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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
fca2::/16
First address
fca2::
Last address
fca2: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
fca2:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
2.a.c.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fca2::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fca2::/32fca2:0:ffff:ffff:ffff:ffff:ffff:ffff
2fca2:1::/32fca2:1:ffff:ffff:ffff:ffff:ffff:ffff
3fca2:2::/32fca2:2:ffff:ffff:ffff:ffff:ffff:ffff
4fca2:3::/32fca2:3:ffff:ffff:ffff:ffff:ffff:ffff
5fca2:4::/32fca2:4:ffff:ffff:ffff:ffff:ffff:ffff
6fca2:5::/32fca2:5:ffff:ffff:ffff:ffff:ffff:ffff
7fca2:6::/32fca2:6:ffff:ffff:ffff:ffff:ffff:ffff
8fca2:7::/32fca2:7:ffff:ffff:ffff:ffff:ffff:ffff
9fca2:8::/32fca2:8:ffff:ffff:ffff:ffff:ffff:ffff
10fca2:9::/32fca2:9:ffff:ffff:ffff:ffff:ffff:ffff
11fca2:a::/32fca2:a:ffff:ffff:ffff:ffff:ffff:ffff
12fca2:b::/32fca2:b:ffff:ffff:ffff:ffff:ffff:ffff
13fca2:c::/32fca2:c:ffff:ffff:ffff:ffff:ffff:ffff
14fca2:d::/32fca2:d:ffff:ffff:ffff:ffff:ffff:ffff
15fca2:e::/32fca2:e:ffff:ffff:ffff:ffff:ffff:ffff
16fca2:f::/32fca2:f:ffff:ffff:ffff:ffff:ffff:ffff
17fca2:10::/32fca2:10:ffff:ffff:ffff:ffff:ffff:ffff
18fca2:11::/32fca2:11:ffff:ffff:ffff:ffff:ffff:ffff
19fca2:12::/32fca2:12:ffff:ffff:ffff:ffff:ffff:ffff
20fca2:13::/32fca2:13:ffff:ffff:ffff:ffff:ffff:ffff
21fca2:14::/32fca2:14:ffff:ffff:ffff:ffff:ffff:ffff
22fca2:15::/32fca2:15:ffff:ffff:ffff:ffff:ffff:ffff
23fca2:16::/32fca2:16:ffff:ffff:ffff:ffff:ffff:ffff
24fca2:17::/32fca2:17:ffff:ffff:ffff:ffff:ffff:ffff
25fca2:18::/32fca2:18:ffff:ffff:ffff:ffff:ffff:ffff
26fca2:19::/32fca2:19:ffff:ffff:ffff:ffff:ffff:ffff
27fca2:1a::/32fca2:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fca2:1b::/32fca2:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fca2:1c::/32fca2:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fca2:1d::/32fca2:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fca2:1e::/32fca2:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fca2:1f::/32fca2:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fca2:20::/32fca2:20:ffff:ffff:ffff:ffff:ffff:ffff
34fca2:21::/32fca2:21:ffff:ffff:ffff:ffff:ffff:ffff
35fca2:22::/32fca2:22:ffff:ffff:ffff:ffff:ffff:ffff
36fca2:23::/32fca2:23:ffff:ffff:ffff:ffff:ffff:ffff
37fca2:24::/32fca2:24:ffff:ffff:ffff:ffff:ffff:ffff
38fca2:25::/32fca2:25:ffff:ffff:ffff:ffff:ffff:ffff
39fca2:26::/32fca2:26:ffff:ffff:ffff:ffff:ffff:ffff
40fca2:27::/32fca2:27:ffff:ffff:ffff:ffff:ffff:ffff
41fca2:28::/32fca2:28:ffff:ffff:ffff:ffff:ffff:ffff
42fca2:29::/32fca2:29:ffff:ffff:ffff:ffff:ffff:ffff
43fca2:2a::/32fca2:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fca2:2b::/32fca2:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fca2:2c::/32fca2:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fca2:2d::/32fca2:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fca2:2e::/32fca2:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fca2:2f::/32fca2:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fca2:30::/32fca2:30:ffff:ffff:ffff:ffff:ffff:ffff
50fca2:31::/32fca2:31:ffff:ffff:ffff:ffff:ffff:ffff
51fca2:32::/32fca2:32:ffff:ffff:ffff:ffff:ffff:ffff
52fca2:33::/32fca2:33:ffff:ffff:ffff:ffff:ffff:ffff
53fca2:34::/32fca2:34:ffff:ffff:ffff:ffff:ffff:ffff
54fca2:35::/32fca2:35:ffff:ffff:ffff:ffff:ffff:ffff
55fca2:36::/32fca2:36:ffff:ffff:ffff:ffff:ffff:ffff
56fca2:37::/32fca2:37:ffff:ffff:ffff:ffff:ffff:ffff
57fca2:38::/32fca2:38:ffff:ffff:ffff:ffff:ffff:ffff
58fca2:39::/32fca2:39:ffff:ffff:ffff:ffff:ffff:ffff
59fca2:3a::/32fca2:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fca2:3b::/32fca2:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fca2:3c::/32fca2:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fca2:3d::/32fca2:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fca2:3e::/32fca2:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fca2:3f::/32fca2:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fca2:40::/32fca2:40:ffff:ffff:ffff:ffff:ffff:ffff
66fca2:41::/32fca2:41:ffff:ffff:ffff:ffff:ffff:ffff
67fca2:42::/32fca2:42:ffff:ffff:ffff:ffff:ffff:ffff
68fca2:43::/32fca2:43:ffff:ffff:ffff:ffff:ffff:ffff
69fca2:44::/32fca2:44:ffff:ffff:ffff:ffff:ffff:ffff
70fca2:45::/32fca2:45:ffff:ffff:ffff:ffff:ffff:ffff
71fca2:46::/32fca2:46:ffff:ffff:ffff:ffff:ffff:ffff
72fca2:47::/32fca2:47:ffff:ffff:ffff:ffff:ffff:ffff
73fca2:48::/32fca2:48:ffff:ffff:ffff:ffff:ffff:ffff
74fca2:49::/32fca2:49:ffff:ffff:ffff:ffff:ffff:ffff
75fca2:4a::/32fca2:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fca2:4b::/32fca2:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fca2:4c::/32fca2:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fca2:4d::/32fca2:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fca2:4e::/32fca2:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fca2:4f::/32fca2:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fca2:50::/32fca2:50:ffff:ffff:ffff:ffff:ffff:ffff
82fca2:51::/32fca2:51:ffff:ffff:ffff:ffff:ffff:ffff
83fca2:52::/32fca2:52:ffff:ffff:ffff:ffff:ffff:ffff
84fca2:53::/32fca2:53:ffff:ffff:ffff:ffff:ffff:ffff
85fca2:54::/32fca2:54:ffff:ffff:ffff:ffff:ffff:ffff
86fca2:55::/32fca2:55:ffff:ffff:ffff:ffff:ffff:ffff
87fca2:56::/32fca2:56:ffff:ffff:ffff:ffff:ffff:ffff
88fca2:57::/32fca2:57:ffff:ffff:ffff:ffff:ffff:ffff
89fca2:58::/32fca2:58:ffff:ffff:ffff:ffff:ffff:ffff
90fca2:59::/32fca2:59:ffff:ffff:ffff:ffff:ffff:ffff
91fca2:5a::/32fca2:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fca2:5b::/32fca2:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fca2:5c::/32fca2:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fca2:5d::/32fca2:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fca2:5e::/32fca2:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fca2:5f::/32fca2:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fca2:60::/32fca2:60:ffff:ffff:ffff:ffff:ffff:ffff
98fca2:61::/32fca2:61:ffff:ffff:ffff:ffff:ffff:ffff
99fca2:62::/32fca2:62:ffff:ffff:ffff:ffff:ffff:ffff
100fca2:63::/32fca2:63:ffff:ffff:ffff:ffff:ffff:ffff
101fca2:64::/32fca2:64:ffff:ffff:ffff:ffff:ffff:ffff
102fca2:65::/32fca2:65:ffff:ffff:ffff:ffff:ffff:ffff
103fca2:66::/32fca2:66:ffff:ffff:ffff:ffff:ffff:ffff
104fca2:67::/32fca2:67:ffff:ffff:ffff:ffff:ffff:ffff
105fca2:68::/32fca2:68:ffff:ffff:ffff:ffff:ffff:ffff
106fca2:69::/32fca2:69:ffff:ffff:ffff:ffff:ffff:ffff
107fca2:6a::/32fca2:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fca2:6b::/32fca2:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fca2:6c::/32fca2:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fca2:6d::/32fca2:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fca2:6e::/32fca2:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fca2:6f::/32fca2:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fca2:70::/32fca2:70:ffff:ffff:ffff:ffff:ffff:ffff
114fca2:71::/32fca2:71:ffff:ffff:ffff:ffff:ffff:ffff
115fca2:72::/32fca2:72:ffff:ffff:ffff:ffff:ffff:ffff
116fca2:73::/32fca2:73:ffff:ffff:ffff:ffff:ffff:ffff
117fca2:74::/32fca2:74:ffff:ffff:ffff:ffff:ffff:ffff
118fca2:75::/32fca2:75:ffff:ffff:ffff:ffff:ffff:ffff
119fca2:76::/32fca2:76:ffff:ffff:ffff:ffff:ffff:ffff
120fca2:77::/32fca2:77:ffff:ffff:ffff:ffff:ffff:ffff
121fca2:78::/32fca2:78:ffff:ffff:ffff:ffff:ffff:ffff
122fca2:79::/32fca2:79:ffff:ffff:ffff:ffff:ffff:ffff
123fca2:7a::/32fca2:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fca2:7b::/32fca2:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fca2:7c::/32fca2:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fca2:7d::/32fca2:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fca2:7e::/32fca2:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fca2:7f::/32fca2:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fca2:80::/32fca2:80:ffff:ffff:ffff:ffff:ffff:ffff
130fca2:81::/32fca2:81:ffff:ffff:ffff:ffff:ffff:ffff
131fca2:82::/32fca2:82:ffff:ffff:ffff:ffff:ffff:ffff
132fca2:83::/32fca2:83:ffff:ffff:ffff:ffff:ffff:ffff
133fca2:84::/32fca2:84:ffff:ffff:ffff:ffff:ffff:ffff
134fca2:85::/32fca2:85:ffff:ffff:ffff:ffff:ffff:ffff
135fca2:86::/32fca2:86:ffff:ffff:ffff:ffff:ffff:ffff
136fca2:87::/32fca2:87:ffff:ffff:ffff:ffff:ffff:ffff
137fca2:88::/32fca2:88:ffff:ffff:ffff:ffff:ffff:ffff
138fca2:89::/32fca2:89:ffff:ffff:ffff:ffff:ffff:ffff
139fca2:8a::/32fca2:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fca2:8b::/32fca2:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fca2:8c::/32fca2:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fca2:8d::/32fca2:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fca2:8e::/32fca2:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fca2:8f::/32fca2:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fca2:90::/32fca2:90:ffff:ffff:ffff:ffff:ffff:ffff
146fca2:91::/32fca2:91:ffff:ffff:ffff:ffff:ffff:ffff
147fca2:92::/32fca2:92:ffff:ffff:ffff:ffff:ffff:ffff
148fca2:93::/32fca2:93:ffff:ffff:ffff:ffff:ffff:ffff
149fca2:94::/32fca2:94:ffff:ffff:ffff:ffff:ffff:ffff
150fca2:95::/32fca2:95:ffff:ffff:ffff:ffff:ffff:ffff
151fca2:96::/32fca2:96:ffff:ffff:ffff:ffff:ffff:ffff
152fca2:97::/32fca2:97:ffff:ffff:ffff:ffff:ffff:ffff
153fca2:98::/32fca2:98:ffff:ffff:ffff:ffff:ffff:ffff
154fca2:99::/32fca2:99:ffff:ffff:ffff:ffff:ffff:ffff
155fca2:9a::/32fca2:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fca2:9b::/32fca2:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fca2:9c::/32fca2:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fca2:9d::/32fca2:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fca2:9e::/32fca2:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fca2:9f::/32fca2:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fca2:a0::/32fca2:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fca2:a1::/32fca2:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fca2:a2::/32fca2:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fca2:a3::/32fca2:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fca2:a4::/32fca2:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fca2:a5::/32fca2:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fca2:a6::/32fca2:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fca2:a7::/32fca2:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fca2:a8::/32fca2:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fca2:a9::/32fca2:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fca2:aa::/32fca2:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fca2:ab::/32fca2:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fca2:ac::/32fca2:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fca2:ad::/32fca2:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fca2:ae::/32fca2:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fca2:af::/32fca2:af:ffff:ffff:ffff:ffff:ffff:ffff
177fca2:b0::/32fca2:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fca2:b1::/32fca2:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fca2:b2::/32fca2:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fca2:b3::/32fca2:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fca2:b4::/32fca2:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fca2:b5::/32fca2:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fca2:b6::/32fca2:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fca2:b7::/32fca2:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fca2:b8::/32fca2:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fca2:b9::/32fca2:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fca2:ba::/32fca2:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fca2:bb::/32fca2:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fca2:bc::/32fca2:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fca2:bd::/32fca2:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fca2:be::/32fca2:be:ffff:ffff:ffff:ffff:ffff:ffff
192fca2:bf::/32fca2:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fca2:c0::/32fca2:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fca2:c1::/32fca2:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fca2:c2::/32fca2:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fca2:c3::/32fca2:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fca2:c4::/32fca2:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fca2:c5::/32fca2:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fca2:c6::/32fca2:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fca2:c7::/32fca2:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fca2:c8::/32fca2:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fca2:c9::/32fca2:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fca2:ca::/32fca2:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fca2:cb::/32fca2:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fca2:cc::/32fca2:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fca2:cd::/32fca2:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fca2:ce::/32fca2:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fca2:cf::/32fca2:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fca2:d0::/32fca2:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fca2:d1::/32fca2:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fca2:d2::/32fca2:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fca2:d3::/32fca2:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fca2:d4::/32fca2:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fca2:d5::/32fca2:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fca2:d6::/32fca2:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fca2:d7::/32fca2:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fca2:d8::/32fca2:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fca2:d9::/32fca2:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fca2:da::/32fca2:da:ffff:ffff:ffff:ffff:ffff:ffff
220fca2:db::/32fca2:db:ffff:ffff:ffff:ffff:ffff:ffff
221fca2:dc::/32fca2:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fca2:dd::/32fca2:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fca2:de::/32fca2:de:ffff:ffff:ffff:ffff:ffff:ffff
224fca2:df::/32fca2:df:ffff:ffff:ffff:ffff:ffff:ffff
225fca2:e0::/32fca2:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fca2:e1::/32fca2:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fca2:e2::/32fca2:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fca2:e3::/32fca2:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fca2:e4::/32fca2:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fca2:e5::/32fca2:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fca2:e6::/32fca2:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fca2:e7::/32fca2:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fca2:e8::/32fca2:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fca2:e9::/32fca2:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fca2:ea::/32fca2:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fca2:eb::/32fca2:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fca2:ec::/32fca2:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fca2:ed::/32fca2:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fca2:ee::/32fca2:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fca2:ef::/32fca2:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fca2:f0::/32fca2:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fca2:f1::/32fca2:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fca2:f2::/32fca2:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fca2:f3::/32fca2:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fca2:f4::/32fca2:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fca2:f5::/32fca2:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fca2:f6::/32fca2:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fca2:f7::/32fca2:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fca2:f8::/32fca2:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fca2:f9::/32fca2:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fca2:fa::/32fca2:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fca2:fb::/32fca2:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fca2:fc::/32fca2:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fca2:fd::/32fca2:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fca2:fe::/32fca2:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fca2:ff::/32fca2:ff: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.