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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.

Network115.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
115.0.0.0
Broadcast address
115.255.255.255
First usable
115.0.0.1
Last usable
115.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 73000000 · Integer 1929379840 to 1946157055
Reverse DNS zone
115.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110011..00000000.00000000.00000000115.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01110011..00000000.00000000.00000000115.0.0.0
Broadcast01110011..11111111.11111111.11111111115.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

115.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1115.0.0.0/19115.0.0.1 to 115.0.31.254115.0.31.2558,190
2115.0.32.0/19115.0.32.1 to 115.0.63.254115.0.63.2558,190
3115.0.64.0/19115.0.64.1 to 115.0.95.254115.0.95.2558,190
4115.0.96.0/19115.0.96.1 to 115.0.127.254115.0.127.2558,190
5115.0.128.0/19115.0.128.1 to 115.0.159.254115.0.159.2558,190
6115.0.160.0/19115.0.160.1 to 115.0.191.254115.0.191.2558,190
7115.0.192.0/19115.0.192.1 to 115.0.223.254115.0.223.2558,190
8115.0.224.0/19115.0.224.1 to 115.0.255.254115.0.255.2558,190
9115.1.0.0/19115.1.0.1 to 115.1.31.254115.1.31.2558,190
10115.1.32.0/19115.1.32.1 to 115.1.63.254115.1.63.2558,190
11115.1.64.0/19115.1.64.1 to 115.1.95.254115.1.95.2558,190
12115.1.96.0/19115.1.96.1 to 115.1.127.254115.1.127.2558,190
13115.1.128.0/19115.1.128.1 to 115.1.159.254115.1.159.2558,190
14115.1.160.0/19115.1.160.1 to 115.1.191.254115.1.191.2558,190
15115.1.192.0/19115.1.192.1 to 115.1.223.254115.1.223.2558,190
16115.1.224.0/19115.1.224.1 to 115.1.255.254115.1.255.2558,190
17115.2.0.0/19115.2.0.1 to 115.2.31.254115.2.31.2558,190
18115.2.32.0/19115.2.32.1 to 115.2.63.254115.2.63.2558,190
19115.2.64.0/19115.2.64.1 to 115.2.95.254115.2.95.2558,190
20115.2.96.0/19115.2.96.1 to 115.2.127.254115.2.127.2558,190
21115.2.128.0/19115.2.128.1 to 115.2.159.254115.2.159.2558,190
22115.2.160.0/19115.2.160.1 to 115.2.191.254115.2.191.2558,190
23115.2.192.0/19115.2.192.1 to 115.2.223.254115.2.223.2558,190
24115.2.224.0/19115.2.224.1 to 115.2.255.254115.2.255.2558,190
25115.3.0.0/19115.3.0.1 to 115.3.31.254115.3.31.2558,190
26115.3.32.0/19115.3.32.1 to 115.3.63.254115.3.63.2558,190
27115.3.64.0/19115.3.64.1 to 115.3.95.254115.3.95.2558,190
28115.3.96.0/19115.3.96.1 to 115.3.127.254115.3.127.2558,190
29115.3.128.0/19115.3.128.1 to 115.3.159.254115.3.159.2558,190
30115.3.160.0/19115.3.160.1 to 115.3.191.254115.3.191.2558,190
31115.3.192.0/19115.3.192.1 to 115.3.223.254115.3.223.2558,190
32115.3.224.0/19115.3.224.1 to 115.3.255.254115.3.255.2558,190
33115.4.0.0/19115.4.0.1 to 115.4.31.254115.4.31.2558,190
34115.4.32.0/19115.4.32.1 to 115.4.63.254115.4.63.2558,190
35115.4.64.0/19115.4.64.1 to 115.4.95.254115.4.95.2558,190
36115.4.96.0/19115.4.96.1 to 115.4.127.254115.4.127.2558,190
37115.4.128.0/19115.4.128.1 to 115.4.159.254115.4.159.2558,190
38115.4.160.0/19115.4.160.1 to 115.4.191.254115.4.191.2558,190
39115.4.192.0/19115.4.192.1 to 115.4.223.254115.4.223.2558,190
40115.4.224.0/19115.4.224.1 to 115.4.255.254115.4.255.2558,190
41115.5.0.0/19115.5.0.1 to 115.5.31.254115.5.31.2558,190
42115.5.32.0/19115.5.32.1 to 115.5.63.254115.5.63.2558,190
43115.5.64.0/19115.5.64.1 to 115.5.95.254115.5.95.2558,190
44115.5.96.0/19115.5.96.1 to 115.5.127.254115.5.127.2558,190
45115.5.128.0/19115.5.128.1 to 115.5.159.254115.5.159.2558,190
46115.5.160.0/19115.5.160.1 to 115.5.191.254115.5.191.2558,190
47115.5.192.0/19115.5.192.1 to 115.5.223.254115.5.223.2558,190
48115.5.224.0/19115.5.224.1 to 115.5.255.254115.5.255.2558,190
49115.6.0.0/19115.6.0.1 to 115.6.31.254115.6.31.2558,190
50115.6.32.0/19115.6.32.1 to 115.6.63.254115.6.63.2558,190
51115.6.64.0/19115.6.64.1 to 115.6.95.254115.6.95.2558,190
52115.6.96.0/19115.6.96.1 to 115.6.127.254115.6.127.2558,190
53115.6.128.0/19115.6.128.1 to 115.6.159.254115.6.159.2558,190
54115.6.160.0/19115.6.160.1 to 115.6.191.254115.6.191.2558,190
55115.6.192.0/19115.6.192.1 to 115.6.223.254115.6.223.2558,190
56115.6.224.0/19115.6.224.1 to 115.6.255.254115.6.255.2558,190
57115.7.0.0/19115.7.0.1 to 115.7.31.254115.7.31.2558,190
58115.7.32.0/19115.7.32.1 to 115.7.63.254115.7.63.2558,190
59115.7.64.0/19115.7.64.1 to 115.7.95.254115.7.95.2558,190
60115.7.96.0/19115.7.96.1 to 115.7.127.254115.7.127.2558,190
61115.7.128.0/19115.7.128.1 to 115.7.159.254115.7.159.2558,190
62115.7.160.0/19115.7.160.1 to 115.7.191.254115.7.191.2558,190
63115.7.192.0/19115.7.192.1 to 115.7.223.254115.7.223.2558,190
64115.7.224.0/19115.7.224.1 to 115.7.255.254115.7.255.2558,190
65115.8.0.0/19115.8.0.1 to 115.8.31.254115.8.31.2558,190
66115.8.32.0/19115.8.32.1 to 115.8.63.254115.8.63.2558,190
67115.8.64.0/19115.8.64.1 to 115.8.95.254115.8.95.2558,190
68115.8.96.0/19115.8.96.1 to 115.8.127.254115.8.127.2558,190
69115.8.128.0/19115.8.128.1 to 115.8.159.254115.8.159.2558,190
70115.8.160.0/19115.8.160.1 to 115.8.191.254115.8.191.2558,190
71115.8.192.0/19115.8.192.1 to 115.8.223.254115.8.223.2558,190
72115.8.224.0/19115.8.224.1 to 115.8.255.254115.8.255.2558,190
73115.9.0.0/19115.9.0.1 to 115.9.31.254115.9.31.2558,190
74115.9.32.0/19115.9.32.1 to 115.9.63.254115.9.63.2558,190
75115.9.64.0/19115.9.64.1 to 115.9.95.254115.9.95.2558,190
76115.9.96.0/19115.9.96.1 to 115.9.127.254115.9.127.2558,190
77115.9.128.0/19115.9.128.1 to 115.9.159.254115.9.159.2558,190
78115.9.160.0/19115.9.160.1 to 115.9.191.254115.9.191.2558,190
79115.9.192.0/19115.9.192.1 to 115.9.223.254115.9.223.2558,190
80115.9.224.0/19115.9.224.1 to 115.9.255.254115.9.255.2558,190
81115.10.0.0/19115.10.0.1 to 115.10.31.254115.10.31.2558,190
82115.10.32.0/19115.10.32.1 to 115.10.63.254115.10.63.2558,190
83115.10.64.0/19115.10.64.1 to 115.10.95.254115.10.95.2558,190
84115.10.96.0/19115.10.96.1 to 115.10.127.254115.10.127.2558,190
85115.10.128.0/19115.10.128.1 to 115.10.159.254115.10.159.2558,190
86115.10.160.0/19115.10.160.1 to 115.10.191.254115.10.191.2558,190
87115.10.192.0/19115.10.192.1 to 115.10.223.254115.10.223.2558,190
88115.10.224.0/19115.10.224.1 to 115.10.255.254115.10.255.2558,190
89115.11.0.0/19115.11.0.1 to 115.11.31.254115.11.31.2558,190
90115.11.32.0/19115.11.32.1 to 115.11.63.254115.11.63.2558,190
91115.11.64.0/19115.11.64.1 to 115.11.95.254115.11.95.2558,190
92115.11.96.0/19115.11.96.1 to 115.11.127.254115.11.127.2558,190
93115.11.128.0/19115.11.128.1 to 115.11.159.254115.11.159.2558,190
94115.11.160.0/19115.11.160.1 to 115.11.191.254115.11.191.2558,190
95115.11.192.0/19115.11.192.1 to 115.11.223.254115.11.223.2558,190
96115.11.224.0/19115.11.224.1 to 115.11.255.254115.11.255.2558,190
97115.12.0.0/19115.12.0.1 to 115.12.31.254115.12.31.2558,190
98115.12.32.0/19115.12.32.1 to 115.12.63.254115.12.63.2558,190
99115.12.64.0/19115.12.64.1 to 115.12.95.254115.12.95.2558,190
100115.12.96.0/19115.12.96.1 to 115.12.127.254115.12.127.2558,190
101115.12.128.0/19115.12.128.1 to 115.12.159.254115.12.159.2558,190
102115.12.160.0/19115.12.160.1 to 115.12.191.254115.12.191.2558,190
103115.12.192.0/19115.12.192.1 to 115.12.223.254115.12.223.2558,190
104115.12.224.0/19115.12.224.1 to 115.12.255.254115.12.255.2558,190
105115.13.0.0/19115.13.0.1 to 115.13.31.254115.13.31.2558,190
106115.13.32.0/19115.13.32.1 to 115.13.63.254115.13.63.2558,190
107115.13.64.0/19115.13.64.1 to 115.13.95.254115.13.95.2558,190
108115.13.96.0/19115.13.96.1 to 115.13.127.254115.13.127.2558,190
109115.13.128.0/19115.13.128.1 to 115.13.159.254115.13.159.2558,190
110115.13.160.0/19115.13.160.1 to 115.13.191.254115.13.191.2558,190
111115.13.192.0/19115.13.192.1 to 115.13.223.254115.13.223.2558,190
112115.13.224.0/19115.13.224.1 to 115.13.255.254115.13.255.2558,190
113115.14.0.0/19115.14.0.1 to 115.14.31.254115.14.31.2558,190
114115.14.32.0/19115.14.32.1 to 115.14.63.254115.14.63.2558,190
115115.14.64.0/19115.14.64.1 to 115.14.95.254115.14.95.2558,190
116115.14.96.0/19115.14.96.1 to 115.14.127.254115.14.127.2558,190
117115.14.128.0/19115.14.128.1 to 115.14.159.254115.14.159.2558,190
118115.14.160.0/19115.14.160.1 to 115.14.191.254115.14.191.2558,190
119115.14.192.0/19115.14.192.1 to 115.14.223.254115.14.223.2558,190
120115.14.224.0/19115.14.224.1 to 115.14.255.254115.14.255.2558,190
121115.15.0.0/19115.15.0.1 to 115.15.31.254115.15.31.2558,190
122115.15.32.0/19115.15.32.1 to 115.15.63.254115.15.63.2558,190
123115.15.64.0/19115.15.64.1 to 115.15.95.254115.15.95.2558,190
124115.15.96.0/19115.15.96.1 to 115.15.127.254115.15.127.2558,190
125115.15.128.0/19115.15.128.1 to 115.15.159.254115.15.159.2558,190
126115.15.160.0/19115.15.160.1 to 115.15.191.254115.15.191.2558,190
127115.15.192.0/19115.15.192.1 to 115.15.223.254115.15.223.2558,190
128115.15.224.0/19115.15.224.1 to 115.15.255.254115.15.255.2558,190
129115.16.0.0/19115.16.0.1 to 115.16.31.254115.16.31.2558,190
130115.16.32.0/19115.16.32.1 to 115.16.63.254115.16.63.2558,190
131115.16.64.0/19115.16.64.1 to 115.16.95.254115.16.95.2558,190
132115.16.96.0/19115.16.96.1 to 115.16.127.254115.16.127.2558,190
133115.16.128.0/19115.16.128.1 to 115.16.159.254115.16.159.2558,190
134115.16.160.0/19115.16.160.1 to 115.16.191.254115.16.191.2558,190
135115.16.192.0/19115.16.192.1 to 115.16.223.254115.16.223.2558,190
136115.16.224.0/19115.16.224.1 to 115.16.255.254115.16.255.2558,190
137115.17.0.0/19115.17.0.1 to 115.17.31.254115.17.31.2558,190
138115.17.32.0/19115.17.32.1 to 115.17.63.254115.17.63.2558,190
139115.17.64.0/19115.17.64.1 to 115.17.95.254115.17.95.2558,190
140115.17.96.0/19115.17.96.1 to 115.17.127.254115.17.127.2558,190
141115.17.128.0/19115.17.128.1 to 115.17.159.254115.17.159.2558,190
142115.17.160.0/19115.17.160.1 to 115.17.191.254115.17.191.2558,190
143115.17.192.0/19115.17.192.1 to 115.17.223.254115.17.223.2558,190
144115.17.224.0/19115.17.224.1 to 115.17.255.254115.17.255.2558,190
145115.18.0.0/19115.18.0.1 to 115.18.31.254115.18.31.2558,190
146115.18.32.0/19115.18.32.1 to 115.18.63.254115.18.63.2558,190
147115.18.64.0/19115.18.64.1 to 115.18.95.254115.18.95.2558,190
148115.18.96.0/19115.18.96.1 to 115.18.127.254115.18.127.2558,190
149115.18.128.0/19115.18.128.1 to 115.18.159.254115.18.159.2558,190
150115.18.160.0/19115.18.160.1 to 115.18.191.254115.18.191.2558,190
151115.18.192.0/19115.18.192.1 to 115.18.223.254115.18.223.2558,190
152115.18.224.0/19115.18.224.1 to 115.18.255.254115.18.255.2558,190
153115.19.0.0/19115.19.0.1 to 115.19.31.254115.19.31.2558,190
154115.19.32.0/19115.19.32.1 to 115.19.63.254115.19.63.2558,190
155115.19.64.0/19115.19.64.1 to 115.19.95.254115.19.95.2558,190
156115.19.96.0/19115.19.96.1 to 115.19.127.254115.19.127.2558,190
157115.19.128.0/19115.19.128.1 to 115.19.159.254115.19.159.2558,190
158115.19.160.0/19115.19.160.1 to 115.19.191.254115.19.191.2558,190
159115.19.192.0/19115.19.192.1 to 115.19.223.254115.19.223.2558,190
160115.19.224.0/19115.19.224.1 to 115.19.255.254115.19.255.2558,190
161115.20.0.0/19115.20.0.1 to 115.20.31.254115.20.31.2558,190
162115.20.32.0/19115.20.32.1 to 115.20.63.254115.20.63.2558,190
163115.20.64.0/19115.20.64.1 to 115.20.95.254115.20.95.2558,190
164115.20.96.0/19115.20.96.1 to 115.20.127.254115.20.127.2558,190
165115.20.128.0/19115.20.128.1 to 115.20.159.254115.20.159.2558,190
166115.20.160.0/19115.20.160.1 to 115.20.191.254115.20.191.2558,190
167115.20.192.0/19115.20.192.1 to 115.20.223.254115.20.223.2558,190
168115.20.224.0/19115.20.224.1 to 115.20.255.254115.20.255.2558,190
169115.21.0.0/19115.21.0.1 to 115.21.31.254115.21.31.2558,190
170115.21.32.0/19115.21.32.1 to 115.21.63.254115.21.63.2558,190
171115.21.64.0/19115.21.64.1 to 115.21.95.254115.21.95.2558,190
172115.21.96.0/19115.21.96.1 to 115.21.127.254115.21.127.2558,190
173115.21.128.0/19115.21.128.1 to 115.21.159.254115.21.159.2558,190
174115.21.160.0/19115.21.160.1 to 115.21.191.254115.21.191.2558,190
175115.21.192.0/19115.21.192.1 to 115.21.223.254115.21.223.2558,190
176115.21.224.0/19115.21.224.1 to 115.21.255.254115.21.255.2558,190
177115.22.0.0/19115.22.0.1 to 115.22.31.254115.22.31.2558,190
178115.22.32.0/19115.22.32.1 to 115.22.63.254115.22.63.2558,190
179115.22.64.0/19115.22.64.1 to 115.22.95.254115.22.95.2558,190
180115.22.96.0/19115.22.96.1 to 115.22.127.254115.22.127.2558,190
181115.22.128.0/19115.22.128.1 to 115.22.159.254115.22.159.2558,190
182115.22.160.0/19115.22.160.1 to 115.22.191.254115.22.191.2558,190
183115.22.192.0/19115.22.192.1 to 115.22.223.254115.22.223.2558,190
184115.22.224.0/19115.22.224.1 to 115.22.255.254115.22.255.2558,190
185115.23.0.0/19115.23.0.1 to 115.23.31.254115.23.31.2558,190
186115.23.32.0/19115.23.32.1 to 115.23.63.254115.23.63.2558,190
187115.23.64.0/19115.23.64.1 to 115.23.95.254115.23.95.2558,190
188115.23.96.0/19115.23.96.1 to 115.23.127.254115.23.127.2558,190
189115.23.128.0/19115.23.128.1 to 115.23.159.254115.23.159.2558,190
190115.23.160.0/19115.23.160.1 to 115.23.191.254115.23.191.2558,190
191115.23.192.0/19115.23.192.1 to 115.23.223.254115.23.223.2558,190
192115.23.224.0/19115.23.224.1 to 115.23.255.254115.23.255.2558,190
193115.24.0.0/19115.24.0.1 to 115.24.31.254115.24.31.2558,190
194115.24.32.0/19115.24.32.1 to 115.24.63.254115.24.63.2558,190
195115.24.64.0/19115.24.64.1 to 115.24.95.254115.24.95.2558,190
196115.24.96.0/19115.24.96.1 to 115.24.127.254115.24.127.2558,190
197115.24.128.0/19115.24.128.1 to 115.24.159.254115.24.159.2558,190
198115.24.160.0/19115.24.160.1 to 115.24.191.254115.24.191.2558,190
199115.24.192.0/19115.24.192.1 to 115.24.223.254115.24.223.2558,190
200115.24.224.0/19115.24.224.1 to 115.24.255.254115.24.255.2558,190
201115.25.0.0/19115.25.0.1 to 115.25.31.254115.25.31.2558,190
202115.25.32.0/19115.25.32.1 to 115.25.63.254115.25.63.2558,190
203115.25.64.0/19115.25.64.1 to 115.25.95.254115.25.95.2558,190
204115.25.96.0/19115.25.96.1 to 115.25.127.254115.25.127.2558,190
205115.25.128.0/19115.25.128.1 to 115.25.159.254115.25.159.2558,190
206115.25.160.0/19115.25.160.1 to 115.25.191.254115.25.191.2558,190
207115.25.192.0/19115.25.192.1 to 115.25.223.254115.25.223.2558,190
208115.25.224.0/19115.25.224.1 to 115.25.255.254115.25.255.2558,190
209115.26.0.0/19115.26.0.1 to 115.26.31.254115.26.31.2558,190
210115.26.32.0/19115.26.32.1 to 115.26.63.254115.26.63.2558,190
211115.26.64.0/19115.26.64.1 to 115.26.95.254115.26.95.2558,190
212115.26.96.0/19115.26.96.1 to 115.26.127.254115.26.127.2558,190
213115.26.128.0/19115.26.128.1 to 115.26.159.254115.26.159.2558,190
214115.26.160.0/19115.26.160.1 to 115.26.191.254115.26.191.2558,190
215115.26.192.0/19115.26.192.1 to 115.26.223.254115.26.223.2558,190
216115.26.224.0/19115.26.224.1 to 115.26.255.254115.26.255.2558,190
217115.27.0.0/19115.27.0.1 to 115.27.31.254115.27.31.2558,190
218115.27.32.0/19115.27.32.1 to 115.27.63.254115.27.63.2558,190
219115.27.64.0/19115.27.64.1 to 115.27.95.254115.27.95.2558,190
220115.27.96.0/19115.27.96.1 to 115.27.127.254115.27.127.2558,190
221115.27.128.0/19115.27.128.1 to 115.27.159.254115.27.159.2558,190
222115.27.160.0/19115.27.160.1 to 115.27.191.254115.27.191.2558,190
223115.27.192.0/19115.27.192.1 to 115.27.223.254115.27.223.2558,190
224115.27.224.0/19115.27.224.1 to 115.27.255.254115.27.255.2558,190
225115.28.0.0/19115.28.0.1 to 115.28.31.254115.28.31.2558,190
226115.28.32.0/19115.28.32.1 to 115.28.63.254115.28.63.2558,190
227115.28.64.0/19115.28.64.1 to 115.28.95.254115.28.95.2558,190
228115.28.96.0/19115.28.96.1 to 115.28.127.254115.28.127.2558,190
229115.28.128.0/19115.28.128.1 to 115.28.159.254115.28.159.2558,190
230115.28.160.0/19115.28.160.1 to 115.28.191.254115.28.191.2558,190
231115.28.192.0/19115.28.192.1 to 115.28.223.254115.28.223.2558,190
232115.28.224.0/19115.28.224.1 to 115.28.255.254115.28.255.2558,190
233115.29.0.0/19115.29.0.1 to 115.29.31.254115.29.31.2558,190
234115.29.32.0/19115.29.32.1 to 115.29.63.254115.29.63.2558,190
235115.29.64.0/19115.29.64.1 to 115.29.95.254115.29.95.2558,190
236115.29.96.0/19115.29.96.1 to 115.29.127.254115.29.127.2558,190
237115.29.128.0/19115.29.128.1 to 115.29.159.254115.29.159.2558,190
238115.29.160.0/19115.29.160.1 to 115.29.191.254115.29.191.2558,190
239115.29.192.0/19115.29.192.1 to 115.29.223.254115.29.223.2558,190
240115.29.224.0/19115.29.224.1 to 115.29.255.254115.29.255.2558,190
241115.30.0.0/19115.30.0.1 to 115.30.31.254115.30.31.2558,190
242115.30.32.0/19115.30.32.1 to 115.30.63.254115.30.63.2558,190
243115.30.64.0/19115.30.64.1 to 115.30.95.254115.30.95.2558,190
244115.30.96.0/19115.30.96.1 to 115.30.127.254115.30.127.2558,190
245115.30.128.0/19115.30.128.1 to 115.30.159.254115.30.159.2558,190
246115.30.160.0/19115.30.160.1 to 115.30.191.254115.30.191.2558,190
247115.30.192.0/19115.30.192.1 to 115.30.223.254115.30.223.2558,190
248115.30.224.0/19115.30.224.1 to 115.30.255.254115.30.255.2558,190
249115.31.0.0/19115.31.0.1 to 115.31.31.254115.31.31.2558,190
250115.31.32.0/19115.31.32.1 to 115.31.63.254115.31.63.2558,190
251115.31.64.0/19115.31.64.1 to 115.31.95.254115.31.95.2558,190
252115.31.96.0/19115.31.96.1 to 115.31.127.254115.31.127.2558,190
253115.31.128.0/19115.31.128.1 to 115.31.159.254115.31.159.2558,190
254115.31.160.0/19115.31.160.1 to 115.31.191.254115.31.191.2558,190
255115.31.192.0/19115.31.192.1 to 115.31.223.254115.31.223.2558,190
256115.31.224.0/19115.31.224.1 to 115.31.255.254115.31.255.2558,190

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.