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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/19
Addresses2^109
/64 networks2^45
Network
ffef::/19
First address
ffef::
Last address
ffef:1fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
649,037,107,316,853,453,566,312,041,152,512 (2^109)
/64 networks (LANs)
35,184,372,088,832 (2^45)
Full form
ffef:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zones
0.f.e.f.f.ip6.arpa
1.f.e.f.f.ip6.arpa
/19 is not on a 4-bit boundary, so it takes 2 /20 zones.
Split into smaller subnets/28
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/28 (512)/32 (8,192)

ffef::/19 makes 512 subnets of /28; the first 256 are listed.

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