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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.

Network212.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
212.0.0.0
Broadcast address
213.255.255.255
First usable
212.0.0.1
Last usable
213.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
C (default /24)
As numbers
Hex D4000000 · Integer 3556769792 to 3590324223
Reverse DNS zones
212.in-addr.arpa
213.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010100.00000000.00000000.00000000212.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11010100.00000000.00000000.00000000212.0.0.0
Broadcast11010101.11111111.11111111.11111111213.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

212.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.0.0.0/19212.0.0.1 to 212.0.31.254212.0.31.2558,190
2212.0.32.0/19212.0.32.1 to 212.0.63.254212.0.63.2558,190
3212.0.64.0/19212.0.64.1 to 212.0.95.254212.0.95.2558,190
4212.0.96.0/19212.0.96.1 to 212.0.127.254212.0.127.2558,190
5212.0.128.0/19212.0.128.1 to 212.0.159.254212.0.159.2558,190
6212.0.160.0/19212.0.160.1 to 212.0.191.254212.0.191.2558,190
7212.0.192.0/19212.0.192.1 to 212.0.223.254212.0.223.2558,190
8212.0.224.0/19212.0.224.1 to 212.0.255.254212.0.255.2558,190
9212.1.0.0/19212.1.0.1 to 212.1.31.254212.1.31.2558,190
10212.1.32.0/19212.1.32.1 to 212.1.63.254212.1.63.2558,190
11212.1.64.0/19212.1.64.1 to 212.1.95.254212.1.95.2558,190
12212.1.96.0/19212.1.96.1 to 212.1.127.254212.1.127.2558,190
13212.1.128.0/19212.1.128.1 to 212.1.159.254212.1.159.2558,190
14212.1.160.0/19212.1.160.1 to 212.1.191.254212.1.191.2558,190
15212.1.192.0/19212.1.192.1 to 212.1.223.254212.1.223.2558,190
16212.1.224.0/19212.1.224.1 to 212.1.255.254212.1.255.2558,190
17212.2.0.0/19212.2.0.1 to 212.2.31.254212.2.31.2558,190
18212.2.32.0/19212.2.32.1 to 212.2.63.254212.2.63.2558,190
19212.2.64.0/19212.2.64.1 to 212.2.95.254212.2.95.2558,190
20212.2.96.0/19212.2.96.1 to 212.2.127.254212.2.127.2558,190
21212.2.128.0/19212.2.128.1 to 212.2.159.254212.2.159.2558,190
22212.2.160.0/19212.2.160.1 to 212.2.191.254212.2.191.2558,190
23212.2.192.0/19212.2.192.1 to 212.2.223.254212.2.223.2558,190
24212.2.224.0/19212.2.224.1 to 212.2.255.254212.2.255.2558,190
25212.3.0.0/19212.3.0.1 to 212.3.31.254212.3.31.2558,190
26212.3.32.0/19212.3.32.1 to 212.3.63.254212.3.63.2558,190
27212.3.64.0/19212.3.64.1 to 212.3.95.254212.3.95.2558,190
28212.3.96.0/19212.3.96.1 to 212.3.127.254212.3.127.2558,190
29212.3.128.0/19212.3.128.1 to 212.3.159.254212.3.159.2558,190
30212.3.160.0/19212.3.160.1 to 212.3.191.254212.3.191.2558,190
31212.3.192.0/19212.3.192.1 to 212.3.223.254212.3.223.2558,190
32212.3.224.0/19212.3.224.1 to 212.3.255.254212.3.255.2558,190
33212.4.0.0/19212.4.0.1 to 212.4.31.254212.4.31.2558,190
34212.4.32.0/19212.4.32.1 to 212.4.63.254212.4.63.2558,190
35212.4.64.0/19212.4.64.1 to 212.4.95.254212.4.95.2558,190
36212.4.96.0/19212.4.96.1 to 212.4.127.254212.4.127.2558,190
37212.4.128.0/19212.4.128.1 to 212.4.159.254212.4.159.2558,190
38212.4.160.0/19212.4.160.1 to 212.4.191.254212.4.191.2558,190
39212.4.192.0/19212.4.192.1 to 212.4.223.254212.4.223.2558,190
40212.4.224.0/19212.4.224.1 to 212.4.255.254212.4.255.2558,190
41212.5.0.0/19212.5.0.1 to 212.5.31.254212.5.31.2558,190
42212.5.32.0/19212.5.32.1 to 212.5.63.254212.5.63.2558,190
43212.5.64.0/19212.5.64.1 to 212.5.95.254212.5.95.2558,190
44212.5.96.0/19212.5.96.1 to 212.5.127.254212.5.127.2558,190
45212.5.128.0/19212.5.128.1 to 212.5.159.254212.5.159.2558,190
46212.5.160.0/19212.5.160.1 to 212.5.191.254212.5.191.2558,190
47212.5.192.0/19212.5.192.1 to 212.5.223.254212.5.223.2558,190
48212.5.224.0/19212.5.224.1 to 212.5.255.254212.5.255.2558,190
49212.6.0.0/19212.6.0.1 to 212.6.31.254212.6.31.2558,190
50212.6.32.0/19212.6.32.1 to 212.6.63.254212.6.63.2558,190
51212.6.64.0/19212.6.64.1 to 212.6.95.254212.6.95.2558,190
52212.6.96.0/19212.6.96.1 to 212.6.127.254212.6.127.2558,190
53212.6.128.0/19212.6.128.1 to 212.6.159.254212.6.159.2558,190
54212.6.160.0/19212.6.160.1 to 212.6.191.254212.6.191.2558,190
55212.6.192.0/19212.6.192.1 to 212.6.223.254212.6.223.2558,190
56212.6.224.0/19212.6.224.1 to 212.6.255.254212.6.255.2558,190
57212.7.0.0/19212.7.0.1 to 212.7.31.254212.7.31.2558,190
58212.7.32.0/19212.7.32.1 to 212.7.63.254212.7.63.2558,190
59212.7.64.0/19212.7.64.1 to 212.7.95.254212.7.95.2558,190
60212.7.96.0/19212.7.96.1 to 212.7.127.254212.7.127.2558,190
61212.7.128.0/19212.7.128.1 to 212.7.159.254212.7.159.2558,190
62212.7.160.0/19212.7.160.1 to 212.7.191.254212.7.191.2558,190
63212.7.192.0/19212.7.192.1 to 212.7.223.254212.7.223.2558,190
64212.7.224.0/19212.7.224.1 to 212.7.255.254212.7.255.2558,190
65212.8.0.0/19212.8.0.1 to 212.8.31.254212.8.31.2558,190
66212.8.32.0/19212.8.32.1 to 212.8.63.254212.8.63.2558,190
67212.8.64.0/19212.8.64.1 to 212.8.95.254212.8.95.2558,190
68212.8.96.0/19212.8.96.1 to 212.8.127.254212.8.127.2558,190
69212.8.128.0/19212.8.128.1 to 212.8.159.254212.8.159.2558,190
70212.8.160.0/19212.8.160.1 to 212.8.191.254212.8.191.2558,190
71212.8.192.0/19212.8.192.1 to 212.8.223.254212.8.223.2558,190
72212.8.224.0/19212.8.224.1 to 212.8.255.254212.8.255.2558,190
73212.9.0.0/19212.9.0.1 to 212.9.31.254212.9.31.2558,190
74212.9.32.0/19212.9.32.1 to 212.9.63.254212.9.63.2558,190
75212.9.64.0/19212.9.64.1 to 212.9.95.254212.9.95.2558,190
76212.9.96.0/19212.9.96.1 to 212.9.127.254212.9.127.2558,190
77212.9.128.0/19212.9.128.1 to 212.9.159.254212.9.159.2558,190
78212.9.160.0/19212.9.160.1 to 212.9.191.254212.9.191.2558,190
79212.9.192.0/19212.9.192.1 to 212.9.223.254212.9.223.2558,190
80212.9.224.0/19212.9.224.1 to 212.9.255.254212.9.255.2558,190
81212.10.0.0/19212.10.0.1 to 212.10.31.254212.10.31.2558,190
82212.10.32.0/19212.10.32.1 to 212.10.63.254212.10.63.2558,190
83212.10.64.0/19212.10.64.1 to 212.10.95.254212.10.95.2558,190
84212.10.96.0/19212.10.96.1 to 212.10.127.254212.10.127.2558,190
85212.10.128.0/19212.10.128.1 to 212.10.159.254212.10.159.2558,190
86212.10.160.0/19212.10.160.1 to 212.10.191.254212.10.191.2558,190
87212.10.192.0/19212.10.192.1 to 212.10.223.254212.10.223.2558,190
88212.10.224.0/19212.10.224.1 to 212.10.255.254212.10.255.2558,190
89212.11.0.0/19212.11.0.1 to 212.11.31.254212.11.31.2558,190
90212.11.32.0/19212.11.32.1 to 212.11.63.254212.11.63.2558,190
91212.11.64.0/19212.11.64.1 to 212.11.95.254212.11.95.2558,190
92212.11.96.0/19212.11.96.1 to 212.11.127.254212.11.127.2558,190
93212.11.128.0/19212.11.128.1 to 212.11.159.254212.11.159.2558,190
94212.11.160.0/19212.11.160.1 to 212.11.191.254212.11.191.2558,190
95212.11.192.0/19212.11.192.1 to 212.11.223.254212.11.223.2558,190
96212.11.224.0/19212.11.224.1 to 212.11.255.254212.11.255.2558,190
97212.12.0.0/19212.12.0.1 to 212.12.31.254212.12.31.2558,190
98212.12.32.0/19212.12.32.1 to 212.12.63.254212.12.63.2558,190
99212.12.64.0/19212.12.64.1 to 212.12.95.254212.12.95.2558,190
100212.12.96.0/19212.12.96.1 to 212.12.127.254212.12.127.2558,190
101212.12.128.0/19212.12.128.1 to 212.12.159.254212.12.159.2558,190
102212.12.160.0/19212.12.160.1 to 212.12.191.254212.12.191.2558,190
103212.12.192.0/19212.12.192.1 to 212.12.223.254212.12.223.2558,190
104212.12.224.0/19212.12.224.1 to 212.12.255.254212.12.255.2558,190
105212.13.0.0/19212.13.0.1 to 212.13.31.254212.13.31.2558,190
106212.13.32.0/19212.13.32.1 to 212.13.63.254212.13.63.2558,190
107212.13.64.0/19212.13.64.1 to 212.13.95.254212.13.95.2558,190
108212.13.96.0/19212.13.96.1 to 212.13.127.254212.13.127.2558,190
109212.13.128.0/19212.13.128.1 to 212.13.159.254212.13.159.2558,190
110212.13.160.0/19212.13.160.1 to 212.13.191.254212.13.191.2558,190
111212.13.192.0/19212.13.192.1 to 212.13.223.254212.13.223.2558,190
112212.13.224.0/19212.13.224.1 to 212.13.255.254212.13.255.2558,190
113212.14.0.0/19212.14.0.1 to 212.14.31.254212.14.31.2558,190
114212.14.32.0/19212.14.32.1 to 212.14.63.254212.14.63.2558,190
115212.14.64.0/19212.14.64.1 to 212.14.95.254212.14.95.2558,190
116212.14.96.0/19212.14.96.1 to 212.14.127.254212.14.127.2558,190
117212.14.128.0/19212.14.128.1 to 212.14.159.254212.14.159.2558,190
118212.14.160.0/19212.14.160.1 to 212.14.191.254212.14.191.2558,190
119212.14.192.0/19212.14.192.1 to 212.14.223.254212.14.223.2558,190
120212.14.224.0/19212.14.224.1 to 212.14.255.254212.14.255.2558,190
121212.15.0.0/19212.15.0.1 to 212.15.31.254212.15.31.2558,190
122212.15.32.0/19212.15.32.1 to 212.15.63.254212.15.63.2558,190
123212.15.64.0/19212.15.64.1 to 212.15.95.254212.15.95.2558,190
124212.15.96.0/19212.15.96.1 to 212.15.127.254212.15.127.2558,190
125212.15.128.0/19212.15.128.1 to 212.15.159.254212.15.159.2558,190
126212.15.160.0/19212.15.160.1 to 212.15.191.254212.15.191.2558,190
127212.15.192.0/19212.15.192.1 to 212.15.223.254212.15.223.2558,190
128212.15.224.0/19212.15.224.1 to 212.15.255.254212.15.255.2558,190
129212.16.0.0/19212.16.0.1 to 212.16.31.254212.16.31.2558,190
130212.16.32.0/19212.16.32.1 to 212.16.63.254212.16.63.2558,190
131212.16.64.0/19212.16.64.1 to 212.16.95.254212.16.95.2558,190
132212.16.96.0/19212.16.96.1 to 212.16.127.254212.16.127.2558,190
133212.16.128.0/19212.16.128.1 to 212.16.159.254212.16.159.2558,190
134212.16.160.0/19212.16.160.1 to 212.16.191.254212.16.191.2558,190
135212.16.192.0/19212.16.192.1 to 212.16.223.254212.16.223.2558,190
136212.16.224.0/19212.16.224.1 to 212.16.255.254212.16.255.2558,190
137212.17.0.0/19212.17.0.1 to 212.17.31.254212.17.31.2558,190
138212.17.32.0/19212.17.32.1 to 212.17.63.254212.17.63.2558,190
139212.17.64.0/19212.17.64.1 to 212.17.95.254212.17.95.2558,190
140212.17.96.0/19212.17.96.1 to 212.17.127.254212.17.127.2558,190
141212.17.128.0/19212.17.128.1 to 212.17.159.254212.17.159.2558,190
142212.17.160.0/19212.17.160.1 to 212.17.191.254212.17.191.2558,190
143212.17.192.0/19212.17.192.1 to 212.17.223.254212.17.223.2558,190
144212.17.224.0/19212.17.224.1 to 212.17.255.254212.17.255.2558,190
145212.18.0.0/19212.18.0.1 to 212.18.31.254212.18.31.2558,190
146212.18.32.0/19212.18.32.1 to 212.18.63.254212.18.63.2558,190
147212.18.64.0/19212.18.64.1 to 212.18.95.254212.18.95.2558,190
148212.18.96.0/19212.18.96.1 to 212.18.127.254212.18.127.2558,190
149212.18.128.0/19212.18.128.1 to 212.18.159.254212.18.159.2558,190
150212.18.160.0/19212.18.160.1 to 212.18.191.254212.18.191.2558,190
151212.18.192.0/19212.18.192.1 to 212.18.223.254212.18.223.2558,190
152212.18.224.0/19212.18.224.1 to 212.18.255.254212.18.255.2558,190
153212.19.0.0/19212.19.0.1 to 212.19.31.254212.19.31.2558,190
154212.19.32.0/19212.19.32.1 to 212.19.63.254212.19.63.2558,190
155212.19.64.0/19212.19.64.1 to 212.19.95.254212.19.95.2558,190
156212.19.96.0/19212.19.96.1 to 212.19.127.254212.19.127.2558,190
157212.19.128.0/19212.19.128.1 to 212.19.159.254212.19.159.2558,190
158212.19.160.0/19212.19.160.1 to 212.19.191.254212.19.191.2558,190
159212.19.192.0/19212.19.192.1 to 212.19.223.254212.19.223.2558,190
160212.19.224.0/19212.19.224.1 to 212.19.255.254212.19.255.2558,190
161212.20.0.0/19212.20.0.1 to 212.20.31.254212.20.31.2558,190
162212.20.32.0/19212.20.32.1 to 212.20.63.254212.20.63.2558,190
163212.20.64.0/19212.20.64.1 to 212.20.95.254212.20.95.2558,190
164212.20.96.0/19212.20.96.1 to 212.20.127.254212.20.127.2558,190
165212.20.128.0/19212.20.128.1 to 212.20.159.254212.20.159.2558,190
166212.20.160.0/19212.20.160.1 to 212.20.191.254212.20.191.2558,190
167212.20.192.0/19212.20.192.1 to 212.20.223.254212.20.223.2558,190
168212.20.224.0/19212.20.224.1 to 212.20.255.254212.20.255.2558,190
169212.21.0.0/19212.21.0.1 to 212.21.31.254212.21.31.2558,190
170212.21.32.0/19212.21.32.1 to 212.21.63.254212.21.63.2558,190
171212.21.64.0/19212.21.64.1 to 212.21.95.254212.21.95.2558,190
172212.21.96.0/19212.21.96.1 to 212.21.127.254212.21.127.2558,190
173212.21.128.0/19212.21.128.1 to 212.21.159.254212.21.159.2558,190
174212.21.160.0/19212.21.160.1 to 212.21.191.254212.21.191.2558,190
175212.21.192.0/19212.21.192.1 to 212.21.223.254212.21.223.2558,190
176212.21.224.0/19212.21.224.1 to 212.21.255.254212.21.255.2558,190
177212.22.0.0/19212.22.0.1 to 212.22.31.254212.22.31.2558,190
178212.22.32.0/19212.22.32.1 to 212.22.63.254212.22.63.2558,190
179212.22.64.0/19212.22.64.1 to 212.22.95.254212.22.95.2558,190
180212.22.96.0/19212.22.96.1 to 212.22.127.254212.22.127.2558,190
181212.22.128.0/19212.22.128.1 to 212.22.159.254212.22.159.2558,190
182212.22.160.0/19212.22.160.1 to 212.22.191.254212.22.191.2558,190
183212.22.192.0/19212.22.192.1 to 212.22.223.254212.22.223.2558,190
184212.22.224.0/19212.22.224.1 to 212.22.255.254212.22.255.2558,190
185212.23.0.0/19212.23.0.1 to 212.23.31.254212.23.31.2558,190
186212.23.32.0/19212.23.32.1 to 212.23.63.254212.23.63.2558,190
187212.23.64.0/19212.23.64.1 to 212.23.95.254212.23.95.2558,190
188212.23.96.0/19212.23.96.1 to 212.23.127.254212.23.127.2558,190
189212.23.128.0/19212.23.128.1 to 212.23.159.254212.23.159.2558,190
190212.23.160.0/19212.23.160.1 to 212.23.191.254212.23.191.2558,190
191212.23.192.0/19212.23.192.1 to 212.23.223.254212.23.223.2558,190
192212.23.224.0/19212.23.224.1 to 212.23.255.254212.23.255.2558,190
193212.24.0.0/19212.24.0.1 to 212.24.31.254212.24.31.2558,190
194212.24.32.0/19212.24.32.1 to 212.24.63.254212.24.63.2558,190
195212.24.64.0/19212.24.64.1 to 212.24.95.254212.24.95.2558,190
196212.24.96.0/19212.24.96.1 to 212.24.127.254212.24.127.2558,190
197212.24.128.0/19212.24.128.1 to 212.24.159.254212.24.159.2558,190
198212.24.160.0/19212.24.160.1 to 212.24.191.254212.24.191.2558,190
199212.24.192.0/19212.24.192.1 to 212.24.223.254212.24.223.2558,190
200212.24.224.0/19212.24.224.1 to 212.24.255.254212.24.255.2558,190
201212.25.0.0/19212.25.0.1 to 212.25.31.254212.25.31.2558,190
202212.25.32.0/19212.25.32.1 to 212.25.63.254212.25.63.2558,190
203212.25.64.0/19212.25.64.1 to 212.25.95.254212.25.95.2558,190
204212.25.96.0/19212.25.96.1 to 212.25.127.254212.25.127.2558,190
205212.25.128.0/19212.25.128.1 to 212.25.159.254212.25.159.2558,190
206212.25.160.0/19212.25.160.1 to 212.25.191.254212.25.191.2558,190
207212.25.192.0/19212.25.192.1 to 212.25.223.254212.25.223.2558,190
208212.25.224.0/19212.25.224.1 to 212.25.255.254212.25.255.2558,190
209212.26.0.0/19212.26.0.1 to 212.26.31.254212.26.31.2558,190
210212.26.32.0/19212.26.32.1 to 212.26.63.254212.26.63.2558,190
211212.26.64.0/19212.26.64.1 to 212.26.95.254212.26.95.2558,190
212212.26.96.0/19212.26.96.1 to 212.26.127.254212.26.127.2558,190
213212.26.128.0/19212.26.128.1 to 212.26.159.254212.26.159.2558,190
214212.26.160.0/19212.26.160.1 to 212.26.191.254212.26.191.2558,190
215212.26.192.0/19212.26.192.1 to 212.26.223.254212.26.223.2558,190
216212.26.224.0/19212.26.224.1 to 212.26.255.254212.26.255.2558,190
217212.27.0.0/19212.27.0.1 to 212.27.31.254212.27.31.2558,190
218212.27.32.0/19212.27.32.1 to 212.27.63.254212.27.63.2558,190
219212.27.64.0/19212.27.64.1 to 212.27.95.254212.27.95.2558,190
220212.27.96.0/19212.27.96.1 to 212.27.127.254212.27.127.2558,190
221212.27.128.0/19212.27.128.1 to 212.27.159.254212.27.159.2558,190
222212.27.160.0/19212.27.160.1 to 212.27.191.254212.27.191.2558,190
223212.27.192.0/19212.27.192.1 to 212.27.223.254212.27.223.2558,190
224212.27.224.0/19212.27.224.1 to 212.27.255.254212.27.255.2558,190
225212.28.0.0/19212.28.0.1 to 212.28.31.254212.28.31.2558,190
226212.28.32.0/19212.28.32.1 to 212.28.63.254212.28.63.2558,190
227212.28.64.0/19212.28.64.1 to 212.28.95.254212.28.95.2558,190
228212.28.96.0/19212.28.96.1 to 212.28.127.254212.28.127.2558,190
229212.28.128.0/19212.28.128.1 to 212.28.159.254212.28.159.2558,190
230212.28.160.0/19212.28.160.1 to 212.28.191.254212.28.191.2558,190
231212.28.192.0/19212.28.192.1 to 212.28.223.254212.28.223.2558,190
232212.28.224.0/19212.28.224.1 to 212.28.255.254212.28.255.2558,190
233212.29.0.0/19212.29.0.1 to 212.29.31.254212.29.31.2558,190
234212.29.32.0/19212.29.32.1 to 212.29.63.254212.29.63.2558,190
235212.29.64.0/19212.29.64.1 to 212.29.95.254212.29.95.2558,190
236212.29.96.0/19212.29.96.1 to 212.29.127.254212.29.127.2558,190
237212.29.128.0/19212.29.128.1 to 212.29.159.254212.29.159.2558,190
238212.29.160.0/19212.29.160.1 to 212.29.191.254212.29.191.2558,190
239212.29.192.0/19212.29.192.1 to 212.29.223.254212.29.223.2558,190
240212.29.224.0/19212.29.224.1 to 212.29.255.254212.29.255.2558,190
241212.30.0.0/19212.30.0.1 to 212.30.31.254212.30.31.2558,190
242212.30.32.0/19212.30.32.1 to 212.30.63.254212.30.63.2558,190
243212.30.64.0/19212.30.64.1 to 212.30.95.254212.30.95.2558,190
244212.30.96.0/19212.30.96.1 to 212.30.127.254212.30.127.2558,190
245212.30.128.0/19212.30.128.1 to 212.30.159.254212.30.159.2558,190
246212.30.160.0/19212.30.160.1 to 212.30.191.254212.30.191.2558,190
247212.30.192.0/19212.30.192.1 to 212.30.223.254212.30.223.2558,190
248212.30.224.0/19212.30.224.1 to 212.30.255.254212.30.255.2558,190
249212.31.0.0/19212.31.0.1 to 212.31.31.254212.31.31.2558,190
250212.31.32.0/19212.31.32.1 to 212.31.63.254212.31.63.2558,190
251212.31.64.0/19212.31.64.1 to 212.31.95.254212.31.95.2558,190
252212.31.96.0/19212.31.96.1 to 212.31.127.254212.31.127.2558,190
253212.31.128.0/19212.31.128.1 to 212.31.159.254212.31.159.2558,190
254212.31.160.0/19212.31.160.1 to 212.31.191.254212.31.191.2558,190
255212.31.192.0/19212.31.192.1 to 212.31.223.254212.31.223.2558,190
256212.31.224.0/19212.31.224.1 to 212.31.255.254212.31.255.2558,190

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.