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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/18
Addresses2^110
/64 networks2^46
Network
febd::/18
First address
febd::
Last address
febd:3fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
1,298,074,214,633,706,907,132,624,082,305,024 (2^110)
/64 networks (LANs)
70,368,744,177,664 (2^46)
Full form
febd:0000:0000:0000:0000:0000:0000:0000
Type
Link-local fe80::/10
Every IPv6 interface has one; not routed
Reverse DNS zones
0.d.b.e.f.ip6.arpa
1.d.b.e.f.ip6.arpa
2.d.b.e.f.ip6.arpa
3.d.b.e.f.ip6.arpa
/18 is not on a 4-bit boundary, so it takes 4 /20 zones.
Split into smaller subnets/28
/19 (2)/20 (4)/21 (8)/22 (16)/24 (64)/28 (1,024)/32 (16,384)

febd::/18 makes 1,024 subnets of /28; the first 256 are listed.

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