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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.

Network188.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
188.0.0.0
Broadcast address
188.255.255.255
First usable
188.0.0.1
Last usable
188.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex BC000000 · Integer 3154116608 to 3170893823
Reverse DNS zone
188.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111100..00000000.00000000.00000000188.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10111100..00000000.00000000.00000000188.0.0.0
Broadcast10111100..11111111.11111111.11111111188.255.255.255
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

188.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.0.0.0/20188.0.0.1 to 188.0.15.254188.0.15.2554,094
2188.0.16.0/20188.0.16.1 to 188.0.31.254188.0.31.2554,094
3188.0.32.0/20188.0.32.1 to 188.0.47.254188.0.47.2554,094
4188.0.48.0/20188.0.48.1 to 188.0.63.254188.0.63.2554,094
5188.0.64.0/20188.0.64.1 to 188.0.79.254188.0.79.2554,094
6188.0.80.0/20188.0.80.1 to 188.0.95.254188.0.95.2554,094
7188.0.96.0/20188.0.96.1 to 188.0.111.254188.0.111.2554,094
8188.0.112.0/20188.0.112.1 to 188.0.127.254188.0.127.2554,094
9188.0.128.0/20188.0.128.1 to 188.0.143.254188.0.143.2554,094
10188.0.144.0/20188.0.144.1 to 188.0.159.254188.0.159.2554,094
11188.0.160.0/20188.0.160.1 to 188.0.175.254188.0.175.2554,094
12188.0.176.0/20188.0.176.1 to 188.0.191.254188.0.191.2554,094
13188.0.192.0/20188.0.192.1 to 188.0.207.254188.0.207.2554,094
14188.0.208.0/20188.0.208.1 to 188.0.223.254188.0.223.2554,094
15188.0.224.0/20188.0.224.1 to 188.0.239.254188.0.239.2554,094
16188.0.240.0/20188.0.240.1 to 188.0.255.254188.0.255.2554,094
17188.1.0.0/20188.1.0.1 to 188.1.15.254188.1.15.2554,094
18188.1.16.0/20188.1.16.1 to 188.1.31.254188.1.31.2554,094
19188.1.32.0/20188.1.32.1 to 188.1.47.254188.1.47.2554,094
20188.1.48.0/20188.1.48.1 to 188.1.63.254188.1.63.2554,094
21188.1.64.0/20188.1.64.1 to 188.1.79.254188.1.79.2554,094
22188.1.80.0/20188.1.80.1 to 188.1.95.254188.1.95.2554,094
23188.1.96.0/20188.1.96.1 to 188.1.111.254188.1.111.2554,094
24188.1.112.0/20188.1.112.1 to 188.1.127.254188.1.127.2554,094
25188.1.128.0/20188.1.128.1 to 188.1.143.254188.1.143.2554,094
26188.1.144.0/20188.1.144.1 to 188.1.159.254188.1.159.2554,094
27188.1.160.0/20188.1.160.1 to 188.1.175.254188.1.175.2554,094
28188.1.176.0/20188.1.176.1 to 188.1.191.254188.1.191.2554,094
29188.1.192.0/20188.1.192.1 to 188.1.207.254188.1.207.2554,094
30188.1.208.0/20188.1.208.1 to 188.1.223.254188.1.223.2554,094
31188.1.224.0/20188.1.224.1 to 188.1.239.254188.1.239.2554,094
32188.1.240.0/20188.1.240.1 to 188.1.255.254188.1.255.2554,094
33188.2.0.0/20188.2.0.1 to 188.2.15.254188.2.15.2554,094
34188.2.16.0/20188.2.16.1 to 188.2.31.254188.2.31.2554,094
35188.2.32.0/20188.2.32.1 to 188.2.47.254188.2.47.2554,094
36188.2.48.0/20188.2.48.1 to 188.2.63.254188.2.63.2554,094
37188.2.64.0/20188.2.64.1 to 188.2.79.254188.2.79.2554,094
38188.2.80.0/20188.2.80.1 to 188.2.95.254188.2.95.2554,094
39188.2.96.0/20188.2.96.1 to 188.2.111.254188.2.111.2554,094
40188.2.112.0/20188.2.112.1 to 188.2.127.254188.2.127.2554,094
41188.2.128.0/20188.2.128.1 to 188.2.143.254188.2.143.2554,094
42188.2.144.0/20188.2.144.1 to 188.2.159.254188.2.159.2554,094
43188.2.160.0/20188.2.160.1 to 188.2.175.254188.2.175.2554,094
44188.2.176.0/20188.2.176.1 to 188.2.191.254188.2.191.2554,094
45188.2.192.0/20188.2.192.1 to 188.2.207.254188.2.207.2554,094
46188.2.208.0/20188.2.208.1 to 188.2.223.254188.2.223.2554,094
47188.2.224.0/20188.2.224.1 to 188.2.239.254188.2.239.2554,094
48188.2.240.0/20188.2.240.1 to 188.2.255.254188.2.255.2554,094
49188.3.0.0/20188.3.0.1 to 188.3.15.254188.3.15.2554,094
50188.3.16.0/20188.3.16.1 to 188.3.31.254188.3.31.2554,094
51188.3.32.0/20188.3.32.1 to 188.3.47.254188.3.47.2554,094
52188.3.48.0/20188.3.48.1 to 188.3.63.254188.3.63.2554,094
53188.3.64.0/20188.3.64.1 to 188.3.79.254188.3.79.2554,094
54188.3.80.0/20188.3.80.1 to 188.3.95.254188.3.95.2554,094
55188.3.96.0/20188.3.96.1 to 188.3.111.254188.3.111.2554,094
56188.3.112.0/20188.3.112.1 to 188.3.127.254188.3.127.2554,094
57188.3.128.0/20188.3.128.1 to 188.3.143.254188.3.143.2554,094
58188.3.144.0/20188.3.144.1 to 188.3.159.254188.3.159.2554,094
59188.3.160.0/20188.3.160.1 to 188.3.175.254188.3.175.2554,094
60188.3.176.0/20188.3.176.1 to 188.3.191.254188.3.191.2554,094
61188.3.192.0/20188.3.192.1 to 188.3.207.254188.3.207.2554,094
62188.3.208.0/20188.3.208.1 to 188.3.223.254188.3.223.2554,094
63188.3.224.0/20188.3.224.1 to 188.3.239.254188.3.239.2554,094
64188.3.240.0/20188.3.240.1 to 188.3.255.254188.3.255.2554,094
65188.4.0.0/20188.4.0.1 to 188.4.15.254188.4.15.2554,094
66188.4.16.0/20188.4.16.1 to 188.4.31.254188.4.31.2554,094
67188.4.32.0/20188.4.32.1 to 188.4.47.254188.4.47.2554,094
68188.4.48.0/20188.4.48.1 to 188.4.63.254188.4.63.2554,094
69188.4.64.0/20188.4.64.1 to 188.4.79.254188.4.79.2554,094
70188.4.80.0/20188.4.80.1 to 188.4.95.254188.4.95.2554,094
71188.4.96.0/20188.4.96.1 to 188.4.111.254188.4.111.2554,094
72188.4.112.0/20188.4.112.1 to 188.4.127.254188.4.127.2554,094
73188.4.128.0/20188.4.128.1 to 188.4.143.254188.4.143.2554,094
74188.4.144.0/20188.4.144.1 to 188.4.159.254188.4.159.2554,094
75188.4.160.0/20188.4.160.1 to 188.4.175.254188.4.175.2554,094
76188.4.176.0/20188.4.176.1 to 188.4.191.254188.4.191.2554,094
77188.4.192.0/20188.4.192.1 to 188.4.207.254188.4.207.2554,094
78188.4.208.0/20188.4.208.1 to 188.4.223.254188.4.223.2554,094
79188.4.224.0/20188.4.224.1 to 188.4.239.254188.4.239.2554,094
80188.4.240.0/20188.4.240.1 to 188.4.255.254188.4.255.2554,094
81188.5.0.0/20188.5.0.1 to 188.5.15.254188.5.15.2554,094
82188.5.16.0/20188.5.16.1 to 188.5.31.254188.5.31.2554,094
83188.5.32.0/20188.5.32.1 to 188.5.47.254188.5.47.2554,094
84188.5.48.0/20188.5.48.1 to 188.5.63.254188.5.63.2554,094
85188.5.64.0/20188.5.64.1 to 188.5.79.254188.5.79.2554,094
86188.5.80.0/20188.5.80.1 to 188.5.95.254188.5.95.2554,094
87188.5.96.0/20188.5.96.1 to 188.5.111.254188.5.111.2554,094
88188.5.112.0/20188.5.112.1 to 188.5.127.254188.5.127.2554,094
89188.5.128.0/20188.5.128.1 to 188.5.143.254188.5.143.2554,094
90188.5.144.0/20188.5.144.1 to 188.5.159.254188.5.159.2554,094
91188.5.160.0/20188.5.160.1 to 188.5.175.254188.5.175.2554,094
92188.5.176.0/20188.5.176.1 to 188.5.191.254188.5.191.2554,094
93188.5.192.0/20188.5.192.1 to 188.5.207.254188.5.207.2554,094
94188.5.208.0/20188.5.208.1 to 188.5.223.254188.5.223.2554,094
95188.5.224.0/20188.5.224.1 to 188.5.239.254188.5.239.2554,094
96188.5.240.0/20188.5.240.1 to 188.5.255.254188.5.255.2554,094
97188.6.0.0/20188.6.0.1 to 188.6.15.254188.6.15.2554,094
98188.6.16.0/20188.6.16.1 to 188.6.31.254188.6.31.2554,094
99188.6.32.0/20188.6.32.1 to 188.6.47.254188.6.47.2554,094
100188.6.48.0/20188.6.48.1 to 188.6.63.254188.6.63.2554,094
101188.6.64.0/20188.6.64.1 to 188.6.79.254188.6.79.2554,094
102188.6.80.0/20188.6.80.1 to 188.6.95.254188.6.95.2554,094
103188.6.96.0/20188.6.96.1 to 188.6.111.254188.6.111.2554,094
104188.6.112.0/20188.6.112.1 to 188.6.127.254188.6.127.2554,094
105188.6.128.0/20188.6.128.1 to 188.6.143.254188.6.143.2554,094
106188.6.144.0/20188.6.144.1 to 188.6.159.254188.6.159.2554,094
107188.6.160.0/20188.6.160.1 to 188.6.175.254188.6.175.2554,094
108188.6.176.0/20188.6.176.1 to 188.6.191.254188.6.191.2554,094
109188.6.192.0/20188.6.192.1 to 188.6.207.254188.6.207.2554,094
110188.6.208.0/20188.6.208.1 to 188.6.223.254188.6.223.2554,094
111188.6.224.0/20188.6.224.1 to 188.6.239.254188.6.239.2554,094
112188.6.240.0/20188.6.240.1 to 188.6.255.254188.6.255.2554,094
113188.7.0.0/20188.7.0.1 to 188.7.15.254188.7.15.2554,094
114188.7.16.0/20188.7.16.1 to 188.7.31.254188.7.31.2554,094
115188.7.32.0/20188.7.32.1 to 188.7.47.254188.7.47.2554,094
116188.7.48.0/20188.7.48.1 to 188.7.63.254188.7.63.2554,094
117188.7.64.0/20188.7.64.1 to 188.7.79.254188.7.79.2554,094
118188.7.80.0/20188.7.80.1 to 188.7.95.254188.7.95.2554,094
119188.7.96.0/20188.7.96.1 to 188.7.111.254188.7.111.2554,094
120188.7.112.0/20188.7.112.1 to 188.7.127.254188.7.127.2554,094
121188.7.128.0/20188.7.128.1 to 188.7.143.254188.7.143.2554,094
122188.7.144.0/20188.7.144.1 to 188.7.159.254188.7.159.2554,094
123188.7.160.0/20188.7.160.1 to 188.7.175.254188.7.175.2554,094
124188.7.176.0/20188.7.176.1 to 188.7.191.254188.7.191.2554,094
125188.7.192.0/20188.7.192.1 to 188.7.207.254188.7.207.2554,094
126188.7.208.0/20188.7.208.1 to 188.7.223.254188.7.223.2554,094
127188.7.224.0/20188.7.224.1 to 188.7.239.254188.7.239.2554,094
128188.7.240.0/20188.7.240.1 to 188.7.255.254188.7.255.2554,094
129188.8.0.0/20188.8.0.1 to 188.8.15.254188.8.15.2554,094
130188.8.16.0/20188.8.16.1 to 188.8.31.254188.8.31.2554,094
131188.8.32.0/20188.8.32.1 to 188.8.47.254188.8.47.2554,094
132188.8.48.0/20188.8.48.1 to 188.8.63.254188.8.63.2554,094
133188.8.64.0/20188.8.64.1 to 188.8.79.254188.8.79.2554,094
134188.8.80.0/20188.8.80.1 to 188.8.95.254188.8.95.2554,094
135188.8.96.0/20188.8.96.1 to 188.8.111.254188.8.111.2554,094
136188.8.112.0/20188.8.112.1 to 188.8.127.254188.8.127.2554,094
137188.8.128.0/20188.8.128.1 to 188.8.143.254188.8.143.2554,094
138188.8.144.0/20188.8.144.1 to 188.8.159.254188.8.159.2554,094
139188.8.160.0/20188.8.160.1 to 188.8.175.254188.8.175.2554,094
140188.8.176.0/20188.8.176.1 to 188.8.191.254188.8.191.2554,094
141188.8.192.0/20188.8.192.1 to 188.8.207.254188.8.207.2554,094
142188.8.208.0/20188.8.208.1 to 188.8.223.254188.8.223.2554,094
143188.8.224.0/20188.8.224.1 to 188.8.239.254188.8.239.2554,094
144188.8.240.0/20188.8.240.1 to 188.8.255.254188.8.255.2554,094
145188.9.0.0/20188.9.0.1 to 188.9.15.254188.9.15.2554,094
146188.9.16.0/20188.9.16.1 to 188.9.31.254188.9.31.2554,094
147188.9.32.0/20188.9.32.1 to 188.9.47.254188.9.47.2554,094
148188.9.48.0/20188.9.48.1 to 188.9.63.254188.9.63.2554,094
149188.9.64.0/20188.9.64.1 to 188.9.79.254188.9.79.2554,094
150188.9.80.0/20188.9.80.1 to 188.9.95.254188.9.95.2554,094
151188.9.96.0/20188.9.96.1 to 188.9.111.254188.9.111.2554,094
152188.9.112.0/20188.9.112.1 to 188.9.127.254188.9.127.2554,094
153188.9.128.0/20188.9.128.1 to 188.9.143.254188.9.143.2554,094
154188.9.144.0/20188.9.144.1 to 188.9.159.254188.9.159.2554,094
155188.9.160.0/20188.9.160.1 to 188.9.175.254188.9.175.2554,094
156188.9.176.0/20188.9.176.1 to 188.9.191.254188.9.191.2554,094
157188.9.192.0/20188.9.192.1 to 188.9.207.254188.9.207.2554,094
158188.9.208.0/20188.9.208.1 to 188.9.223.254188.9.223.2554,094
159188.9.224.0/20188.9.224.1 to 188.9.239.254188.9.239.2554,094
160188.9.240.0/20188.9.240.1 to 188.9.255.254188.9.255.2554,094
161188.10.0.0/20188.10.0.1 to 188.10.15.254188.10.15.2554,094
162188.10.16.0/20188.10.16.1 to 188.10.31.254188.10.31.2554,094
163188.10.32.0/20188.10.32.1 to 188.10.47.254188.10.47.2554,094
164188.10.48.0/20188.10.48.1 to 188.10.63.254188.10.63.2554,094
165188.10.64.0/20188.10.64.1 to 188.10.79.254188.10.79.2554,094
166188.10.80.0/20188.10.80.1 to 188.10.95.254188.10.95.2554,094
167188.10.96.0/20188.10.96.1 to 188.10.111.254188.10.111.2554,094
168188.10.112.0/20188.10.112.1 to 188.10.127.254188.10.127.2554,094
169188.10.128.0/20188.10.128.1 to 188.10.143.254188.10.143.2554,094
170188.10.144.0/20188.10.144.1 to 188.10.159.254188.10.159.2554,094
171188.10.160.0/20188.10.160.1 to 188.10.175.254188.10.175.2554,094
172188.10.176.0/20188.10.176.1 to 188.10.191.254188.10.191.2554,094
173188.10.192.0/20188.10.192.1 to 188.10.207.254188.10.207.2554,094
174188.10.208.0/20188.10.208.1 to 188.10.223.254188.10.223.2554,094
175188.10.224.0/20188.10.224.1 to 188.10.239.254188.10.239.2554,094
176188.10.240.0/20188.10.240.1 to 188.10.255.254188.10.255.2554,094
177188.11.0.0/20188.11.0.1 to 188.11.15.254188.11.15.2554,094
178188.11.16.0/20188.11.16.1 to 188.11.31.254188.11.31.2554,094
179188.11.32.0/20188.11.32.1 to 188.11.47.254188.11.47.2554,094
180188.11.48.0/20188.11.48.1 to 188.11.63.254188.11.63.2554,094
181188.11.64.0/20188.11.64.1 to 188.11.79.254188.11.79.2554,094
182188.11.80.0/20188.11.80.1 to 188.11.95.254188.11.95.2554,094
183188.11.96.0/20188.11.96.1 to 188.11.111.254188.11.111.2554,094
184188.11.112.0/20188.11.112.1 to 188.11.127.254188.11.127.2554,094
185188.11.128.0/20188.11.128.1 to 188.11.143.254188.11.143.2554,094
186188.11.144.0/20188.11.144.1 to 188.11.159.254188.11.159.2554,094
187188.11.160.0/20188.11.160.1 to 188.11.175.254188.11.175.2554,094
188188.11.176.0/20188.11.176.1 to 188.11.191.254188.11.191.2554,094
189188.11.192.0/20188.11.192.1 to 188.11.207.254188.11.207.2554,094
190188.11.208.0/20188.11.208.1 to 188.11.223.254188.11.223.2554,094
191188.11.224.0/20188.11.224.1 to 188.11.239.254188.11.239.2554,094
192188.11.240.0/20188.11.240.1 to 188.11.255.254188.11.255.2554,094
193188.12.0.0/20188.12.0.1 to 188.12.15.254188.12.15.2554,094
194188.12.16.0/20188.12.16.1 to 188.12.31.254188.12.31.2554,094
195188.12.32.0/20188.12.32.1 to 188.12.47.254188.12.47.2554,094
196188.12.48.0/20188.12.48.1 to 188.12.63.254188.12.63.2554,094
197188.12.64.0/20188.12.64.1 to 188.12.79.254188.12.79.2554,094
198188.12.80.0/20188.12.80.1 to 188.12.95.254188.12.95.2554,094
199188.12.96.0/20188.12.96.1 to 188.12.111.254188.12.111.2554,094
200188.12.112.0/20188.12.112.1 to 188.12.127.254188.12.127.2554,094
201188.12.128.0/20188.12.128.1 to 188.12.143.254188.12.143.2554,094
202188.12.144.0/20188.12.144.1 to 188.12.159.254188.12.159.2554,094
203188.12.160.0/20188.12.160.1 to 188.12.175.254188.12.175.2554,094
204188.12.176.0/20188.12.176.1 to 188.12.191.254188.12.191.2554,094
205188.12.192.0/20188.12.192.1 to 188.12.207.254188.12.207.2554,094
206188.12.208.0/20188.12.208.1 to 188.12.223.254188.12.223.2554,094
207188.12.224.0/20188.12.224.1 to 188.12.239.254188.12.239.2554,094
208188.12.240.0/20188.12.240.1 to 188.12.255.254188.12.255.2554,094
209188.13.0.0/20188.13.0.1 to 188.13.15.254188.13.15.2554,094
210188.13.16.0/20188.13.16.1 to 188.13.31.254188.13.31.2554,094
211188.13.32.0/20188.13.32.1 to 188.13.47.254188.13.47.2554,094
212188.13.48.0/20188.13.48.1 to 188.13.63.254188.13.63.2554,094
213188.13.64.0/20188.13.64.1 to 188.13.79.254188.13.79.2554,094
214188.13.80.0/20188.13.80.1 to 188.13.95.254188.13.95.2554,094
215188.13.96.0/20188.13.96.1 to 188.13.111.254188.13.111.2554,094
216188.13.112.0/20188.13.112.1 to 188.13.127.254188.13.127.2554,094
217188.13.128.0/20188.13.128.1 to 188.13.143.254188.13.143.2554,094
218188.13.144.0/20188.13.144.1 to 188.13.159.254188.13.159.2554,094
219188.13.160.0/20188.13.160.1 to 188.13.175.254188.13.175.2554,094
220188.13.176.0/20188.13.176.1 to 188.13.191.254188.13.191.2554,094
221188.13.192.0/20188.13.192.1 to 188.13.207.254188.13.207.2554,094
222188.13.208.0/20188.13.208.1 to 188.13.223.254188.13.223.2554,094
223188.13.224.0/20188.13.224.1 to 188.13.239.254188.13.239.2554,094
224188.13.240.0/20188.13.240.1 to 188.13.255.254188.13.255.2554,094
225188.14.0.0/20188.14.0.1 to 188.14.15.254188.14.15.2554,094
226188.14.16.0/20188.14.16.1 to 188.14.31.254188.14.31.2554,094
227188.14.32.0/20188.14.32.1 to 188.14.47.254188.14.47.2554,094
228188.14.48.0/20188.14.48.1 to 188.14.63.254188.14.63.2554,094
229188.14.64.0/20188.14.64.1 to 188.14.79.254188.14.79.2554,094
230188.14.80.0/20188.14.80.1 to 188.14.95.254188.14.95.2554,094
231188.14.96.0/20188.14.96.1 to 188.14.111.254188.14.111.2554,094
232188.14.112.0/20188.14.112.1 to 188.14.127.254188.14.127.2554,094
233188.14.128.0/20188.14.128.1 to 188.14.143.254188.14.143.2554,094
234188.14.144.0/20188.14.144.1 to 188.14.159.254188.14.159.2554,094
235188.14.160.0/20188.14.160.1 to 188.14.175.254188.14.175.2554,094
236188.14.176.0/20188.14.176.1 to 188.14.191.254188.14.191.2554,094
237188.14.192.0/20188.14.192.1 to 188.14.207.254188.14.207.2554,094
238188.14.208.0/20188.14.208.1 to 188.14.223.254188.14.223.2554,094
239188.14.224.0/20188.14.224.1 to 188.14.239.254188.14.239.2554,094
240188.14.240.0/20188.14.240.1 to 188.14.255.254188.14.255.2554,094
241188.15.0.0/20188.15.0.1 to 188.15.15.254188.15.15.2554,094
242188.15.16.0/20188.15.16.1 to 188.15.31.254188.15.31.2554,094
243188.15.32.0/20188.15.32.1 to 188.15.47.254188.15.47.2554,094
244188.15.48.0/20188.15.48.1 to 188.15.63.254188.15.63.2554,094
245188.15.64.0/20188.15.64.1 to 188.15.79.254188.15.79.2554,094
246188.15.80.0/20188.15.80.1 to 188.15.95.254188.15.95.2554,094
247188.15.96.0/20188.15.96.1 to 188.15.111.254188.15.111.2554,094
248188.15.112.0/20188.15.112.1 to 188.15.127.254188.15.127.2554,094
249188.15.128.0/20188.15.128.1 to 188.15.143.254188.15.143.2554,094
250188.15.144.0/20188.15.144.1 to 188.15.159.254188.15.159.2554,094
251188.15.160.0/20188.15.160.1 to 188.15.175.254188.15.175.2554,094
252188.15.176.0/20188.15.176.1 to 188.15.191.254188.15.191.2554,094
253188.15.192.0/20188.15.192.1 to 188.15.207.254188.15.207.2554,094
254188.15.208.0/20188.15.208.1 to 188.15.223.254188.15.223.2554,094
255188.15.224.0/20188.15.224.1 to 188.15.239.254188.15.239.2554,094
256188.15.240.0/20188.15.240.1 to 188.15.255.254188.15.255.2554,094

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.