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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.

Network181.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
181.232.0.0
Broadcast address
181.239.255.255
First usable
181.232.0.1
Last usable
181.239.255.254
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 B5E80000 · Integer 3051880448 to 3052404735
Reverse DNS zones
232.181.in-addr.arpa
233.181.in-addr.arpa
234.181.in-addr.arpa
235.181.in-addr.arpa
236.181.in-addr.arpa
237.181.in-addr.arpa
238.181.in-addr.arpa
239.181.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
Address10110101.11101000.00000000.00000000181.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10110101.11101000.00000000.00000000181.232.0.0
Broadcast10110101.11101111.11111111.11111111181.239.255.255
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)

181.232.0.0/13 makes 512 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1181.232.0.0/22181.232.0.1 to 181.232.3.254181.232.3.2551,022
2181.232.4.0/22181.232.4.1 to 181.232.7.254181.232.7.2551,022
3181.232.8.0/22181.232.8.1 to 181.232.11.254181.232.11.2551,022
4181.232.12.0/22181.232.12.1 to 181.232.15.254181.232.15.2551,022
5181.232.16.0/22181.232.16.1 to 181.232.19.254181.232.19.2551,022
6181.232.20.0/22181.232.20.1 to 181.232.23.254181.232.23.2551,022
7181.232.24.0/22181.232.24.1 to 181.232.27.254181.232.27.2551,022
8181.232.28.0/22181.232.28.1 to 181.232.31.254181.232.31.2551,022
9181.232.32.0/22181.232.32.1 to 181.232.35.254181.232.35.2551,022
10181.232.36.0/22181.232.36.1 to 181.232.39.254181.232.39.2551,022
11181.232.40.0/22181.232.40.1 to 181.232.43.254181.232.43.2551,022
12181.232.44.0/22181.232.44.1 to 181.232.47.254181.232.47.2551,022
13181.232.48.0/22181.232.48.1 to 181.232.51.254181.232.51.2551,022
14181.232.52.0/22181.232.52.1 to 181.232.55.254181.232.55.2551,022
15181.232.56.0/22181.232.56.1 to 181.232.59.254181.232.59.2551,022
16181.232.60.0/22181.232.60.1 to 181.232.63.254181.232.63.2551,022
17181.232.64.0/22181.232.64.1 to 181.232.67.254181.232.67.2551,022
18181.232.68.0/22181.232.68.1 to 181.232.71.254181.232.71.2551,022
19181.232.72.0/22181.232.72.1 to 181.232.75.254181.232.75.2551,022
20181.232.76.0/22181.232.76.1 to 181.232.79.254181.232.79.2551,022
21181.232.80.0/22181.232.80.1 to 181.232.83.254181.232.83.2551,022
22181.232.84.0/22181.232.84.1 to 181.232.87.254181.232.87.2551,022
23181.232.88.0/22181.232.88.1 to 181.232.91.254181.232.91.2551,022
24181.232.92.0/22181.232.92.1 to 181.232.95.254181.232.95.2551,022
25181.232.96.0/22181.232.96.1 to 181.232.99.254181.232.99.2551,022
26181.232.100.0/22181.232.100.1 to 181.232.103.254181.232.103.2551,022
27181.232.104.0/22181.232.104.1 to 181.232.107.254181.232.107.2551,022
28181.232.108.0/22181.232.108.1 to 181.232.111.254181.232.111.2551,022
29181.232.112.0/22181.232.112.1 to 181.232.115.254181.232.115.2551,022
30181.232.116.0/22181.232.116.1 to 181.232.119.254181.232.119.2551,022
31181.232.120.0/22181.232.120.1 to 181.232.123.254181.232.123.2551,022
32181.232.124.0/22181.232.124.1 to 181.232.127.254181.232.127.2551,022
33181.232.128.0/22181.232.128.1 to 181.232.131.254181.232.131.2551,022
34181.232.132.0/22181.232.132.1 to 181.232.135.254181.232.135.2551,022
35181.232.136.0/22181.232.136.1 to 181.232.139.254181.232.139.2551,022
36181.232.140.0/22181.232.140.1 to 181.232.143.254181.232.143.2551,022
37181.232.144.0/22181.232.144.1 to 181.232.147.254181.232.147.2551,022
38181.232.148.0/22181.232.148.1 to 181.232.151.254181.232.151.2551,022
39181.232.152.0/22181.232.152.1 to 181.232.155.254181.232.155.2551,022
40181.232.156.0/22181.232.156.1 to 181.232.159.254181.232.159.2551,022
41181.232.160.0/22181.232.160.1 to 181.232.163.254181.232.163.2551,022
42181.232.164.0/22181.232.164.1 to 181.232.167.254181.232.167.2551,022
43181.232.168.0/22181.232.168.1 to 181.232.171.254181.232.171.2551,022
44181.232.172.0/22181.232.172.1 to 181.232.175.254181.232.175.2551,022
45181.232.176.0/22181.232.176.1 to 181.232.179.254181.232.179.2551,022
46181.232.180.0/22181.232.180.1 to 181.232.183.254181.232.183.2551,022
47181.232.184.0/22181.232.184.1 to 181.232.187.254181.232.187.2551,022
48181.232.188.0/22181.232.188.1 to 181.232.191.254181.232.191.2551,022
49181.232.192.0/22181.232.192.1 to 181.232.195.254181.232.195.2551,022
50181.232.196.0/22181.232.196.1 to 181.232.199.254181.232.199.2551,022
51181.232.200.0/22181.232.200.1 to 181.232.203.254181.232.203.2551,022
52181.232.204.0/22181.232.204.1 to 181.232.207.254181.232.207.2551,022
53181.232.208.0/22181.232.208.1 to 181.232.211.254181.232.211.2551,022
54181.232.212.0/22181.232.212.1 to 181.232.215.254181.232.215.2551,022
55181.232.216.0/22181.232.216.1 to 181.232.219.254181.232.219.2551,022
56181.232.220.0/22181.232.220.1 to 181.232.223.254181.232.223.2551,022
57181.232.224.0/22181.232.224.1 to 181.232.227.254181.232.227.2551,022
58181.232.228.0/22181.232.228.1 to 181.232.231.254181.232.231.2551,022
59181.232.232.0/22181.232.232.1 to 181.232.235.254181.232.235.2551,022
60181.232.236.0/22181.232.236.1 to 181.232.239.254181.232.239.2551,022
61181.232.240.0/22181.232.240.1 to 181.232.243.254181.232.243.2551,022
62181.232.244.0/22181.232.244.1 to 181.232.247.254181.232.247.2551,022
63181.232.248.0/22181.232.248.1 to 181.232.251.254181.232.251.2551,022
64181.232.252.0/22181.232.252.1 to 181.232.255.254181.232.255.2551,022
65181.233.0.0/22181.233.0.1 to 181.233.3.254181.233.3.2551,022
66181.233.4.0/22181.233.4.1 to 181.233.7.254181.233.7.2551,022
67181.233.8.0/22181.233.8.1 to 181.233.11.254181.233.11.2551,022
68181.233.12.0/22181.233.12.1 to 181.233.15.254181.233.15.2551,022
69181.233.16.0/22181.233.16.1 to 181.233.19.254181.233.19.2551,022
70181.233.20.0/22181.233.20.1 to 181.233.23.254181.233.23.2551,022
71181.233.24.0/22181.233.24.1 to 181.233.27.254181.233.27.2551,022
72181.233.28.0/22181.233.28.1 to 181.233.31.254181.233.31.2551,022
73181.233.32.0/22181.233.32.1 to 181.233.35.254181.233.35.2551,022
74181.233.36.0/22181.233.36.1 to 181.233.39.254181.233.39.2551,022
75181.233.40.0/22181.233.40.1 to 181.233.43.254181.233.43.2551,022
76181.233.44.0/22181.233.44.1 to 181.233.47.254181.233.47.2551,022
77181.233.48.0/22181.233.48.1 to 181.233.51.254181.233.51.2551,022
78181.233.52.0/22181.233.52.1 to 181.233.55.254181.233.55.2551,022
79181.233.56.0/22181.233.56.1 to 181.233.59.254181.233.59.2551,022
80181.233.60.0/22181.233.60.1 to 181.233.63.254181.233.63.2551,022
81181.233.64.0/22181.233.64.1 to 181.233.67.254181.233.67.2551,022
82181.233.68.0/22181.233.68.1 to 181.233.71.254181.233.71.2551,022
83181.233.72.0/22181.233.72.1 to 181.233.75.254181.233.75.2551,022
84181.233.76.0/22181.233.76.1 to 181.233.79.254181.233.79.2551,022
85181.233.80.0/22181.233.80.1 to 181.233.83.254181.233.83.2551,022
86181.233.84.0/22181.233.84.1 to 181.233.87.254181.233.87.2551,022
87181.233.88.0/22181.233.88.1 to 181.233.91.254181.233.91.2551,022
88181.233.92.0/22181.233.92.1 to 181.233.95.254181.233.95.2551,022
89181.233.96.0/22181.233.96.1 to 181.233.99.254181.233.99.2551,022
90181.233.100.0/22181.233.100.1 to 181.233.103.254181.233.103.2551,022
91181.233.104.0/22181.233.104.1 to 181.233.107.254181.233.107.2551,022
92181.233.108.0/22181.233.108.1 to 181.233.111.254181.233.111.2551,022
93181.233.112.0/22181.233.112.1 to 181.233.115.254181.233.115.2551,022
94181.233.116.0/22181.233.116.1 to 181.233.119.254181.233.119.2551,022
95181.233.120.0/22181.233.120.1 to 181.233.123.254181.233.123.2551,022
96181.233.124.0/22181.233.124.1 to 181.233.127.254181.233.127.2551,022
97181.233.128.0/22181.233.128.1 to 181.233.131.254181.233.131.2551,022
98181.233.132.0/22181.233.132.1 to 181.233.135.254181.233.135.2551,022
99181.233.136.0/22181.233.136.1 to 181.233.139.254181.233.139.2551,022
100181.233.140.0/22181.233.140.1 to 181.233.143.254181.233.143.2551,022
101181.233.144.0/22181.233.144.1 to 181.233.147.254181.233.147.2551,022
102181.233.148.0/22181.233.148.1 to 181.233.151.254181.233.151.2551,022
103181.233.152.0/22181.233.152.1 to 181.233.155.254181.233.155.2551,022
104181.233.156.0/22181.233.156.1 to 181.233.159.254181.233.159.2551,022
105181.233.160.0/22181.233.160.1 to 181.233.163.254181.233.163.2551,022
106181.233.164.0/22181.233.164.1 to 181.233.167.254181.233.167.2551,022
107181.233.168.0/22181.233.168.1 to 181.233.171.254181.233.171.2551,022
108181.233.172.0/22181.233.172.1 to 181.233.175.254181.233.175.2551,022
109181.233.176.0/22181.233.176.1 to 181.233.179.254181.233.179.2551,022
110181.233.180.0/22181.233.180.1 to 181.233.183.254181.233.183.2551,022
111181.233.184.0/22181.233.184.1 to 181.233.187.254181.233.187.2551,022
112181.233.188.0/22181.233.188.1 to 181.233.191.254181.233.191.2551,022
113181.233.192.0/22181.233.192.1 to 181.233.195.254181.233.195.2551,022
114181.233.196.0/22181.233.196.1 to 181.233.199.254181.233.199.2551,022
115181.233.200.0/22181.233.200.1 to 181.233.203.254181.233.203.2551,022
116181.233.204.0/22181.233.204.1 to 181.233.207.254181.233.207.2551,022
117181.233.208.0/22181.233.208.1 to 181.233.211.254181.233.211.2551,022
118181.233.212.0/22181.233.212.1 to 181.233.215.254181.233.215.2551,022
119181.233.216.0/22181.233.216.1 to 181.233.219.254181.233.219.2551,022
120181.233.220.0/22181.233.220.1 to 181.233.223.254181.233.223.2551,022
121181.233.224.0/22181.233.224.1 to 181.233.227.254181.233.227.2551,022
122181.233.228.0/22181.233.228.1 to 181.233.231.254181.233.231.2551,022
123181.233.232.0/22181.233.232.1 to 181.233.235.254181.233.235.2551,022
124181.233.236.0/22181.233.236.1 to 181.233.239.254181.233.239.2551,022
125181.233.240.0/22181.233.240.1 to 181.233.243.254181.233.243.2551,022
126181.233.244.0/22181.233.244.1 to 181.233.247.254181.233.247.2551,022
127181.233.248.0/22181.233.248.1 to 181.233.251.254181.233.251.2551,022
128181.233.252.0/22181.233.252.1 to 181.233.255.254181.233.255.2551,022
129181.234.0.0/22181.234.0.1 to 181.234.3.254181.234.3.2551,022
130181.234.4.0/22181.234.4.1 to 181.234.7.254181.234.7.2551,022
131181.234.8.0/22181.234.8.1 to 181.234.11.254181.234.11.2551,022
132181.234.12.0/22181.234.12.1 to 181.234.15.254181.234.15.2551,022
133181.234.16.0/22181.234.16.1 to 181.234.19.254181.234.19.2551,022
134181.234.20.0/22181.234.20.1 to 181.234.23.254181.234.23.2551,022
135181.234.24.0/22181.234.24.1 to 181.234.27.254181.234.27.2551,022
136181.234.28.0/22181.234.28.1 to 181.234.31.254181.234.31.2551,022
137181.234.32.0/22181.234.32.1 to 181.234.35.254181.234.35.2551,022
138181.234.36.0/22181.234.36.1 to 181.234.39.254181.234.39.2551,022
139181.234.40.0/22181.234.40.1 to 181.234.43.254181.234.43.2551,022
140181.234.44.0/22181.234.44.1 to 181.234.47.254181.234.47.2551,022
141181.234.48.0/22181.234.48.1 to 181.234.51.254181.234.51.2551,022
142181.234.52.0/22181.234.52.1 to 181.234.55.254181.234.55.2551,022
143181.234.56.0/22181.234.56.1 to 181.234.59.254181.234.59.2551,022
144181.234.60.0/22181.234.60.1 to 181.234.63.254181.234.63.2551,022
145181.234.64.0/22181.234.64.1 to 181.234.67.254181.234.67.2551,022
146181.234.68.0/22181.234.68.1 to 181.234.71.254181.234.71.2551,022
147181.234.72.0/22181.234.72.1 to 181.234.75.254181.234.75.2551,022
148181.234.76.0/22181.234.76.1 to 181.234.79.254181.234.79.2551,022
149181.234.80.0/22181.234.80.1 to 181.234.83.254181.234.83.2551,022
150181.234.84.0/22181.234.84.1 to 181.234.87.254181.234.87.2551,022
151181.234.88.0/22181.234.88.1 to 181.234.91.254181.234.91.2551,022
152181.234.92.0/22181.234.92.1 to 181.234.95.254181.234.95.2551,022
153181.234.96.0/22181.234.96.1 to 181.234.99.254181.234.99.2551,022
154181.234.100.0/22181.234.100.1 to 181.234.103.254181.234.103.2551,022
155181.234.104.0/22181.234.104.1 to 181.234.107.254181.234.107.2551,022
156181.234.108.0/22181.234.108.1 to 181.234.111.254181.234.111.2551,022
157181.234.112.0/22181.234.112.1 to 181.234.115.254181.234.115.2551,022
158181.234.116.0/22181.234.116.1 to 181.234.119.254181.234.119.2551,022
159181.234.120.0/22181.234.120.1 to 181.234.123.254181.234.123.2551,022
160181.234.124.0/22181.234.124.1 to 181.234.127.254181.234.127.2551,022
161181.234.128.0/22181.234.128.1 to 181.234.131.254181.234.131.2551,022
162181.234.132.0/22181.234.132.1 to 181.234.135.254181.234.135.2551,022
163181.234.136.0/22181.234.136.1 to 181.234.139.254181.234.139.2551,022
164181.234.140.0/22181.234.140.1 to 181.234.143.254181.234.143.2551,022
165181.234.144.0/22181.234.144.1 to 181.234.147.254181.234.147.2551,022
166181.234.148.0/22181.234.148.1 to 181.234.151.254181.234.151.2551,022
167181.234.152.0/22181.234.152.1 to 181.234.155.254181.234.155.2551,022
168181.234.156.0/22181.234.156.1 to 181.234.159.254181.234.159.2551,022
169181.234.160.0/22181.234.160.1 to 181.234.163.254181.234.163.2551,022
170181.234.164.0/22181.234.164.1 to 181.234.167.254181.234.167.2551,022
171181.234.168.0/22181.234.168.1 to 181.234.171.254181.234.171.2551,022
172181.234.172.0/22181.234.172.1 to 181.234.175.254181.234.175.2551,022
173181.234.176.0/22181.234.176.1 to 181.234.179.254181.234.179.2551,022
174181.234.180.0/22181.234.180.1 to 181.234.183.254181.234.183.2551,022
175181.234.184.0/22181.234.184.1 to 181.234.187.254181.234.187.2551,022
176181.234.188.0/22181.234.188.1 to 181.234.191.254181.234.191.2551,022
177181.234.192.0/22181.234.192.1 to 181.234.195.254181.234.195.2551,022
178181.234.196.0/22181.234.196.1 to 181.234.199.254181.234.199.2551,022
179181.234.200.0/22181.234.200.1 to 181.234.203.254181.234.203.2551,022
180181.234.204.0/22181.234.204.1 to 181.234.207.254181.234.207.2551,022
181181.234.208.0/22181.234.208.1 to 181.234.211.254181.234.211.2551,022
182181.234.212.0/22181.234.212.1 to 181.234.215.254181.234.215.2551,022
183181.234.216.0/22181.234.216.1 to 181.234.219.254181.234.219.2551,022
184181.234.220.0/22181.234.220.1 to 181.234.223.254181.234.223.2551,022
185181.234.224.0/22181.234.224.1 to 181.234.227.254181.234.227.2551,022
186181.234.228.0/22181.234.228.1 to 181.234.231.254181.234.231.2551,022
187181.234.232.0/22181.234.232.1 to 181.234.235.254181.234.235.2551,022
188181.234.236.0/22181.234.236.1 to 181.234.239.254181.234.239.2551,022
189181.234.240.0/22181.234.240.1 to 181.234.243.254181.234.243.2551,022
190181.234.244.0/22181.234.244.1 to 181.234.247.254181.234.247.2551,022
191181.234.248.0/22181.234.248.1 to 181.234.251.254181.234.251.2551,022
192181.234.252.0/22181.234.252.1 to 181.234.255.254181.234.255.2551,022
193181.235.0.0/22181.235.0.1 to 181.235.3.254181.235.3.2551,022
194181.235.4.0/22181.235.4.1 to 181.235.7.254181.235.7.2551,022
195181.235.8.0/22181.235.8.1 to 181.235.11.254181.235.11.2551,022
196181.235.12.0/22181.235.12.1 to 181.235.15.254181.235.15.2551,022
197181.235.16.0/22181.235.16.1 to 181.235.19.254181.235.19.2551,022
198181.235.20.0/22181.235.20.1 to 181.235.23.254181.235.23.2551,022
199181.235.24.0/22181.235.24.1 to 181.235.27.254181.235.27.2551,022
200181.235.28.0/22181.235.28.1 to 181.235.31.254181.235.31.2551,022
201181.235.32.0/22181.235.32.1 to 181.235.35.254181.235.35.2551,022
202181.235.36.0/22181.235.36.1 to 181.235.39.254181.235.39.2551,022
203181.235.40.0/22181.235.40.1 to 181.235.43.254181.235.43.2551,022
204181.235.44.0/22181.235.44.1 to 181.235.47.254181.235.47.2551,022
205181.235.48.0/22181.235.48.1 to 181.235.51.254181.235.51.2551,022
206181.235.52.0/22181.235.52.1 to 181.235.55.254181.235.55.2551,022
207181.235.56.0/22181.235.56.1 to 181.235.59.254181.235.59.2551,022
208181.235.60.0/22181.235.60.1 to 181.235.63.254181.235.63.2551,022
209181.235.64.0/22181.235.64.1 to 181.235.67.254181.235.67.2551,022
210181.235.68.0/22181.235.68.1 to 181.235.71.254181.235.71.2551,022
211181.235.72.0/22181.235.72.1 to 181.235.75.254181.235.75.2551,022
212181.235.76.0/22181.235.76.1 to 181.235.79.254181.235.79.2551,022
213181.235.80.0/22181.235.80.1 to 181.235.83.254181.235.83.2551,022
214181.235.84.0/22181.235.84.1 to 181.235.87.254181.235.87.2551,022
215181.235.88.0/22181.235.88.1 to 181.235.91.254181.235.91.2551,022
216181.235.92.0/22181.235.92.1 to 181.235.95.254181.235.95.2551,022
217181.235.96.0/22181.235.96.1 to 181.235.99.254181.235.99.2551,022
218181.235.100.0/22181.235.100.1 to 181.235.103.254181.235.103.2551,022
219181.235.104.0/22181.235.104.1 to 181.235.107.254181.235.107.2551,022
220181.235.108.0/22181.235.108.1 to 181.235.111.254181.235.111.2551,022
221181.235.112.0/22181.235.112.1 to 181.235.115.254181.235.115.2551,022
222181.235.116.0/22181.235.116.1 to 181.235.119.254181.235.119.2551,022
223181.235.120.0/22181.235.120.1 to 181.235.123.254181.235.123.2551,022
224181.235.124.0/22181.235.124.1 to 181.235.127.254181.235.127.2551,022
225181.235.128.0/22181.235.128.1 to 181.235.131.254181.235.131.2551,022
226181.235.132.0/22181.235.132.1 to 181.235.135.254181.235.135.2551,022
227181.235.136.0/22181.235.136.1 to 181.235.139.254181.235.139.2551,022
228181.235.140.0/22181.235.140.1 to 181.235.143.254181.235.143.2551,022
229181.235.144.0/22181.235.144.1 to 181.235.147.254181.235.147.2551,022
230181.235.148.0/22181.235.148.1 to 181.235.151.254181.235.151.2551,022
231181.235.152.0/22181.235.152.1 to 181.235.155.254181.235.155.2551,022
232181.235.156.0/22181.235.156.1 to 181.235.159.254181.235.159.2551,022
233181.235.160.0/22181.235.160.1 to 181.235.163.254181.235.163.2551,022
234181.235.164.0/22181.235.164.1 to 181.235.167.254181.235.167.2551,022
235181.235.168.0/22181.235.168.1 to 181.235.171.254181.235.171.2551,022
236181.235.172.0/22181.235.172.1 to 181.235.175.254181.235.175.2551,022
237181.235.176.0/22181.235.176.1 to 181.235.179.254181.235.179.2551,022
238181.235.180.0/22181.235.180.1 to 181.235.183.254181.235.183.2551,022
239181.235.184.0/22181.235.184.1 to 181.235.187.254181.235.187.2551,022
240181.235.188.0/22181.235.188.1 to 181.235.191.254181.235.191.2551,022
241181.235.192.0/22181.235.192.1 to 181.235.195.254181.235.195.2551,022
242181.235.196.0/22181.235.196.1 to 181.235.199.254181.235.199.2551,022
243181.235.200.0/22181.235.200.1 to 181.235.203.254181.235.203.2551,022
244181.235.204.0/22181.235.204.1 to 181.235.207.254181.235.207.2551,022
245181.235.208.0/22181.235.208.1 to 181.235.211.254181.235.211.2551,022
246181.235.212.0/22181.235.212.1 to 181.235.215.254181.235.215.2551,022
247181.235.216.0/22181.235.216.1 to 181.235.219.254181.235.219.2551,022
248181.235.220.0/22181.235.220.1 to 181.235.223.254181.235.223.2551,022
249181.235.224.0/22181.235.224.1 to 181.235.227.254181.235.227.2551,022
250181.235.228.0/22181.235.228.1 to 181.235.231.254181.235.231.2551,022
251181.235.232.0/22181.235.232.1 to 181.235.235.254181.235.235.2551,022
252181.235.236.0/22181.235.236.1 to 181.235.239.254181.235.239.2551,022
253181.235.240.0/22181.235.240.1 to 181.235.243.254181.235.243.2551,022
254181.235.244.0/22181.235.244.1 to 181.235.247.254181.235.247.2551,022
255181.235.248.0/22181.235.248.1 to 181.235.251.254181.235.251.2551,022
256181.235.252.0/22181.235.252.1 to 181.235.255.254181.235.255.2551,022

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.