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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/12
Addresses2^116
/64 networks2^52
Network
fdf0::/12
First address
fdf0::
Last address
fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
83,076,749,736,557,242,056,487,941,267,521,536 (2^116)
/64 networks (LANs)
4,503,599,627,370,496 (2^52)
Full form
fdf0:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
f.d.f.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

fdf0::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fdf0::/28fdf0:f:ffff:ffff:ffff:ffff:ffff:ffff
2fdf0:10::/28fdf0:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fdf0:20::/28fdf0:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fdf0:30::/28fdf0:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fdf0:40::/28fdf0:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fdf0:50::/28fdf0:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fdf0:60::/28fdf0:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fdf0:70::/28fdf0:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fdf0:80::/28fdf0:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fdf0:90::/28fdf0:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fdf0:a0::/28fdf0:af:ffff:ffff:ffff:ffff:ffff:ffff
12fdf0:b0::/28fdf0:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fdf0:c0::/28fdf0:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fdf0:d0::/28fdf0:df:ffff:ffff:ffff:ffff:ffff:ffff
15fdf0:e0::/28fdf0:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fdf0:f0::/28fdf0:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fdf0:100::/28fdf0:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fdf0:110::/28fdf0:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fdf0:120::/28fdf0:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fdf0:130::/28fdf0:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fdf0:140::/28fdf0:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fdf0:150::/28fdf0:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fdf0:160::/28fdf0:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fdf0:170::/28fdf0:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fdf0:180::/28fdf0:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fdf0:190::/28fdf0:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fdf0:1a0::/28fdf0:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fdf0:1b0::/28fdf0:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fdf0:1c0::/28fdf0:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fdf0:1d0::/28fdf0:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fdf0:1e0::/28fdf0:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fdf0:1f0::/28fdf0:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fdf0:200::/28fdf0:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fdf0:210::/28fdf0:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fdf0:220::/28fdf0:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fdf0:230::/28fdf0:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fdf0:240::/28fdf0:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fdf0:250::/28fdf0:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fdf0:260::/28fdf0:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fdf0:270::/28fdf0:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fdf0:280::/28fdf0:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fdf0:290::/28fdf0:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fdf0:2a0::/28fdf0:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fdf0:2b0::/28fdf0:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fdf0:2c0::/28fdf0:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fdf0:2d0::/28fdf0:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fdf0:2e0::/28fdf0:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fdf0:2f0::/28fdf0:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fdf0:300::/28fdf0:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fdf0:310::/28fdf0:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fdf0:320::/28fdf0:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fdf0:330::/28fdf0:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fdf0:340::/28fdf0:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fdf0:350::/28fdf0:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fdf0:360::/28fdf0:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fdf0:370::/28fdf0:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fdf0:380::/28fdf0:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fdf0:390::/28fdf0:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fdf0:3a0::/28fdf0:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fdf0:3b0::/28fdf0:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fdf0:3c0::/28fdf0:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fdf0:3d0::/28fdf0:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fdf0:3e0::/28fdf0:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fdf0:3f0::/28fdf0:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fdf0:400::/28fdf0:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fdf0:410::/28fdf0:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fdf0:420::/28fdf0:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fdf0:430::/28fdf0:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fdf0:440::/28fdf0:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fdf0:450::/28fdf0:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fdf0:460::/28fdf0:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fdf0:470::/28fdf0:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fdf0:480::/28fdf0:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fdf0:490::/28fdf0:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fdf0:4a0::/28fdf0:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fdf0:4b0::/28fdf0:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fdf0:4c0::/28fdf0:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fdf0:4d0::/28fdf0:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fdf0:4e0::/28fdf0:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fdf0:4f0::/28fdf0:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fdf0:500::/28fdf0:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fdf0:510::/28fdf0:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fdf0:520::/28fdf0:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fdf0:530::/28fdf0:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fdf0:540::/28fdf0:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fdf0:550::/28fdf0:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fdf0:560::/28fdf0:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fdf0:570::/28fdf0:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fdf0:580::/28fdf0:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fdf0:590::/28fdf0:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fdf0:5a0::/28fdf0:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fdf0:5b0::/28fdf0:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fdf0:5c0::/28fdf0:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fdf0:5d0::/28fdf0:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fdf0:5e0::/28fdf0:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fdf0:5f0::/28fdf0:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fdf0:600::/28fdf0:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fdf0:610::/28fdf0:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fdf0:620::/28fdf0:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fdf0:630::/28fdf0:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fdf0:640::/28fdf0:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fdf0:650::/28fdf0:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fdf0:660::/28fdf0:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fdf0:670::/28fdf0:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fdf0:680::/28fdf0:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fdf0:690::/28fdf0:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fdf0:6a0::/28fdf0:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fdf0:6b0::/28fdf0:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fdf0:6c0::/28fdf0:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fdf0:6d0::/28fdf0:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fdf0:6e0::/28fdf0:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fdf0:6f0::/28fdf0:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fdf0:700::/28fdf0:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fdf0:710::/28fdf0:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fdf0:720::/28fdf0:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fdf0:730::/28fdf0:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fdf0:740::/28fdf0:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fdf0:750::/28fdf0:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fdf0:760::/28fdf0:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fdf0:770::/28fdf0:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fdf0:780::/28fdf0:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fdf0:790::/28fdf0:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fdf0:7a0::/28fdf0:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fdf0:7b0::/28fdf0:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fdf0:7c0::/28fdf0:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fdf0:7d0::/28fdf0:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fdf0:7e0::/28fdf0:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fdf0:7f0::/28fdf0:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fdf0:800::/28fdf0:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fdf0:810::/28fdf0:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fdf0:820::/28fdf0:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fdf0:830::/28fdf0:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fdf0:840::/28fdf0:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fdf0:850::/28fdf0:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fdf0:860::/28fdf0:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fdf0:870::/28fdf0:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fdf0:880::/28fdf0:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fdf0:890::/28fdf0:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fdf0:8a0::/28fdf0:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fdf0:8b0::/28fdf0:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fdf0:8c0::/28fdf0:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fdf0:8d0::/28fdf0:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fdf0:8e0::/28fdf0:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fdf0:8f0::/28fdf0:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fdf0:900::/28fdf0:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fdf0:910::/28fdf0:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fdf0:920::/28fdf0:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fdf0:930::/28fdf0:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fdf0:940::/28fdf0:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fdf0:950::/28fdf0:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fdf0:960::/28fdf0:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fdf0:970::/28fdf0:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fdf0:980::/28fdf0:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fdf0:990::/28fdf0:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fdf0:9a0::/28fdf0:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fdf0:9b0::/28fdf0:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fdf0:9c0::/28fdf0:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fdf0:9d0::/28fdf0:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fdf0:9e0::/28fdf0:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fdf0:9f0::/28fdf0:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fdf0:a00::/28fdf0:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fdf0:a10::/28fdf0:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fdf0:a20::/28fdf0:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fdf0:a30::/28fdf0:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fdf0:a40::/28fdf0:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fdf0:a50::/28fdf0:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fdf0:a60::/28fdf0:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fdf0:a70::/28fdf0:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fdf0:a80::/28fdf0:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fdf0:a90::/28fdf0:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fdf0:aa0::/28fdf0:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fdf0:ab0::/28fdf0:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fdf0:ac0::/28fdf0:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fdf0:ad0::/28fdf0:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fdf0:ae0::/28fdf0:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fdf0:af0::/28fdf0:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fdf0:b00::/28fdf0:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fdf0:b10::/28fdf0:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fdf0:b20::/28fdf0:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fdf0:b30::/28fdf0:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fdf0:b40::/28fdf0:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fdf0:b50::/28fdf0:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fdf0:b60::/28fdf0:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fdf0:b70::/28fdf0:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fdf0:b80::/28fdf0:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fdf0:b90::/28fdf0:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fdf0:ba0::/28fdf0:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fdf0:bb0::/28fdf0:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fdf0:bc0::/28fdf0:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fdf0:bd0::/28fdf0:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fdf0:be0::/28fdf0:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fdf0:bf0::/28fdf0:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fdf0:c00::/28fdf0:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fdf0:c10::/28fdf0:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fdf0:c20::/28fdf0:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fdf0:c30::/28fdf0:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fdf0:c40::/28fdf0:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fdf0:c50::/28fdf0:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fdf0:c60::/28fdf0:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fdf0:c70::/28fdf0:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fdf0:c80::/28fdf0:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fdf0:c90::/28fdf0:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fdf0:ca0::/28fdf0:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fdf0:cb0::/28fdf0:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fdf0:cc0::/28fdf0:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fdf0:cd0::/28fdf0:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fdf0:ce0::/28fdf0:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fdf0:cf0::/28fdf0:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fdf0:d00::/28fdf0:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fdf0:d10::/28fdf0:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fdf0:d20::/28fdf0:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fdf0:d30::/28fdf0:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fdf0:d40::/28fdf0:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fdf0:d50::/28fdf0:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fdf0:d60::/28fdf0:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fdf0:d70::/28fdf0:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fdf0:d80::/28fdf0:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fdf0:d90::/28fdf0:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fdf0:da0::/28fdf0:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fdf0:db0::/28fdf0:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fdf0:dc0::/28fdf0:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fdf0:dd0::/28fdf0:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fdf0:de0::/28fdf0:def:ffff:ffff:ffff:ffff:ffff:ffff
224fdf0:df0::/28fdf0:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fdf0:e00::/28fdf0:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fdf0:e10::/28fdf0:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fdf0:e20::/28fdf0:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fdf0:e30::/28fdf0:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fdf0:e40::/28fdf0:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fdf0:e50::/28fdf0:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fdf0:e60::/28fdf0:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fdf0:e70::/28fdf0:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fdf0:e80::/28fdf0:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fdf0:e90::/28fdf0:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fdf0:ea0::/28fdf0:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fdf0:eb0::/28fdf0:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fdf0:ec0::/28fdf0:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fdf0:ed0::/28fdf0:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fdf0:ee0::/28fdf0:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fdf0:ef0::/28fdf0:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fdf0:f00::/28fdf0:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fdf0:f10::/28fdf0:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fdf0:f20::/28fdf0:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fdf0:f30::/28fdf0:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fdf0:f40::/28fdf0:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fdf0:f50::/28fdf0:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fdf0:f60::/28fdf0:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fdf0:f70::/28fdf0:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fdf0:f80::/28fdf0:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fdf0:f90::/28fdf0:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fdf0:fa0::/28fdf0:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fdf0:fb0::/28fdf0:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fdf0:fc0::/28fdf0:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fdf0:fd0::/28fdf0:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fdf0:fe0::/28fdf0:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fdf0:ff0::/28fdf0: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.