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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.

Network115.72.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
115.72.0.0
Broadcast address
115.73.255.255
First usable
115.72.0.1
Last usable
115.73.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 73480000 · Integer 1934098432 to 1934229503
Reverse DNS zones
72.115.in-addr.arpa
73.115.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110011.01001000.00000000.00000000115.72.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01110011.01001000.00000000.00000000115.72.0.0
Broadcast01110011.01001001.11111111.11111111115.73.255.255
Split into smaller subnets/23
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

115.72.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1115.72.0.0/23115.72.0.1 to 115.72.1.254115.72.1.255510
2115.72.2.0/23115.72.2.1 to 115.72.3.254115.72.3.255510
3115.72.4.0/23115.72.4.1 to 115.72.5.254115.72.5.255510
4115.72.6.0/23115.72.6.1 to 115.72.7.254115.72.7.255510
5115.72.8.0/23115.72.8.1 to 115.72.9.254115.72.9.255510
6115.72.10.0/23115.72.10.1 to 115.72.11.254115.72.11.255510
7115.72.12.0/23115.72.12.1 to 115.72.13.254115.72.13.255510
8115.72.14.0/23115.72.14.1 to 115.72.15.254115.72.15.255510
9115.72.16.0/23115.72.16.1 to 115.72.17.254115.72.17.255510
10115.72.18.0/23115.72.18.1 to 115.72.19.254115.72.19.255510
11115.72.20.0/23115.72.20.1 to 115.72.21.254115.72.21.255510
12115.72.22.0/23115.72.22.1 to 115.72.23.254115.72.23.255510
13115.72.24.0/23115.72.24.1 to 115.72.25.254115.72.25.255510
14115.72.26.0/23115.72.26.1 to 115.72.27.254115.72.27.255510
15115.72.28.0/23115.72.28.1 to 115.72.29.254115.72.29.255510
16115.72.30.0/23115.72.30.1 to 115.72.31.254115.72.31.255510
17115.72.32.0/23115.72.32.1 to 115.72.33.254115.72.33.255510
18115.72.34.0/23115.72.34.1 to 115.72.35.254115.72.35.255510
19115.72.36.0/23115.72.36.1 to 115.72.37.254115.72.37.255510
20115.72.38.0/23115.72.38.1 to 115.72.39.254115.72.39.255510
21115.72.40.0/23115.72.40.1 to 115.72.41.254115.72.41.255510
22115.72.42.0/23115.72.42.1 to 115.72.43.254115.72.43.255510
23115.72.44.0/23115.72.44.1 to 115.72.45.254115.72.45.255510
24115.72.46.0/23115.72.46.1 to 115.72.47.254115.72.47.255510
25115.72.48.0/23115.72.48.1 to 115.72.49.254115.72.49.255510
26115.72.50.0/23115.72.50.1 to 115.72.51.254115.72.51.255510
27115.72.52.0/23115.72.52.1 to 115.72.53.254115.72.53.255510
28115.72.54.0/23115.72.54.1 to 115.72.55.254115.72.55.255510
29115.72.56.0/23115.72.56.1 to 115.72.57.254115.72.57.255510
30115.72.58.0/23115.72.58.1 to 115.72.59.254115.72.59.255510
31115.72.60.0/23115.72.60.1 to 115.72.61.254115.72.61.255510
32115.72.62.0/23115.72.62.1 to 115.72.63.254115.72.63.255510
33115.72.64.0/23115.72.64.1 to 115.72.65.254115.72.65.255510
34115.72.66.0/23115.72.66.1 to 115.72.67.254115.72.67.255510
35115.72.68.0/23115.72.68.1 to 115.72.69.254115.72.69.255510
36115.72.70.0/23115.72.70.1 to 115.72.71.254115.72.71.255510
37115.72.72.0/23115.72.72.1 to 115.72.73.254115.72.73.255510
38115.72.74.0/23115.72.74.1 to 115.72.75.254115.72.75.255510
39115.72.76.0/23115.72.76.1 to 115.72.77.254115.72.77.255510
40115.72.78.0/23115.72.78.1 to 115.72.79.254115.72.79.255510
41115.72.80.0/23115.72.80.1 to 115.72.81.254115.72.81.255510
42115.72.82.0/23115.72.82.1 to 115.72.83.254115.72.83.255510
43115.72.84.0/23115.72.84.1 to 115.72.85.254115.72.85.255510
44115.72.86.0/23115.72.86.1 to 115.72.87.254115.72.87.255510
45115.72.88.0/23115.72.88.1 to 115.72.89.254115.72.89.255510
46115.72.90.0/23115.72.90.1 to 115.72.91.254115.72.91.255510
47115.72.92.0/23115.72.92.1 to 115.72.93.254115.72.93.255510
48115.72.94.0/23115.72.94.1 to 115.72.95.254115.72.95.255510
49115.72.96.0/23115.72.96.1 to 115.72.97.254115.72.97.255510
50115.72.98.0/23115.72.98.1 to 115.72.99.254115.72.99.255510
51115.72.100.0/23115.72.100.1 to 115.72.101.254115.72.101.255510
52115.72.102.0/23115.72.102.1 to 115.72.103.254115.72.103.255510
53115.72.104.0/23115.72.104.1 to 115.72.105.254115.72.105.255510
54115.72.106.0/23115.72.106.1 to 115.72.107.254115.72.107.255510
55115.72.108.0/23115.72.108.1 to 115.72.109.254115.72.109.255510
56115.72.110.0/23115.72.110.1 to 115.72.111.254115.72.111.255510
57115.72.112.0/23115.72.112.1 to 115.72.113.254115.72.113.255510
58115.72.114.0/23115.72.114.1 to 115.72.115.254115.72.115.255510
59115.72.116.0/23115.72.116.1 to 115.72.117.254115.72.117.255510
60115.72.118.0/23115.72.118.1 to 115.72.119.254115.72.119.255510
61115.72.120.0/23115.72.120.1 to 115.72.121.254115.72.121.255510
62115.72.122.0/23115.72.122.1 to 115.72.123.254115.72.123.255510
63115.72.124.0/23115.72.124.1 to 115.72.125.254115.72.125.255510
64115.72.126.0/23115.72.126.1 to 115.72.127.254115.72.127.255510
65115.72.128.0/23115.72.128.1 to 115.72.129.254115.72.129.255510
66115.72.130.0/23115.72.130.1 to 115.72.131.254115.72.131.255510
67115.72.132.0/23115.72.132.1 to 115.72.133.254115.72.133.255510
68115.72.134.0/23115.72.134.1 to 115.72.135.254115.72.135.255510
69115.72.136.0/23115.72.136.1 to 115.72.137.254115.72.137.255510
70115.72.138.0/23115.72.138.1 to 115.72.139.254115.72.139.255510
71115.72.140.0/23115.72.140.1 to 115.72.141.254115.72.141.255510
72115.72.142.0/23115.72.142.1 to 115.72.143.254115.72.143.255510
73115.72.144.0/23115.72.144.1 to 115.72.145.254115.72.145.255510
74115.72.146.0/23115.72.146.1 to 115.72.147.254115.72.147.255510
75115.72.148.0/23115.72.148.1 to 115.72.149.254115.72.149.255510
76115.72.150.0/23115.72.150.1 to 115.72.151.254115.72.151.255510
77115.72.152.0/23115.72.152.1 to 115.72.153.254115.72.153.255510
78115.72.154.0/23115.72.154.1 to 115.72.155.254115.72.155.255510
79115.72.156.0/23115.72.156.1 to 115.72.157.254115.72.157.255510
80115.72.158.0/23115.72.158.1 to 115.72.159.254115.72.159.255510
81115.72.160.0/23115.72.160.1 to 115.72.161.254115.72.161.255510
82115.72.162.0/23115.72.162.1 to 115.72.163.254115.72.163.255510
83115.72.164.0/23115.72.164.1 to 115.72.165.254115.72.165.255510
84115.72.166.0/23115.72.166.1 to 115.72.167.254115.72.167.255510
85115.72.168.0/23115.72.168.1 to 115.72.169.254115.72.169.255510
86115.72.170.0/23115.72.170.1 to 115.72.171.254115.72.171.255510
87115.72.172.0/23115.72.172.1 to 115.72.173.254115.72.173.255510
88115.72.174.0/23115.72.174.1 to 115.72.175.254115.72.175.255510
89115.72.176.0/23115.72.176.1 to 115.72.177.254115.72.177.255510
90115.72.178.0/23115.72.178.1 to 115.72.179.254115.72.179.255510
91115.72.180.0/23115.72.180.1 to 115.72.181.254115.72.181.255510
92115.72.182.0/23115.72.182.1 to 115.72.183.254115.72.183.255510
93115.72.184.0/23115.72.184.1 to 115.72.185.254115.72.185.255510
94115.72.186.0/23115.72.186.1 to 115.72.187.254115.72.187.255510
95115.72.188.0/23115.72.188.1 to 115.72.189.254115.72.189.255510
96115.72.190.0/23115.72.190.1 to 115.72.191.254115.72.191.255510
97115.72.192.0/23115.72.192.1 to 115.72.193.254115.72.193.255510
98115.72.194.0/23115.72.194.1 to 115.72.195.254115.72.195.255510
99115.72.196.0/23115.72.196.1 to 115.72.197.254115.72.197.255510
100115.72.198.0/23115.72.198.1 to 115.72.199.254115.72.199.255510
101115.72.200.0/23115.72.200.1 to 115.72.201.254115.72.201.255510
102115.72.202.0/23115.72.202.1 to 115.72.203.254115.72.203.255510
103115.72.204.0/23115.72.204.1 to 115.72.205.254115.72.205.255510
104115.72.206.0/23115.72.206.1 to 115.72.207.254115.72.207.255510
105115.72.208.0/23115.72.208.1 to 115.72.209.254115.72.209.255510
106115.72.210.0/23115.72.210.1 to 115.72.211.254115.72.211.255510
107115.72.212.0/23115.72.212.1 to 115.72.213.254115.72.213.255510
108115.72.214.0/23115.72.214.1 to 115.72.215.254115.72.215.255510
109115.72.216.0/23115.72.216.1 to 115.72.217.254115.72.217.255510
110115.72.218.0/23115.72.218.1 to 115.72.219.254115.72.219.255510
111115.72.220.0/23115.72.220.1 to 115.72.221.254115.72.221.255510
112115.72.222.0/23115.72.222.1 to 115.72.223.254115.72.223.255510
113115.72.224.0/23115.72.224.1 to 115.72.225.254115.72.225.255510
114115.72.226.0/23115.72.226.1 to 115.72.227.254115.72.227.255510
115115.72.228.0/23115.72.228.1 to 115.72.229.254115.72.229.255510
116115.72.230.0/23115.72.230.1 to 115.72.231.254115.72.231.255510
117115.72.232.0/23115.72.232.1 to 115.72.233.254115.72.233.255510
118115.72.234.0/23115.72.234.1 to 115.72.235.254115.72.235.255510
119115.72.236.0/23115.72.236.1 to 115.72.237.254115.72.237.255510
120115.72.238.0/23115.72.238.1 to 115.72.239.254115.72.239.255510
121115.72.240.0/23115.72.240.1 to 115.72.241.254115.72.241.255510
122115.72.242.0/23115.72.242.1 to 115.72.243.254115.72.243.255510
123115.72.244.0/23115.72.244.1 to 115.72.245.254115.72.245.255510
124115.72.246.0/23115.72.246.1 to 115.72.247.254115.72.247.255510
125115.72.248.0/23115.72.248.1 to 115.72.249.254115.72.249.255510
126115.72.250.0/23115.72.250.1 to 115.72.251.254115.72.251.255510
127115.72.252.0/23115.72.252.1 to 115.72.253.254115.72.253.255510
128115.72.254.0/23115.72.254.1 to 115.72.255.254115.72.255.255510
129115.73.0.0/23115.73.0.1 to 115.73.1.254115.73.1.255510
130115.73.2.0/23115.73.2.1 to 115.73.3.254115.73.3.255510
131115.73.4.0/23115.73.4.1 to 115.73.5.254115.73.5.255510
132115.73.6.0/23115.73.6.1 to 115.73.7.254115.73.7.255510
133115.73.8.0/23115.73.8.1 to 115.73.9.254115.73.9.255510
134115.73.10.0/23115.73.10.1 to 115.73.11.254115.73.11.255510
135115.73.12.0/23115.73.12.1 to 115.73.13.254115.73.13.255510
136115.73.14.0/23115.73.14.1 to 115.73.15.254115.73.15.255510
137115.73.16.0/23115.73.16.1 to 115.73.17.254115.73.17.255510
138115.73.18.0/23115.73.18.1 to 115.73.19.254115.73.19.255510
139115.73.20.0/23115.73.20.1 to 115.73.21.254115.73.21.255510
140115.73.22.0/23115.73.22.1 to 115.73.23.254115.73.23.255510
141115.73.24.0/23115.73.24.1 to 115.73.25.254115.73.25.255510
142115.73.26.0/23115.73.26.1 to 115.73.27.254115.73.27.255510
143115.73.28.0/23115.73.28.1 to 115.73.29.254115.73.29.255510
144115.73.30.0/23115.73.30.1 to 115.73.31.254115.73.31.255510
145115.73.32.0/23115.73.32.1 to 115.73.33.254115.73.33.255510
146115.73.34.0/23115.73.34.1 to 115.73.35.254115.73.35.255510
147115.73.36.0/23115.73.36.1 to 115.73.37.254115.73.37.255510
148115.73.38.0/23115.73.38.1 to 115.73.39.254115.73.39.255510
149115.73.40.0/23115.73.40.1 to 115.73.41.254115.73.41.255510
150115.73.42.0/23115.73.42.1 to 115.73.43.254115.73.43.255510
151115.73.44.0/23115.73.44.1 to 115.73.45.254115.73.45.255510
152115.73.46.0/23115.73.46.1 to 115.73.47.254115.73.47.255510
153115.73.48.0/23115.73.48.1 to 115.73.49.254115.73.49.255510
154115.73.50.0/23115.73.50.1 to 115.73.51.254115.73.51.255510
155115.73.52.0/23115.73.52.1 to 115.73.53.254115.73.53.255510
156115.73.54.0/23115.73.54.1 to 115.73.55.254115.73.55.255510
157115.73.56.0/23115.73.56.1 to 115.73.57.254115.73.57.255510
158115.73.58.0/23115.73.58.1 to 115.73.59.254115.73.59.255510
159115.73.60.0/23115.73.60.1 to 115.73.61.254115.73.61.255510
160115.73.62.0/23115.73.62.1 to 115.73.63.254115.73.63.255510
161115.73.64.0/23115.73.64.1 to 115.73.65.254115.73.65.255510
162115.73.66.0/23115.73.66.1 to 115.73.67.254115.73.67.255510
163115.73.68.0/23115.73.68.1 to 115.73.69.254115.73.69.255510
164115.73.70.0/23115.73.70.1 to 115.73.71.254115.73.71.255510
165115.73.72.0/23115.73.72.1 to 115.73.73.254115.73.73.255510
166115.73.74.0/23115.73.74.1 to 115.73.75.254115.73.75.255510
167115.73.76.0/23115.73.76.1 to 115.73.77.254115.73.77.255510
168115.73.78.0/23115.73.78.1 to 115.73.79.254115.73.79.255510
169115.73.80.0/23115.73.80.1 to 115.73.81.254115.73.81.255510
170115.73.82.0/23115.73.82.1 to 115.73.83.254115.73.83.255510
171115.73.84.0/23115.73.84.1 to 115.73.85.254115.73.85.255510
172115.73.86.0/23115.73.86.1 to 115.73.87.254115.73.87.255510
173115.73.88.0/23115.73.88.1 to 115.73.89.254115.73.89.255510
174115.73.90.0/23115.73.90.1 to 115.73.91.254115.73.91.255510
175115.73.92.0/23115.73.92.1 to 115.73.93.254115.73.93.255510
176115.73.94.0/23115.73.94.1 to 115.73.95.254115.73.95.255510
177115.73.96.0/23115.73.96.1 to 115.73.97.254115.73.97.255510
178115.73.98.0/23115.73.98.1 to 115.73.99.254115.73.99.255510
179115.73.100.0/23115.73.100.1 to 115.73.101.254115.73.101.255510
180115.73.102.0/23115.73.102.1 to 115.73.103.254115.73.103.255510
181115.73.104.0/23115.73.104.1 to 115.73.105.254115.73.105.255510
182115.73.106.0/23115.73.106.1 to 115.73.107.254115.73.107.255510
183115.73.108.0/23115.73.108.1 to 115.73.109.254115.73.109.255510
184115.73.110.0/23115.73.110.1 to 115.73.111.254115.73.111.255510
185115.73.112.0/23115.73.112.1 to 115.73.113.254115.73.113.255510
186115.73.114.0/23115.73.114.1 to 115.73.115.254115.73.115.255510
187115.73.116.0/23115.73.116.1 to 115.73.117.254115.73.117.255510
188115.73.118.0/23115.73.118.1 to 115.73.119.254115.73.119.255510
189115.73.120.0/23115.73.120.1 to 115.73.121.254115.73.121.255510
190115.73.122.0/23115.73.122.1 to 115.73.123.254115.73.123.255510
191115.73.124.0/23115.73.124.1 to 115.73.125.254115.73.125.255510
192115.73.126.0/23115.73.126.1 to 115.73.127.254115.73.127.255510
193115.73.128.0/23115.73.128.1 to 115.73.129.254115.73.129.255510
194115.73.130.0/23115.73.130.1 to 115.73.131.254115.73.131.255510
195115.73.132.0/23115.73.132.1 to 115.73.133.254115.73.133.255510
196115.73.134.0/23115.73.134.1 to 115.73.135.254115.73.135.255510
197115.73.136.0/23115.73.136.1 to 115.73.137.254115.73.137.255510
198115.73.138.0/23115.73.138.1 to 115.73.139.254115.73.139.255510
199115.73.140.0/23115.73.140.1 to 115.73.141.254115.73.141.255510
200115.73.142.0/23115.73.142.1 to 115.73.143.254115.73.143.255510
201115.73.144.0/23115.73.144.1 to 115.73.145.254115.73.145.255510
202115.73.146.0/23115.73.146.1 to 115.73.147.254115.73.147.255510
203115.73.148.0/23115.73.148.1 to 115.73.149.254115.73.149.255510
204115.73.150.0/23115.73.150.1 to 115.73.151.254115.73.151.255510
205115.73.152.0/23115.73.152.1 to 115.73.153.254115.73.153.255510
206115.73.154.0/23115.73.154.1 to 115.73.155.254115.73.155.255510
207115.73.156.0/23115.73.156.1 to 115.73.157.254115.73.157.255510
208115.73.158.0/23115.73.158.1 to 115.73.159.254115.73.159.255510
209115.73.160.0/23115.73.160.1 to 115.73.161.254115.73.161.255510
210115.73.162.0/23115.73.162.1 to 115.73.163.254115.73.163.255510
211115.73.164.0/23115.73.164.1 to 115.73.165.254115.73.165.255510
212115.73.166.0/23115.73.166.1 to 115.73.167.254115.73.167.255510
213115.73.168.0/23115.73.168.1 to 115.73.169.254115.73.169.255510
214115.73.170.0/23115.73.170.1 to 115.73.171.254115.73.171.255510
215115.73.172.0/23115.73.172.1 to 115.73.173.254115.73.173.255510
216115.73.174.0/23115.73.174.1 to 115.73.175.254115.73.175.255510
217115.73.176.0/23115.73.176.1 to 115.73.177.254115.73.177.255510
218115.73.178.0/23115.73.178.1 to 115.73.179.254115.73.179.255510
219115.73.180.0/23115.73.180.1 to 115.73.181.254115.73.181.255510
220115.73.182.0/23115.73.182.1 to 115.73.183.254115.73.183.255510
221115.73.184.0/23115.73.184.1 to 115.73.185.254115.73.185.255510
222115.73.186.0/23115.73.186.1 to 115.73.187.254115.73.187.255510
223115.73.188.0/23115.73.188.1 to 115.73.189.254115.73.189.255510
224115.73.190.0/23115.73.190.1 to 115.73.191.254115.73.191.255510
225115.73.192.0/23115.73.192.1 to 115.73.193.254115.73.193.255510
226115.73.194.0/23115.73.194.1 to 115.73.195.254115.73.195.255510
227115.73.196.0/23115.73.196.1 to 115.73.197.254115.73.197.255510
228115.73.198.0/23115.73.198.1 to 115.73.199.254115.73.199.255510
229115.73.200.0/23115.73.200.1 to 115.73.201.254115.73.201.255510
230115.73.202.0/23115.73.202.1 to 115.73.203.254115.73.203.255510
231115.73.204.0/23115.73.204.1 to 115.73.205.254115.73.205.255510
232115.73.206.0/23115.73.206.1 to 115.73.207.254115.73.207.255510
233115.73.208.0/23115.73.208.1 to 115.73.209.254115.73.209.255510
234115.73.210.0/23115.73.210.1 to 115.73.211.254115.73.211.255510
235115.73.212.0/23115.73.212.1 to 115.73.213.254115.73.213.255510
236115.73.214.0/23115.73.214.1 to 115.73.215.254115.73.215.255510
237115.73.216.0/23115.73.216.1 to 115.73.217.254115.73.217.255510
238115.73.218.0/23115.73.218.1 to 115.73.219.254115.73.219.255510
239115.73.220.0/23115.73.220.1 to 115.73.221.254115.73.221.255510
240115.73.222.0/23115.73.222.1 to 115.73.223.254115.73.223.255510
241115.73.224.0/23115.73.224.1 to 115.73.225.254115.73.225.255510
242115.73.226.0/23115.73.226.1 to 115.73.227.254115.73.227.255510
243115.73.228.0/23115.73.228.1 to 115.73.229.254115.73.229.255510
244115.73.230.0/23115.73.230.1 to 115.73.231.254115.73.231.255510
245115.73.232.0/23115.73.232.1 to 115.73.233.254115.73.233.255510
246115.73.234.0/23115.73.234.1 to 115.73.235.254115.73.235.255510
247115.73.236.0/23115.73.236.1 to 115.73.237.254115.73.237.255510
248115.73.238.0/23115.73.238.1 to 115.73.239.254115.73.239.255510
249115.73.240.0/23115.73.240.1 to 115.73.241.254115.73.241.255510
250115.73.242.0/23115.73.242.1 to 115.73.243.254115.73.243.255510
251115.73.244.0/23115.73.244.1 to 115.73.245.254115.73.245.255510
252115.73.246.0/23115.73.246.1 to 115.73.247.254115.73.247.255510
253115.73.248.0/23115.73.248.1 to 115.73.249.254115.73.249.255510
254115.73.250.0/23115.73.250.1 to 115.73.251.254115.73.251.255510
255115.73.252.0/23115.73.252.1 to 115.73.253.254115.73.253.255510
256115.73.254.0/23115.73.254.1 to 115.73.255.254115.73.255.255510

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.