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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.

Network115.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
115.0.0.0
Broadcast address
115.127.255.255
First usable
115.0.0.1
Last usable
115.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 73000000 · Integer 1929379840 to 1937768447
Reverse DNS zones
0.115.in-addr.arpa
1.115.in-addr.arpa
2.115.in-addr.arpa
3.115.in-addr.arpa
4.115.in-addr.arpa
5.115.in-addr.arpa
6.115.in-addr.arpa
7.115.in-addr.arpa
8.115.in-addr.arpa
9.115.in-addr.arpa
10.115.in-addr.arpa
11.115.in-addr.arpa
12.115.in-addr.arpa
13.115.in-addr.arpa
14.115.in-addr.arpa
15.115.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110011.00000000.00000000.00000000115.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01110011.00000000.00000000.00000000115.0.0.0
Broadcast01110011.01111111.11111111.11111111115.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

115.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1115.0.0.0/20115.0.0.1 to 115.0.15.254115.0.15.2554,094
2115.0.16.0/20115.0.16.1 to 115.0.31.254115.0.31.2554,094
3115.0.32.0/20115.0.32.1 to 115.0.47.254115.0.47.2554,094
4115.0.48.0/20115.0.48.1 to 115.0.63.254115.0.63.2554,094
5115.0.64.0/20115.0.64.1 to 115.0.79.254115.0.79.2554,094
6115.0.80.0/20115.0.80.1 to 115.0.95.254115.0.95.2554,094
7115.0.96.0/20115.0.96.1 to 115.0.111.254115.0.111.2554,094
8115.0.112.0/20115.0.112.1 to 115.0.127.254115.0.127.2554,094
9115.0.128.0/20115.0.128.1 to 115.0.143.254115.0.143.2554,094
10115.0.144.0/20115.0.144.1 to 115.0.159.254115.0.159.2554,094
11115.0.160.0/20115.0.160.1 to 115.0.175.254115.0.175.2554,094
12115.0.176.0/20115.0.176.1 to 115.0.191.254115.0.191.2554,094
13115.0.192.0/20115.0.192.1 to 115.0.207.254115.0.207.2554,094
14115.0.208.0/20115.0.208.1 to 115.0.223.254115.0.223.2554,094
15115.0.224.0/20115.0.224.1 to 115.0.239.254115.0.239.2554,094
16115.0.240.0/20115.0.240.1 to 115.0.255.254115.0.255.2554,094
17115.1.0.0/20115.1.0.1 to 115.1.15.254115.1.15.2554,094
18115.1.16.0/20115.1.16.1 to 115.1.31.254115.1.31.2554,094
19115.1.32.0/20115.1.32.1 to 115.1.47.254115.1.47.2554,094
20115.1.48.0/20115.1.48.1 to 115.1.63.254115.1.63.2554,094
21115.1.64.0/20115.1.64.1 to 115.1.79.254115.1.79.2554,094
22115.1.80.0/20115.1.80.1 to 115.1.95.254115.1.95.2554,094
23115.1.96.0/20115.1.96.1 to 115.1.111.254115.1.111.2554,094
24115.1.112.0/20115.1.112.1 to 115.1.127.254115.1.127.2554,094
25115.1.128.0/20115.1.128.1 to 115.1.143.254115.1.143.2554,094
26115.1.144.0/20115.1.144.1 to 115.1.159.254115.1.159.2554,094
27115.1.160.0/20115.1.160.1 to 115.1.175.254115.1.175.2554,094
28115.1.176.0/20115.1.176.1 to 115.1.191.254115.1.191.2554,094
29115.1.192.0/20115.1.192.1 to 115.1.207.254115.1.207.2554,094
30115.1.208.0/20115.1.208.1 to 115.1.223.254115.1.223.2554,094
31115.1.224.0/20115.1.224.1 to 115.1.239.254115.1.239.2554,094
32115.1.240.0/20115.1.240.1 to 115.1.255.254115.1.255.2554,094
33115.2.0.0/20115.2.0.1 to 115.2.15.254115.2.15.2554,094
34115.2.16.0/20115.2.16.1 to 115.2.31.254115.2.31.2554,094
35115.2.32.0/20115.2.32.1 to 115.2.47.254115.2.47.2554,094
36115.2.48.0/20115.2.48.1 to 115.2.63.254115.2.63.2554,094
37115.2.64.0/20115.2.64.1 to 115.2.79.254115.2.79.2554,094
38115.2.80.0/20115.2.80.1 to 115.2.95.254115.2.95.2554,094
39115.2.96.0/20115.2.96.1 to 115.2.111.254115.2.111.2554,094
40115.2.112.0/20115.2.112.1 to 115.2.127.254115.2.127.2554,094
41115.2.128.0/20115.2.128.1 to 115.2.143.254115.2.143.2554,094
42115.2.144.0/20115.2.144.1 to 115.2.159.254115.2.159.2554,094
43115.2.160.0/20115.2.160.1 to 115.2.175.254115.2.175.2554,094
44115.2.176.0/20115.2.176.1 to 115.2.191.254115.2.191.2554,094
45115.2.192.0/20115.2.192.1 to 115.2.207.254115.2.207.2554,094
46115.2.208.0/20115.2.208.1 to 115.2.223.254115.2.223.2554,094
47115.2.224.0/20115.2.224.1 to 115.2.239.254115.2.239.2554,094
48115.2.240.0/20115.2.240.1 to 115.2.255.254115.2.255.2554,094
49115.3.0.0/20115.3.0.1 to 115.3.15.254115.3.15.2554,094
50115.3.16.0/20115.3.16.1 to 115.3.31.254115.3.31.2554,094
51115.3.32.0/20115.3.32.1 to 115.3.47.254115.3.47.2554,094
52115.3.48.0/20115.3.48.1 to 115.3.63.254115.3.63.2554,094
53115.3.64.0/20115.3.64.1 to 115.3.79.254115.3.79.2554,094
54115.3.80.0/20115.3.80.1 to 115.3.95.254115.3.95.2554,094
55115.3.96.0/20115.3.96.1 to 115.3.111.254115.3.111.2554,094
56115.3.112.0/20115.3.112.1 to 115.3.127.254115.3.127.2554,094
57115.3.128.0/20115.3.128.1 to 115.3.143.254115.3.143.2554,094
58115.3.144.0/20115.3.144.1 to 115.3.159.254115.3.159.2554,094
59115.3.160.0/20115.3.160.1 to 115.3.175.254115.3.175.2554,094
60115.3.176.0/20115.3.176.1 to 115.3.191.254115.3.191.2554,094
61115.3.192.0/20115.3.192.1 to 115.3.207.254115.3.207.2554,094
62115.3.208.0/20115.3.208.1 to 115.3.223.254115.3.223.2554,094
63115.3.224.0/20115.3.224.1 to 115.3.239.254115.3.239.2554,094
64115.3.240.0/20115.3.240.1 to 115.3.255.254115.3.255.2554,094
65115.4.0.0/20115.4.0.1 to 115.4.15.254115.4.15.2554,094
66115.4.16.0/20115.4.16.1 to 115.4.31.254115.4.31.2554,094
67115.4.32.0/20115.4.32.1 to 115.4.47.254115.4.47.2554,094
68115.4.48.0/20115.4.48.1 to 115.4.63.254115.4.63.2554,094
69115.4.64.0/20115.4.64.1 to 115.4.79.254115.4.79.2554,094
70115.4.80.0/20115.4.80.1 to 115.4.95.254115.4.95.2554,094
71115.4.96.0/20115.4.96.1 to 115.4.111.254115.4.111.2554,094
72115.4.112.0/20115.4.112.1 to 115.4.127.254115.4.127.2554,094
73115.4.128.0/20115.4.128.1 to 115.4.143.254115.4.143.2554,094
74115.4.144.0/20115.4.144.1 to 115.4.159.254115.4.159.2554,094
75115.4.160.0/20115.4.160.1 to 115.4.175.254115.4.175.2554,094
76115.4.176.0/20115.4.176.1 to 115.4.191.254115.4.191.2554,094
77115.4.192.0/20115.4.192.1 to 115.4.207.254115.4.207.2554,094
78115.4.208.0/20115.4.208.1 to 115.4.223.254115.4.223.2554,094
79115.4.224.0/20115.4.224.1 to 115.4.239.254115.4.239.2554,094
80115.4.240.0/20115.4.240.1 to 115.4.255.254115.4.255.2554,094
81115.5.0.0/20115.5.0.1 to 115.5.15.254115.5.15.2554,094
82115.5.16.0/20115.5.16.1 to 115.5.31.254115.5.31.2554,094
83115.5.32.0/20115.5.32.1 to 115.5.47.254115.5.47.2554,094
84115.5.48.0/20115.5.48.1 to 115.5.63.254115.5.63.2554,094
85115.5.64.0/20115.5.64.1 to 115.5.79.254115.5.79.2554,094
86115.5.80.0/20115.5.80.1 to 115.5.95.254115.5.95.2554,094
87115.5.96.0/20115.5.96.1 to 115.5.111.254115.5.111.2554,094
88115.5.112.0/20115.5.112.1 to 115.5.127.254115.5.127.2554,094
89115.5.128.0/20115.5.128.1 to 115.5.143.254115.5.143.2554,094
90115.5.144.0/20115.5.144.1 to 115.5.159.254115.5.159.2554,094
91115.5.160.0/20115.5.160.1 to 115.5.175.254115.5.175.2554,094
92115.5.176.0/20115.5.176.1 to 115.5.191.254115.5.191.2554,094
93115.5.192.0/20115.5.192.1 to 115.5.207.254115.5.207.2554,094
94115.5.208.0/20115.5.208.1 to 115.5.223.254115.5.223.2554,094
95115.5.224.0/20115.5.224.1 to 115.5.239.254115.5.239.2554,094
96115.5.240.0/20115.5.240.1 to 115.5.255.254115.5.255.2554,094
97115.6.0.0/20115.6.0.1 to 115.6.15.254115.6.15.2554,094
98115.6.16.0/20115.6.16.1 to 115.6.31.254115.6.31.2554,094
99115.6.32.0/20115.6.32.1 to 115.6.47.254115.6.47.2554,094
100115.6.48.0/20115.6.48.1 to 115.6.63.254115.6.63.2554,094
101115.6.64.0/20115.6.64.1 to 115.6.79.254115.6.79.2554,094
102115.6.80.0/20115.6.80.1 to 115.6.95.254115.6.95.2554,094
103115.6.96.0/20115.6.96.1 to 115.6.111.254115.6.111.2554,094
104115.6.112.0/20115.6.112.1 to 115.6.127.254115.6.127.2554,094
105115.6.128.0/20115.6.128.1 to 115.6.143.254115.6.143.2554,094
106115.6.144.0/20115.6.144.1 to 115.6.159.254115.6.159.2554,094
107115.6.160.0/20115.6.160.1 to 115.6.175.254115.6.175.2554,094
108115.6.176.0/20115.6.176.1 to 115.6.191.254115.6.191.2554,094
109115.6.192.0/20115.6.192.1 to 115.6.207.254115.6.207.2554,094
110115.6.208.0/20115.6.208.1 to 115.6.223.254115.6.223.2554,094
111115.6.224.0/20115.6.224.1 to 115.6.239.254115.6.239.2554,094
112115.6.240.0/20115.6.240.1 to 115.6.255.254115.6.255.2554,094
113115.7.0.0/20115.7.0.1 to 115.7.15.254115.7.15.2554,094
114115.7.16.0/20115.7.16.1 to 115.7.31.254115.7.31.2554,094
115115.7.32.0/20115.7.32.1 to 115.7.47.254115.7.47.2554,094
116115.7.48.0/20115.7.48.1 to 115.7.63.254115.7.63.2554,094
117115.7.64.0/20115.7.64.1 to 115.7.79.254115.7.79.2554,094
118115.7.80.0/20115.7.80.1 to 115.7.95.254115.7.95.2554,094
119115.7.96.0/20115.7.96.1 to 115.7.111.254115.7.111.2554,094
120115.7.112.0/20115.7.112.1 to 115.7.127.254115.7.127.2554,094
121115.7.128.0/20115.7.128.1 to 115.7.143.254115.7.143.2554,094
122115.7.144.0/20115.7.144.1 to 115.7.159.254115.7.159.2554,094
123115.7.160.0/20115.7.160.1 to 115.7.175.254115.7.175.2554,094
124115.7.176.0/20115.7.176.1 to 115.7.191.254115.7.191.2554,094
125115.7.192.0/20115.7.192.1 to 115.7.207.254115.7.207.2554,094
126115.7.208.0/20115.7.208.1 to 115.7.223.254115.7.223.2554,094
127115.7.224.0/20115.7.224.1 to 115.7.239.254115.7.239.2554,094
128115.7.240.0/20115.7.240.1 to 115.7.255.254115.7.255.2554,094
129115.8.0.0/20115.8.0.1 to 115.8.15.254115.8.15.2554,094
130115.8.16.0/20115.8.16.1 to 115.8.31.254115.8.31.2554,094
131115.8.32.0/20115.8.32.1 to 115.8.47.254115.8.47.2554,094
132115.8.48.0/20115.8.48.1 to 115.8.63.254115.8.63.2554,094
133115.8.64.0/20115.8.64.1 to 115.8.79.254115.8.79.2554,094
134115.8.80.0/20115.8.80.1 to 115.8.95.254115.8.95.2554,094
135115.8.96.0/20115.8.96.1 to 115.8.111.254115.8.111.2554,094
136115.8.112.0/20115.8.112.1 to 115.8.127.254115.8.127.2554,094
137115.8.128.0/20115.8.128.1 to 115.8.143.254115.8.143.2554,094
138115.8.144.0/20115.8.144.1 to 115.8.159.254115.8.159.2554,094
139115.8.160.0/20115.8.160.1 to 115.8.175.254115.8.175.2554,094
140115.8.176.0/20115.8.176.1 to 115.8.191.254115.8.191.2554,094
141115.8.192.0/20115.8.192.1 to 115.8.207.254115.8.207.2554,094
142115.8.208.0/20115.8.208.1 to 115.8.223.254115.8.223.2554,094
143115.8.224.0/20115.8.224.1 to 115.8.239.254115.8.239.2554,094
144115.8.240.0/20115.8.240.1 to 115.8.255.254115.8.255.2554,094
145115.9.0.0/20115.9.0.1 to 115.9.15.254115.9.15.2554,094
146115.9.16.0/20115.9.16.1 to 115.9.31.254115.9.31.2554,094
147115.9.32.0/20115.9.32.1 to 115.9.47.254115.9.47.2554,094
148115.9.48.0/20115.9.48.1 to 115.9.63.254115.9.63.2554,094
149115.9.64.0/20115.9.64.1 to 115.9.79.254115.9.79.2554,094
150115.9.80.0/20115.9.80.1 to 115.9.95.254115.9.95.2554,094
151115.9.96.0/20115.9.96.1 to 115.9.111.254115.9.111.2554,094
152115.9.112.0/20115.9.112.1 to 115.9.127.254115.9.127.2554,094
153115.9.128.0/20115.9.128.1 to 115.9.143.254115.9.143.2554,094
154115.9.144.0/20115.9.144.1 to 115.9.159.254115.9.159.2554,094
155115.9.160.0/20115.9.160.1 to 115.9.175.254115.9.175.2554,094
156115.9.176.0/20115.9.176.1 to 115.9.191.254115.9.191.2554,094
157115.9.192.0/20115.9.192.1 to 115.9.207.254115.9.207.2554,094
158115.9.208.0/20115.9.208.1 to 115.9.223.254115.9.223.2554,094
159115.9.224.0/20115.9.224.1 to 115.9.239.254115.9.239.2554,094
160115.9.240.0/20115.9.240.1 to 115.9.255.254115.9.255.2554,094
161115.10.0.0/20115.10.0.1 to 115.10.15.254115.10.15.2554,094
162115.10.16.0/20115.10.16.1 to 115.10.31.254115.10.31.2554,094
163115.10.32.0/20115.10.32.1 to 115.10.47.254115.10.47.2554,094
164115.10.48.0/20115.10.48.1 to 115.10.63.254115.10.63.2554,094
165115.10.64.0/20115.10.64.1 to 115.10.79.254115.10.79.2554,094
166115.10.80.0/20115.10.80.1 to 115.10.95.254115.10.95.2554,094
167115.10.96.0/20115.10.96.1 to 115.10.111.254115.10.111.2554,094
168115.10.112.0/20115.10.112.1 to 115.10.127.254115.10.127.2554,094
169115.10.128.0/20115.10.128.1 to 115.10.143.254115.10.143.2554,094
170115.10.144.0/20115.10.144.1 to 115.10.159.254115.10.159.2554,094
171115.10.160.0/20115.10.160.1 to 115.10.175.254115.10.175.2554,094
172115.10.176.0/20115.10.176.1 to 115.10.191.254115.10.191.2554,094
173115.10.192.0/20115.10.192.1 to 115.10.207.254115.10.207.2554,094
174115.10.208.0/20115.10.208.1 to 115.10.223.254115.10.223.2554,094
175115.10.224.0/20115.10.224.1 to 115.10.239.254115.10.239.2554,094
176115.10.240.0/20115.10.240.1 to 115.10.255.254115.10.255.2554,094
177115.11.0.0/20115.11.0.1 to 115.11.15.254115.11.15.2554,094
178115.11.16.0/20115.11.16.1 to 115.11.31.254115.11.31.2554,094
179115.11.32.0/20115.11.32.1 to 115.11.47.254115.11.47.2554,094
180115.11.48.0/20115.11.48.1 to 115.11.63.254115.11.63.2554,094
181115.11.64.0/20115.11.64.1 to 115.11.79.254115.11.79.2554,094
182115.11.80.0/20115.11.80.1 to 115.11.95.254115.11.95.2554,094
183115.11.96.0/20115.11.96.1 to 115.11.111.254115.11.111.2554,094
184115.11.112.0/20115.11.112.1 to 115.11.127.254115.11.127.2554,094
185115.11.128.0/20115.11.128.1 to 115.11.143.254115.11.143.2554,094
186115.11.144.0/20115.11.144.1 to 115.11.159.254115.11.159.2554,094
187115.11.160.0/20115.11.160.1 to 115.11.175.254115.11.175.2554,094
188115.11.176.0/20115.11.176.1 to 115.11.191.254115.11.191.2554,094
189115.11.192.0/20115.11.192.1 to 115.11.207.254115.11.207.2554,094
190115.11.208.0/20115.11.208.1 to 115.11.223.254115.11.223.2554,094
191115.11.224.0/20115.11.224.1 to 115.11.239.254115.11.239.2554,094
192115.11.240.0/20115.11.240.1 to 115.11.255.254115.11.255.2554,094
193115.12.0.0/20115.12.0.1 to 115.12.15.254115.12.15.2554,094
194115.12.16.0/20115.12.16.1 to 115.12.31.254115.12.31.2554,094
195115.12.32.0/20115.12.32.1 to 115.12.47.254115.12.47.2554,094
196115.12.48.0/20115.12.48.1 to 115.12.63.254115.12.63.2554,094
197115.12.64.0/20115.12.64.1 to 115.12.79.254115.12.79.2554,094
198115.12.80.0/20115.12.80.1 to 115.12.95.254115.12.95.2554,094
199115.12.96.0/20115.12.96.1 to 115.12.111.254115.12.111.2554,094
200115.12.112.0/20115.12.112.1 to 115.12.127.254115.12.127.2554,094
201115.12.128.0/20115.12.128.1 to 115.12.143.254115.12.143.2554,094
202115.12.144.0/20115.12.144.1 to 115.12.159.254115.12.159.2554,094
203115.12.160.0/20115.12.160.1 to 115.12.175.254115.12.175.2554,094
204115.12.176.0/20115.12.176.1 to 115.12.191.254115.12.191.2554,094
205115.12.192.0/20115.12.192.1 to 115.12.207.254115.12.207.2554,094
206115.12.208.0/20115.12.208.1 to 115.12.223.254115.12.223.2554,094
207115.12.224.0/20115.12.224.1 to 115.12.239.254115.12.239.2554,094
208115.12.240.0/20115.12.240.1 to 115.12.255.254115.12.255.2554,094
209115.13.0.0/20115.13.0.1 to 115.13.15.254115.13.15.2554,094
210115.13.16.0/20115.13.16.1 to 115.13.31.254115.13.31.2554,094
211115.13.32.0/20115.13.32.1 to 115.13.47.254115.13.47.2554,094
212115.13.48.0/20115.13.48.1 to 115.13.63.254115.13.63.2554,094
213115.13.64.0/20115.13.64.1 to 115.13.79.254115.13.79.2554,094
214115.13.80.0/20115.13.80.1 to 115.13.95.254115.13.95.2554,094
215115.13.96.0/20115.13.96.1 to 115.13.111.254115.13.111.2554,094
216115.13.112.0/20115.13.112.1 to 115.13.127.254115.13.127.2554,094
217115.13.128.0/20115.13.128.1 to 115.13.143.254115.13.143.2554,094
218115.13.144.0/20115.13.144.1 to 115.13.159.254115.13.159.2554,094
219115.13.160.0/20115.13.160.1 to 115.13.175.254115.13.175.2554,094
220115.13.176.0/20115.13.176.1 to 115.13.191.254115.13.191.2554,094
221115.13.192.0/20115.13.192.1 to 115.13.207.254115.13.207.2554,094
222115.13.208.0/20115.13.208.1 to 115.13.223.254115.13.223.2554,094
223115.13.224.0/20115.13.224.1 to 115.13.239.254115.13.239.2554,094
224115.13.240.0/20115.13.240.1 to 115.13.255.254115.13.255.2554,094
225115.14.0.0/20115.14.0.1 to 115.14.15.254115.14.15.2554,094
226115.14.16.0/20115.14.16.1 to 115.14.31.254115.14.31.2554,094
227115.14.32.0/20115.14.32.1 to 115.14.47.254115.14.47.2554,094
228115.14.48.0/20115.14.48.1 to 115.14.63.254115.14.63.2554,094
229115.14.64.0/20115.14.64.1 to 115.14.79.254115.14.79.2554,094
230115.14.80.0/20115.14.80.1 to 115.14.95.254115.14.95.2554,094
231115.14.96.0/20115.14.96.1 to 115.14.111.254115.14.111.2554,094
232115.14.112.0/20115.14.112.1 to 115.14.127.254115.14.127.2554,094
233115.14.128.0/20115.14.128.1 to 115.14.143.254115.14.143.2554,094
234115.14.144.0/20115.14.144.1 to 115.14.159.254115.14.159.2554,094
235115.14.160.0/20115.14.160.1 to 115.14.175.254115.14.175.2554,094
236115.14.176.0/20115.14.176.1 to 115.14.191.254115.14.191.2554,094
237115.14.192.0/20115.14.192.1 to 115.14.207.254115.14.207.2554,094
238115.14.208.0/20115.14.208.1 to 115.14.223.254115.14.223.2554,094
239115.14.224.0/20115.14.224.1 to 115.14.239.254115.14.239.2554,094
240115.14.240.0/20115.14.240.1 to 115.14.255.254115.14.255.2554,094
241115.15.0.0/20115.15.0.1 to 115.15.15.254115.15.15.2554,094
242115.15.16.0/20115.15.16.1 to 115.15.31.254115.15.31.2554,094
243115.15.32.0/20115.15.32.1 to 115.15.47.254115.15.47.2554,094
244115.15.48.0/20115.15.48.1 to 115.15.63.254115.15.63.2554,094
245115.15.64.0/20115.15.64.1 to 115.15.79.254115.15.79.2554,094
246115.15.80.0/20115.15.80.1 to 115.15.95.254115.15.95.2554,094
247115.15.96.0/20115.15.96.1 to 115.15.111.254115.15.111.2554,094
248115.15.112.0/20115.15.112.1 to 115.15.127.254115.15.127.2554,094
249115.15.128.0/20115.15.128.1 to 115.15.143.254115.15.143.2554,094
250115.15.144.0/20115.15.144.1 to 115.15.159.254115.15.159.2554,094
251115.15.160.0/20115.15.160.1 to 115.15.175.254115.15.175.2554,094
252115.15.176.0/20115.15.176.1 to 115.15.191.254115.15.191.2554,094
253115.15.192.0/20115.15.192.1 to 115.15.207.254115.15.207.2554,094
254115.15.208.0/20115.15.208.1 to 115.15.223.254115.15.223.2554,094
255115.15.224.0/20115.15.224.1 to 115.15.239.254115.15.239.2554,094
256115.15.240.0/20115.15.240.1 to 115.15.255.254115.15.255.2554,094

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.