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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
366b::/16
First address
366b::
Last address
366b: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
366b:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
b.6.6.3.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

366b::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1366b::/28366b:f:ffff:ffff:ffff:ffff:ffff:ffff
2366b:10::/28366b:1f:ffff:ffff:ffff:ffff:ffff:ffff
3366b:20::/28366b:2f:ffff:ffff:ffff:ffff:ffff:ffff
4366b:30::/28366b:3f:ffff:ffff:ffff:ffff:ffff:ffff
5366b:40::/28366b:4f:ffff:ffff:ffff:ffff:ffff:ffff
6366b:50::/28366b:5f:ffff:ffff:ffff:ffff:ffff:ffff
7366b:60::/28366b:6f:ffff:ffff:ffff:ffff:ffff:ffff
8366b:70::/28366b:7f:ffff:ffff:ffff:ffff:ffff:ffff
9366b:80::/28366b:8f:ffff:ffff:ffff:ffff:ffff:ffff
10366b:90::/28366b:9f:ffff:ffff:ffff:ffff:ffff:ffff
11366b:a0::/28366b:af:ffff:ffff:ffff:ffff:ffff:ffff
12366b:b0::/28366b:bf:ffff:ffff:ffff:ffff:ffff:ffff
13366b:c0::/28366b:cf:ffff:ffff:ffff:ffff:ffff:ffff
14366b:d0::/28366b:df:ffff:ffff:ffff:ffff:ffff:ffff
15366b:e0::/28366b:ef:ffff:ffff:ffff:ffff:ffff:ffff
16366b:f0::/28366b:ff:ffff:ffff:ffff:ffff:ffff:ffff
17366b:100::/28366b:10f:ffff:ffff:ffff:ffff:ffff:ffff
18366b:110::/28366b:11f:ffff:ffff:ffff:ffff:ffff:ffff
19366b:120::/28366b:12f:ffff:ffff:ffff:ffff:ffff:ffff
20366b:130::/28366b:13f:ffff:ffff:ffff:ffff:ffff:ffff
21366b:140::/28366b:14f:ffff:ffff:ffff:ffff:ffff:ffff
22366b:150::/28366b:15f:ffff:ffff:ffff:ffff:ffff:ffff
23366b:160::/28366b:16f:ffff:ffff:ffff:ffff:ffff:ffff
24366b:170::/28366b:17f:ffff:ffff:ffff:ffff:ffff:ffff
25366b:180::/28366b:18f:ffff:ffff:ffff:ffff:ffff:ffff
26366b:190::/28366b:19f:ffff:ffff:ffff:ffff:ffff:ffff
27366b:1a0::/28366b:1af:ffff:ffff:ffff:ffff:ffff:ffff
28366b:1b0::/28366b:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29366b:1c0::/28366b:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30366b:1d0::/28366b:1df:ffff:ffff:ffff:ffff:ffff:ffff
31366b:1e0::/28366b:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32366b:1f0::/28366b:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33366b:200::/28366b:20f:ffff:ffff:ffff:ffff:ffff:ffff
34366b:210::/28366b:21f:ffff:ffff:ffff:ffff:ffff:ffff
35366b:220::/28366b:22f:ffff:ffff:ffff:ffff:ffff:ffff
36366b:230::/28366b:23f:ffff:ffff:ffff:ffff:ffff:ffff
37366b:240::/28366b:24f:ffff:ffff:ffff:ffff:ffff:ffff
38366b:250::/28366b:25f:ffff:ffff:ffff:ffff:ffff:ffff
39366b:260::/28366b:26f:ffff:ffff:ffff:ffff:ffff:ffff
40366b:270::/28366b:27f:ffff:ffff:ffff:ffff:ffff:ffff
41366b:280::/28366b:28f:ffff:ffff:ffff:ffff:ffff:ffff
42366b:290::/28366b:29f:ffff:ffff:ffff:ffff:ffff:ffff
43366b:2a0::/28366b:2af:ffff:ffff:ffff:ffff:ffff:ffff
44366b:2b0::/28366b:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45366b:2c0::/28366b:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46366b:2d0::/28366b:2df:ffff:ffff:ffff:ffff:ffff:ffff
47366b:2e0::/28366b:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48366b:2f0::/28366b:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49366b:300::/28366b:30f:ffff:ffff:ffff:ffff:ffff:ffff
50366b:310::/28366b:31f:ffff:ffff:ffff:ffff:ffff:ffff
51366b:320::/28366b:32f:ffff:ffff:ffff:ffff:ffff:ffff
52366b:330::/28366b:33f:ffff:ffff:ffff:ffff:ffff:ffff
53366b:340::/28366b:34f:ffff:ffff:ffff:ffff:ffff:ffff
54366b:350::/28366b:35f:ffff:ffff:ffff:ffff:ffff:ffff
55366b:360::/28366b:36f:ffff:ffff:ffff:ffff:ffff:ffff
56366b:370::/28366b:37f:ffff:ffff:ffff:ffff:ffff:ffff
57366b:380::/28366b:38f:ffff:ffff:ffff:ffff:ffff:ffff
58366b:390::/28366b:39f:ffff:ffff:ffff:ffff:ffff:ffff
59366b:3a0::/28366b:3af:ffff:ffff:ffff:ffff:ffff:ffff
60366b:3b0::/28366b:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61366b:3c0::/28366b:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62366b:3d0::/28366b:3df:ffff:ffff:ffff:ffff:ffff:ffff
63366b:3e0::/28366b:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64366b:3f0::/28366b:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65366b:400::/28366b:40f:ffff:ffff:ffff:ffff:ffff:ffff
66366b:410::/28366b:41f:ffff:ffff:ffff:ffff:ffff:ffff
67366b:420::/28366b:42f:ffff:ffff:ffff:ffff:ffff:ffff
68366b:430::/28366b:43f:ffff:ffff:ffff:ffff:ffff:ffff
69366b:440::/28366b:44f:ffff:ffff:ffff:ffff:ffff:ffff
70366b:450::/28366b:45f:ffff:ffff:ffff:ffff:ffff:ffff
71366b:460::/28366b:46f:ffff:ffff:ffff:ffff:ffff:ffff
72366b:470::/28366b:47f:ffff:ffff:ffff:ffff:ffff:ffff
73366b:480::/28366b:48f:ffff:ffff:ffff:ffff:ffff:ffff
74366b:490::/28366b:49f:ffff:ffff:ffff:ffff:ffff:ffff
75366b:4a0::/28366b:4af:ffff:ffff:ffff:ffff:ffff:ffff
76366b:4b0::/28366b:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77366b:4c0::/28366b:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78366b:4d0::/28366b:4df:ffff:ffff:ffff:ffff:ffff:ffff
79366b:4e0::/28366b:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80366b:4f0::/28366b:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81366b:500::/28366b:50f:ffff:ffff:ffff:ffff:ffff:ffff
82366b:510::/28366b:51f:ffff:ffff:ffff:ffff:ffff:ffff
83366b:520::/28366b:52f:ffff:ffff:ffff:ffff:ffff:ffff
84366b:530::/28366b:53f:ffff:ffff:ffff:ffff:ffff:ffff
85366b:540::/28366b:54f:ffff:ffff:ffff:ffff:ffff:ffff
86366b:550::/28366b:55f:ffff:ffff:ffff:ffff:ffff:ffff
87366b:560::/28366b:56f:ffff:ffff:ffff:ffff:ffff:ffff
88366b:570::/28366b:57f:ffff:ffff:ffff:ffff:ffff:ffff
89366b:580::/28366b:58f:ffff:ffff:ffff:ffff:ffff:ffff
90366b:590::/28366b:59f:ffff:ffff:ffff:ffff:ffff:ffff
91366b:5a0::/28366b:5af:ffff:ffff:ffff:ffff:ffff:ffff
92366b:5b0::/28366b:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93366b:5c0::/28366b:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94366b:5d0::/28366b:5df:ffff:ffff:ffff:ffff:ffff:ffff
95366b:5e0::/28366b:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96366b:5f0::/28366b:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97366b:600::/28366b:60f:ffff:ffff:ffff:ffff:ffff:ffff
98366b:610::/28366b:61f:ffff:ffff:ffff:ffff:ffff:ffff
99366b:620::/28366b:62f:ffff:ffff:ffff:ffff:ffff:ffff
100366b:630::/28366b:63f:ffff:ffff:ffff:ffff:ffff:ffff
101366b:640::/28366b:64f:ffff:ffff:ffff:ffff:ffff:ffff
102366b:650::/28366b:65f:ffff:ffff:ffff:ffff:ffff:ffff
103366b:660::/28366b:66f:ffff:ffff:ffff:ffff:ffff:ffff
104366b:670::/28366b:67f:ffff:ffff:ffff:ffff:ffff:ffff
105366b:680::/28366b:68f:ffff:ffff:ffff:ffff:ffff:ffff
106366b:690::/28366b:69f:ffff:ffff:ffff:ffff:ffff:ffff
107366b:6a0::/28366b:6af:ffff:ffff:ffff:ffff:ffff:ffff
108366b:6b0::/28366b:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109366b:6c0::/28366b:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110366b:6d0::/28366b:6df:ffff:ffff:ffff:ffff:ffff:ffff
111366b:6e0::/28366b:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112366b:6f0::/28366b:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113366b:700::/28366b:70f:ffff:ffff:ffff:ffff:ffff:ffff
114366b:710::/28366b:71f:ffff:ffff:ffff:ffff:ffff:ffff
115366b:720::/28366b:72f:ffff:ffff:ffff:ffff:ffff:ffff
116366b:730::/28366b:73f:ffff:ffff:ffff:ffff:ffff:ffff
117366b:740::/28366b:74f:ffff:ffff:ffff:ffff:ffff:ffff
118366b:750::/28366b:75f:ffff:ffff:ffff:ffff:ffff:ffff
119366b:760::/28366b:76f:ffff:ffff:ffff:ffff:ffff:ffff
120366b:770::/28366b:77f:ffff:ffff:ffff:ffff:ffff:ffff
121366b:780::/28366b:78f:ffff:ffff:ffff:ffff:ffff:ffff
122366b:790::/28366b:79f:ffff:ffff:ffff:ffff:ffff:ffff
123366b:7a0::/28366b:7af:ffff:ffff:ffff:ffff:ffff:ffff
124366b:7b0::/28366b:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125366b:7c0::/28366b:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126366b:7d0::/28366b:7df:ffff:ffff:ffff:ffff:ffff:ffff
127366b:7e0::/28366b:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128366b:7f0::/28366b:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129366b:800::/28366b:80f:ffff:ffff:ffff:ffff:ffff:ffff
130366b:810::/28366b:81f:ffff:ffff:ffff:ffff:ffff:ffff
131366b:820::/28366b:82f:ffff:ffff:ffff:ffff:ffff:ffff
132366b:830::/28366b:83f:ffff:ffff:ffff:ffff:ffff:ffff
133366b:840::/28366b:84f:ffff:ffff:ffff:ffff:ffff:ffff
134366b:850::/28366b:85f:ffff:ffff:ffff:ffff:ffff:ffff
135366b:860::/28366b:86f:ffff:ffff:ffff:ffff:ffff:ffff
136366b:870::/28366b:87f:ffff:ffff:ffff:ffff:ffff:ffff
137366b:880::/28366b:88f:ffff:ffff:ffff:ffff:ffff:ffff
138366b:890::/28366b:89f:ffff:ffff:ffff:ffff:ffff:ffff
139366b:8a0::/28366b:8af:ffff:ffff:ffff:ffff:ffff:ffff
140366b:8b0::/28366b:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141366b:8c0::/28366b:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142366b:8d0::/28366b:8df:ffff:ffff:ffff:ffff:ffff:ffff
143366b:8e0::/28366b:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144366b:8f0::/28366b:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145366b:900::/28366b:90f:ffff:ffff:ffff:ffff:ffff:ffff
146366b:910::/28366b:91f:ffff:ffff:ffff:ffff:ffff:ffff
147366b:920::/28366b:92f:ffff:ffff:ffff:ffff:ffff:ffff
148366b:930::/28366b:93f:ffff:ffff:ffff:ffff:ffff:ffff
149366b:940::/28366b:94f:ffff:ffff:ffff:ffff:ffff:ffff
150366b:950::/28366b:95f:ffff:ffff:ffff:ffff:ffff:ffff
151366b:960::/28366b:96f:ffff:ffff:ffff:ffff:ffff:ffff
152366b:970::/28366b:97f:ffff:ffff:ffff:ffff:ffff:ffff
153366b:980::/28366b:98f:ffff:ffff:ffff:ffff:ffff:ffff
154366b:990::/28366b:99f:ffff:ffff:ffff:ffff:ffff:ffff
155366b:9a0::/28366b:9af:ffff:ffff:ffff:ffff:ffff:ffff
156366b:9b0::/28366b:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157366b:9c0::/28366b:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158366b:9d0::/28366b:9df:ffff:ffff:ffff:ffff:ffff:ffff
159366b:9e0::/28366b:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160366b:9f0::/28366b:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161366b:a00::/28366b:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162366b:a10::/28366b:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163366b:a20::/28366b:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164366b:a30::/28366b:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165366b:a40::/28366b:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166366b:a50::/28366b:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167366b:a60::/28366b:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168366b:a70::/28366b:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169366b:a80::/28366b:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170366b:a90::/28366b:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171366b:aa0::/28366b:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172366b:ab0::/28366b:abf:ffff:ffff:ffff:ffff:ffff:ffff
173366b:ac0::/28366b:acf:ffff:ffff:ffff:ffff:ffff:ffff
174366b:ad0::/28366b:adf:ffff:ffff:ffff:ffff:ffff:ffff
175366b:ae0::/28366b:aef:ffff:ffff:ffff:ffff:ffff:ffff
176366b:af0::/28366b:aff:ffff:ffff:ffff:ffff:ffff:ffff
177366b:b00::/28366b:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178366b:b10::/28366b:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179366b:b20::/28366b:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180366b:b30::/28366b:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181366b:b40::/28366b:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182366b:b50::/28366b:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183366b:b60::/28366b:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184366b:b70::/28366b:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185366b:b80::/28366b:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186366b:b90::/28366b:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187366b:ba0::/28366b:baf:ffff:ffff:ffff:ffff:ffff:ffff
188366b:bb0::/28366b:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189366b:bc0::/28366b:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190366b:bd0::/28366b:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191366b:be0::/28366b:bef:ffff:ffff:ffff:ffff:ffff:ffff
192366b:bf0::/28366b:bff:ffff:ffff:ffff:ffff:ffff:ffff
193366b:c00::/28366b:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194366b:c10::/28366b:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195366b:c20::/28366b:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196366b:c30::/28366b:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197366b:c40::/28366b:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198366b:c50::/28366b:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199366b:c60::/28366b:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200366b:c70::/28366b:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201366b:c80::/28366b:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202366b:c90::/28366b:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203366b:ca0::/28366b:caf:ffff:ffff:ffff:ffff:ffff:ffff
204366b:cb0::/28366b:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205366b:cc0::/28366b:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206366b:cd0::/28366b:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207366b:ce0::/28366b:cef:ffff:ffff:ffff:ffff:ffff:ffff
208366b:cf0::/28366b:cff:ffff:ffff:ffff:ffff:ffff:ffff
209366b:d00::/28366b:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210366b:d10::/28366b:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211366b:d20::/28366b:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212366b:d30::/28366b:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213366b:d40::/28366b:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214366b:d50::/28366b:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215366b:d60::/28366b:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216366b:d70::/28366b:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217366b:d80::/28366b:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218366b:d90::/28366b:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219366b:da0::/28366b:daf:ffff:ffff:ffff:ffff:ffff:ffff
220366b:db0::/28366b:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221366b:dc0::/28366b:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222366b:dd0::/28366b:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223366b:de0::/28366b:def:ffff:ffff:ffff:ffff:ffff:ffff
224366b:df0::/28366b:dff:ffff:ffff:ffff:ffff:ffff:ffff
225366b:e00::/28366b:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226366b:e10::/28366b:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227366b:e20::/28366b:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228366b:e30::/28366b:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229366b:e40::/28366b:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230366b:e50::/28366b:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231366b:e60::/28366b:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232366b:e70::/28366b:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233366b:e80::/28366b:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234366b:e90::/28366b:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235366b:ea0::/28366b:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236366b:eb0::/28366b:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237366b:ec0::/28366b:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238366b:ed0::/28366b:edf:ffff:ffff:ffff:ffff:ffff:ffff
239366b:ee0::/28366b:eef:ffff:ffff:ffff:ffff:ffff:ffff
240366b:ef0::/28366b:eff:ffff:ffff:ffff:ffff:ffff:ffff
241366b:f00::/28366b:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242366b:f10::/28366b:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243366b:f20::/28366b:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244366b:f30::/28366b:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245366b:f40::/28366b:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246366b:f50::/28366b:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247366b:f60::/28366b:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248366b:f70::/28366b:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249366b:f80::/28366b:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250366b:f90::/28366b:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251366b:fa0::/28366b:faf:ffff:ffff:ffff:ffff:ffff:ffff
252366b:fb0::/28366b:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253366b:fc0::/28366b:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254366b:fd0::/28366b:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255366b:fe0::/28366b:fef:ffff:ffff:ffff:ffff:ffff:ffff
256366b:ff0::/28366b: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.