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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/15
Addresses2^113
/64 networks2^49
Network
fca8::/15
First address
fca8::
Last address
fca9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
10,384,593,717,069,655,257,060,992,658,440,192 (2^113)
/64 networks (LANs)
562,949,953,421,312 (2^49)
Full form
fca8:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zones
8.a.c.f.ip6.arpa
9.a.c.f.ip6.arpa
/15 is not on a 4-bit boundary, so it takes 2 /16 zones.
Split into smaller subnets/28
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/24 (512)/28 (8,192)

fca8::/15 makes 8,192 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fca8::/28fca8:f:ffff:ffff:ffff:ffff:ffff:ffff
2fca8:10::/28fca8:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fca8:20::/28fca8:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fca8:30::/28fca8:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fca8:40::/28fca8:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fca8:50::/28fca8:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fca8:60::/28fca8:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fca8:70::/28fca8:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fca8:80::/28fca8:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fca8:90::/28fca8:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fca8:a0::/28fca8:af:ffff:ffff:ffff:ffff:ffff:ffff
12fca8:b0::/28fca8:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fca8:c0::/28fca8:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fca8:d0::/28fca8:df:ffff:ffff:ffff:ffff:ffff:ffff
15fca8:e0::/28fca8:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fca8:f0::/28fca8:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fca8:100::/28fca8:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fca8:110::/28fca8:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fca8:120::/28fca8:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fca8:130::/28fca8:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fca8:140::/28fca8:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fca8:150::/28fca8:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fca8:160::/28fca8:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fca8:170::/28fca8:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fca8:180::/28fca8:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fca8:190::/28fca8:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fca8:1a0::/28fca8:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fca8:1b0::/28fca8:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fca8:1c0::/28fca8:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fca8:1d0::/28fca8:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fca8:1e0::/28fca8:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fca8:1f0::/28fca8:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fca8:200::/28fca8:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fca8:210::/28fca8:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fca8:220::/28fca8:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fca8:230::/28fca8:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fca8:240::/28fca8:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fca8:250::/28fca8:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fca8:260::/28fca8:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fca8:270::/28fca8:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fca8:280::/28fca8:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fca8:290::/28fca8:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fca8:2a0::/28fca8:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fca8:2b0::/28fca8:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fca8:2c0::/28fca8:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fca8:2d0::/28fca8:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fca8:2e0::/28fca8:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fca8:2f0::/28fca8:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fca8:300::/28fca8:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fca8:310::/28fca8:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fca8:320::/28fca8:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fca8:330::/28fca8:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fca8:340::/28fca8:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fca8:350::/28fca8:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fca8:360::/28fca8:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fca8:370::/28fca8:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fca8:380::/28fca8:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fca8:390::/28fca8:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fca8:3a0::/28fca8:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fca8:3b0::/28fca8:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fca8:3c0::/28fca8:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fca8:3d0::/28fca8:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fca8:3e0::/28fca8:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fca8:3f0::/28fca8:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fca8:400::/28fca8:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fca8:410::/28fca8:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fca8:420::/28fca8:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fca8:430::/28fca8:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fca8:440::/28fca8:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fca8:450::/28fca8:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fca8:460::/28fca8:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fca8:470::/28fca8:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fca8:480::/28fca8:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fca8:490::/28fca8:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fca8:4a0::/28fca8:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fca8:4b0::/28fca8:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fca8:4c0::/28fca8:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fca8:4d0::/28fca8:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fca8:4e0::/28fca8:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fca8:4f0::/28fca8:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fca8:500::/28fca8:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fca8:510::/28fca8:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fca8:520::/28fca8:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fca8:530::/28fca8:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fca8:540::/28fca8:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fca8:550::/28fca8:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fca8:560::/28fca8:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fca8:570::/28fca8:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fca8:580::/28fca8:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fca8:590::/28fca8:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fca8:5a0::/28fca8:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fca8:5b0::/28fca8:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fca8:5c0::/28fca8:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fca8:5d0::/28fca8:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fca8:5e0::/28fca8:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fca8:5f0::/28fca8:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fca8:600::/28fca8:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fca8:610::/28fca8:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fca8:620::/28fca8:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fca8:630::/28fca8:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fca8:640::/28fca8:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fca8:650::/28fca8:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fca8:660::/28fca8:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fca8:670::/28fca8:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fca8:680::/28fca8:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fca8:690::/28fca8:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fca8:6a0::/28fca8:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fca8:6b0::/28fca8:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fca8:6c0::/28fca8:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fca8:6d0::/28fca8:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fca8:6e0::/28fca8:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fca8:6f0::/28fca8:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fca8:700::/28fca8:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fca8:710::/28fca8:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fca8:720::/28fca8:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fca8:730::/28fca8:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fca8:740::/28fca8:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fca8:750::/28fca8:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fca8:760::/28fca8:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fca8:770::/28fca8:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fca8:780::/28fca8:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fca8:790::/28fca8:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fca8:7a0::/28fca8:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fca8:7b0::/28fca8:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fca8:7c0::/28fca8:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fca8:7d0::/28fca8:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fca8:7e0::/28fca8:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fca8:7f0::/28fca8:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fca8:800::/28fca8:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fca8:810::/28fca8:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fca8:820::/28fca8:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fca8:830::/28fca8:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fca8:840::/28fca8:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fca8:850::/28fca8:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fca8:860::/28fca8:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fca8:870::/28fca8:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fca8:880::/28fca8:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fca8:890::/28fca8:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fca8:8a0::/28fca8:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fca8:8b0::/28fca8:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fca8:8c0::/28fca8:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fca8:8d0::/28fca8:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fca8:8e0::/28fca8:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fca8:8f0::/28fca8:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fca8:900::/28fca8:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fca8:910::/28fca8:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fca8:920::/28fca8:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fca8:930::/28fca8:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fca8:940::/28fca8:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fca8:950::/28fca8:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fca8:960::/28fca8:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fca8:970::/28fca8:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fca8:980::/28fca8:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fca8:990::/28fca8:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fca8:9a0::/28fca8:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fca8:9b0::/28fca8:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fca8:9c0::/28fca8:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fca8:9d0::/28fca8:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fca8:9e0::/28fca8:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fca8:9f0::/28fca8:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fca8:a00::/28fca8:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fca8:a10::/28fca8:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fca8:a20::/28fca8:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fca8:a30::/28fca8:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fca8:a40::/28fca8:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fca8:a50::/28fca8:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fca8:a60::/28fca8:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fca8:a70::/28fca8:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fca8:a80::/28fca8:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fca8:a90::/28fca8:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fca8:aa0::/28fca8:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fca8:ab0::/28fca8:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fca8:ac0::/28fca8:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fca8:ad0::/28fca8:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fca8:ae0::/28fca8:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fca8:af0::/28fca8:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fca8:b00::/28fca8:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fca8:b10::/28fca8:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fca8:b20::/28fca8:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fca8:b30::/28fca8:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fca8:b40::/28fca8:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fca8:b50::/28fca8:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fca8:b60::/28fca8:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fca8:b70::/28fca8:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fca8:b80::/28fca8:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fca8:b90::/28fca8:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fca8:ba0::/28fca8:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fca8:bb0::/28fca8:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fca8:bc0::/28fca8:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fca8:bd0::/28fca8:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fca8:be0::/28fca8:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fca8:bf0::/28fca8:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fca8:c00::/28fca8:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fca8:c10::/28fca8:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fca8:c20::/28fca8:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fca8:c30::/28fca8:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fca8:c40::/28fca8:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fca8:c50::/28fca8:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fca8:c60::/28fca8:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fca8:c70::/28fca8:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fca8:c80::/28fca8:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fca8:c90::/28fca8:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fca8:ca0::/28fca8:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fca8:cb0::/28fca8:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fca8:cc0::/28fca8:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fca8:cd0::/28fca8:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fca8:ce0::/28fca8:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fca8:cf0::/28fca8:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fca8:d00::/28fca8:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fca8:d10::/28fca8:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fca8:d20::/28fca8:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fca8:d30::/28fca8:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fca8:d40::/28fca8:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fca8:d50::/28fca8:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fca8:d60::/28fca8:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fca8:d70::/28fca8:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fca8:d80::/28fca8:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fca8:d90::/28fca8:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fca8:da0::/28fca8:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fca8:db0::/28fca8:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fca8:dc0::/28fca8:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fca8:dd0::/28fca8:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fca8:de0::/28fca8:def:ffff:ffff:ffff:ffff:ffff:ffff
224fca8:df0::/28fca8:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fca8:e00::/28fca8:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fca8:e10::/28fca8:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fca8:e20::/28fca8:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fca8:e30::/28fca8:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fca8:e40::/28fca8:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fca8:e50::/28fca8:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fca8:e60::/28fca8:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fca8:e70::/28fca8:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fca8:e80::/28fca8:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fca8:e90::/28fca8:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fca8:ea0::/28fca8:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fca8:eb0::/28fca8:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fca8:ec0::/28fca8:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fca8:ed0::/28fca8:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fca8:ee0::/28fca8:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fca8:ef0::/28fca8:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fca8:f00::/28fca8:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fca8:f10::/28fca8:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fca8:f20::/28fca8:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fca8:f30::/28fca8:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fca8:f40::/28fca8:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fca8:f50::/28fca8:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fca8:f60::/28fca8:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fca8:f70::/28fca8:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fca8:f80::/28fca8:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fca8:f90::/28fca8:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fca8:fa0::/28fca8:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fca8:fb0::/28fca8:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fca8:fc0::/28fca8:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fca8:fd0::/28fca8:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fca8:fe0::/28fca8:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fca8:ff0::/28fca8: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.