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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.

Network184.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
184.0.0.0
Broadcast address
191.255.255.255
First usable
184.0.0.1
Last usable
191.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
B (default /16)
As numbers
Hex B8000000 · Integer 3087007744 to 3221225471
Reverse DNS zones
184.in-addr.arpa
185.in-addr.arpa
186.in-addr.arpa
187.in-addr.arpa
188.in-addr.arpa
189.in-addr.arpa
190.in-addr.arpa
191.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111000.00000000.00000000.00000000184.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network10111000.00000000.00000000.00000000184.0.0.0
Broadcast10111111.11111111.11111111.11111111191.255.255.255
Split into smaller subnets/14
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

184.0.0.0/5 makes 512 subnets of /14; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1184.0.0.0/14184.0.0.1 to 184.3.255.254184.3.255.255262,142
2184.4.0.0/14184.4.0.1 to 184.7.255.254184.7.255.255262,142
3184.8.0.0/14184.8.0.1 to 184.11.255.254184.11.255.255262,142
4184.12.0.0/14184.12.0.1 to 184.15.255.254184.15.255.255262,142
5184.16.0.0/14184.16.0.1 to 184.19.255.254184.19.255.255262,142
6184.20.0.0/14184.20.0.1 to 184.23.255.254184.23.255.255262,142
7184.24.0.0/14184.24.0.1 to 184.27.255.254184.27.255.255262,142
8184.28.0.0/14184.28.0.1 to 184.31.255.254184.31.255.255262,142
9184.32.0.0/14184.32.0.1 to 184.35.255.254184.35.255.255262,142
10184.36.0.0/14184.36.0.1 to 184.39.255.254184.39.255.255262,142
11184.40.0.0/14184.40.0.1 to 184.43.255.254184.43.255.255262,142
12184.44.0.0/14184.44.0.1 to 184.47.255.254184.47.255.255262,142
13184.48.0.0/14184.48.0.1 to 184.51.255.254184.51.255.255262,142
14184.52.0.0/14184.52.0.1 to 184.55.255.254184.55.255.255262,142
15184.56.0.0/14184.56.0.1 to 184.59.255.254184.59.255.255262,142
16184.60.0.0/14184.60.0.1 to 184.63.255.254184.63.255.255262,142
17184.64.0.0/14184.64.0.1 to 184.67.255.254184.67.255.255262,142
18184.68.0.0/14184.68.0.1 to 184.71.255.254184.71.255.255262,142
19184.72.0.0/14184.72.0.1 to 184.75.255.254184.75.255.255262,142
20184.76.0.0/14184.76.0.1 to 184.79.255.254184.79.255.255262,142
21184.80.0.0/14184.80.0.1 to 184.83.255.254184.83.255.255262,142
22184.84.0.0/14184.84.0.1 to 184.87.255.254184.87.255.255262,142
23184.88.0.0/14184.88.0.1 to 184.91.255.254184.91.255.255262,142
24184.92.0.0/14184.92.0.1 to 184.95.255.254184.95.255.255262,142
25184.96.0.0/14184.96.0.1 to 184.99.255.254184.99.255.255262,142
26184.100.0.0/14184.100.0.1 to 184.103.255.254184.103.255.255262,142
27184.104.0.0/14184.104.0.1 to 184.107.255.254184.107.255.255262,142
28184.108.0.0/14184.108.0.1 to 184.111.255.254184.111.255.255262,142
29184.112.0.0/14184.112.0.1 to 184.115.255.254184.115.255.255262,142
30184.116.0.0/14184.116.0.1 to 184.119.255.254184.119.255.255262,142
31184.120.0.0/14184.120.0.1 to 184.123.255.254184.123.255.255262,142
32184.124.0.0/14184.124.0.1 to 184.127.255.254184.127.255.255262,142
33184.128.0.0/14184.128.0.1 to 184.131.255.254184.131.255.255262,142
34184.132.0.0/14184.132.0.1 to 184.135.255.254184.135.255.255262,142
35184.136.0.0/14184.136.0.1 to 184.139.255.254184.139.255.255262,142
36184.140.0.0/14184.140.0.1 to 184.143.255.254184.143.255.255262,142
37184.144.0.0/14184.144.0.1 to 184.147.255.254184.147.255.255262,142
38184.148.0.0/14184.148.0.1 to 184.151.255.254184.151.255.255262,142
39184.152.0.0/14184.152.0.1 to 184.155.255.254184.155.255.255262,142
40184.156.0.0/14184.156.0.1 to 184.159.255.254184.159.255.255262,142
41184.160.0.0/14184.160.0.1 to 184.163.255.254184.163.255.255262,142
42184.164.0.0/14184.164.0.1 to 184.167.255.254184.167.255.255262,142
43184.168.0.0/14184.168.0.1 to 184.171.255.254184.171.255.255262,142
44184.172.0.0/14184.172.0.1 to 184.175.255.254184.175.255.255262,142
45184.176.0.0/14184.176.0.1 to 184.179.255.254184.179.255.255262,142
46184.180.0.0/14184.180.0.1 to 184.183.255.254184.183.255.255262,142
47184.184.0.0/14184.184.0.1 to 184.187.255.254184.187.255.255262,142
48184.188.0.0/14184.188.0.1 to 184.191.255.254184.191.255.255262,142
49184.192.0.0/14184.192.0.1 to 184.195.255.254184.195.255.255262,142
50184.196.0.0/14184.196.0.1 to 184.199.255.254184.199.255.255262,142
51184.200.0.0/14184.200.0.1 to 184.203.255.254184.203.255.255262,142
52184.204.0.0/14184.204.0.1 to 184.207.255.254184.207.255.255262,142
53184.208.0.0/14184.208.0.1 to 184.211.255.254184.211.255.255262,142
54184.212.0.0/14184.212.0.1 to 184.215.255.254184.215.255.255262,142
55184.216.0.0/14184.216.0.1 to 184.219.255.254184.219.255.255262,142
56184.220.0.0/14184.220.0.1 to 184.223.255.254184.223.255.255262,142
57184.224.0.0/14184.224.0.1 to 184.227.255.254184.227.255.255262,142
58184.228.0.0/14184.228.0.1 to 184.231.255.254184.231.255.255262,142
59184.232.0.0/14184.232.0.1 to 184.235.255.254184.235.255.255262,142
60184.236.0.0/14184.236.0.1 to 184.239.255.254184.239.255.255262,142
61184.240.0.0/14184.240.0.1 to 184.243.255.254184.243.255.255262,142
62184.244.0.0/14184.244.0.1 to 184.247.255.254184.247.255.255262,142
63184.248.0.0/14184.248.0.1 to 184.251.255.254184.251.255.255262,142
64184.252.0.0/14184.252.0.1 to 184.255.255.254184.255.255.255262,142
65185.0.0.0/14185.0.0.1 to 185.3.255.254185.3.255.255262,142
66185.4.0.0/14185.4.0.1 to 185.7.255.254185.7.255.255262,142
67185.8.0.0/14185.8.0.1 to 185.11.255.254185.11.255.255262,142
68185.12.0.0/14185.12.0.1 to 185.15.255.254185.15.255.255262,142
69185.16.0.0/14185.16.0.1 to 185.19.255.254185.19.255.255262,142
70185.20.0.0/14185.20.0.1 to 185.23.255.254185.23.255.255262,142
71185.24.0.0/14185.24.0.1 to 185.27.255.254185.27.255.255262,142
72185.28.0.0/14185.28.0.1 to 185.31.255.254185.31.255.255262,142
73185.32.0.0/14185.32.0.1 to 185.35.255.254185.35.255.255262,142
74185.36.0.0/14185.36.0.1 to 185.39.255.254185.39.255.255262,142
75185.40.0.0/14185.40.0.1 to 185.43.255.254185.43.255.255262,142
76185.44.0.0/14185.44.0.1 to 185.47.255.254185.47.255.255262,142
77185.48.0.0/14185.48.0.1 to 185.51.255.254185.51.255.255262,142
78185.52.0.0/14185.52.0.1 to 185.55.255.254185.55.255.255262,142
79185.56.0.0/14185.56.0.1 to 185.59.255.254185.59.255.255262,142
80185.60.0.0/14185.60.0.1 to 185.63.255.254185.63.255.255262,142
81185.64.0.0/14185.64.0.1 to 185.67.255.254185.67.255.255262,142
82185.68.0.0/14185.68.0.1 to 185.71.255.254185.71.255.255262,142
83185.72.0.0/14185.72.0.1 to 185.75.255.254185.75.255.255262,142
84185.76.0.0/14185.76.0.1 to 185.79.255.254185.79.255.255262,142
85185.80.0.0/14185.80.0.1 to 185.83.255.254185.83.255.255262,142
86185.84.0.0/14185.84.0.1 to 185.87.255.254185.87.255.255262,142
87185.88.0.0/14185.88.0.1 to 185.91.255.254185.91.255.255262,142
88185.92.0.0/14185.92.0.1 to 185.95.255.254185.95.255.255262,142
89185.96.0.0/14185.96.0.1 to 185.99.255.254185.99.255.255262,142
90185.100.0.0/14185.100.0.1 to 185.103.255.254185.103.255.255262,142
91185.104.0.0/14185.104.0.1 to 185.107.255.254185.107.255.255262,142
92185.108.0.0/14185.108.0.1 to 185.111.255.254185.111.255.255262,142
93185.112.0.0/14185.112.0.1 to 185.115.255.254185.115.255.255262,142
94185.116.0.0/14185.116.0.1 to 185.119.255.254185.119.255.255262,142
95185.120.0.0/14185.120.0.1 to 185.123.255.254185.123.255.255262,142
96185.124.0.0/14185.124.0.1 to 185.127.255.254185.127.255.255262,142
97185.128.0.0/14185.128.0.1 to 185.131.255.254185.131.255.255262,142
98185.132.0.0/14185.132.0.1 to 185.135.255.254185.135.255.255262,142
99185.136.0.0/14185.136.0.1 to 185.139.255.254185.139.255.255262,142
100185.140.0.0/14185.140.0.1 to 185.143.255.254185.143.255.255262,142
101185.144.0.0/14185.144.0.1 to 185.147.255.254185.147.255.255262,142
102185.148.0.0/14185.148.0.1 to 185.151.255.254185.151.255.255262,142
103185.152.0.0/14185.152.0.1 to 185.155.255.254185.155.255.255262,142
104185.156.0.0/14185.156.0.1 to 185.159.255.254185.159.255.255262,142
105185.160.0.0/14185.160.0.1 to 185.163.255.254185.163.255.255262,142
106185.164.0.0/14185.164.0.1 to 185.167.255.254185.167.255.255262,142
107185.168.0.0/14185.168.0.1 to 185.171.255.254185.171.255.255262,142
108185.172.0.0/14185.172.0.1 to 185.175.255.254185.175.255.255262,142
109185.176.0.0/14185.176.0.1 to 185.179.255.254185.179.255.255262,142
110185.180.0.0/14185.180.0.1 to 185.183.255.254185.183.255.255262,142
111185.184.0.0/14185.184.0.1 to 185.187.255.254185.187.255.255262,142
112185.188.0.0/14185.188.0.1 to 185.191.255.254185.191.255.255262,142
113185.192.0.0/14185.192.0.1 to 185.195.255.254185.195.255.255262,142
114185.196.0.0/14185.196.0.1 to 185.199.255.254185.199.255.255262,142
115185.200.0.0/14185.200.0.1 to 185.203.255.254185.203.255.255262,142
116185.204.0.0/14185.204.0.1 to 185.207.255.254185.207.255.255262,142
117185.208.0.0/14185.208.0.1 to 185.211.255.254185.211.255.255262,142
118185.212.0.0/14185.212.0.1 to 185.215.255.254185.215.255.255262,142
119185.216.0.0/14185.216.0.1 to 185.219.255.254185.219.255.255262,142
120185.220.0.0/14185.220.0.1 to 185.223.255.254185.223.255.255262,142
121185.224.0.0/14185.224.0.1 to 185.227.255.254185.227.255.255262,142
122185.228.0.0/14185.228.0.1 to 185.231.255.254185.231.255.255262,142
123185.232.0.0/14185.232.0.1 to 185.235.255.254185.235.255.255262,142
124185.236.0.0/14185.236.0.1 to 185.239.255.254185.239.255.255262,142
125185.240.0.0/14185.240.0.1 to 185.243.255.254185.243.255.255262,142
126185.244.0.0/14185.244.0.1 to 185.247.255.254185.247.255.255262,142
127185.248.0.0/14185.248.0.1 to 185.251.255.254185.251.255.255262,142
128185.252.0.0/14185.252.0.1 to 185.255.255.254185.255.255.255262,142
129186.0.0.0/14186.0.0.1 to 186.3.255.254186.3.255.255262,142
130186.4.0.0/14186.4.0.1 to 186.7.255.254186.7.255.255262,142
131186.8.0.0/14186.8.0.1 to 186.11.255.254186.11.255.255262,142
132186.12.0.0/14186.12.0.1 to 186.15.255.254186.15.255.255262,142
133186.16.0.0/14186.16.0.1 to 186.19.255.254186.19.255.255262,142
134186.20.0.0/14186.20.0.1 to 186.23.255.254186.23.255.255262,142
135186.24.0.0/14186.24.0.1 to 186.27.255.254186.27.255.255262,142
136186.28.0.0/14186.28.0.1 to 186.31.255.254186.31.255.255262,142
137186.32.0.0/14186.32.0.1 to 186.35.255.254186.35.255.255262,142
138186.36.0.0/14186.36.0.1 to 186.39.255.254186.39.255.255262,142
139186.40.0.0/14186.40.0.1 to 186.43.255.254186.43.255.255262,142
140186.44.0.0/14186.44.0.1 to 186.47.255.254186.47.255.255262,142
141186.48.0.0/14186.48.0.1 to 186.51.255.254186.51.255.255262,142
142186.52.0.0/14186.52.0.1 to 186.55.255.254186.55.255.255262,142
143186.56.0.0/14186.56.0.1 to 186.59.255.254186.59.255.255262,142
144186.60.0.0/14186.60.0.1 to 186.63.255.254186.63.255.255262,142
145186.64.0.0/14186.64.0.1 to 186.67.255.254186.67.255.255262,142
146186.68.0.0/14186.68.0.1 to 186.71.255.254186.71.255.255262,142
147186.72.0.0/14186.72.0.1 to 186.75.255.254186.75.255.255262,142
148186.76.0.0/14186.76.0.1 to 186.79.255.254186.79.255.255262,142
149186.80.0.0/14186.80.0.1 to 186.83.255.254186.83.255.255262,142
150186.84.0.0/14186.84.0.1 to 186.87.255.254186.87.255.255262,142
151186.88.0.0/14186.88.0.1 to 186.91.255.254186.91.255.255262,142
152186.92.0.0/14186.92.0.1 to 186.95.255.254186.95.255.255262,142
153186.96.0.0/14186.96.0.1 to 186.99.255.254186.99.255.255262,142
154186.100.0.0/14186.100.0.1 to 186.103.255.254186.103.255.255262,142
155186.104.0.0/14186.104.0.1 to 186.107.255.254186.107.255.255262,142
156186.108.0.0/14186.108.0.1 to 186.111.255.254186.111.255.255262,142
157186.112.0.0/14186.112.0.1 to 186.115.255.254186.115.255.255262,142
158186.116.0.0/14186.116.0.1 to 186.119.255.254186.119.255.255262,142
159186.120.0.0/14186.120.0.1 to 186.123.255.254186.123.255.255262,142
160186.124.0.0/14186.124.0.1 to 186.127.255.254186.127.255.255262,142
161186.128.0.0/14186.128.0.1 to 186.131.255.254186.131.255.255262,142
162186.132.0.0/14186.132.0.1 to 186.135.255.254186.135.255.255262,142
163186.136.0.0/14186.136.0.1 to 186.139.255.254186.139.255.255262,142
164186.140.0.0/14186.140.0.1 to 186.143.255.254186.143.255.255262,142
165186.144.0.0/14186.144.0.1 to 186.147.255.254186.147.255.255262,142
166186.148.0.0/14186.148.0.1 to 186.151.255.254186.151.255.255262,142
167186.152.0.0/14186.152.0.1 to 186.155.255.254186.155.255.255262,142
168186.156.0.0/14186.156.0.1 to 186.159.255.254186.159.255.255262,142
169186.160.0.0/14186.160.0.1 to 186.163.255.254186.163.255.255262,142
170186.164.0.0/14186.164.0.1 to 186.167.255.254186.167.255.255262,142
171186.168.0.0/14186.168.0.1 to 186.171.255.254186.171.255.255262,142
172186.172.0.0/14186.172.0.1 to 186.175.255.254186.175.255.255262,142
173186.176.0.0/14186.176.0.1 to 186.179.255.254186.179.255.255262,142
174186.180.0.0/14186.180.0.1 to 186.183.255.254186.183.255.255262,142
175186.184.0.0/14186.184.0.1 to 186.187.255.254186.187.255.255262,142
176186.188.0.0/14186.188.0.1 to 186.191.255.254186.191.255.255262,142
177186.192.0.0/14186.192.0.1 to 186.195.255.254186.195.255.255262,142
178186.196.0.0/14186.196.0.1 to 186.199.255.254186.199.255.255262,142
179186.200.0.0/14186.200.0.1 to 186.203.255.254186.203.255.255262,142
180186.204.0.0/14186.204.0.1 to 186.207.255.254186.207.255.255262,142
181186.208.0.0/14186.208.0.1 to 186.211.255.254186.211.255.255262,142
182186.212.0.0/14186.212.0.1 to 186.215.255.254186.215.255.255262,142
183186.216.0.0/14186.216.0.1 to 186.219.255.254186.219.255.255262,142
184186.220.0.0/14186.220.0.1 to 186.223.255.254186.223.255.255262,142
185186.224.0.0/14186.224.0.1 to 186.227.255.254186.227.255.255262,142
186186.228.0.0/14186.228.0.1 to 186.231.255.254186.231.255.255262,142
187186.232.0.0/14186.232.0.1 to 186.235.255.254186.235.255.255262,142
188186.236.0.0/14186.236.0.1 to 186.239.255.254186.239.255.255262,142
189186.240.0.0/14186.240.0.1 to 186.243.255.254186.243.255.255262,142
190186.244.0.0/14186.244.0.1 to 186.247.255.254186.247.255.255262,142
191186.248.0.0/14186.248.0.1 to 186.251.255.254186.251.255.255262,142
192186.252.0.0/14186.252.0.1 to 186.255.255.254186.255.255.255262,142
193187.0.0.0/14187.0.0.1 to 187.3.255.254187.3.255.255262,142
194187.4.0.0/14187.4.0.1 to 187.7.255.254187.7.255.255262,142
195187.8.0.0/14187.8.0.1 to 187.11.255.254187.11.255.255262,142
196187.12.0.0/14187.12.0.1 to 187.15.255.254187.15.255.255262,142
197187.16.0.0/14187.16.0.1 to 187.19.255.254187.19.255.255262,142
198187.20.0.0/14187.20.0.1 to 187.23.255.254187.23.255.255262,142
199187.24.0.0/14187.24.0.1 to 187.27.255.254187.27.255.255262,142
200187.28.0.0/14187.28.0.1 to 187.31.255.254187.31.255.255262,142
201187.32.0.0/14187.32.0.1 to 187.35.255.254187.35.255.255262,142
202187.36.0.0/14187.36.0.1 to 187.39.255.254187.39.255.255262,142
203187.40.0.0/14187.40.0.1 to 187.43.255.254187.43.255.255262,142
204187.44.0.0/14187.44.0.1 to 187.47.255.254187.47.255.255262,142
205187.48.0.0/14187.48.0.1 to 187.51.255.254187.51.255.255262,142
206187.52.0.0/14187.52.0.1 to 187.55.255.254187.55.255.255262,142
207187.56.0.0/14187.56.0.1 to 187.59.255.254187.59.255.255262,142
208187.60.0.0/14187.60.0.1 to 187.63.255.254187.63.255.255262,142
209187.64.0.0/14187.64.0.1 to 187.67.255.254187.67.255.255262,142
210187.68.0.0/14187.68.0.1 to 187.71.255.254187.71.255.255262,142
211187.72.0.0/14187.72.0.1 to 187.75.255.254187.75.255.255262,142
212187.76.0.0/14187.76.0.1 to 187.79.255.254187.79.255.255262,142
213187.80.0.0/14187.80.0.1 to 187.83.255.254187.83.255.255262,142
214187.84.0.0/14187.84.0.1 to 187.87.255.254187.87.255.255262,142
215187.88.0.0/14187.88.0.1 to 187.91.255.254187.91.255.255262,142
216187.92.0.0/14187.92.0.1 to 187.95.255.254187.95.255.255262,142
217187.96.0.0/14187.96.0.1 to 187.99.255.254187.99.255.255262,142
218187.100.0.0/14187.100.0.1 to 187.103.255.254187.103.255.255262,142
219187.104.0.0/14187.104.0.1 to 187.107.255.254187.107.255.255262,142
220187.108.0.0/14187.108.0.1 to 187.111.255.254187.111.255.255262,142
221187.112.0.0/14187.112.0.1 to 187.115.255.254187.115.255.255262,142
222187.116.0.0/14187.116.0.1 to 187.119.255.254187.119.255.255262,142
223187.120.0.0/14187.120.0.1 to 187.123.255.254187.123.255.255262,142
224187.124.0.0/14187.124.0.1 to 187.127.255.254187.127.255.255262,142
225187.128.0.0/14187.128.0.1 to 187.131.255.254187.131.255.255262,142
226187.132.0.0/14187.132.0.1 to 187.135.255.254187.135.255.255262,142
227187.136.0.0/14187.136.0.1 to 187.139.255.254187.139.255.255262,142
228187.140.0.0/14187.140.0.1 to 187.143.255.254187.143.255.255262,142
229187.144.0.0/14187.144.0.1 to 187.147.255.254187.147.255.255262,142
230187.148.0.0/14187.148.0.1 to 187.151.255.254187.151.255.255262,142
231187.152.0.0/14187.152.0.1 to 187.155.255.254187.155.255.255262,142
232187.156.0.0/14187.156.0.1 to 187.159.255.254187.159.255.255262,142
233187.160.0.0/14187.160.0.1 to 187.163.255.254187.163.255.255262,142
234187.164.0.0/14187.164.0.1 to 187.167.255.254187.167.255.255262,142
235187.168.0.0/14187.168.0.1 to 187.171.255.254187.171.255.255262,142
236187.172.0.0/14187.172.0.1 to 187.175.255.254187.175.255.255262,142
237187.176.0.0/14187.176.0.1 to 187.179.255.254187.179.255.255262,142
238187.180.0.0/14187.180.0.1 to 187.183.255.254187.183.255.255262,142
239187.184.0.0/14187.184.0.1 to 187.187.255.254187.187.255.255262,142
240187.188.0.0/14187.188.0.1 to 187.191.255.254187.191.255.255262,142
241187.192.0.0/14187.192.0.1 to 187.195.255.254187.195.255.255262,142
242187.196.0.0/14187.196.0.1 to 187.199.255.254187.199.255.255262,142
243187.200.0.0/14187.200.0.1 to 187.203.255.254187.203.255.255262,142
244187.204.0.0/14187.204.0.1 to 187.207.255.254187.207.255.255262,142
245187.208.0.0/14187.208.0.1 to 187.211.255.254187.211.255.255262,142
246187.212.0.0/14187.212.0.1 to 187.215.255.254187.215.255.255262,142
247187.216.0.0/14187.216.0.1 to 187.219.255.254187.219.255.255262,142
248187.220.0.0/14187.220.0.1 to 187.223.255.254187.223.255.255262,142
249187.224.0.0/14187.224.0.1 to 187.227.255.254187.227.255.255262,142
250187.228.0.0/14187.228.0.1 to 187.231.255.254187.231.255.255262,142
251187.232.0.0/14187.232.0.1 to 187.235.255.254187.235.255.255262,142
252187.236.0.0/14187.236.0.1 to 187.239.255.254187.239.255.255262,142
253187.240.0.0/14187.240.0.1 to 187.243.255.254187.243.255.255262,142
254187.244.0.0/14187.244.0.1 to 187.247.255.254187.247.255.255262,142
255187.248.0.0/14187.248.0.1 to 187.251.255.254187.251.255.255262,142
256187.252.0.0/14187.252.0.1 to 187.255.255.254187.255.255.255262,142

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.