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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/18
/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 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.0.0.0/18188.0.0.1 to 188.0.63.254188.0.63.25516,382
2188.0.64.0/18188.0.64.1 to 188.0.127.254188.0.127.25516,382
3188.0.128.0/18188.0.128.1 to 188.0.191.254188.0.191.25516,382
4188.0.192.0/18188.0.192.1 to 188.0.255.254188.0.255.25516,382
5188.1.0.0/18188.1.0.1 to 188.1.63.254188.1.63.25516,382
6188.1.64.0/18188.1.64.1 to 188.1.127.254188.1.127.25516,382
7188.1.128.0/18188.1.128.1 to 188.1.191.254188.1.191.25516,382
8188.1.192.0/18188.1.192.1 to 188.1.255.254188.1.255.25516,382
9188.2.0.0/18188.2.0.1 to 188.2.63.254188.2.63.25516,382
10188.2.64.0/18188.2.64.1 to 188.2.127.254188.2.127.25516,382
11188.2.128.0/18188.2.128.1 to 188.2.191.254188.2.191.25516,382
12188.2.192.0/18188.2.192.1 to 188.2.255.254188.2.255.25516,382
13188.3.0.0/18188.3.0.1 to 188.3.63.254188.3.63.25516,382
14188.3.64.0/18188.3.64.1 to 188.3.127.254188.3.127.25516,382
15188.3.128.0/18188.3.128.1 to 188.3.191.254188.3.191.25516,382
16188.3.192.0/18188.3.192.1 to 188.3.255.254188.3.255.25516,382
17188.4.0.0/18188.4.0.1 to 188.4.63.254188.4.63.25516,382
18188.4.64.0/18188.4.64.1 to 188.4.127.254188.4.127.25516,382
19188.4.128.0/18188.4.128.1 to 188.4.191.254188.4.191.25516,382
20188.4.192.0/18188.4.192.1 to 188.4.255.254188.4.255.25516,382
21188.5.0.0/18188.5.0.1 to 188.5.63.254188.5.63.25516,382
22188.5.64.0/18188.5.64.1 to 188.5.127.254188.5.127.25516,382
23188.5.128.0/18188.5.128.1 to 188.5.191.254188.5.191.25516,382
24188.5.192.0/18188.5.192.1 to 188.5.255.254188.5.255.25516,382
25188.6.0.0/18188.6.0.1 to 188.6.63.254188.6.63.25516,382
26188.6.64.0/18188.6.64.1 to 188.6.127.254188.6.127.25516,382
27188.6.128.0/18188.6.128.1 to 188.6.191.254188.6.191.25516,382
28188.6.192.0/18188.6.192.1 to 188.6.255.254188.6.255.25516,382
29188.7.0.0/18188.7.0.1 to 188.7.63.254188.7.63.25516,382
30188.7.64.0/18188.7.64.1 to 188.7.127.254188.7.127.25516,382
31188.7.128.0/18188.7.128.1 to 188.7.191.254188.7.191.25516,382
32188.7.192.0/18188.7.192.1 to 188.7.255.254188.7.255.25516,382
33188.8.0.0/18188.8.0.1 to 188.8.63.254188.8.63.25516,382
34188.8.64.0/18188.8.64.1 to 188.8.127.254188.8.127.25516,382
35188.8.128.0/18188.8.128.1 to 188.8.191.254188.8.191.25516,382
36188.8.192.0/18188.8.192.1 to 188.8.255.254188.8.255.25516,382
37188.9.0.0/18188.9.0.1 to 188.9.63.254188.9.63.25516,382
38188.9.64.0/18188.9.64.1 to 188.9.127.254188.9.127.25516,382
39188.9.128.0/18188.9.128.1 to 188.9.191.254188.9.191.25516,382
40188.9.192.0/18188.9.192.1 to 188.9.255.254188.9.255.25516,382
41188.10.0.0/18188.10.0.1 to 188.10.63.254188.10.63.25516,382
42188.10.64.0/18188.10.64.1 to 188.10.127.254188.10.127.25516,382
43188.10.128.0/18188.10.128.1 to 188.10.191.254188.10.191.25516,382
44188.10.192.0/18188.10.192.1 to 188.10.255.254188.10.255.25516,382
45188.11.0.0/18188.11.0.1 to 188.11.63.254188.11.63.25516,382
46188.11.64.0/18188.11.64.1 to 188.11.127.254188.11.127.25516,382
47188.11.128.0/18188.11.128.1 to 188.11.191.254188.11.191.25516,382
48188.11.192.0/18188.11.192.1 to 188.11.255.254188.11.255.25516,382
49188.12.0.0/18188.12.0.1 to 188.12.63.254188.12.63.25516,382
50188.12.64.0/18188.12.64.1 to 188.12.127.254188.12.127.25516,382
51188.12.128.0/18188.12.128.1 to 188.12.191.254188.12.191.25516,382
52188.12.192.0/18188.12.192.1 to 188.12.255.254188.12.255.25516,382
53188.13.0.0/18188.13.0.1 to 188.13.63.254188.13.63.25516,382
54188.13.64.0/18188.13.64.1 to 188.13.127.254188.13.127.25516,382
55188.13.128.0/18188.13.128.1 to 188.13.191.254188.13.191.25516,382
56188.13.192.0/18188.13.192.1 to 188.13.255.254188.13.255.25516,382
57188.14.0.0/18188.14.0.1 to 188.14.63.254188.14.63.25516,382
58188.14.64.0/18188.14.64.1 to 188.14.127.254188.14.127.25516,382
59188.14.128.0/18188.14.128.1 to 188.14.191.254188.14.191.25516,382
60188.14.192.0/18188.14.192.1 to 188.14.255.254188.14.255.25516,382
61188.15.0.0/18188.15.0.1 to 188.15.63.254188.15.63.25516,382
62188.15.64.0/18188.15.64.1 to 188.15.127.254188.15.127.25516,382
63188.15.128.0/18188.15.128.1 to 188.15.191.254188.15.191.25516,382
64188.15.192.0/18188.15.192.1 to 188.15.255.254188.15.255.25516,382
65188.16.0.0/18188.16.0.1 to 188.16.63.254188.16.63.25516,382
66188.16.64.0/18188.16.64.1 to 188.16.127.254188.16.127.25516,382
67188.16.128.0/18188.16.128.1 to 188.16.191.254188.16.191.25516,382
68188.16.192.0/18188.16.192.1 to 188.16.255.254188.16.255.25516,382
69188.17.0.0/18188.17.0.1 to 188.17.63.254188.17.63.25516,382
70188.17.64.0/18188.17.64.1 to 188.17.127.254188.17.127.25516,382
71188.17.128.0/18188.17.128.1 to 188.17.191.254188.17.191.25516,382
72188.17.192.0/18188.17.192.1 to 188.17.255.254188.17.255.25516,382
73188.18.0.0/18188.18.0.1 to 188.18.63.254188.18.63.25516,382
74188.18.64.0/18188.18.64.1 to 188.18.127.254188.18.127.25516,382
75188.18.128.0/18188.18.128.1 to 188.18.191.254188.18.191.25516,382
76188.18.192.0/18188.18.192.1 to 188.18.255.254188.18.255.25516,382
77188.19.0.0/18188.19.0.1 to 188.19.63.254188.19.63.25516,382
78188.19.64.0/18188.19.64.1 to 188.19.127.254188.19.127.25516,382
79188.19.128.0/18188.19.128.1 to 188.19.191.254188.19.191.25516,382
80188.19.192.0/18188.19.192.1 to 188.19.255.254188.19.255.25516,382
81188.20.0.0/18188.20.0.1 to 188.20.63.254188.20.63.25516,382
82188.20.64.0/18188.20.64.1 to 188.20.127.254188.20.127.25516,382
83188.20.128.0/18188.20.128.1 to 188.20.191.254188.20.191.25516,382
84188.20.192.0/18188.20.192.1 to 188.20.255.254188.20.255.25516,382
85188.21.0.0/18188.21.0.1 to 188.21.63.254188.21.63.25516,382
86188.21.64.0/18188.21.64.1 to 188.21.127.254188.21.127.25516,382
87188.21.128.0/18188.21.128.1 to 188.21.191.254188.21.191.25516,382
88188.21.192.0/18188.21.192.1 to 188.21.255.254188.21.255.25516,382
89188.22.0.0/18188.22.0.1 to 188.22.63.254188.22.63.25516,382
90188.22.64.0/18188.22.64.1 to 188.22.127.254188.22.127.25516,382
91188.22.128.0/18188.22.128.1 to 188.22.191.254188.22.191.25516,382
92188.22.192.0/18188.22.192.1 to 188.22.255.254188.22.255.25516,382
93188.23.0.0/18188.23.0.1 to 188.23.63.254188.23.63.25516,382
94188.23.64.0/18188.23.64.1 to 188.23.127.254188.23.127.25516,382
95188.23.128.0/18188.23.128.1 to 188.23.191.254188.23.191.25516,382
96188.23.192.0/18188.23.192.1 to 188.23.255.254188.23.255.25516,382
97188.24.0.0/18188.24.0.1 to 188.24.63.254188.24.63.25516,382
98188.24.64.0/18188.24.64.1 to 188.24.127.254188.24.127.25516,382
99188.24.128.0/18188.24.128.1 to 188.24.191.254188.24.191.25516,382
100188.24.192.0/18188.24.192.1 to 188.24.255.254188.24.255.25516,382
101188.25.0.0/18188.25.0.1 to 188.25.63.254188.25.63.25516,382
102188.25.64.0/18188.25.64.1 to 188.25.127.254188.25.127.25516,382
103188.25.128.0/18188.25.128.1 to 188.25.191.254188.25.191.25516,382
104188.25.192.0/18188.25.192.1 to 188.25.255.254188.25.255.25516,382
105188.26.0.0/18188.26.0.1 to 188.26.63.254188.26.63.25516,382
106188.26.64.0/18188.26.64.1 to 188.26.127.254188.26.127.25516,382
107188.26.128.0/18188.26.128.1 to 188.26.191.254188.26.191.25516,382
108188.26.192.0/18188.26.192.1 to 188.26.255.254188.26.255.25516,382
109188.27.0.0/18188.27.0.1 to 188.27.63.254188.27.63.25516,382
110188.27.64.0/18188.27.64.1 to 188.27.127.254188.27.127.25516,382
111188.27.128.0/18188.27.128.1 to 188.27.191.254188.27.191.25516,382
112188.27.192.0/18188.27.192.1 to 188.27.255.254188.27.255.25516,382
113188.28.0.0/18188.28.0.1 to 188.28.63.254188.28.63.25516,382
114188.28.64.0/18188.28.64.1 to 188.28.127.254188.28.127.25516,382
115188.28.128.0/18188.28.128.1 to 188.28.191.254188.28.191.25516,382
116188.28.192.0/18188.28.192.1 to 188.28.255.254188.28.255.25516,382
117188.29.0.0/18188.29.0.1 to 188.29.63.254188.29.63.25516,382
118188.29.64.0/18188.29.64.1 to 188.29.127.254188.29.127.25516,382
119188.29.128.0/18188.29.128.1 to 188.29.191.254188.29.191.25516,382
120188.29.192.0/18188.29.192.1 to 188.29.255.254188.29.255.25516,382
121188.30.0.0/18188.30.0.1 to 188.30.63.254188.30.63.25516,382
122188.30.64.0/18188.30.64.1 to 188.30.127.254188.30.127.25516,382
123188.30.128.0/18188.30.128.1 to 188.30.191.254188.30.191.25516,382
124188.30.192.0/18188.30.192.1 to 188.30.255.254188.30.255.25516,382
125188.31.0.0/18188.31.0.1 to 188.31.63.254188.31.63.25516,382
126188.31.64.0/18188.31.64.1 to 188.31.127.254188.31.127.25516,382
127188.31.128.0/18188.31.128.1 to 188.31.191.254188.31.191.25516,382
128188.31.192.0/18188.31.192.1 to 188.31.255.254188.31.255.25516,382
129188.32.0.0/18188.32.0.1 to 188.32.63.254188.32.63.25516,382
130188.32.64.0/18188.32.64.1 to 188.32.127.254188.32.127.25516,382
131188.32.128.0/18188.32.128.1 to 188.32.191.254188.32.191.25516,382
132188.32.192.0/18188.32.192.1 to 188.32.255.254188.32.255.25516,382
133188.33.0.0/18188.33.0.1 to 188.33.63.254188.33.63.25516,382
134188.33.64.0/18188.33.64.1 to 188.33.127.254188.33.127.25516,382
135188.33.128.0/18188.33.128.1 to 188.33.191.254188.33.191.25516,382
136188.33.192.0/18188.33.192.1 to 188.33.255.254188.33.255.25516,382
137188.34.0.0/18188.34.0.1 to 188.34.63.254188.34.63.25516,382
138188.34.64.0/18188.34.64.1 to 188.34.127.254188.34.127.25516,382
139188.34.128.0/18188.34.128.1 to 188.34.191.254188.34.191.25516,382
140188.34.192.0/18188.34.192.1 to 188.34.255.254188.34.255.25516,382
141188.35.0.0/18188.35.0.1 to 188.35.63.254188.35.63.25516,382
142188.35.64.0/18188.35.64.1 to 188.35.127.254188.35.127.25516,382
143188.35.128.0/18188.35.128.1 to 188.35.191.254188.35.191.25516,382
144188.35.192.0/18188.35.192.1 to 188.35.255.254188.35.255.25516,382
145188.36.0.0/18188.36.0.1 to 188.36.63.254188.36.63.25516,382
146188.36.64.0/18188.36.64.1 to 188.36.127.254188.36.127.25516,382
147188.36.128.0/18188.36.128.1 to 188.36.191.254188.36.191.25516,382
148188.36.192.0/18188.36.192.1 to 188.36.255.254188.36.255.25516,382
149188.37.0.0/18188.37.0.1 to 188.37.63.254188.37.63.25516,382
150188.37.64.0/18188.37.64.1 to 188.37.127.254188.37.127.25516,382
151188.37.128.0/18188.37.128.1 to 188.37.191.254188.37.191.25516,382
152188.37.192.0/18188.37.192.1 to 188.37.255.254188.37.255.25516,382
153188.38.0.0/18188.38.0.1 to 188.38.63.254188.38.63.25516,382
154188.38.64.0/18188.38.64.1 to 188.38.127.254188.38.127.25516,382
155188.38.128.0/18188.38.128.1 to 188.38.191.254188.38.191.25516,382
156188.38.192.0/18188.38.192.1 to 188.38.255.254188.38.255.25516,382
157188.39.0.0/18188.39.0.1 to 188.39.63.254188.39.63.25516,382
158188.39.64.0/18188.39.64.1 to 188.39.127.254188.39.127.25516,382
159188.39.128.0/18188.39.128.1 to 188.39.191.254188.39.191.25516,382
160188.39.192.0/18188.39.192.1 to 188.39.255.254188.39.255.25516,382
161188.40.0.0/18188.40.0.1 to 188.40.63.254188.40.63.25516,382
162188.40.64.0/18188.40.64.1 to 188.40.127.254188.40.127.25516,382
163188.40.128.0/18188.40.128.1 to 188.40.191.254188.40.191.25516,382
164188.40.192.0/18188.40.192.1 to 188.40.255.254188.40.255.25516,382
165188.41.0.0/18188.41.0.1 to 188.41.63.254188.41.63.25516,382
166188.41.64.0/18188.41.64.1 to 188.41.127.254188.41.127.25516,382
167188.41.128.0/18188.41.128.1 to 188.41.191.254188.41.191.25516,382
168188.41.192.0/18188.41.192.1 to 188.41.255.254188.41.255.25516,382
169188.42.0.0/18188.42.0.1 to 188.42.63.254188.42.63.25516,382
170188.42.64.0/18188.42.64.1 to 188.42.127.254188.42.127.25516,382
171188.42.128.0/18188.42.128.1 to 188.42.191.254188.42.191.25516,382
172188.42.192.0/18188.42.192.1 to 188.42.255.254188.42.255.25516,382
173188.43.0.0/18188.43.0.1 to 188.43.63.254188.43.63.25516,382
174188.43.64.0/18188.43.64.1 to 188.43.127.254188.43.127.25516,382
175188.43.128.0/18188.43.128.1 to 188.43.191.254188.43.191.25516,382
176188.43.192.0/18188.43.192.1 to 188.43.255.254188.43.255.25516,382
177188.44.0.0/18188.44.0.1 to 188.44.63.254188.44.63.25516,382
178188.44.64.0/18188.44.64.1 to 188.44.127.254188.44.127.25516,382
179188.44.128.0/18188.44.128.1 to 188.44.191.254188.44.191.25516,382
180188.44.192.0/18188.44.192.1 to 188.44.255.254188.44.255.25516,382
181188.45.0.0/18188.45.0.1 to 188.45.63.254188.45.63.25516,382
182188.45.64.0/18188.45.64.1 to 188.45.127.254188.45.127.25516,382
183188.45.128.0/18188.45.128.1 to 188.45.191.254188.45.191.25516,382
184188.45.192.0/18188.45.192.1 to 188.45.255.254188.45.255.25516,382
185188.46.0.0/18188.46.0.1 to 188.46.63.254188.46.63.25516,382
186188.46.64.0/18188.46.64.1 to 188.46.127.254188.46.127.25516,382
187188.46.128.0/18188.46.128.1 to 188.46.191.254188.46.191.25516,382
188188.46.192.0/18188.46.192.1 to 188.46.255.254188.46.255.25516,382
189188.47.0.0/18188.47.0.1 to 188.47.63.254188.47.63.25516,382
190188.47.64.0/18188.47.64.1 to 188.47.127.254188.47.127.25516,382
191188.47.128.0/18188.47.128.1 to 188.47.191.254188.47.191.25516,382
192188.47.192.0/18188.47.192.1 to 188.47.255.254188.47.255.25516,382
193188.48.0.0/18188.48.0.1 to 188.48.63.254188.48.63.25516,382
194188.48.64.0/18188.48.64.1 to 188.48.127.254188.48.127.25516,382
195188.48.128.0/18188.48.128.1 to 188.48.191.254188.48.191.25516,382
196188.48.192.0/18188.48.192.1 to 188.48.255.254188.48.255.25516,382
197188.49.0.0/18188.49.0.1 to 188.49.63.254188.49.63.25516,382
198188.49.64.0/18188.49.64.1 to 188.49.127.254188.49.127.25516,382
199188.49.128.0/18188.49.128.1 to 188.49.191.254188.49.191.25516,382
200188.49.192.0/18188.49.192.1 to 188.49.255.254188.49.255.25516,382
201188.50.0.0/18188.50.0.1 to 188.50.63.254188.50.63.25516,382
202188.50.64.0/18188.50.64.1 to 188.50.127.254188.50.127.25516,382
203188.50.128.0/18188.50.128.1 to 188.50.191.254188.50.191.25516,382
204188.50.192.0/18188.50.192.1 to 188.50.255.254188.50.255.25516,382
205188.51.0.0/18188.51.0.1 to 188.51.63.254188.51.63.25516,382
206188.51.64.0/18188.51.64.1 to 188.51.127.254188.51.127.25516,382
207188.51.128.0/18188.51.128.1 to 188.51.191.254188.51.191.25516,382
208188.51.192.0/18188.51.192.1 to 188.51.255.254188.51.255.25516,382
209188.52.0.0/18188.52.0.1 to 188.52.63.254188.52.63.25516,382
210188.52.64.0/18188.52.64.1 to 188.52.127.254188.52.127.25516,382
211188.52.128.0/18188.52.128.1 to 188.52.191.254188.52.191.25516,382
212188.52.192.0/18188.52.192.1 to 188.52.255.254188.52.255.25516,382
213188.53.0.0/18188.53.0.1 to 188.53.63.254188.53.63.25516,382
214188.53.64.0/18188.53.64.1 to 188.53.127.254188.53.127.25516,382
215188.53.128.0/18188.53.128.1 to 188.53.191.254188.53.191.25516,382
216188.53.192.0/18188.53.192.1 to 188.53.255.254188.53.255.25516,382
217188.54.0.0/18188.54.0.1 to 188.54.63.254188.54.63.25516,382
218188.54.64.0/18188.54.64.1 to 188.54.127.254188.54.127.25516,382
219188.54.128.0/18188.54.128.1 to 188.54.191.254188.54.191.25516,382
220188.54.192.0/18188.54.192.1 to 188.54.255.254188.54.255.25516,382
221188.55.0.0/18188.55.0.1 to 188.55.63.254188.55.63.25516,382
222188.55.64.0/18188.55.64.1 to 188.55.127.254188.55.127.25516,382
223188.55.128.0/18188.55.128.1 to 188.55.191.254188.55.191.25516,382
224188.55.192.0/18188.55.192.1 to 188.55.255.254188.55.255.25516,382
225188.56.0.0/18188.56.0.1 to 188.56.63.254188.56.63.25516,382
226188.56.64.0/18188.56.64.1 to 188.56.127.254188.56.127.25516,382
227188.56.128.0/18188.56.128.1 to 188.56.191.254188.56.191.25516,382
228188.56.192.0/18188.56.192.1 to 188.56.255.254188.56.255.25516,382
229188.57.0.0/18188.57.0.1 to 188.57.63.254188.57.63.25516,382
230188.57.64.0/18188.57.64.1 to 188.57.127.254188.57.127.25516,382
231188.57.128.0/18188.57.128.1 to 188.57.191.254188.57.191.25516,382
232188.57.192.0/18188.57.192.1 to 188.57.255.254188.57.255.25516,382
233188.58.0.0/18188.58.0.1 to 188.58.63.254188.58.63.25516,382
234188.58.64.0/18188.58.64.1 to 188.58.127.254188.58.127.25516,382
235188.58.128.0/18188.58.128.1 to 188.58.191.254188.58.191.25516,382
236188.58.192.0/18188.58.192.1 to 188.58.255.254188.58.255.25516,382
237188.59.0.0/18188.59.0.1 to 188.59.63.254188.59.63.25516,382
238188.59.64.0/18188.59.64.1 to 188.59.127.254188.59.127.25516,382
239188.59.128.0/18188.59.128.1 to 188.59.191.254188.59.191.25516,382
240188.59.192.0/18188.59.192.1 to 188.59.255.254188.59.255.25516,382
241188.60.0.0/18188.60.0.1 to 188.60.63.254188.60.63.25516,382
242188.60.64.0/18188.60.64.1 to 188.60.127.254188.60.127.25516,382
243188.60.128.0/18188.60.128.1 to 188.60.191.254188.60.191.25516,382
244188.60.192.0/18188.60.192.1 to 188.60.255.254188.60.255.25516,382
245188.61.0.0/18188.61.0.1 to 188.61.63.254188.61.63.25516,382
246188.61.64.0/18188.61.64.1 to 188.61.127.254188.61.127.25516,382
247188.61.128.0/18188.61.128.1 to 188.61.191.254188.61.191.25516,382
248188.61.192.0/18188.61.192.1 to 188.61.255.254188.61.255.25516,382
249188.62.0.0/18188.62.0.1 to 188.62.63.254188.62.63.25516,382
250188.62.64.0/18188.62.64.1 to 188.62.127.254188.62.127.25516,382
251188.62.128.0/18188.62.128.1 to 188.62.191.254188.62.191.25516,382
252188.62.192.0/18188.62.192.1 to 188.62.255.254188.62.255.25516,382
253188.63.0.0/18188.63.0.1 to 188.63.63.254188.63.63.25516,382
254188.63.64.0/18188.63.64.1 to 188.63.127.254188.63.127.25516,382
255188.63.128.0/18188.63.128.1 to 188.63.191.254188.63.191.25516,382
256188.63.192.0/18188.63.192.1 to 188.63.255.254188.63.255.25516,382

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.