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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
fffe::/16
First address
fffe::
Last address
fffe: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
fffe:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
e.f.f.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

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

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