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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.

Network115.72.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
115.72.0.0
Broadcast address
115.79.255.255
First usable
115.72.0.1
Last usable
115.79.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 73480000 · Integer 1934098432 to 1934622719
Reverse DNS zones
72.115.in-addr.arpa
73.115.in-addr.arpa
74.115.in-addr.arpa
75.115.in-addr.arpa
76.115.in-addr.arpa
77.115.in-addr.arpa
78.115.in-addr.arpa
79.115.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110011.01001000.00000000.00000000115.72.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network01110011.01001000.00000000.00000000115.72.0.0
Broadcast01110011.01001111.11111111.11111111115.79.255.255
Split into smaller subnets/21
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

115.72.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1115.72.0.0/21115.72.0.1 to 115.72.7.254115.72.7.2552,046
2115.72.8.0/21115.72.8.1 to 115.72.15.254115.72.15.2552,046
3115.72.16.0/21115.72.16.1 to 115.72.23.254115.72.23.2552,046
4115.72.24.0/21115.72.24.1 to 115.72.31.254115.72.31.2552,046
5115.72.32.0/21115.72.32.1 to 115.72.39.254115.72.39.2552,046
6115.72.40.0/21115.72.40.1 to 115.72.47.254115.72.47.2552,046
7115.72.48.0/21115.72.48.1 to 115.72.55.254115.72.55.2552,046
8115.72.56.0/21115.72.56.1 to 115.72.63.254115.72.63.2552,046
9115.72.64.0/21115.72.64.1 to 115.72.71.254115.72.71.2552,046
10115.72.72.0/21115.72.72.1 to 115.72.79.254115.72.79.2552,046
11115.72.80.0/21115.72.80.1 to 115.72.87.254115.72.87.2552,046
12115.72.88.0/21115.72.88.1 to 115.72.95.254115.72.95.2552,046
13115.72.96.0/21115.72.96.1 to 115.72.103.254115.72.103.2552,046
14115.72.104.0/21115.72.104.1 to 115.72.111.254115.72.111.2552,046
15115.72.112.0/21115.72.112.1 to 115.72.119.254115.72.119.2552,046
16115.72.120.0/21115.72.120.1 to 115.72.127.254115.72.127.2552,046
17115.72.128.0/21115.72.128.1 to 115.72.135.254115.72.135.2552,046
18115.72.136.0/21115.72.136.1 to 115.72.143.254115.72.143.2552,046
19115.72.144.0/21115.72.144.1 to 115.72.151.254115.72.151.2552,046
20115.72.152.0/21115.72.152.1 to 115.72.159.254115.72.159.2552,046
21115.72.160.0/21115.72.160.1 to 115.72.167.254115.72.167.2552,046
22115.72.168.0/21115.72.168.1 to 115.72.175.254115.72.175.2552,046
23115.72.176.0/21115.72.176.1 to 115.72.183.254115.72.183.2552,046
24115.72.184.0/21115.72.184.1 to 115.72.191.254115.72.191.2552,046
25115.72.192.0/21115.72.192.1 to 115.72.199.254115.72.199.2552,046
26115.72.200.0/21115.72.200.1 to 115.72.207.254115.72.207.2552,046
27115.72.208.0/21115.72.208.1 to 115.72.215.254115.72.215.2552,046
28115.72.216.0/21115.72.216.1 to 115.72.223.254115.72.223.2552,046
29115.72.224.0/21115.72.224.1 to 115.72.231.254115.72.231.2552,046
30115.72.232.0/21115.72.232.1 to 115.72.239.254115.72.239.2552,046
31115.72.240.0/21115.72.240.1 to 115.72.247.254115.72.247.2552,046
32115.72.248.0/21115.72.248.1 to 115.72.255.254115.72.255.2552,046
33115.73.0.0/21115.73.0.1 to 115.73.7.254115.73.7.2552,046
34115.73.8.0/21115.73.8.1 to 115.73.15.254115.73.15.2552,046
35115.73.16.0/21115.73.16.1 to 115.73.23.254115.73.23.2552,046
36115.73.24.0/21115.73.24.1 to 115.73.31.254115.73.31.2552,046
37115.73.32.0/21115.73.32.1 to 115.73.39.254115.73.39.2552,046
38115.73.40.0/21115.73.40.1 to 115.73.47.254115.73.47.2552,046
39115.73.48.0/21115.73.48.1 to 115.73.55.254115.73.55.2552,046
40115.73.56.0/21115.73.56.1 to 115.73.63.254115.73.63.2552,046
41115.73.64.0/21115.73.64.1 to 115.73.71.254115.73.71.2552,046
42115.73.72.0/21115.73.72.1 to 115.73.79.254115.73.79.2552,046
43115.73.80.0/21115.73.80.1 to 115.73.87.254115.73.87.2552,046
44115.73.88.0/21115.73.88.1 to 115.73.95.254115.73.95.2552,046
45115.73.96.0/21115.73.96.1 to 115.73.103.254115.73.103.2552,046
46115.73.104.0/21115.73.104.1 to 115.73.111.254115.73.111.2552,046
47115.73.112.0/21115.73.112.1 to 115.73.119.254115.73.119.2552,046
48115.73.120.0/21115.73.120.1 to 115.73.127.254115.73.127.2552,046
49115.73.128.0/21115.73.128.1 to 115.73.135.254115.73.135.2552,046
50115.73.136.0/21115.73.136.1 to 115.73.143.254115.73.143.2552,046
51115.73.144.0/21115.73.144.1 to 115.73.151.254115.73.151.2552,046
52115.73.152.0/21115.73.152.1 to 115.73.159.254115.73.159.2552,046
53115.73.160.0/21115.73.160.1 to 115.73.167.254115.73.167.2552,046
54115.73.168.0/21115.73.168.1 to 115.73.175.254115.73.175.2552,046
55115.73.176.0/21115.73.176.1 to 115.73.183.254115.73.183.2552,046
56115.73.184.0/21115.73.184.1 to 115.73.191.254115.73.191.2552,046
57115.73.192.0/21115.73.192.1 to 115.73.199.254115.73.199.2552,046
58115.73.200.0/21115.73.200.1 to 115.73.207.254115.73.207.2552,046
59115.73.208.0/21115.73.208.1 to 115.73.215.254115.73.215.2552,046
60115.73.216.0/21115.73.216.1 to 115.73.223.254115.73.223.2552,046
61115.73.224.0/21115.73.224.1 to 115.73.231.254115.73.231.2552,046
62115.73.232.0/21115.73.232.1 to 115.73.239.254115.73.239.2552,046
63115.73.240.0/21115.73.240.1 to 115.73.247.254115.73.247.2552,046
64115.73.248.0/21115.73.248.1 to 115.73.255.254115.73.255.2552,046
65115.74.0.0/21115.74.0.1 to 115.74.7.254115.74.7.2552,046
66115.74.8.0/21115.74.8.1 to 115.74.15.254115.74.15.2552,046
67115.74.16.0/21115.74.16.1 to 115.74.23.254115.74.23.2552,046
68115.74.24.0/21115.74.24.1 to 115.74.31.254115.74.31.2552,046
69115.74.32.0/21115.74.32.1 to 115.74.39.254115.74.39.2552,046
70115.74.40.0/21115.74.40.1 to 115.74.47.254115.74.47.2552,046
71115.74.48.0/21115.74.48.1 to 115.74.55.254115.74.55.2552,046
72115.74.56.0/21115.74.56.1 to 115.74.63.254115.74.63.2552,046
73115.74.64.0/21115.74.64.1 to 115.74.71.254115.74.71.2552,046
74115.74.72.0/21115.74.72.1 to 115.74.79.254115.74.79.2552,046
75115.74.80.0/21115.74.80.1 to 115.74.87.254115.74.87.2552,046
76115.74.88.0/21115.74.88.1 to 115.74.95.254115.74.95.2552,046
77115.74.96.0/21115.74.96.1 to 115.74.103.254115.74.103.2552,046
78115.74.104.0/21115.74.104.1 to 115.74.111.254115.74.111.2552,046
79115.74.112.0/21115.74.112.1 to 115.74.119.254115.74.119.2552,046
80115.74.120.0/21115.74.120.1 to 115.74.127.254115.74.127.2552,046
81115.74.128.0/21115.74.128.1 to 115.74.135.254115.74.135.2552,046
82115.74.136.0/21115.74.136.1 to 115.74.143.254115.74.143.2552,046
83115.74.144.0/21115.74.144.1 to 115.74.151.254115.74.151.2552,046
84115.74.152.0/21115.74.152.1 to 115.74.159.254115.74.159.2552,046
85115.74.160.0/21115.74.160.1 to 115.74.167.254115.74.167.2552,046
86115.74.168.0/21115.74.168.1 to 115.74.175.254115.74.175.2552,046
87115.74.176.0/21115.74.176.1 to 115.74.183.254115.74.183.2552,046
88115.74.184.0/21115.74.184.1 to 115.74.191.254115.74.191.2552,046
89115.74.192.0/21115.74.192.1 to 115.74.199.254115.74.199.2552,046
90115.74.200.0/21115.74.200.1 to 115.74.207.254115.74.207.2552,046
91115.74.208.0/21115.74.208.1 to 115.74.215.254115.74.215.2552,046
92115.74.216.0/21115.74.216.1 to 115.74.223.254115.74.223.2552,046
93115.74.224.0/21115.74.224.1 to 115.74.231.254115.74.231.2552,046
94115.74.232.0/21115.74.232.1 to 115.74.239.254115.74.239.2552,046
95115.74.240.0/21115.74.240.1 to 115.74.247.254115.74.247.2552,046
96115.74.248.0/21115.74.248.1 to 115.74.255.254115.74.255.2552,046
97115.75.0.0/21115.75.0.1 to 115.75.7.254115.75.7.2552,046
98115.75.8.0/21115.75.8.1 to 115.75.15.254115.75.15.2552,046
99115.75.16.0/21115.75.16.1 to 115.75.23.254115.75.23.2552,046
100115.75.24.0/21115.75.24.1 to 115.75.31.254115.75.31.2552,046
101115.75.32.0/21115.75.32.1 to 115.75.39.254115.75.39.2552,046
102115.75.40.0/21115.75.40.1 to 115.75.47.254115.75.47.2552,046
103115.75.48.0/21115.75.48.1 to 115.75.55.254115.75.55.2552,046
104115.75.56.0/21115.75.56.1 to 115.75.63.254115.75.63.2552,046
105115.75.64.0/21115.75.64.1 to 115.75.71.254115.75.71.2552,046
106115.75.72.0/21115.75.72.1 to 115.75.79.254115.75.79.2552,046
107115.75.80.0/21115.75.80.1 to 115.75.87.254115.75.87.2552,046
108115.75.88.0/21115.75.88.1 to 115.75.95.254115.75.95.2552,046
109115.75.96.0/21115.75.96.1 to 115.75.103.254115.75.103.2552,046
110115.75.104.0/21115.75.104.1 to 115.75.111.254115.75.111.2552,046
111115.75.112.0/21115.75.112.1 to 115.75.119.254115.75.119.2552,046
112115.75.120.0/21115.75.120.1 to 115.75.127.254115.75.127.2552,046
113115.75.128.0/21115.75.128.1 to 115.75.135.254115.75.135.2552,046
114115.75.136.0/21115.75.136.1 to 115.75.143.254115.75.143.2552,046
115115.75.144.0/21115.75.144.1 to 115.75.151.254115.75.151.2552,046
116115.75.152.0/21115.75.152.1 to 115.75.159.254115.75.159.2552,046
117115.75.160.0/21115.75.160.1 to 115.75.167.254115.75.167.2552,046
118115.75.168.0/21115.75.168.1 to 115.75.175.254115.75.175.2552,046
119115.75.176.0/21115.75.176.1 to 115.75.183.254115.75.183.2552,046
120115.75.184.0/21115.75.184.1 to 115.75.191.254115.75.191.2552,046
121115.75.192.0/21115.75.192.1 to 115.75.199.254115.75.199.2552,046
122115.75.200.0/21115.75.200.1 to 115.75.207.254115.75.207.2552,046
123115.75.208.0/21115.75.208.1 to 115.75.215.254115.75.215.2552,046
124115.75.216.0/21115.75.216.1 to 115.75.223.254115.75.223.2552,046
125115.75.224.0/21115.75.224.1 to 115.75.231.254115.75.231.2552,046
126115.75.232.0/21115.75.232.1 to 115.75.239.254115.75.239.2552,046
127115.75.240.0/21115.75.240.1 to 115.75.247.254115.75.247.2552,046
128115.75.248.0/21115.75.248.1 to 115.75.255.254115.75.255.2552,046
129115.76.0.0/21115.76.0.1 to 115.76.7.254115.76.7.2552,046
130115.76.8.0/21115.76.8.1 to 115.76.15.254115.76.15.2552,046
131115.76.16.0/21115.76.16.1 to 115.76.23.254115.76.23.2552,046
132115.76.24.0/21115.76.24.1 to 115.76.31.254115.76.31.2552,046
133115.76.32.0/21115.76.32.1 to 115.76.39.254115.76.39.2552,046
134115.76.40.0/21115.76.40.1 to 115.76.47.254115.76.47.2552,046
135115.76.48.0/21115.76.48.1 to 115.76.55.254115.76.55.2552,046
136115.76.56.0/21115.76.56.1 to 115.76.63.254115.76.63.2552,046
137115.76.64.0/21115.76.64.1 to 115.76.71.254115.76.71.2552,046
138115.76.72.0/21115.76.72.1 to 115.76.79.254115.76.79.2552,046
139115.76.80.0/21115.76.80.1 to 115.76.87.254115.76.87.2552,046
140115.76.88.0/21115.76.88.1 to 115.76.95.254115.76.95.2552,046
141115.76.96.0/21115.76.96.1 to 115.76.103.254115.76.103.2552,046
142115.76.104.0/21115.76.104.1 to 115.76.111.254115.76.111.2552,046
143115.76.112.0/21115.76.112.1 to 115.76.119.254115.76.119.2552,046
144115.76.120.0/21115.76.120.1 to 115.76.127.254115.76.127.2552,046
145115.76.128.0/21115.76.128.1 to 115.76.135.254115.76.135.2552,046
146115.76.136.0/21115.76.136.1 to 115.76.143.254115.76.143.2552,046
147115.76.144.0/21115.76.144.1 to 115.76.151.254115.76.151.2552,046
148115.76.152.0/21115.76.152.1 to 115.76.159.254115.76.159.2552,046
149115.76.160.0/21115.76.160.1 to 115.76.167.254115.76.167.2552,046
150115.76.168.0/21115.76.168.1 to 115.76.175.254115.76.175.2552,046
151115.76.176.0/21115.76.176.1 to 115.76.183.254115.76.183.2552,046
152115.76.184.0/21115.76.184.1 to 115.76.191.254115.76.191.2552,046
153115.76.192.0/21115.76.192.1 to 115.76.199.254115.76.199.2552,046
154115.76.200.0/21115.76.200.1 to 115.76.207.254115.76.207.2552,046
155115.76.208.0/21115.76.208.1 to 115.76.215.254115.76.215.2552,046
156115.76.216.0/21115.76.216.1 to 115.76.223.254115.76.223.2552,046
157115.76.224.0/21115.76.224.1 to 115.76.231.254115.76.231.2552,046
158115.76.232.0/21115.76.232.1 to 115.76.239.254115.76.239.2552,046
159115.76.240.0/21115.76.240.1 to 115.76.247.254115.76.247.2552,046
160115.76.248.0/21115.76.248.1 to 115.76.255.254115.76.255.2552,046
161115.77.0.0/21115.77.0.1 to 115.77.7.254115.77.7.2552,046
162115.77.8.0/21115.77.8.1 to 115.77.15.254115.77.15.2552,046
163115.77.16.0/21115.77.16.1 to 115.77.23.254115.77.23.2552,046
164115.77.24.0/21115.77.24.1 to 115.77.31.254115.77.31.2552,046
165115.77.32.0/21115.77.32.1 to 115.77.39.254115.77.39.2552,046
166115.77.40.0/21115.77.40.1 to 115.77.47.254115.77.47.2552,046
167115.77.48.0/21115.77.48.1 to 115.77.55.254115.77.55.2552,046
168115.77.56.0/21115.77.56.1 to 115.77.63.254115.77.63.2552,046
169115.77.64.0/21115.77.64.1 to 115.77.71.254115.77.71.2552,046
170115.77.72.0/21115.77.72.1 to 115.77.79.254115.77.79.2552,046
171115.77.80.0/21115.77.80.1 to 115.77.87.254115.77.87.2552,046
172115.77.88.0/21115.77.88.1 to 115.77.95.254115.77.95.2552,046
173115.77.96.0/21115.77.96.1 to 115.77.103.254115.77.103.2552,046
174115.77.104.0/21115.77.104.1 to 115.77.111.254115.77.111.2552,046
175115.77.112.0/21115.77.112.1 to 115.77.119.254115.77.119.2552,046
176115.77.120.0/21115.77.120.1 to 115.77.127.254115.77.127.2552,046
177115.77.128.0/21115.77.128.1 to 115.77.135.254115.77.135.2552,046
178115.77.136.0/21115.77.136.1 to 115.77.143.254115.77.143.2552,046
179115.77.144.0/21115.77.144.1 to 115.77.151.254115.77.151.2552,046
180115.77.152.0/21115.77.152.1 to 115.77.159.254115.77.159.2552,046
181115.77.160.0/21115.77.160.1 to 115.77.167.254115.77.167.2552,046
182115.77.168.0/21115.77.168.1 to 115.77.175.254115.77.175.2552,046
183115.77.176.0/21115.77.176.1 to 115.77.183.254115.77.183.2552,046
184115.77.184.0/21115.77.184.1 to 115.77.191.254115.77.191.2552,046
185115.77.192.0/21115.77.192.1 to 115.77.199.254115.77.199.2552,046
186115.77.200.0/21115.77.200.1 to 115.77.207.254115.77.207.2552,046
187115.77.208.0/21115.77.208.1 to 115.77.215.254115.77.215.2552,046
188115.77.216.0/21115.77.216.1 to 115.77.223.254115.77.223.2552,046
189115.77.224.0/21115.77.224.1 to 115.77.231.254115.77.231.2552,046
190115.77.232.0/21115.77.232.1 to 115.77.239.254115.77.239.2552,046
191115.77.240.0/21115.77.240.1 to 115.77.247.254115.77.247.2552,046
192115.77.248.0/21115.77.248.1 to 115.77.255.254115.77.255.2552,046
193115.78.0.0/21115.78.0.1 to 115.78.7.254115.78.7.2552,046
194115.78.8.0/21115.78.8.1 to 115.78.15.254115.78.15.2552,046
195115.78.16.0/21115.78.16.1 to 115.78.23.254115.78.23.2552,046
196115.78.24.0/21115.78.24.1 to 115.78.31.254115.78.31.2552,046
197115.78.32.0/21115.78.32.1 to 115.78.39.254115.78.39.2552,046
198115.78.40.0/21115.78.40.1 to 115.78.47.254115.78.47.2552,046
199115.78.48.0/21115.78.48.1 to 115.78.55.254115.78.55.2552,046
200115.78.56.0/21115.78.56.1 to 115.78.63.254115.78.63.2552,046
201115.78.64.0/21115.78.64.1 to 115.78.71.254115.78.71.2552,046
202115.78.72.0/21115.78.72.1 to 115.78.79.254115.78.79.2552,046
203115.78.80.0/21115.78.80.1 to 115.78.87.254115.78.87.2552,046
204115.78.88.0/21115.78.88.1 to 115.78.95.254115.78.95.2552,046
205115.78.96.0/21115.78.96.1 to 115.78.103.254115.78.103.2552,046
206115.78.104.0/21115.78.104.1 to 115.78.111.254115.78.111.2552,046
207115.78.112.0/21115.78.112.1 to 115.78.119.254115.78.119.2552,046
208115.78.120.0/21115.78.120.1 to 115.78.127.254115.78.127.2552,046
209115.78.128.0/21115.78.128.1 to 115.78.135.254115.78.135.2552,046
210115.78.136.0/21115.78.136.1 to 115.78.143.254115.78.143.2552,046
211115.78.144.0/21115.78.144.1 to 115.78.151.254115.78.151.2552,046
212115.78.152.0/21115.78.152.1 to 115.78.159.254115.78.159.2552,046
213115.78.160.0/21115.78.160.1 to 115.78.167.254115.78.167.2552,046
214115.78.168.0/21115.78.168.1 to 115.78.175.254115.78.175.2552,046
215115.78.176.0/21115.78.176.1 to 115.78.183.254115.78.183.2552,046
216115.78.184.0/21115.78.184.1 to 115.78.191.254115.78.191.2552,046
217115.78.192.0/21115.78.192.1 to 115.78.199.254115.78.199.2552,046
218115.78.200.0/21115.78.200.1 to 115.78.207.254115.78.207.2552,046
219115.78.208.0/21115.78.208.1 to 115.78.215.254115.78.215.2552,046
220115.78.216.0/21115.78.216.1 to 115.78.223.254115.78.223.2552,046
221115.78.224.0/21115.78.224.1 to 115.78.231.254115.78.231.2552,046
222115.78.232.0/21115.78.232.1 to 115.78.239.254115.78.239.2552,046
223115.78.240.0/21115.78.240.1 to 115.78.247.254115.78.247.2552,046
224115.78.248.0/21115.78.248.1 to 115.78.255.254115.78.255.2552,046
225115.79.0.0/21115.79.0.1 to 115.79.7.254115.79.7.2552,046
226115.79.8.0/21115.79.8.1 to 115.79.15.254115.79.15.2552,046
227115.79.16.0/21115.79.16.1 to 115.79.23.254115.79.23.2552,046
228115.79.24.0/21115.79.24.1 to 115.79.31.254115.79.31.2552,046
229115.79.32.0/21115.79.32.1 to 115.79.39.254115.79.39.2552,046
230115.79.40.0/21115.79.40.1 to 115.79.47.254115.79.47.2552,046
231115.79.48.0/21115.79.48.1 to 115.79.55.254115.79.55.2552,046
232115.79.56.0/21115.79.56.1 to 115.79.63.254115.79.63.2552,046
233115.79.64.0/21115.79.64.1 to 115.79.71.254115.79.71.2552,046
234115.79.72.0/21115.79.72.1 to 115.79.79.254115.79.79.2552,046
235115.79.80.0/21115.79.80.1 to 115.79.87.254115.79.87.2552,046
236115.79.88.0/21115.79.88.1 to 115.79.95.254115.79.95.2552,046
237115.79.96.0/21115.79.96.1 to 115.79.103.254115.79.103.2552,046
238115.79.104.0/21115.79.104.1 to 115.79.111.254115.79.111.2552,046
239115.79.112.0/21115.79.112.1 to 115.79.119.254115.79.119.2552,046
240115.79.120.0/21115.79.120.1 to 115.79.127.254115.79.127.2552,046
241115.79.128.0/21115.79.128.1 to 115.79.135.254115.79.135.2552,046
242115.79.136.0/21115.79.136.1 to 115.79.143.254115.79.143.2552,046
243115.79.144.0/21115.79.144.1 to 115.79.151.254115.79.151.2552,046
244115.79.152.0/21115.79.152.1 to 115.79.159.254115.79.159.2552,046
245115.79.160.0/21115.79.160.1 to 115.79.167.254115.79.167.2552,046
246115.79.168.0/21115.79.168.1 to 115.79.175.254115.79.175.2552,046
247115.79.176.0/21115.79.176.1 to 115.79.183.254115.79.183.2552,046
248115.79.184.0/21115.79.184.1 to 115.79.191.254115.79.191.2552,046
249115.79.192.0/21115.79.192.1 to 115.79.199.254115.79.199.2552,046
250115.79.200.0/21115.79.200.1 to 115.79.207.254115.79.207.2552,046
251115.79.208.0/21115.79.208.1 to 115.79.215.254115.79.215.2552,046
252115.79.216.0/21115.79.216.1 to 115.79.223.254115.79.223.2552,046
253115.79.224.0/21115.79.224.1 to 115.79.231.254115.79.231.2552,046
254115.79.232.0/21115.79.232.1 to 115.79.239.254115.79.239.2552,046
255115.79.240.0/21115.79.240.1 to 115.79.247.254115.79.247.2552,046
256115.79.248.0/21115.79.248.1 to 115.79.255.254115.79.255.2552,046

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.