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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.

Network188.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
188.0.0.0
Broadcast address
188.127.255.255
First usable
188.0.0.1
Last usable
188.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
B (default /16)
As numbers
Hex BC000000 · Integer 3154116608 to 3162505215
Reverse DNS zones
0.188.in-addr.arpa
1.188.in-addr.arpa
2.188.in-addr.arpa
3.188.in-addr.arpa
4.188.in-addr.arpa
5.188.in-addr.arpa
6.188.in-addr.arpa
7.188.in-addr.arpa
8.188.in-addr.arpa
9.188.in-addr.arpa
10.188.in-addr.arpa
11.188.in-addr.arpa
12.188.in-addr.arpa
13.188.in-addr.arpa
14.188.in-addr.arpa
15.188.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111100.00000000.00000000.00000000188.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network10111100.00000000.00000000.00000000188.0.0.0
Broadcast10111100.01111111.11111111.11111111188.127.255.255
Split into smaller subnets/21
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

188.0.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.0.0.0/21188.0.0.1 to 188.0.7.254188.0.7.2552,046
2188.0.8.0/21188.0.8.1 to 188.0.15.254188.0.15.2552,046
3188.0.16.0/21188.0.16.1 to 188.0.23.254188.0.23.2552,046
4188.0.24.0/21188.0.24.1 to 188.0.31.254188.0.31.2552,046
5188.0.32.0/21188.0.32.1 to 188.0.39.254188.0.39.2552,046
6188.0.40.0/21188.0.40.1 to 188.0.47.254188.0.47.2552,046
7188.0.48.0/21188.0.48.1 to 188.0.55.254188.0.55.2552,046
8188.0.56.0/21188.0.56.1 to 188.0.63.254188.0.63.2552,046
9188.0.64.0/21188.0.64.1 to 188.0.71.254188.0.71.2552,046
10188.0.72.0/21188.0.72.1 to 188.0.79.254188.0.79.2552,046
11188.0.80.0/21188.0.80.1 to 188.0.87.254188.0.87.2552,046
12188.0.88.0/21188.0.88.1 to 188.0.95.254188.0.95.2552,046
13188.0.96.0/21188.0.96.1 to 188.0.103.254188.0.103.2552,046
14188.0.104.0/21188.0.104.1 to 188.0.111.254188.0.111.2552,046
15188.0.112.0/21188.0.112.1 to 188.0.119.254188.0.119.2552,046
16188.0.120.0/21188.0.120.1 to 188.0.127.254188.0.127.2552,046
17188.0.128.0/21188.0.128.1 to 188.0.135.254188.0.135.2552,046
18188.0.136.0/21188.0.136.1 to 188.0.143.254188.0.143.2552,046
19188.0.144.0/21188.0.144.1 to 188.0.151.254188.0.151.2552,046
20188.0.152.0/21188.0.152.1 to 188.0.159.254188.0.159.2552,046
21188.0.160.0/21188.0.160.1 to 188.0.167.254188.0.167.2552,046
22188.0.168.0/21188.0.168.1 to 188.0.175.254188.0.175.2552,046
23188.0.176.0/21188.0.176.1 to 188.0.183.254188.0.183.2552,046
24188.0.184.0/21188.0.184.1 to 188.0.191.254188.0.191.2552,046
25188.0.192.0/21188.0.192.1 to 188.0.199.254188.0.199.2552,046
26188.0.200.0/21188.0.200.1 to 188.0.207.254188.0.207.2552,046
27188.0.208.0/21188.0.208.1 to 188.0.215.254188.0.215.2552,046
28188.0.216.0/21188.0.216.1 to 188.0.223.254188.0.223.2552,046
29188.0.224.0/21188.0.224.1 to 188.0.231.254188.0.231.2552,046
30188.0.232.0/21188.0.232.1 to 188.0.239.254188.0.239.2552,046
31188.0.240.0/21188.0.240.1 to 188.0.247.254188.0.247.2552,046
32188.0.248.0/21188.0.248.1 to 188.0.255.254188.0.255.2552,046
33188.1.0.0/21188.1.0.1 to 188.1.7.254188.1.7.2552,046
34188.1.8.0/21188.1.8.1 to 188.1.15.254188.1.15.2552,046
35188.1.16.0/21188.1.16.1 to 188.1.23.254188.1.23.2552,046
36188.1.24.0/21188.1.24.1 to 188.1.31.254188.1.31.2552,046
37188.1.32.0/21188.1.32.1 to 188.1.39.254188.1.39.2552,046
38188.1.40.0/21188.1.40.1 to 188.1.47.254188.1.47.2552,046
39188.1.48.0/21188.1.48.1 to 188.1.55.254188.1.55.2552,046
40188.1.56.0/21188.1.56.1 to 188.1.63.254188.1.63.2552,046
41188.1.64.0/21188.1.64.1 to 188.1.71.254188.1.71.2552,046
42188.1.72.0/21188.1.72.1 to 188.1.79.254188.1.79.2552,046
43188.1.80.0/21188.1.80.1 to 188.1.87.254188.1.87.2552,046
44188.1.88.0/21188.1.88.1 to 188.1.95.254188.1.95.2552,046
45188.1.96.0/21188.1.96.1 to 188.1.103.254188.1.103.2552,046
46188.1.104.0/21188.1.104.1 to 188.1.111.254188.1.111.2552,046
47188.1.112.0/21188.1.112.1 to 188.1.119.254188.1.119.2552,046
48188.1.120.0/21188.1.120.1 to 188.1.127.254188.1.127.2552,046
49188.1.128.0/21188.1.128.1 to 188.1.135.254188.1.135.2552,046
50188.1.136.0/21188.1.136.1 to 188.1.143.254188.1.143.2552,046
51188.1.144.0/21188.1.144.1 to 188.1.151.254188.1.151.2552,046
52188.1.152.0/21188.1.152.1 to 188.1.159.254188.1.159.2552,046
53188.1.160.0/21188.1.160.1 to 188.1.167.254188.1.167.2552,046
54188.1.168.0/21188.1.168.1 to 188.1.175.254188.1.175.2552,046
55188.1.176.0/21188.1.176.1 to 188.1.183.254188.1.183.2552,046
56188.1.184.0/21188.1.184.1 to 188.1.191.254188.1.191.2552,046
57188.1.192.0/21188.1.192.1 to 188.1.199.254188.1.199.2552,046
58188.1.200.0/21188.1.200.1 to 188.1.207.254188.1.207.2552,046
59188.1.208.0/21188.1.208.1 to 188.1.215.254188.1.215.2552,046
60188.1.216.0/21188.1.216.1 to 188.1.223.254188.1.223.2552,046
61188.1.224.0/21188.1.224.1 to 188.1.231.254188.1.231.2552,046
62188.1.232.0/21188.1.232.1 to 188.1.239.254188.1.239.2552,046
63188.1.240.0/21188.1.240.1 to 188.1.247.254188.1.247.2552,046
64188.1.248.0/21188.1.248.1 to 188.1.255.254188.1.255.2552,046
65188.2.0.0/21188.2.0.1 to 188.2.7.254188.2.7.2552,046
66188.2.8.0/21188.2.8.1 to 188.2.15.254188.2.15.2552,046
67188.2.16.0/21188.2.16.1 to 188.2.23.254188.2.23.2552,046
68188.2.24.0/21188.2.24.1 to 188.2.31.254188.2.31.2552,046
69188.2.32.0/21188.2.32.1 to 188.2.39.254188.2.39.2552,046
70188.2.40.0/21188.2.40.1 to 188.2.47.254188.2.47.2552,046
71188.2.48.0/21188.2.48.1 to 188.2.55.254188.2.55.2552,046
72188.2.56.0/21188.2.56.1 to 188.2.63.254188.2.63.2552,046
73188.2.64.0/21188.2.64.1 to 188.2.71.254188.2.71.2552,046
74188.2.72.0/21188.2.72.1 to 188.2.79.254188.2.79.2552,046
75188.2.80.0/21188.2.80.1 to 188.2.87.254188.2.87.2552,046
76188.2.88.0/21188.2.88.1 to 188.2.95.254188.2.95.2552,046
77188.2.96.0/21188.2.96.1 to 188.2.103.254188.2.103.2552,046
78188.2.104.0/21188.2.104.1 to 188.2.111.254188.2.111.2552,046
79188.2.112.0/21188.2.112.1 to 188.2.119.254188.2.119.2552,046
80188.2.120.0/21188.2.120.1 to 188.2.127.254188.2.127.2552,046
81188.2.128.0/21188.2.128.1 to 188.2.135.254188.2.135.2552,046
82188.2.136.0/21188.2.136.1 to 188.2.143.254188.2.143.2552,046
83188.2.144.0/21188.2.144.1 to 188.2.151.254188.2.151.2552,046
84188.2.152.0/21188.2.152.1 to 188.2.159.254188.2.159.2552,046
85188.2.160.0/21188.2.160.1 to 188.2.167.254188.2.167.2552,046
86188.2.168.0/21188.2.168.1 to 188.2.175.254188.2.175.2552,046
87188.2.176.0/21188.2.176.1 to 188.2.183.254188.2.183.2552,046
88188.2.184.0/21188.2.184.1 to 188.2.191.254188.2.191.2552,046
89188.2.192.0/21188.2.192.1 to 188.2.199.254188.2.199.2552,046
90188.2.200.0/21188.2.200.1 to 188.2.207.254188.2.207.2552,046
91188.2.208.0/21188.2.208.1 to 188.2.215.254188.2.215.2552,046
92188.2.216.0/21188.2.216.1 to 188.2.223.254188.2.223.2552,046
93188.2.224.0/21188.2.224.1 to 188.2.231.254188.2.231.2552,046
94188.2.232.0/21188.2.232.1 to 188.2.239.254188.2.239.2552,046
95188.2.240.0/21188.2.240.1 to 188.2.247.254188.2.247.2552,046
96188.2.248.0/21188.2.248.1 to 188.2.255.254188.2.255.2552,046
97188.3.0.0/21188.3.0.1 to 188.3.7.254188.3.7.2552,046
98188.3.8.0/21188.3.8.1 to 188.3.15.254188.3.15.2552,046
99188.3.16.0/21188.3.16.1 to 188.3.23.254188.3.23.2552,046
100188.3.24.0/21188.3.24.1 to 188.3.31.254188.3.31.2552,046
101188.3.32.0/21188.3.32.1 to 188.3.39.254188.3.39.2552,046
102188.3.40.0/21188.3.40.1 to 188.3.47.254188.3.47.2552,046
103188.3.48.0/21188.3.48.1 to 188.3.55.254188.3.55.2552,046
104188.3.56.0/21188.3.56.1 to 188.3.63.254188.3.63.2552,046
105188.3.64.0/21188.3.64.1 to 188.3.71.254188.3.71.2552,046
106188.3.72.0/21188.3.72.1 to 188.3.79.254188.3.79.2552,046
107188.3.80.0/21188.3.80.1 to 188.3.87.254188.3.87.2552,046
108188.3.88.0/21188.3.88.1 to 188.3.95.254188.3.95.2552,046
109188.3.96.0/21188.3.96.1 to 188.3.103.254188.3.103.2552,046
110188.3.104.0/21188.3.104.1 to 188.3.111.254188.3.111.2552,046
111188.3.112.0/21188.3.112.1 to 188.3.119.254188.3.119.2552,046
112188.3.120.0/21188.3.120.1 to 188.3.127.254188.3.127.2552,046
113188.3.128.0/21188.3.128.1 to 188.3.135.254188.3.135.2552,046
114188.3.136.0/21188.3.136.1 to 188.3.143.254188.3.143.2552,046
115188.3.144.0/21188.3.144.1 to 188.3.151.254188.3.151.2552,046
116188.3.152.0/21188.3.152.1 to 188.3.159.254188.3.159.2552,046
117188.3.160.0/21188.3.160.1 to 188.3.167.254188.3.167.2552,046
118188.3.168.0/21188.3.168.1 to 188.3.175.254188.3.175.2552,046
119188.3.176.0/21188.3.176.1 to 188.3.183.254188.3.183.2552,046
120188.3.184.0/21188.3.184.1 to 188.3.191.254188.3.191.2552,046
121188.3.192.0/21188.3.192.1 to 188.3.199.254188.3.199.2552,046
122188.3.200.0/21188.3.200.1 to 188.3.207.254188.3.207.2552,046
123188.3.208.0/21188.3.208.1 to 188.3.215.254188.3.215.2552,046
124188.3.216.0/21188.3.216.1 to 188.3.223.254188.3.223.2552,046
125188.3.224.0/21188.3.224.1 to 188.3.231.254188.3.231.2552,046
126188.3.232.0/21188.3.232.1 to 188.3.239.254188.3.239.2552,046
127188.3.240.0/21188.3.240.1 to 188.3.247.254188.3.247.2552,046
128188.3.248.0/21188.3.248.1 to 188.3.255.254188.3.255.2552,046
129188.4.0.0/21188.4.0.1 to 188.4.7.254188.4.7.2552,046
130188.4.8.0/21188.4.8.1 to 188.4.15.254188.4.15.2552,046
131188.4.16.0/21188.4.16.1 to 188.4.23.254188.4.23.2552,046
132188.4.24.0/21188.4.24.1 to 188.4.31.254188.4.31.2552,046
133188.4.32.0/21188.4.32.1 to 188.4.39.254188.4.39.2552,046
134188.4.40.0/21188.4.40.1 to 188.4.47.254188.4.47.2552,046
135188.4.48.0/21188.4.48.1 to 188.4.55.254188.4.55.2552,046
136188.4.56.0/21188.4.56.1 to 188.4.63.254188.4.63.2552,046
137188.4.64.0/21188.4.64.1 to 188.4.71.254188.4.71.2552,046
138188.4.72.0/21188.4.72.1 to 188.4.79.254188.4.79.2552,046
139188.4.80.0/21188.4.80.1 to 188.4.87.254188.4.87.2552,046
140188.4.88.0/21188.4.88.1 to 188.4.95.254188.4.95.2552,046
141188.4.96.0/21188.4.96.1 to 188.4.103.254188.4.103.2552,046
142188.4.104.0/21188.4.104.1 to 188.4.111.254188.4.111.2552,046
143188.4.112.0/21188.4.112.1 to 188.4.119.254188.4.119.2552,046
144188.4.120.0/21188.4.120.1 to 188.4.127.254188.4.127.2552,046
145188.4.128.0/21188.4.128.1 to 188.4.135.254188.4.135.2552,046
146188.4.136.0/21188.4.136.1 to 188.4.143.254188.4.143.2552,046
147188.4.144.0/21188.4.144.1 to 188.4.151.254188.4.151.2552,046
148188.4.152.0/21188.4.152.1 to 188.4.159.254188.4.159.2552,046
149188.4.160.0/21188.4.160.1 to 188.4.167.254188.4.167.2552,046
150188.4.168.0/21188.4.168.1 to 188.4.175.254188.4.175.2552,046
151188.4.176.0/21188.4.176.1 to 188.4.183.254188.4.183.2552,046
152188.4.184.0/21188.4.184.1 to 188.4.191.254188.4.191.2552,046
153188.4.192.0/21188.4.192.1 to 188.4.199.254188.4.199.2552,046
154188.4.200.0/21188.4.200.1 to 188.4.207.254188.4.207.2552,046
155188.4.208.0/21188.4.208.1 to 188.4.215.254188.4.215.2552,046
156188.4.216.0/21188.4.216.1 to 188.4.223.254188.4.223.2552,046
157188.4.224.0/21188.4.224.1 to 188.4.231.254188.4.231.2552,046
158188.4.232.0/21188.4.232.1 to 188.4.239.254188.4.239.2552,046
159188.4.240.0/21188.4.240.1 to 188.4.247.254188.4.247.2552,046
160188.4.248.0/21188.4.248.1 to 188.4.255.254188.4.255.2552,046
161188.5.0.0/21188.5.0.1 to 188.5.7.254188.5.7.2552,046
162188.5.8.0/21188.5.8.1 to 188.5.15.254188.5.15.2552,046
163188.5.16.0/21188.5.16.1 to 188.5.23.254188.5.23.2552,046
164188.5.24.0/21188.5.24.1 to 188.5.31.254188.5.31.2552,046
165188.5.32.0/21188.5.32.1 to 188.5.39.254188.5.39.2552,046
166188.5.40.0/21188.5.40.1 to 188.5.47.254188.5.47.2552,046
167188.5.48.0/21188.5.48.1 to 188.5.55.254188.5.55.2552,046
168188.5.56.0/21188.5.56.1 to 188.5.63.254188.5.63.2552,046
169188.5.64.0/21188.5.64.1 to 188.5.71.254188.5.71.2552,046
170188.5.72.0/21188.5.72.1 to 188.5.79.254188.5.79.2552,046
171188.5.80.0/21188.5.80.1 to 188.5.87.254188.5.87.2552,046
172188.5.88.0/21188.5.88.1 to 188.5.95.254188.5.95.2552,046
173188.5.96.0/21188.5.96.1 to 188.5.103.254188.5.103.2552,046
174188.5.104.0/21188.5.104.1 to 188.5.111.254188.5.111.2552,046
175188.5.112.0/21188.5.112.1 to 188.5.119.254188.5.119.2552,046
176188.5.120.0/21188.5.120.1 to 188.5.127.254188.5.127.2552,046
177188.5.128.0/21188.5.128.1 to 188.5.135.254188.5.135.2552,046
178188.5.136.0/21188.5.136.1 to 188.5.143.254188.5.143.2552,046
179188.5.144.0/21188.5.144.1 to 188.5.151.254188.5.151.2552,046
180188.5.152.0/21188.5.152.1 to 188.5.159.254188.5.159.2552,046
181188.5.160.0/21188.5.160.1 to 188.5.167.254188.5.167.2552,046
182188.5.168.0/21188.5.168.1 to 188.5.175.254188.5.175.2552,046
183188.5.176.0/21188.5.176.1 to 188.5.183.254188.5.183.2552,046
184188.5.184.0/21188.5.184.1 to 188.5.191.254188.5.191.2552,046
185188.5.192.0/21188.5.192.1 to 188.5.199.254188.5.199.2552,046
186188.5.200.0/21188.5.200.1 to 188.5.207.254188.5.207.2552,046
187188.5.208.0/21188.5.208.1 to 188.5.215.254188.5.215.2552,046
188188.5.216.0/21188.5.216.1 to 188.5.223.254188.5.223.2552,046
189188.5.224.0/21188.5.224.1 to 188.5.231.254188.5.231.2552,046
190188.5.232.0/21188.5.232.1 to 188.5.239.254188.5.239.2552,046
191188.5.240.0/21188.5.240.1 to 188.5.247.254188.5.247.2552,046
192188.5.248.0/21188.5.248.1 to 188.5.255.254188.5.255.2552,046
193188.6.0.0/21188.6.0.1 to 188.6.7.254188.6.7.2552,046
194188.6.8.0/21188.6.8.1 to 188.6.15.254188.6.15.2552,046
195188.6.16.0/21188.6.16.1 to 188.6.23.254188.6.23.2552,046
196188.6.24.0/21188.6.24.1 to 188.6.31.254188.6.31.2552,046
197188.6.32.0/21188.6.32.1 to 188.6.39.254188.6.39.2552,046
198188.6.40.0/21188.6.40.1 to 188.6.47.254188.6.47.2552,046
199188.6.48.0/21188.6.48.1 to 188.6.55.254188.6.55.2552,046
200188.6.56.0/21188.6.56.1 to 188.6.63.254188.6.63.2552,046
201188.6.64.0/21188.6.64.1 to 188.6.71.254188.6.71.2552,046
202188.6.72.0/21188.6.72.1 to 188.6.79.254188.6.79.2552,046
203188.6.80.0/21188.6.80.1 to 188.6.87.254188.6.87.2552,046
204188.6.88.0/21188.6.88.1 to 188.6.95.254188.6.95.2552,046
205188.6.96.0/21188.6.96.1 to 188.6.103.254188.6.103.2552,046
206188.6.104.0/21188.6.104.1 to 188.6.111.254188.6.111.2552,046
207188.6.112.0/21188.6.112.1 to 188.6.119.254188.6.119.2552,046
208188.6.120.0/21188.6.120.1 to 188.6.127.254188.6.127.2552,046
209188.6.128.0/21188.6.128.1 to 188.6.135.254188.6.135.2552,046
210188.6.136.0/21188.6.136.1 to 188.6.143.254188.6.143.2552,046
211188.6.144.0/21188.6.144.1 to 188.6.151.254188.6.151.2552,046
212188.6.152.0/21188.6.152.1 to 188.6.159.254188.6.159.2552,046
213188.6.160.0/21188.6.160.1 to 188.6.167.254188.6.167.2552,046
214188.6.168.0/21188.6.168.1 to 188.6.175.254188.6.175.2552,046
215188.6.176.0/21188.6.176.1 to 188.6.183.254188.6.183.2552,046
216188.6.184.0/21188.6.184.1 to 188.6.191.254188.6.191.2552,046
217188.6.192.0/21188.6.192.1 to 188.6.199.254188.6.199.2552,046
218188.6.200.0/21188.6.200.1 to 188.6.207.254188.6.207.2552,046
219188.6.208.0/21188.6.208.1 to 188.6.215.254188.6.215.2552,046
220188.6.216.0/21188.6.216.1 to 188.6.223.254188.6.223.2552,046
221188.6.224.0/21188.6.224.1 to 188.6.231.254188.6.231.2552,046
222188.6.232.0/21188.6.232.1 to 188.6.239.254188.6.239.2552,046
223188.6.240.0/21188.6.240.1 to 188.6.247.254188.6.247.2552,046
224188.6.248.0/21188.6.248.1 to 188.6.255.254188.6.255.2552,046
225188.7.0.0/21188.7.0.1 to 188.7.7.254188.7.7.2552,046
226188.7.8.0/21188.7.8.1 to 188.7.15.254188.7.15.2552,046
227188.7.16.0/21188.7.16.1 to 188.7.23.254188.7.23.2552,046
228188.7.24.0/21188.7.24.1 to 188.7.31.254188.7.31.2552,046
229188.7.32.0/21188.7.32.1 to 188.7.39.254188.7.39.2552,046
230188.7.40.0/21188.7.40.1 to 188.7.47.254188.7.47.2552,046
231188.7.48.0/21188.7.48.1 to 188.7.55.254188.7.55.2552,046
232188.7.56.0/21188.7.56.1 to 188.7.63.254188.7.63.2552,046
233188.7.64.0/21188.7.64.1 to 188.7.71.254188.7.71.2552,046
234188.7.72.0/21188.7.72.1 to 188.7.79.254188.7.79.2552,046
235188.7.80.0/21188.7.80.1 to 188.7.87.254188.7.87.2552,046
236188.7.88.0/21188.7.88.1 to 188.7.95.254188.7.95.2552,046
237188.7.96.0/21188.7.96.1 to 188.7.103.254188.7.103.2552,046
238188.7.104.0/21188.7.104.1 to 188.7.111.254188.7.111.2552,046
239188.7.112.0/21188.7.112.1 to 188.7.119.254188.7.119.2552,046
240188.7.120.0/21188.7.120.1 to 188.7.127.254188.7.127.2552,046
241188.7.128.0/21188.7.128.1 to 188.7.135.254188.7.135.2552,046
242188.7.136.0/21188.7.136.1 to 188.7.143.254188.7.143.2552,046
243188.7.144.0/21188.7.144.1 to 188.7.151.254188.7.151.2552,046
244188.7.152.0/21188.7.152.1 to 188.7.159.254188.7.159.2552,046
245188.7.160.0/21188.7.160.1 to 188.7.167.254188.7.167.2552,046
246188.7.168.0/21188.7.168.1 to 188.7.175.254188.7.175.2552,046
247188.7.176.0/21188.7.176.1 to 188.7.183.254188.7.183.2552,046
248188.7.184.0/21188.7.184.1 to 188.7.191.254188.7.191.2552,046
249188.7.192.0/21188.7.192.1 to 188.7.199.254188.7.199.2552,046
250188.7.200.0/21188.7.200.1 to 188.7.207.254188.7.207.2552,046
251188.7.208.0/21188.7.208.1 to 188.7.215.254188.7.215.2552,046
252188.7.216.0/21188.7.216.1 to 188.7.223.254188.7.223.2552,046
253188.7.224.0/21188.7.224.1 to 188.7.231.254188.7.231.2552,046
254188.7.232.0/21188.7.232.1 to 188.7.239.254188.7.239.2552,046
255188.7.240.0/21188.7.240.1 to 188.7.247.254188.7.247.2552,046
256188.7.248.0/21188.7.248.1 to 188.7.255.254188.7.255.2552,046

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.