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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.

Network187.64.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
187.64.0.0
Broadcast address
187.71.255.255
First usable
187.64.0.1
Last usable
187.71.255.254
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
B (default /16)
As numbers
Hex BB400000 · Integer 3141533696 to 3142057983
Reverse DNS zones
64.187.in-addr.arpa
65.187.in-addr.arpa
66.187.in-addr.arpa
67.187.in-addr.arpa
68.187.in-addr.arpa
69.187.in-addr.arpa
70.187.in-addr.arpa
71.187.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
Address10111011.01000000.00000000.00000000187.64.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10111011.01000000.00000000.00000000187.64.0.0
Broadcast10111011.01000111.11111111.11111111187.71.255.255
Split into smaller subnets/22
/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)

187.64.0.0/13 makes 512 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1187.64.0.0/22187.64.0.1 to 187.64.3.254187.64.3.2551,022
2187.64.4.0/22187.64.4.1 to 187.64.7.254187.64.7.2551,022
3187.64.8.0/22187.64.8.1 to 187.64.11.254187.64.11.2551,022
4187.64.12.0/22187.64.12.1 to 187.64.15.254187.64.15.2551,022
5187.64.16.0/22187.64.16.1 to 187.64.19.254187.64.19.2551,022
6187.64.20.0/22187.64.20.1 to 187.64.23.254187.64.23.2551,022
7187.64.24.0/22187.64.24.1 to 187.64.27.254187.64.27.2551,022
8187.64.28.0/22187.64.28.1 to 187.64.31.254187.64.31.2551,022
9187.64.32.0/22187.64.32.1 to 187.64.35.254187.64.35.2551,022
10187.64.36.0/22187.64.36.1 to 187.64.39.254187.64.39.2551,022
11187.64.40.0/22187.64.40.1 to 187.64.43.254187.64.43.2551,022
12187.64.44.0/22187.64.44.1 to 187.64.47.254187.64.47.2551,022
13187.64.48.0/22187.64.48.1 to 187.64.51.254187.64.51.2551,022
14187.64.52.0/22187.64.52.1 to 187.64.55.254187.64.55.2551,022
15187.64.56.0/22187.64.56.1 to 187.64.59.254187.64.59.2551,022
16187.64.60.0/22187.64.60.1 to 187.64.63.254187.64.63.2551,022
17187.64.64.0/22187.64.64.1 to 187.64.67.254187.64.67.2551,022
18187.64.68.0/22187.64.68.1 to 187.64.71.254187.64.71.2551,022
19187.64.72.0/22187.64.72.1 to 187.64.75.254187.64.75.2551,022
20187.64.76.0/22187.64.76.1 to 187.64.79.254187.64.79.2551,022
21187.64.80.0/22187.64.80.1 to 187.64.83.254187.64.83.2551,022
22187.64.84.0/22187.64.84.1 to 187.64.87.254187.64.87.2551,022
23187.64.88.0/22187.64.88.1 to 187.64.91.254187.64.91.2551,022
24187.64.92.0/22187.64.92.1 to 187.64.95.254187.64.95.2551,022
25187.64.96.0/22187.64.96.1 to 187.64.99.254187.64.99.2551,022
26187.64.100.0/22187.64.100.1 to 187.64.103.254187.64.103.2551,022
27187.64.104.0/22187.64.104.1 to 187.64.107.254187.64.107.2551,022
28187.64.108.0/22187.64.108.1 to 187.64.111.254187.64.111.2551,022
29187.64.112.0/22187.64.112.1 to 187.64.115.254187.64.115.2551,022
30187.64.116.0/22187.64.116.1 to 187.64.119.254187.64.119.2551,022
31187.64.120.0/22187.64.120.1 to 187.64.123.254187.64.123.2551,022
32187.64.124.0/22187.64.124.1 to 187.64.127.254187.64.127.2551,022
33187.64.128.0/22187.64.128.1 to 187.64.131.254187.64.131.2551,022
34187.64.132.0/22187.64.132.1 to 187.64.135.254187.64.135.2551,022
35187.64.136.0/22187.64.136.1 to 187.64.139.254187.64.139.2551,022
36187.64.140.0/22187.64.140.1 to 187.64.143.254187.64.143.2551,022
37187.64.144.0/22187.64.144.1 to 187.64.147.254187.64.147.2551,022
38187.64.148.0/22187.64.148.1 to 187.64.151.254187.64.151.2551,022
39187.64.152.0/22187.64.152.1 to 187.64.155.254187.64.155.2551,022
40187.64.156.0/22187.64.156.1 to 187.64.159.254187.64.159.2551,022
41187.64.160.0/22187.64.160.1 to 187.64.163.254187.64.163.2551,022
42187.64.164.0/22187.64.164.1 to 187.64.167.254187.64.167.2551,022
43187.64.168.0/22187.64.168.1 to 187.64.171.254187.64.171.2551,022
44187.64.172.0/22187.64.172.1 to 187.64.175.254187.64.175.2551,022
45187.64.176.0/22187.64.176.1 to 187.64.179.254187.64.179.2551,022
46187.64.180.0/22187.64.180.1 to 187.64.183.254187.64.183.2551,022
47187.64.184.0/22187.64.184.1 to 187.64.187.254187.64.187.2551,022
48187.64.188.0/22187.64.188.1 to 187.64.191.254187.64.191.2551,022
49187.64.192.0/22187.64.192.1 to 187.64.195.254187.64.195.2551,022
50187.64.196.0/22187.64.196.1 to 187.64.199.254187.64.199.2551,022
51187.64.200.0/22187.64.200.1 to 187.64.203.254187.64.203.2551,022
52187.64.204.0/22187.64.204.1 to 187.64.207.254187.64.207.2551,022
53187.64.208.0/22187.64.208.1 to 187.64.211.254187.64.211.2551,022
54187.64.212.0/22187.64.212.1 to 187.64.215.254187.64.215.2551,022
55187.64.216.0/22187.64.216.1 to 187.64.219.254187.64.219.2551,022
56187.64.220.0/22187.64.220.1 to 187.64.223.254187.64.223.2551,022
57187.64.224.0/22187.64.224.1 to 187.64.227.254187.64.227.2551,022
58187.64.228.0/22187.64.228.1 to 187.64.231.254187.64.231.2551,022
59187.64.232.0/22187.64.232.1 to 187.64.235.254187.64.235.2551,022
60187.64.236.0/22187.64.236.1 to 187.64.239.254187.64.239.2551,022
61187.64.240.0/22187.64.240.1 to 187.64.243.254187.64.243.2551,022
62187.64.244.0/22187.64.244.1 to 187.64.247.254187.64.247.2551,022
63187.64.248.0/22187.64.248.1 to 187.64.251.254187.64.251.2551,022
64187.64.252.0/22187.64.252.1 to 187.64.255.254187.64.255.2551,022
65187.65.0.0/22187.65.0.1 to 187.65.3.254187.65.3.2551,022
66187.65.4.0/22187.65.4.1 to 187.65.7.254187.65.7.2551,022
67187.65.8.0/22187.65.8.1 to 187.65.11.254187.65.11.2551,022
68187.65.12.0/22187.65.12.1 to 187.65.15.254187.65.15.2551,022
69187.65.16.0/22187.65.16.1 to 187.65.19.254187.65.19.2551,022
70187.65.20.0/22187.65.20.1 to 187.65.23.254187.65.23.2551,022
71187.65.24.0/22187.65.24.1 to 187.65.27.254187.65.27.2551,022
72187.65.28.0/22187.65.28.1 to 187.65.31.254187.65.31.2551,022
73187.65.32.0/22187.65.32.1 to 187.65.35.254187.65.35.2551,022
74187.65.36.0/22187.65.36.1 to 187.65.39.254187.65.39.2551,022
75187.65.40.0/22187.65.40.1 to 187.65.43.254187.65.43.2551,022
76187.65.44.0/22187.65.44.1 to 187.65.47.254187.65.47.2551,022
77187.65.48.0/22187.65.48.1 to 187.65.51.254187.65.51.2551,022
78187.65.52.0/22187.65.52.1 to 187.65.55.254187.65.55.2551,022
79187.65.56.0/22187.65.56.1 to 187.65.59.254187.65.59.2551,022
80187.65.60.0/22187.65.60.1 to 187.65.63.254187.65.63.2551,022
81187.65.64.0/22187.65.64.1 to 187.65.67.254187.65.67.2551,022
82187.65.68.0/22187.65.68.1 to 187.65.71.254187.65.71.2551,022
83187.65.72.0/22187.65.72.1 to 187.65.75.254187.65.75.2551,022
84187.65.76.0/22187.65.76.1 to 187.65.79.254187.65.79.2551,022
85187.65.80.0/22187.65.80.1 to 187.65.83.254187.65.83.2551,022
86187.65.84.0/22187.65.84.1 to 187.65.87.254187.65.87.2551,022
87187.65.88.0/22187.65.88.1 to 187.65.91.254187.65.91.2551,022
88187.65.92.0/22187.65.92.1 to 187.65.95.254187.65.95.2551,022
89187.65.96.0/22187.65.96.1 to 187.65.99.254187.65.99.2551,022
90187.65.100.0/22187.65.100.1 to 187.65.103.254187.65.103.2551,022
91187.65.104.0/22187.65.104.1 to 187.65.107.254187.65.107.2551,022
92187.65.108.0/22187.65.108.1 to 187.65.111.254187.65.111.2551,022
93187.65.112.0/22187.65.112.1 to 187.65.115.254187.65.115.2551,022
94187.65.116.0/22187.65.116.1 to 187.65.119.254187.65.119.2551,022
95187.65.120.0/22187.65.120.1 to 187.65.123.254187.65.123.2551,022
96187.65.124.0/22187.65.124.1 to 187.65.127.254187.65.127.2551,022
97187.65.128.0/22187.65.128.1 to 187.65.131.254187.65.131.2551,022
98187.65.132.0/22187.65.132.1 to 187.65.135.254187.65.135.2551,022
99187.65.136.0/22187.65.136.1 to 187.65.139.254187.65.139.2551,022
100187.65.140.0/22187.65.140.1 to 187.65.143.254187.65.143.2551,022
101187.65.144.0/22187.65.144.1 to 187.65.147.254187.65.147.2551,022
102187.65.148.0/22187.65.148.1 to 187.65.151.254187.65.151.2551,022
103187.65.152.0/22187.65.152.1 to 187.65.155.254187.65.155.2551,022
104187.65.156.0/22187.65.156.1 to 187.65.159.254187.65.159.2551,022
105187.65.160.0/22187.65.160.1 to 187.65.163.254187.65.163.2551,022
106187.65.164.0/22187.65.164.1 to 187.65.167.254187.65.167.2551,022
107187.65.168.0/22187.65.168.1 to 187.65.171.254187.65.171.2551,022
108187.65.172.0/22187.65.172.1 to 187.65.175.254187.65.175.2551,022
109187.65.176.0/22187.65.176.1 to 187.65.179.254187.65.179.2551,022
110187.65.180.0/22187.65.180.1 to 187.65.183.254187.65.183.2551,022
111187.65.184.0/22187.65.184.1 to 187.65.187.254187.65.187.2551,022
112187.65.188.0/22187.65.188.1 to 187.65.191.254187.65.191.2551,022
113187.65.192.0/22187.65.192.1 to 187.65.195.254187.65.195.2551,022
114187.65.196.0/22187.65.196.1 to 187.65.199.254187.65.199.2551,022
115187.65.200.0/22187.65.200.1 to 187.65.203.254187.65.203.2551,022
116187.65.204.0/22187.65.204.1 to 187.65.207.254187.65.207.2551,022
117187.65.208.0/22187.65.208.1 to 187.65.211.254187.65.211.2551,022
118187.65.212.0/22187.65.212.1 to 187.65.215.254187.65.215.2551,022
119187.65.216.0/22187.65.216.1 to 187.65.219.254187.65.219.2551,022
120187.65.220.0/22187.65.220.1 to 187.65.223.254187.65.223.2551,022
121187.65.224.0/22187.65.224.1 to 187.65.227.254187.65.227.2551,022
122187.65.228.0/22187.65.228.1 to 187.65.231.254187.65.231.2551,022
123187.65.232.0/22187.65.232.1 to 187.65.235.254187.65.235.2551,022
124187.65.236.0/22187.65.236.1 to 187.65.239.254187.65.239.2551,022
125187.65.240.0/22187.65.240.1 to 187.65.243.254187.65.243.2551,022
126187.65.244.0/22187.65.244.1 to 187.65.247.254187.65.247.2551,022
127187.65.248.0/22187.65.248.1 to 187.65.251.254187.65.251.2551,022
128187.65.252.0/22187.65.252.1 to 187.65.255.254187.65.255.2551,022
129187.66.0.0/22187.66.0.1 to 187.66.3.254187.66.3.2551,022
130187.66.4.0/22187.66.4.1 to 187.66.7.254187.66.7.2551,022
131187.66.8.0/22187.66.8.1 to 187.66.11.254187.66.11.2551,022
132187.66.12.0/22187.66.12.1 to 187.66.15.254187.66.15.2551,022
133187.66.16.0/22187.66.16.1 to 187.66.19.254187.66.19.2551,022
134187.66.20.0/22187.66.20.1 to 187.66.23.254187.66.23.2551,022
135187.66.24.0/22187.66.24.1 to 187.66.27.254187.66.27.2551,022
136187.66.28.0/22187.66.28.1 to 187.66.31.254187.66.31.2551,022
137187.66.32.0/22187.66.32.1 to 187.66.35.254187.66.35.2551,022
138187.66.36.0/22187.66.36.1 to 187.66.39.254187.66.39.2551,022
139187.66.40.0/22187.66.40.1 to 187.66.43.254187.66.43.2551,022
140187.66.44.0/22187.66.44.1 to 187.66.47.254187.66.47.2551,022
141187.66.48.0/22187.66.48.1 to 187.66.51.254187.66.51.2551,022
142187.66.52.0/22187.66.52.1 to 187.66.55.254187.66.55.2551,022
143187.66.56.0/22187.66.56.1 to 187.66.59.254187.66.59.2551,022
144187.66.60.0/22187.66.60.1 to 187.66.63.254187.66.63.2551,022
145187.66.64.0/22187.66.64.1 to 187.66.67.254187.66.67.2551,022
146187.66.68.0/22187.66.68.1 to 187.66.71.254187.66.71.2551,022
147187.66.72.0/22187.66.72.1 to 187.66.75.254187.66.75.2551,022
148187.66.76.0/22187.66.76.1 to 187.66.79.254187.66.79.2551,022
149187.66.80.0/22187.66.80.1 to 187.66.83.254187.66.83.2551,022
150187.66.84.0/22187.66.84.1 to 187.66.87.254187.66.87.2551,022
151187.66.88.0/22187.66.88.1 to 187.66.91.254187.66.91.2551,022
152187.66.92.0/22187.66.92.1 to 187.66.95.254187.66.95.2551,022
153187.66.96.0/22187.66.96.1 to 187.66.99.254187.66.99.2551,022
154187.66.100.0/22187.66.100.1 to 187.66.103.254187.66.103.2551,022
155187.66.104.0/22187.66.104.1 to 187.66.107.254187.66.107.2551,022
156187.66.108.0/22187.66.108.1 to 187.66.111.254187.66.111.2551,022
157187.66.112.0/22187.66.112.1 to 187.66.115.254187.66.115.2551,022
158187.66.116.0/22187.66.116.1 to 187.66.119.254187.66.119.2551,022
159187.66.120.0/22187.66.120.1 to 187.66.123.254187.66.123.2551,022
160187.66.124.0/22187.66.124.1 to 187.66.127.254187.66.127.2551,022
161187.66.128.0/22187.66.128.1 to 187.66.131.254187.66.131.2551,022
162187.66.132.0/22187.66.132.1 to 187.66.135.254187.66.135.2551,022
163187.66.136.0/22187.66.136.1 to 187.66.139.254187.66.139.2551,022
164187.66.140.0/22187.66.140.1 to 187.66.143.254187.66.143.2551,022
165187.66.144.0/22187.66.144.1 to 187.66.147.254187.66.147.2551,022
166187.66.148.0/22187.66.148.1 to 187.66.151.254187.66.151.2551,022
167187.66.152.0/22187.66.152.1 to 187.66.155.254187.66.155.2551,022
168187.66.156.0/22187.66.156.1 to 187.66.159.254187.66.159.2551,022
169187.66.160.0/22187.66.160.1 to 187.66.163.254187.66.163.2551,022
170187.66.164.0/22187.66.164.1 to 187.66.167.254187.66.167.2551,022
171187.66.168.0/22187.66.168.1 to 187.66.171.254187.66.171.2551,022
172187.66.172.0/22187.66.172.1 to 187.66.175.254187.66.175.2551,022
173187.66.176.0/22187.66.176.1 to 187.66.179.254187.66.179.2551,022
174187.66.180.0/22187.66.180.1 to 187.66.183.254187.66.183.2551,022
175187.66.184.0/22187.66.184.1 to 187.66.187.254187.66.187.2551,022
176187.66.188.0/22187.66.188.1 to 187.66.191.254187.66.191.2551,022
177187.66.192.0/22187.66.192.1 to 187.66.195.254187.66.195.2551,022
178187.66.196.0/22187.66.196.1 to 187.66.199.254187.66.199.2551,022
179187.66.200.0/22187.66.200.1 to 187.66.203.254187.66.203.2551,022
180187.66.204.0/22187.66.204.1 to 187.66.207.254187.66.207.2551,022
181187.66.208.0/22187.66.208.1 to 187.66.211.254187.66.211.2551,022
182187.66.212.0/22187.66.212.1 to 187.66.215.254187.66.215.2551,022
183187.66.216.0/22187.66.216.1 to 187.66.219.254187.66.219.2551,022
184187.66.220.0/22187.66.220.1 to 187.66.223.254187.66.223.2551,022
185187.66.224.0/22187.66.224.1 to 187.66.227.254187.66.227.2551,022
186187.66.228.0/22187.66.228.1 to 187.66.231.254187.66.231.2551,022
187187.66.232.0/22187.66.232.1 to 187.66.235.254187.66.235.2551,022
188187.66.236.0/22187.66.236.1 to 187.66.239.254187.66.239.2551,022
189187.66.240.0/22187.66.240.1 to 187.66.243.254187.66.243.2551,022
190187.66.244.0/22187.66.244.1 to 187.66.247.254187.66.247.2551,022
191187.66.248.0/22187.66.248.1 to 187.66.251.254187.66.251.2551,022
192187.66.252.0/22187.66.252.1 to 187.66.255.254187.66.255.2551,022
193187.67.0.0/22187.67.0.1 to 187.67.3.254187.67.3.2551,022
194187.67.4.0/22187.67.4.1 to 187.67.7.254187.67.7.2551,022
195187.67.8.0/22187.67.8.1 to 187.67.11.254187.67.11.2551,022
196187.67.12.0/22187.67.12.1 to 187.67.15.254187.67.15.2551,022
197187.67.16.0/22187.67.16.1 to 187.67.19.254187.67.19.2551,022
198187.67.20.0/22187.67.20.1 to 187.67.23.254187.67.23.2551,022
199187.67.24.0/22187.67.24.1 to 187.67.27.254187.67.27.2551,022
200187.67.28.0/22187.67.28.1 to 187.67.31.254187.67.31.2551,022
201187.67.32.0/22187.67.32.1 to 187.67.35.254187.67.35.2551,022
202187.67.36.0/22187.67.36.1 to 187.67.39.254187.67.39.2551,022
203187.67.40.0/22187.67.40.1 to 187.67.43.254187.67.43.2551,022
204187.67.44.0/22187.67.44.1 to 187.67.47.254187.67.47.2551,022
205187.67.48.0/22187.67.48.1 to 187.67.51.254187.67.51.2551,022
206187.67.52.0/22187.67.52.1 to 187.67.55.254187.67.55.2551,022
207187.67.56.0/22187.67.56.1 to 187.67.59.254187.67.59.2551,022
208187.67.60.0/22187.67.60.1 to 187.67.63.254187.67.63.2551,022
209187.67.64.0/22187.67.64.1 to 187.67.67.254187.67.67.2551,022
210187.67.68.0/22187.67.68.1 to 187.67.71.254187.67.71.2551,022
211187.67.72.0/22187.67.72.1 to 187.67.75.254187.67.75.2551,022
212187.67.76.0/22187.67.76.1 to 187.67.79.254187.67.79.2551,022
213187.67.80.0/22187.67.80.1 to 187.67.83.254187.67.83.2551,022
214187.67.84.0/22187.67.84.1 to 187.67.87.254187.67.87.2551,022
215187.67.88.0/22187.67.88.1 to 187.67.91.254187.67.91.2551,022
216187.67.92.0/22187.67.92.1 to 187.67.95.254187.67.95.2551,022
217187.67.96.0/22187.67.96.1 to 187.67.99.254187.67.99.2551,022
218187.67.100.0/22187.67.100.1 to 187.67.103.254187.67.103.2551,022
219187.67.104.0/22187.67.104.1 to 187.67.107.254187.67.107.2551,022
220187.67.108.0/22187.67.108.1 to 187.67.111.254187.67.111.2551,022
221187.67.112.0/22187.67.112.1 to 187.67.115.254187.67.115.2551,022
222187.67.116.0/22187.67.116.1 to 187.67.119.254187.67.119.2551,022
223187.67.120.0/22187.67.120.1 to 187.67.123.254187.67.123.2551,022
224187.67.124.0/22187.67.124.1 to 187.67.127.254187.67.127.2551,022
225187.67.128.0/22187.67.128.1 to 187.67.131.254187.67.131.2551,022
226187.67.132.0/22187.67.132.1 to 187.67.135.254187.67.135.2551,022
227187.67.136.0/22187.67.136.1 to 187.67.139.254187.67.139.2551,022
228187.67.140.0/22187.67.140.1 to 187.67.143.254187.67.143.2551,022
229187.67.144.0/22187.67.144.1 to 187.67.147.254187.67.147.2551,022
230187.67.148.0/22187.67.148.1 to 187.67.151.254187.67.151.2551,022
231187.67.152.0/22187.67.152.1 to 187.67.155.254187.67.155.2551,022
232187.67.156.0/22187.67.156.1 to 187.67.159.254187.67.159.2551,022
233187.67.160.0/22187.67.160.1 to 187.67.163.254187.67.163.2551,022
234187.67.164.0/22187.67.164.1 to 187.67.167.254187.67.167.2551,022
235187.67.168.0/22187.67.168.1 to 187.67.171.254187.67.171.2551,022
236187.67.172.0/22187.67.172.1 to 187.67.175.254187.67.175.2551,022
237187.67.176.0/22187.67.176.1 to 187.67.179.254187.67.179.2551,022
238187.67.180.0/22187.67.180.1 to 187.67.183.254187.67.183.2551,022
239187.67.184.0/22187.67.184.1 to 187.67.187.254187.67.187.2551,022
240187.67.188.0/22187.67.188.1 to 187.67.191.254187.67.191.2551,022
241187.67.192.0/22187.67.192.1 to 187.67.195.254187.67.195.2551,022
242187.67.196.0/22187.67.196.1 to 187.67.199.254187.67.199.2551,022
243187.67.200.0/22187.67.200.1 to 187.67.203.254187.67.203.2551,022
244187.67.204.0/22187.67.204.1 to 187.67.207.254187.67.207.2551,022
245187.67.208.0/22187.67.208.1 to 187.67.211.254187.67.211.2551,022
246187.67.212.0/22187.67.212.1 to 187.67.215.254187.67.215.2551,022
247187.67.216.0/22187.67.216.1 to 187.67.219.254187.67.219.2551,022
248187.67.220.0/22187.67.220.1 to 187.67.223.254187.67.223.2551,022
249187.67.224.0/22187.67.224.1 to 187.67.227.254187.67.227.2551,022
250187.67.228.0/22187.67.228.1 to 187.67.231.254187.67.231.2551,022
251187.67.232.0/22187.67.232.1 to 187.67.235.254187.67.235.2551,022
252187.67.236.0/22187.67.236.1 to 187.67.239.254187.67.239.2551,022
253187.67.240.0/22187.67.240.1 to 187.67.243.254187.67.243.2551,022
254187.67.244.0/22187.67.244.1 to 187.67.247.254187.67.247.2551,022
255187.67.248.0/22187.67.248.1 to 187.67.251.254187.67.251.2551,022
256187.67.252.0/22187.67.252.1 to 187.67.255.254187.67.255.2551,022

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.