ff3a:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29ff3a:1c0::/28ff3a:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30ff3a:1d0::/28ff3a:1df:ffff:ffff:ffff:ffff:ffff:ffff
31ff3a:1e0::/28ff3a:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32ff3a:1f0::/28ff3a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33ff3a:200::/28ff3a:20f:ffff:ffff:ffff:ffff:ffff:ffff
34ff3a:210::/28ff3a:21f:ffff:ffff:ffff:ffff:ffff:ffff
35ff3a:220::/28ff3a:22f:ffff:ffff:ffff:ffff:ffff:ffff
36ff3a:230::/28ff3a:23f:ffff:ffff:ffff:ffff:ffff:ffff
37ff3a:240::/28ff3a:24f:ffff:ffff:ffff:ffff:ffff:ffff
38ff3a:250::/28ff3a:25f:ffff:ffff:ffff:ffff:ffff:ffff
39ff3a:260::/28ff3a:26f:ffff:ffff:ffff:ffff:ffff:ffff
40ff3a:270::/28ff3a:27f:ffff:ffff:ffff:ffff:ffff:ffff
41ff3a:280::/28ff3a:28f:ffff:ffff:ffff:ffff:ffff:ffff
42ff3a:290::/28ff3a:29f:ffff:ffff:ffff:ffff:ffff:ffff
43ff3a:2a0::/28ff3a:2af:ffff:ffff:ffff:ffff:ffff:ffff
44ff3a:2b0::/28ff3a:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45ff3a:2c0::/28ff3a:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46ff3a:2d0::/28ff3a:2df:ffff:ffff:ffff:ffff:ffff:ffff
47ff3a:2e0::/28ff3a:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48ff3a:2f0::/28ff3a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49ff3a:300::/28ff3a:30f:ffff:ffff:ffff:ffff:ffff:ffff
50ff3a:310::/28ff3a:31f:ffff:ffff:ffff:ffff:ffff:ffff
51ff3a:320::/28ff3a:32f:ffff:ffff:ffff:ffff:ffff:ffff
52ff3a:330::/28ff3a:33f:ffff:ffff:ffff:ffff:ffff:ffff
53ff3a:340::/28ff3a:34f:ffff:ffff:ffff:ffff:ffff:ffff
54ff3a:350::/28ff3a:35f:ffff:ffff:ffff:ffff:ffff:ffff
55ff3a:360::/28ff3a:36f:ffff:ffff:ffff:ffff:ffff:ffff
56ff3a:370::/28ff3a:37f:ffff:ffff:ffff:ffff:ffff:ffff
57ff3a:380::/28ff3a:38f:ffff:ffff:ffff:ffff:ffff:ffff
58ff3a:390::/28ff3a:39f:ffff:ffff:ffff:ffff:ffff:ffff
59ff3a:3a0::/28ff3a:3af:ffff:ffff:ffff:ffff:ffff:ffff
60ff3a:3b0::/28ff3a:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61ff3a:3c0::/28ff3a:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62ff3a:3d0::/28ff3a:3df:ffff:ffff:ffff:ffff:ffff:ffff
63ff3a:3e0::/28ff3a:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64ff3a:3f0::/28ff3a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65ff3a:400::/28ff3a:40f:ffff:ffff:ffff:ffff:ffff:ffff
66ff3a:410::/28ff3a:41f:ffff:ffff:ffff:ffff:ffff:ffff
67ff3a:420::/28ff3a:42f:ffff:ffff:ffff:ffff:ffff:ffff
68ff3a:430::/28ff3a:43f:ffff:ffff:ffff:ffff:ffff:ffff
69ff3a:440::/28ff3a:44f:ffff:ffff:ffff:ffff:ffff:ffff
70ff3a:450::/28ff3a:45f:ffff:ffff:ffff:ffff:ffff:ffff
71ff3a:460::/28ff3a:46f:ffff:ffff:ffff:ffff:ffff:ffff
72ff3a:470::/28ff3a:47f:ffff:ffff:ffff:ffff:ffff:ffff
73ff3a:480::/28ff3a:48f:ffff:ffff:ffff:ffff:ffff:ffff
74ff3a:490::/28ff3a:49f:ffff:ffff:ffff:ffff:ffff:ffff
75ff3a:4a0::/28ff3a:4af:ffff:ffff:ffff:ffff:ffff:ffff
76ff3a:4b0::/28ff3a:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77ff3a:4c0::/28ff3a:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78ff3a:4d0::/28ff3a:4df:ffff:ffff:ffff:ffff:ffff:ffff
79ff3a:4e0::/28ff3a:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80ff3a:4f0::/28ff3a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81ff3a:500::/28ff3a:50f:ffff:ffff:ffff:ffff:ffff:ffff
82ff3a:510::/28ff3a:51f:ffff:ffff:ffff:ffff:ffff:ffff
83ff3a:520::/28ff3a:52f:ffff:ffff:ffff:ffff:ffff:ffff
84ff3a:530::/28ff3a:53f:ffff:ffff:ffff:ffff:ffff:ffff
85ff3a:540::/28ff3a:54f:ffff:ffff:ffff:ffff:ffff:ffff
86ff3a:550::/28ff3a:55f:ffff:ffff:ffff:ffff:ffff:ffff
87ff3a:560::/28ff3a:56f:ffff:ffff:ffff:ffff:ffff:ffff
88ff3a:570::/28ff3a:57f:ffff:ffff:ffff:ffff:ffff:ffff
89ff3a:580::/28ff3a:58f:ffff:ffff:ffff:ffff:ffff:ffff
90ff3a:590::/28ff3a:59f:ffff:ffff:ffff:ffff:ffff:ffff
91ff3a:5a0::/28ff3a:5af:ffff:ffff:ffff:ffff:ffff:ffff
92ff3a:5b0::/28ff3a:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93ff3a:5c0::/28ff3a:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94ff3a:5d0::/28ff3a:5df:ffff:ffff:ffff:ffff:ffff:ffff
95ff3a:5e0::/28ff3a:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96ff3a:5f0::/28ff3a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97ff3a:600::/28ff3a:60f:ffff:ffff:ffff:ffff:ffff:ffff
98ff3a:610::/28ff3a:61f:ffff:ffff:ffff:ffff:ffff:ffff
99ff3a:620::/28ff3a:62f:ffff:ffff:ffff:ffff:ffff:ffff
100ff3a:630::/28ff3a:63f:ffff:ffff:ffff:ffff:ffff:ffff
101ff3a:640::/28ff3a:64f:ffff:ffff:ffff:ffff:ffff:ffff
102ff3a:650::/28ff3a:65f:ffff:ffff:ffff:ffff:ffff:ffff
103ff3a:660::/28ff3a:66f:ffff:ffff:ffff:ffff:ffff:ffff
104ff3a:670::/28ff3a:67f:ffff:ffff:ffff:ffff:ffff:ffff
105ff3a:680::/28ff3a:68f:ffff:ffff:ffff:ffff:ffff:ffff
106ff3a:690::/28ff3a:69f:ffff:ffff:ffff:ffff:ffff:ffff
107ff3a:6a0::/28ff3a:6af:ffff:ffff:ffff:ffff:ffff:ffff
108ff3a:6b0::/28ff3a:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109ff3a:6c0::/28ff3a:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110ff3a:6d0::/28ff3a:6df:ffff:ffff:ffff:ffff:ffff:ffff
111ff3a:6e0::/28ff3a:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112ff3a:6f0::/28ff3a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113ff3a:700::/28ff3a:70f:ffff:ffff:ffff:ffff:ffff:ffff
114ff3a:710::/28ff3a:71f:ffff:ffff:ffff:ffff:ffff:ffff
115ff3a:720::/28ff3a:72f:ffff:ffff:ffff:ffff:ffff:ffff
116ff3a:730::/28ff3a:73f:ffff:ffff:ffff:ffff:ffff:ffff
117ff3a:740::/28ff3a:74f:ffff:ffff:ffff:ffff:ffff:ffff
118ff3a:750::/28ff3a:75f:ffff:ffff:ffff:ffff:ffff:ffff
119ff3a:760::/28ff3a:76f:ffff:ffff:ffff:ffff:ffff:ffff
120ff3a:770::/28ff3a:77f:ffff:ffff:ffff:ffff:ffff:ffff
121ff3a:780::/28ff3a:78f:ffff:ffff:ffff:ffff:ffff:ffff
122ff3a:790::/28ff3a:79f:ffff:ffff:ffff:ffff:ffff:ffff
123ff3a:7a0::/28ff3a:7af:ffff:ffff:ffff:ffff:ffff:ffff
124ff3a:7b0::/28ff3a:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125ff3a:7c0::/28ff3a:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126ff3a:7d0::/28ff3a:7df:ffff:ffff:ffff:ffff:ffff:ffff
127ff3a:7e0::/28ff3a:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128ff3a:7f0::/28ff3a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129ff3a:800::/28ff3a:80f:ffff:ffff:ffff:ffff:ffff:ffff
130ff3a:810::/28ff3a:81f:ffff:ffff:ffff:ffff:ffff:ffff
131ff3a:820::/28ff3a:82f:ffff:ffff:ffff:ffff:ffff:ffff
132ff3a:830::/28ff3a:83f:ffff:ffff:ffff:ffff:ffff:ffff
133ff3a:840::/28ff3a:84f:ffff:ffff:ffff:ffff:ffff:ffff
134ff3a:850::/28ff3a:85f:ffff:ffff:ffff:ffff:ffff:ffff
135ff3a:860::/28ff3a:86f:ffff:ffff:ffff:ffff:ffff:ffff
136ff3a:870::/28ff3a:87f:ffff:ffff:ffff:ffff:ffff:ffff
137ff3a:880::/28ff3a:88f:ffff:ffff:ffff:ffff:ffff:ffff
138ff3a:890::/28ff3a:89f:ffff:ffff:ffff:ffff:ffff:ffff
139ff3a:8a0::/28ff3a:8af:ffff:ffff:ffff:ffff:ffff:ffff
140ff3a:8b0::/28ff3a:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141ff3a:8c0::/28ff3a:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142ff3a:8d0::/28ff3a:8df:ffff:ffff:ffff:ffff:ffff:ffff
143ff3a:8e0::/28ff3a:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144ff3a:8f0::/28ff3a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145ff3a:900::/28ff3a:90f:ffff:ffff:ffff:ffff:ffff:ffff
146ff3a:910::/28ff3a:91f:ffff:ffff:ffff:ffff:ffff:ffff
147ff3a:920::/28ff3a:92f:ffff:ffff:ffff:ffff:ffff:ffff
148ff3a:930::/28ff3a:93f:ffff:ffff:ffff:ffff:ffff:ffff
149ff3a:940::/28ff3a:94f:ffff:ffff:ffff:ffff:ffff:ffff
150ff3a:950::/28ff3a:95f:ffff:ffff:ffff:ffff:ffff:ffff
151ff3a:960::/28ff3a:96f:ffff:ffff:ffff:ffff:ffff:ffff
152ff3a:970::/28ff3a:97f:ffff:ffff:ffff:ffff:ffff:ffff
153ff3a:980::/28ff3a:98f:ffff:ffff:ffff:ffff:ffff:ffff
154ff3a:990::/28ff3a:99f:ffff:ffff:ffff:ffff:ffff:ffff
155ff3a:9a0::/28ff3a:9af:ffff:ffff:ffff:ffff:ffff:ffff
156ff3a:9b0::/28ff3a:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157ff3a:9c0::/28ff3a:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158ff3a:9d0::/28ff3a:9df:ffff:ffff:ffff:ffff:ffff:ffff
159ff3a:9e0::/28ff3a:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160ff3a:9f0::/28ff3a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161ff3a:a00::/28ff3a:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ff3a:a10::/28ff3a:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ff3a:a20::/28ff3a:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ff3a:a30::/28ff3a:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ff3a:a40::/28ff3a:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ff3a:a50::/28ff3a:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ff3a:a60::/28ff3a:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ff3a:a70::/28ff3a:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ff3a:a80::/28ff3a:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ff3a:a90::/28ff3a:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ff3a:aa0::/28ff3a:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ff3a:ab0::/28ff3a:abf:ffff:ffff:ffff:ffff:ffff:ffff
173ff3a:ac0::/28ff3a:acf:ffff:ffff:ffff:ffff:ffff:ffff
174ff3a:ad0::/28ff3a:adf:ffff:ffff:ffff:ffff:ffff:ffff
175ff3a:ae0::/28ff3a:aef:ffff:ffff:ffff:ffff:ffff:ffff
176ff3a:af0::/28ff3a:aff:ffff:ffff:ffff:ffff:ffff:ffff
177ff3a:b00::/28ff3a:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ff3a:b10::/28ff3a:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ff3a:b20::/28ff3a:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ff3a:b30::/28ff3a:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ff3a:b40::/28ff3a:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ff3a:b50::/28ff3a:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ff3a:b60::/28ff3a:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ff3a:b70::/28ff3a:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ff3a:b80::/28ff3a:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ff3a:b90::/28ff3a:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ff3a:ba0::/28ff3a:baf:ffff:ffff:ffff:ffff:ffff:ffff
188ff3a:bb0::/28ff3a:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ff3a:bc0::/28ff3a:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ff3a:bd0::/28ff3a:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ff3a:be0::/28ff3a:bef:ffff:ffff:ffff:ffff:ffff:ffff
192ff3a:bf0::/28ff3a:bff:ffff:ffff:ffff:ffff:ffff:ffff
193ff3a:c00::/28ff3a:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ff3a:c10::/28ff3a:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ff3a:c20::/28ff3a:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ff3a:c30::/28ff3a:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ff3a:c40::/28ff3a:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ff3a:c50::/28ff3a:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ff3a:c60::/28ff3a:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ff3a:c70::/28ff3a:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ff3a:c80::/28ff3a:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ff3a:c90::/28ff3a:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ff3a:ca0::/28ff3a:caf:ffff:ffff:ffff:ffff:ffff:ffff
204ff3a:cb0::/28ff3a:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ff3a:cc0::/28ff3a:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ff3a:cd0::/28ff3a:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ff3a:ce0::/28ff3a:cef:ffff:ffff:ffff:ffff:ffff:ffff
208ff3a:cf0::/28ff3a:cff:ffff:ffff:ffff:ffff:ffff:ffff
209ff3a:d00::/28ff3a:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ff3a:d10::/28ff3a:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ff3a:d20::/28ff3a:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ff3a:d30::/28ff3a:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ff3a:d40::/28ff3a:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ff3a:d50::/28ff3a:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ff3a:d60::/28ff3a:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ff3a:d70::/28ff3a:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ff3a:d80::/28ff3a:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ff3a:d90::/28ff3a:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ff3a:da0::/28ff3a:daf:ffff:ffff:ffff:ffff:ffff:ffff
220ff3a:db0::/28ff3a:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ff3a:dc0::/28ff3a:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ff3a:dd0::/28ff3a:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ff3a:de0::/28ff3a:def:ffff:ffff:ffff:ffff:ffff:ffff
224ff3a:df0::/28ff3a:dff:ffff:ffff:ffff:ffff:ffff:ffff
225ff3a:e00::/28ff3a:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ff3a:e10::/28ff3a:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ff3a:e20::/28ff3a:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ff3a:e30::/28ff3a:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ff3a:e40::/28ff3a:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ff3a:e50::/28ff3a:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ff3a:e60::/28ff3a:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ff3a:e70::/28ff3a:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ff3a:e80::/28ff3a:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ff3a:e90::/28ff3a:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ff3a:ea0::/28ff3a:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ff3a:eb0::/28ff3a:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ff3a:ec0::/28ff3a:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ff3a:ed0::/28ff3a:edf:ffff:ffff:ffff:ffff:ffff:ffff
239ff3a:ee0::/28ff3a:eef:ffff:ffff:ffff:ffff:ffff:ffff
240ff3a:ef0::/28ff3a:eff:ffff:ffff:ffff:ffff:ffff:ffff
241ff3a:f00::/28ff3a:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ff3a:f10::/28ff3a:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ff3a:f20::/28ff3a:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ff3a:f30::/28ff3a:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ff3a:f40::/28ff3a:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ff3a:f50::/28ff3a:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ff3a:f60::/28ff3a:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ff3a:f70::/28ff3a:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ff3a:f80::/28ff3a:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ff3a:f90::/28ff3a:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ff3a:fa0::/28ff3a:faf:ffff:ffff:ffff:ffff:ffff:ffff
252ff3a:fb0::/28ff3a:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ff3a:fc0::/28ff3a:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ff3a:fd0::/28ff3a:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ff3a:fe0::/28ff3a:fef:ffff:ffff:ffff:ffff:ffff:ffff
256ff3a:ff0::/28ff3a: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.