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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.

Network188.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
188.0.0.0
Broadcast address
189.255.255.255
First usable
188.0.0.1
Last usable
189.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex BC000000 · Integer 3154116608 to 3187671039
Reverse DNS zones
188.in-addr.arpa
189.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111100.00000000.00000000.00000000188.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10111100.00000000.00000000.00000000188.0.0.0
Broadcast10111101.11111111.11111111.11111111189.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

188.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.0.0.0/19188.0.0.1 to 188.0.31.254188.0.31.2558,190
2188.0.32.0/19188.0.32.1 to 188.0.63.254188.0.63.2558,190
3188.0.64.0/19188.0.64.1 to 188.0.95.254188.0.95.2558,190
4188.0.96.0/19188.0.96.1 to 188.0.127.254188.0.127.2558,190
5188.0.128.0/19188.0.128.1 to 188.0.159.254188.0.159.2558,190
6188.0.160.0/19188.0.160.1 to 188.0.191.254188.0.191.2558,190
7188.0.192.0/19188.0.192.1 to 188.0.223.254188.0.223.2558,190
8188.0.224.0/19188.0.224.1 to 188.0.255.254188.0.255.2558,190
9188.1.0.0/19188.1.0.1 to 188.1.31.254188.1.31.2558,190
10188.1.32.0/19188.1.32.1 to 188.1.63.254188.1.63.2558,190
11188.1.64.0/19188.1.64.1 to 188.1.95.254188.1.95.2558,190
12188.1.96.0/19188.1.96.1 to 188.1.127.254188.1.127.2558,190
13188.1.128.0/19188.1.128.1 to 188.1.159.254188.1.159.2558,190
14188.1.160.0/19188.1.160.1 to 188.1.191.254188.1.191.2558,190
15188.1.192.0/19188.1.192.1 to 188.1.223.254188.1.223.2558,190
16188.1.224.0/19188.1.224.1 to 188.1.255.254188.1.255.2558,190
17188.2.0.0/19188.2.0.1 to 188.2.31.254188.2.31.2558,190
18188.2.32.0/19188.2.32.1 to 188.2.63.254188.2.63.2558,190
19188.2.64.0/19188.2.64.1 to 188.2.95.254188.2.95.2558,190
20188.2.96.0/19188.2.96.1 to 188.2.127.254188.2.127.2558,190
21188.2.128.0/19188.2.128.1 to 188.2.159.254188.2.159.2558,190
22188.2.160.0/19188.2.160.1 to 188.2.191.254188.2.191.2558,190
23188.2.192.0/19188.2.192.1 to 188.2.223.254188.2.223.2558,190
24188.2.224.0/19188.2.224.1 to 188.2.255.254188.2.255.2558,190
25188.3.0.0/19188.3.0.1 to 188.3.31.254188.3.31.2558,190
26188.3.32.0/19188.3.32.1 to 188.3.63.254188.3.63.2558,190
27188.3.64.0/19188.3.64.1 to 188.3.95.254188.3.95.2558,190
28188.3.96.0/19188.3.96.1 to 188.3.127.254188.3.127.2558,190
29188.3.128.0/19188.3.128.1 to 188.3.159.254188.3.159.2558,190
30188.3.160.0/19188.3.160.1 to 188.3.191.254188.3.191.2558,190
31188.3.192.0/19188.3.192.1 to 188.3.223.254188.3.223.2558,190
32188.3.224.0/19188.3.224.1 to 188.3.255.254188.3.255.2558,190
33188.4.0.0/19188.4.0.1 to 188.4.31.254188.4.31.2558,190
34188.4.32.0/19188.4.32.1 to 188.4.63.254188.4.63.2558,190
35188.4.64.0/19188.4.64.1 to 188.4.95.254188.4.95.2558,190
36188.4.96.0/19188.4.96.1 to 188.4.127.254188.4.127.2558,190
37188.4.128.0/19188.4.128.1 to 188.4.159.254188.4.159.2558,190
38188.4.160.0/19188.4.160.1 to 188.4.191.254188.4.191.2558,190
39188.4.192.0/19188.4.192.1 to 188.4.223.254188.4.223.2558,190
40188.4.224.0/19188.4.224.1 to 188.4.255.254188.4.255.2558,190
41188.5.0.0/19188.5.0.1 to 188.5.31.254188.5.31.2558,190
42188.5.32.0/19188.5.32.1 to 188.5.63.254188.5.63.2558,190
43188.5.64.0/19188.5.64.1 to 188.5.95.254188.5.95.2558,190
44188.5.96.0/19188.5.96.1 to 188.5.127.254188.5.127.2558,190
45188.5.128.0/19188.5.128.1 to 188.5.159.254188.5.159.2558,190
46188.5.160.0/19188.5.160.1 to 188.5.191.254188.5.191.2558,190
47188.5.192.0/19188.5.192.1 to 188.5.223.254188.5.223.2558,190
48188.5.224.0/19188.5.224.1 to 188.5.255.254188.5.255.2558,190
49188.6.0.0/19188.6.0.1 to 188.6.31.254188.6.31.2558,190
50188.6.32.0/19188.6.32.1 to 188.6.63.254188.6.63.2558,190
51188.6.64.0/19188.6.64.1 to 188.6.95.254188.6.95.2558,190
52188.6.96.0/19188.6.96.1 to 188.6.127.254188.6.127.2558,190
53188.6.128.0/19188.6.128.1 to 188.6.159.254188.6.159.2558,190
54188.6.160.0/19188.6.160.1 to 188.6.191.254188.6.191.2558,190
55188.6.192.0/19188.6.192.1 to 188.6.223.254188.6.223.2558,190
56188.6.224.0/19188.6.224.1 to 188.6.255.254188.6.255.2558,190
57188.7.0.0/19188.7.0.1 to 188.7.31.254188.7.31.2558,190
58188.7.32.0/19188.7.32.1 to 188.7.63.254188.7.63.2558,190
59188.7.64.0/19188.7.64.1 to 188.7.95.254188.7.95.2558,190
60188.7.96.0/19188.7.96.1 to 188.7.127.254188.7.127.2558,190
61188.7.128.0/19188.7.128.1 to 188.7.159.254188.7.159.2558,190
62188.7.160.0/19188.7.160.1 to 188.7.191.254188.7.191.2558,190
63188.7.192.0/19188.7.192.1 to 188.7.223.254188.7.223.2558,190
64188.7.224.0/19188.7.224.1 to 188.7.255.254188.7.255.2558,190
65188.8.0.0/19188.8.0.1 to 188.8.31.254188.8.31.2558,190
66188.8.32.0/19188.8.32.1 to 188.8.63.254188.8.63.2558,190
67188.8.64.0/19188.8.64.1 to 188.8.95.254188.8.95.2558,190
68188.8.96.0/19188.8.96.1 to 188.8.127.254188.8.127.2558,190
69188.8.128.0/19188.8.128.1 to 188.8.159.254188.8.159.2558,190
70188.8.160.0/19188.8.160.1 to 188.8.191.254188.8.191.2558,190
71188.8.192.0/19188.8.192.1 to 188.8.223.254188.8.223.2558,190
72188.8.224.0/19188.8.224.1 to 188.8.255.254188.8.255.2558,190
73188.9.0.0/19188.9.0.1 to 188.9.31.254188.9.31.2558,190
74188.9.32.0/19188.9.32.1 to 188.9.63.254188.9.63.2558,190
75188.9.64.0/19188.9.64.1 to 188.9.95.254188.9.95.2558,190
76188.9.96.0/19188.9.96.1 to 188.9.127.254188.9.127.2558,190
77188.9.128.0/19188.9.128.1 to 188.9.159.254188.9.159.2558,190
78188.9.160.0/19188.9.160.1 to 188.9.191.254188.9.191.2558,190
79188.9.192.0/19188.9.192.1 to 188.9.223.254188.9.223.2558,190
80188.9.224.0/19188.9.224.1 to 188.9.255.254188.9.255.2558,190
81188.10.0.0/19188.10.0.1 to 188.10.31.254188.10.31.2558,190
82188.10.32.0/19188.10.32.1 to 188.10.63.254188.10.63.2558,190
83188.10.64.0/19188.10.64.1 to 188.10.95.254188.10.95.2558,190
84188.10.96.0/19188.10.96.1 to 188.10.127.254188.10.127.2558,190
85188.10.128.0/19188.10.128.1 to 188.10.159.254188.10.159.2558,190
86188.10.160.0/19188.10.160.1 to 188.10.191.254188.10.191.2558,190
87188.10.192.0/19188.10.192.1 to 188.10.223.254188.10.223.2558,190
88188.10.224.0/19188.10.224.1 to 188.10.255.254188.10.255.2558,190
89188.11.0.0/19188.11.0.1 to 188.11.31.254188.11.31.2558,190
90188.11.32.0/19188.11.32.1 to 188.11.63.254188.11.63.2558,190
91188.11.64.0/19188.11.64.1 to 188.11.95.254188.11.95.2558,190
92188.11.96.0/19188.11.96.1 to 188.11.127.254188.11.127.2558,190
93188.11.128.0/19188.11.128.1 to 188.11.159.254188.11.159.2558,190
94188.11.160.0/19188.11.160.1 to 188.11.191.254188.11.191.2558,190
95188.11.192.0/19188.11.192.1 to 188.11.223.254188.11.223.2558,190
96188.11.224.0/19188.11.224.1 to 188.11.255.254188.11.255.2558,190
97188.12.0.0/19188.12.0.1 to 188.12.31.254188.12.31.2558,190
98188.12.32.0/19188.12.32.1 to 188.12.63.254188.12.63.2558,190
99188.12.64.0/19188.12.64.1 to 188.12.95.254188.12.95.2558,190
100188.12.96.0/19188.12.96.1 to 188.12.127.254188.12.127.2558,190
101188.12.128.0/19188.12.128.1 to 188.12.159.254188.12.159.2558,190
102188.12.160.0/19188.12.160.1 to 188.12.191.254188.12.191.2558,190
103188.12.192.0/19188.12.192.1 to 188.12.223.254188.12.223.2558,190
104188.12.224.0/19188.12.224.1 to 188.12.255.254188.12.255.2558,190
105188.13.0.0/19188.13.0.1 to 188.13.31.254188.13.31.2558,190
106188.13.32.0/19188.13.32.1 to 188.13.63.254188.13.63.2558,190
107188.13.64.0/19188.13.64.1 to 188.13.95.254188.13.95.2558,190
108188.13.96.0/19188.13.96.1 to 188.13.127.254188.13.127.2558,190
109188.13.128.0/19188.13.128.1 to 188.13.159.254188.13.159.2558,190
110188.13.160.0/19188.13.160.1 to 188.13.191.254188.13.191.2558,190
111188.13.192.0/19188.13.192.1 to 188.13.223.254188.13.223.2558,190
112188.13.224.0/19188.13.224.1 to 188.13.255.254188.13.255.2558,190
113188.14.0.0/19188.14.0.1 to 188.14.31.254188.14.31.2558,190
114188.14.32.0/19188.14.32.1 to 188.14.63.254188.14.63.2558,190
115188.14.64.0/19188.14.64.1 to 188.14.95.254188.14.95.2558,190
116188.14.96.0/19188.14.96.1 to 188.14.127.254188.14.127.2558,190
117188.14.128.0/19188.14.128.1 to 188.14.159.254188.14.159.2558,190
118188.14.160.0/19188.14.160.1 to 188.14.191.254188.14.191.2558,190
119188.14.192.0/19188.14.192.1 to 188.14.223.254188.14.223.2558,190
120188.14.224.0/19188.14.224.1 to 188.14.255.254188.14.255.2558,190
121188.15.0.0/19188.15.0.1 to 188.15.31.254188.15.31.2558,190
122188.15.32.0/19188.15.32.1 to 188.15.63.254188.15.63.2558,190
123188.15.64.0/19188.15.64.1 to 188.15.95.254188.15.95.2558,190
124188.15.96.0/19188.15.96.1 to 188.15.127.254188.15.127.2558,190
125188.15.128.0/19188.15.128.1 to 188.15.159.254188.15.159.2558,190
126188.15.160.0/19188.15.160.1 to 188.15.191.254188.15.191.2558,190
127188.15.192.0/19188.15.192.1 to 188.15.223.254188.15.223.2558,190
128188.15.224.0/19188.15.224.1 to 188.15.255.254188.15.255.2558,190
129188.16.0.0/19188.16.0.1 to 188.16.31.254188.16.31.2558,190
130188.16.32.0/19188.16.32.1 to 188.16.63.254188.16.63.2558,190
131188.16.64.0/19188.16.64.1 to 188.16.95.254188.16.95.2558,190
132188.16.96.0/19188.16.96.1 to 188.16.127.254188.16.127.2558,190
133188.16.128.0/19188.16.128.1 to 188.16.159.254188.16.159.2558,190
134188.16.160.0/19188.16.160.1 to 188.16.191.254188.16.191.2558,190
135188.16.192.0/19188.16.192.1 to 188.16.223.254188.16.223.2558,190
136188.16.224.0/19188.16.224.1 to 188.16.255.254188.16.255.2558,190
137188.17.0.0/19188.17.0.1 to 188.17.31.254188.17.31.2558,190
138188.17.32.0/19188.17.32.1 to 188.17.63.254188.17.63.2558,190
139188.17.64.0/19188.17.64.1 to 188.17.95.254188.17.95.2558,190
140188.17.96.0/19188.17.96.1 to 188.17.127.254188.17.127.2558,190
141188.17.128.0/19188.17.128.1 to 188.17.159.254188.17.159.2558,190
142188.17.160.0/19188.17.160.1 to 188.17.191.254188.17.191.2558,190
143188.17.192.0/19188.17.192.1 to 188.17.223.254188.17.223.2558,190
144188.17.224.0/19188.17.224.1 to 188.17.255.254188.17.255.2558,190
145188.18.0.0/19188.18.0.1 to 188.18.31.254188.18.31.2558,190
146188.18.32.0/19188.18.32.1 to 188.18.63.254188.18.63.2558,190
147188.18.64.0/19188.18.64.1 to 188.18.95.254188.18.95.2558,190
148188.18.96.0/19188.18.96.1 to 188.18.127.254188.18.127.2558,190
149188.18.128.0/19188.18.128.1 to 188.18.159.254188.18.159.2558,190
150188.18.160.0/19188.18.160.1 to 188.18.191.254188.18.191.2558,190
151188.18.192.0/19188.18.192.1 to 188.18.223.254188.18.223.2558,190
152188.18.224.0/19188.18.224.1 to 188.18.255.254188.18.255.2558,190
153188.19.0.0/19188.19.0.1 to 188.19.31.254188.19.31.2558,190
154188.19.32.0/19188.19.32.1 to 188.19.63.254188.19.63.2558,190
155188.19.64.0/19188.19.64.1 to 188.19.95.254188.19.95.2558,190
156188.19.96.0/19188.19.96.1 to 188.19.127.254188.19.127.2558,190
157188.19.128.0/19188.19.128.1 to 188.19.159.254188.19.159.2558,190
158188.19.160.0/19188.19.160.1 to 188.19.191.254188.19.191.2558,190
159188.19.192.0/19188.19.192.1 to 188.19.223.254188.19.223.2558,190
160188.19.224.0/19188.19.224.1 to 188.19.255.254188.19.255.2558,190
161188.20.0.0/19188.20.0.1 to 188.20.31.254188.20.31.2558,190
162188.20.32.0/19188.20.32.1 to 188.20.63.254188.20.63.2558,190
163188.20.64.0/19188.20.64.1 to 188.20.95.254188.20.95.2558,190
164188.20.96.0/19188.20.96.1 to 188.20.127.254188.20.127.2558,190
165188.20.128.0/19188.20.128.1 to 188.20.159.254188.20.159.2558,190
166188.20.160.0/19188.20.160.1 to 188.20.191.254188.20.191.2558,190
167188.20.192.0/19188.20.192.1 to 188.20.223.254188.20.223.2558,190
168188.20.224.0/19188.20.224.1 to 188.20.255.254188.20.255.2558,190
169188.21.0.0/19188.21.0.1 to 188.21.31.254188.21.31.2558,190
170188.21.32.0/19188.21.32.1 to 188.21.63.254188.21.63.2558,190
171188.21.64.0/19188.21.64.1 to 188.21.95.254188.21.95.2558,190
172188.21.96.0/19188.21.96.1 to 188.21.127.254188.21.127.2558,190
173188.21.128.0/19188.21.128.1 to 188.21.159.254188.21.159.2558,190
174188.21.160.0/19188.21.160.1 to 188.21.191.254188.21.191.2558,190
175188.21.192.0/19188.21.192.1 to 188.21.223.254188.21.223.2558,190
176188.21.224.0/19188.21.224.1 to 188.21.255.254188.21.255.2558,190
177188.22.0.0/19188.22.0.1 to 188.22.31.254188.22.31.2558,190
178188.22.32.0/19188.22.32.1 to 188.22.63.254188.22.63.2558,190
179188.22.64.0/19188.22.64.1 to 188.22.95.254188.22.95.2558,190
180188.22.96.0/19188.22.96.1 to 188.22.127.254188.22.127.2558,190
181188.22.128.0/19188.22.128.1 to 188.22.159.254188.22.159.2558,190
182188.22.160.0/19188.22.160.1 to 188.22.191.254188.22.191.2558,190
183188.22.192.0/19188.22.192.1 to 188.22.223.254188.22.223.2558,190
184188.22.224.0/19188.22.224.1 to 188.22.255.254188.22.255.2558,190
185188.23.0.0/19188.23.0.1 to 188.23.31.254188.23.31.2558,190
186188.23.32.0/19188.23.32.1 to 188.23.63.254188.23.63.2558,190
187188.23.64.0/19188.23.64.1 to 188.23.95.254188.23.95.2558,190
188188.23.96.0/19188.23.96.1 to 188.23.127.254188.23.127.2558,190
189188.23.128.0/19188.23.128.1 to 188.23.159.254188.23.159.2558,190
190188.23.160.0/19188.23.160.1 to 188.23.191.254188.23.191.2558,190
191188.23.192.0/19188.23.192.1 to 188.23.223.254188.23.223.2558,190
192188.23.224.0/19188.23.224.1 to 188.23.255.254188.23.255.2558,190
193188.24.0.0/19188.24.0.1 to 188.24.31.254188.24.31.2558,190
194188.24.32.0/19188.24.32.1 to 188.24.63.254188.24.63.2558,190
195188.24.64.0/19188.24.64.1 to 188.24.95.254188.24.95.2558,190
196188.24.96.0/19188.24.96.1 to 188.24.127.254188.24.127.2558,190
197188.24.128.0/19188.24.128.1 to 188.24.159.254188.24.159.2558,190
198188.24.160.0/19188.24.160.1 to 188.24.191.254188.24.191.2558,190
199188.24.192.0/19188.24.192.1 to 188.24.223.254188.24.223.2558,190
200188.24.224.0/19188.24.224.1 to 188.24.255.254188.24.255.2558,190
201188.25.0.0/19188.25.0.1 to 188.25.31.254188.25.31.2558,190
202188.25.32.0/19188.25.32.1 to 188.25.63.254188.25.63.2558,190
203188.25.64.0/19188.25.64.1 to 188.25.95.254188.25.95.2558,190
204188.25.96.0/19188.25.96.1 to 188.25.127.254188.25.127.2558,190
205188.25.128.0/19188.25.128.1 to 188.25.159.254188.25.159.2558,190
206188.25.160.0/19188.25.160.1 to 188.25.191.254188.25.191.2558,190
207188.25.192.0/19188.25.192.1 to 188.25.223.254188.25.223.2558,190
208188.25.224.0/19188.25.224.1 to 188.25.255.254188.25.255.2558,190
209188.26.0.0/19188.26.0.1 to 188.26.31.254188.26.31.2558,190
210188.26.32.0/19188.26.32.1 to 188.26.63.254188.26.63.2558,190
211188.26.64.0/19188.26.64.1 to 188.26.95.254188.26.95.2558,190
212188.26.96.0/19188.26.96.1 to 188.26.127.254188.26.127.2558,190
213188.26.128.0/19188.26.128.1 to 188.26.159.254188.26.159.2558,190
214188.26.160.0/19188.26.160.1 to 188.26.191.254188.26.191.2558,190
215188.26.192.0/19188.26.192.1 to 188.26.223.254188.26.223.2558,190
216188.26.224.0/19188.26.224.1 to 188.26.255.254188.26.255.2558,190
217188.27.0.0/19188.27.0.1 to 188.27.31.254188.27.31.2558,190
218188.27.32.0/19188.27.32.1 to 188.27.63.254188.27.63.2558,190
219188.27.64.0/19188.27.64.1 to 188.27.95.254188.27.95.2558,190
220188.27.96.0/19188.27.96.1 to 188.27.127.254188.27.127.2558,190
221188.27.128.0/19188.27.128.1 to 188.27.159.254188.27.159.2558,190
222188.27.160.0/19188.27.160.1 to 188.27.191.254188.27.191.2558,190
223188.27.192.0/19188.27.192.1 to 188.27.223.254188.27.223.2558,190
224188.27.224.0/19188.27.224.1 to 188.27.255.254188.27.255.2558,190
225188.28.0.0/19188.28.0.1 to 188.28.31.254188.28.31.2558,190
226188.28.32.0/19188.28.32.1 to 188.28.63.254188.28.63.2558,190
227188.28.64.0/19188.28.64.1 to 188.28.95.254188.28.95.2558,190
228188.28.96.0/19188.28.96.1 to 188.28.127.254188.28.127.2558,190
229188.28.128.0/19188.28.128.1 to 188.28.159.254188.28.159.2558,190
230188.28.160.0/19188.28.160.1 to 188.28.191.254188.28.191.2558,190
231188.28.192.0/19188.28.192.1 to 188.28.223.254188.28.223.2558,190
232188.28.224.0/19188.28.224.1 to 188.28.255.254188.28.255.2558,190
233188.29.0.0/19188.29.0.1 to 188.29.31.254188.29.31.2558,190
234188.29.32.0/19188.29.32.1 to 188.29.63.254188.29.63.2558,190
235188.29.64.0/19188.29.64.1 to 188.29.95.254188.29.95.2558,190
236188.29.96.0/19188.29.96.1 to 188.29.127.254188.29.127.2558,190
237188.29.128.0/19188.29.128.1 to 188.29.159.254188.29.159.2558,190
238188.29.160.0/19188.29.160.1 to 188.29.191.254188.29.191.2558,190
239188.29.192.0/19188.29.192.1 to 188.29.223.254188.29.223.2558,190
240188.29.224.0/19188.29.224.1 to 188.29.255.254188.29.255.2558,190
241188.30.0.0/19188.30.0.1 to 188.30.31.254188.30.31.2558,190
242188.30.32.0/19188.30.32.1 to 188.30.63.254188.30.63.2558,190
243188.30.64.0/19188.30.64.1 to 188.30.95.254188.30.95.2558,190
244188.30.96.0/19188.30.96.1 to 188.30.127.254188.30.127.2558,190
245188.30.128.0/19188.30.128.1 to 188.30.159.254188.30.159.2558,190
246188.30.160.0/19188.30.160.1 to 188.30.191.254188.30.191.2558,190
247188.30.192.0/19188.30.192.1 to 188.30.223.254188.30.223.2558,190
248188.30.224.0/19188.30.224.1 to 188.30.255.254188.30.255.2558,190
249188.31.0.0/19188.31.0.1 to 188.31.31.254188.31.31.2558,190
250188.31.32.0/19188.31.32.1 to 188.31.63.254188.31.63.2558,190
251188.31.64.0/19188.31.64.1 to 188.31.95.254188.31.95.2558,190
252188.31.96.0/19188.31.96.1 to 188.31.127.254188.31.127.2558,190
253188.31.128.0/19188.31.128.1 to 188.31.159.254188.31.159.2558,190
254188.31.160.0/19188.31.160.1 to 188.31.191.254188.31.191.2558,190
255188.31.192.0/19188.31.192.1 to 188.31.223.254188.31.223.2558,190
256188.31.224.0/19188.31.224.1 to 188.31.255.254188.31.255.2558,190

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.