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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.

Network188.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
188.136.0.0
Broadcast address
188.137.255.255
First usable
188.136.0.1
Last usable
188.137.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex BC880000 · Integer 3163029504 to 3163160575
Reverse DNS zones
136.188.in-addr.arpa
137.188.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111100.10001000.00000000.00000000188.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10111100.10001000.00000000.00000000188.136.0.0
Broadcast10111100.10001001.11111111.11111111188.137.255.255
Split into smaller subnets/26
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

188.136.0.0/15 makes 2,048 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.136.0.0/26188.136.0.1 to 188.136.0.62188.136.0.6362
2188.136.0.64/26188.136.0.65 to 188.136.0.126188.136.0.12762
3188.136.0.128/26188.136.0.129 to 188.136.0.190188.136.0.19162
4188.136.0.192/26188.136.0.193 to 188.136.0.254188.136.0.25562
5188.136.1.0/26188.136.1.1 to 188.136.1.62188.136.1.6362
6188.136.1.64/26188.136.1.65 to 188.136.1.126188.136.1.12762
7188.136.1.128/26188.136.1.129 to 188.136.1.190188.136.1.19162
8188.136.1.192/26188.136.1.193 to 188.136.1.254188.136.1.25562
9188.136.2.0/26188.136.2.1 to 188.136.2.62188.136.2.6362
10188.136.2.64/26188.136.2.65 to 188.136.2.126188.136.2.12762
11188.136.2.128/26188.136.2.129 to 188.136.2.190188.136.2.19162
12188.136.2.192/26188.136.2.193 to 188.136.2.254188.136.2.25562
13188.136.3.0/26188.136.3.1 to 188.136.3.62188.136.3.6362
14188.136.3.64/26188.136.3.65 to 188.136.3.126188.136.3.12762
15188.136.3.128/26188.136.3.129 to 188.136.3.190188.136.3.19162
16188.136.3.192/26188.136.3.193 to 188.136.3.254188.136.3.25562
17188.136.4.0/26188.136.4.1 to 188.136.4.62188.136.4.6362
18188.136.4.64/26188.136.4.65 to 188.136.4.126188.136.4.12762
19188.136.4.128/26188.136.4.129 to 188.136.4.190188.136.4.19162
20188.136.4.192/26188.136.4.193 to 188.136.4.254188.136.4.25562
21188.136.5.0/26188.136.5.1 to 188.136.5.62188.136.5.6362
22188.136.5.64/26188.136.5.65 to 188.136.5.126188.136.5.12762
23188.136.5.128/26188.136.5.129 to 188.136.5.190188.136.5.19162
24188.136.5.192/26188.136.5.193 to 188.136.5.254188.136.5.25562
25188.136.6.0/26188.136.6.1 to 188.136.6.62188.136.6.6362
26188.136.6.64/26188.136.6.65 to 188.136.6.126188.136.6.12762
27188.136.6.128/26188.136.6.129 to 188.136.6.190188.136.6.19162
28188.136.6.192/26188.136.6.193 to 188.136.6.254188.136.6.25562
29188.136.7.0/26188.136.7.1 to 188.136.7.62188.136.7.6362
30188.136.7.64/26188.136.7.65 to 188.136.7.126188.136.7.12762
31188.136.7.128/26188.136.7.129 to 188.136.7.190188.136.7.19162
32188.136.7.192/26188.136.7.193 to 188.136.7.254188.136.7.25562
33188.136.8.0/26188.136.8.1 to 188.136.8.62188.136.8.6362
34188.136.8.64/26188.136.8.65 to 188.136.8.126188.136.8.12762
35188.136.8.128/26188.136.8.129 to 188.136.8.190188.136.8.19162
36188.136.8.192/26188.136.8.193 to 188.136.8.254188.136.8.25562
37188.136.9.0/26188.136.9.1 to 188.136.9.62188.136.9.6362
38188.136.9.64/26188.136.9.65 to 188.136.9.126188.136.9.12762
39188.136.9.128/26188.136.9.129 to 188.136.9.190188.136.9.19162
40188.136.9.192/26188.136.9.193 to 188.136.9.254188.136.9.25562
41188.136.10.0/26188.136.10.1 to 188.136.10.62188.136.10.6362
42188.136.10.64/26188.136.10.65 to 188.136.10.126188.136.10.12762
43188.136.10.128/26188.136.10.129 to 188.136.10.190188.136.10.19162
44188.136.10.192/26188.136.10.193 to 188.136.10.254188.136.10.25562
45188.136.11.0/26188.136.11.1 to 188.136.11.62188.136.11.6362
46188.136.11.64/26188.136.11.65 to 188.136.11.126188.136.11.12762
47188.136.11.128/26188.136.11.129 to 188.136.11.190188.136.11.19162
48188.136.11.192/26188.136.11.193 to 188.136.11.254188.136.11.25562
49188.136.12.0/26188.136.12.1 to 188.136.12.62188.136.12.6362
50188.136.12.64/26188.136.12.65 to 188.136.12.126188.136.12.12762
51188.136.12.128/26188.136.12.129 to 188.136.12.190188.136.12.19162
52188.136.12.192/26188.136.12.193 to 188.136.12.254188.136.12.25562
53188.136.13.0/26188.136.13.1 to 188.136.13.62188.136.13.6362
54188.136.13.64/26188.136.13.65 to 188.136.13.126188.136.13.12762
55188.136.13.128/26188.136.13.129 to 188.136.13.190188.136.13.19162
56188.136.13.192/26188.136.13.193 to 188.136.13.254188.136.13.25562
57188.136.14.0/26188.136.14.1 to 188.136.14.62188.136.14.6362
58188.136.14.64/26188.136.14.65 to 188.136.14.126188.136.14.12762
59188.136.14.128/26188.136.14.129 to 188.136.14.190188.136.14.19162
60188.136.14.192/26188.136.14.193 to 188.136.14.254188.136.14.25562
61188.136.15.0/26188.136.15.1 to 188.136.15.62188.136.15.6362
62188.136.15.64/26188.136.15.65 to 188.136.15.126188.136.15.12762
63188.136.15.128/26188.136.15.129 to 188.136.15.190188.136.15.19162
64188.136.15.192/26188.136.15.193 to 188.136.15.254188.136.15.25562
65188.136.16.0/26188.136.16.1 to 188.136.16.62188.136.16.6362
66188.136.16.64/26188.136.16.65 to 188.136.16.126188.136.16.12762
67188.136.16.128/26188.136.16.129 to 188.136.16.190188.136.16.19162
68188.136.16.192/26188.136.16.193 to 188.136.16.254188.136.16.25562
69188.136.17.0/26188.136.17.1 to 188.136.17.62188.136.17.6362
70188.136.17.64/26188.136.17.65 to 188.136.17.126188.136.17.12762
71188.136.17.128/26188.136.17.129 to 188.136.17.190188.136.17.19162
72188.136.17.192/26188.136.17.193 to 188.136.17.254188.136.17.25562
73188.136.18.0/26188.136.18.1 to 188.136.18.62188.136.18.6362
74188.136.18.64/26188.136.18.65 to 188.136.18.126188.136.18.12762
75188.136.18.128/26188.136.18.129 to 188.136.18.190188.136.18.19162
76188.136.18.192/26188.136.18.193 to 188.136.18.254188.136.18.25562
77188.136.19.0/26188.136.19.1 to 188.136.19.62188.136.19.6362
78188.136.19.64/26188.136.19.65 to 188.136.19.126188.136.19.12762
79188.136.19.128/26188.136.19.129 to 188.136.19.190188.136.19.19162
80188.136.19.192/26188.136.19.193 to 188.136.19.254188.136.19.25562
81188.136.20.0/26188.136.20.1 to 188.136.20.62188.136.20.6362
82188.136.20.64/26188.136.20.65 to 188.136.20.126188.136.20.12762
83188.136.20.128/26188.136.20.129 to 188.136.20.190188.136.20.19162
84188.136.20.192/26188.136.20.193 to 188.136.20.254188.136.20.25562
85188.136.21.0/26188.136.21.1 to 188.136.21.62188.136.21.6362
86188.136.21.64/26188.136.21.65 to 188.136.21.126188.136.21.12762
87188.136.21.128/26188.136.21.129 to 188.136.21.190188.136.21.19162
88188.136.21.192/26188.136.21.193 to 188.136.21.254188.136.21.25562
89188.136.22.0/26188.136.22.1 to 188.136.22.62188.136.22.6362
90188.136.22.64/26188.136.22.65 to 188.136.22.126188.136.22.12762
91188.136.22.128/26188.136.22.129 to 188.136.22.190188.136.22.19162
92188.136.22.192/26188.136.22.193 to 188.136.22.254188.136.22.25562
93188.136.23.0/26188.136.23.1 to 188.136.23.62188.136.23.6362
94188.136.23.64/26188.136.23.65 to 188.136.23.126188.136.23.12762
95188.136.23.128/26188.136.23.129 to 188.136.23.190188.136.23.19162
96188.136.23.192/26188.136.23.193 to 188.136.23.254188.136.23.25562
97188.136.24.0/26188.136.24.1 to 188.136.24.62188.136.24.6362
98188.136.24.64/26188.136.24.65 to 188.136.24.126188.136.24.12762
99188.136.24.128/26188.136.24.129 to 188.136.24.190188.136.24.19162
100188.136.24.192/26188.136.24.193 to 188.136.24.254188.136.24.25562
101188.136.25.0/26188.136.25.1 to 188.136.25.62188.136.25.6362
102188.136.25.64/26188.136.25.65 to 188.136.25.126188.136.25.12762
103188.136.25.128/26188.136.25.129 to 188.136.25.190188.136.25.19162
104188.136.25.192/26188.136.25.193 to 188.136.25.254188.136.25.25562
105188.136.26.0/26188.136.26.1 to 188.136.26.62188.136.26.6362
106188.136.26.64/26188.136.26.65 to 188.136.26.126188.136.26.12762
107188.136.26.128/26188.136.26.129 to 188.136.26.190188.136.26.19162
108188.136.26.192/26188.136.26.193 to 188.136.26.254188.136.26.25562
109188.136.27.0/26188.136.27.1 to 188.136.27.62188.136.27.6362
110188.136.27.64/26188.136.27.65 to 188.136.27.126188.136.27.12762
111188.136.27.128/26188.136.27.129 to 188.136.27.190188.136.27.19162
112188.136.27.192/26188.136.27.193 to 188.136.27.254188.136.27.25562
113188.136.28.0/26188.136.28.1 to 188.136.28.62188.136.28.6362
114188.136.28.64/26188.136.28.65 to 188.136.28.126188.136.28.12762
115188.136.28.128/26188.136.28.129 to 188.136.28.190188.136.28.19162
116188.136.28.192/26188.136.28.193 to 188.136.28.254188.136.28.25562
117188.136.29.0/26188.136.29.1 to 188.136.29.62188.136.29.6362
118188.136.29.64/26188.136.29.65 to 188.136.29.126188.136.29.12762
119188.136.29.128/26188.136.29.129 to 188.136.29.190188.136.29.19162
120188.136.29.192/26188.136.29.193 to 188.136.29.254188.136.29.25562
121188.136.30.0/26188.136.30.1 to 188.136.30.62188.136.30.6362
122188.136.30.64/26188.136.30.65 to 188.136.30.126188.136.30.12762
123188.136.30.128/26188.136.30.129 to 188.136.30.190188.136.30.19162
124188.136.30.192/26188.136.30.193 to 188.136.30.254188.136.30.25562
125188.136.31.0/26188.136.31.1 to 188.136.31.62188.136.31.6362
126188.136.31.64/26188.136.31.65 to 188.136.31.126188.136.31.12762
127188.136.31.128/26188.136.31.129 to 188.136.31.190188.136.31.19162
128188.136.31.192/26188.136.31.193 to 188.136.31.254188.136.31.25562
129188.136.32.0/26188.136.32.1 to 188.136.32.62188.136.32.6362
130188.136.32.64/26188.136.32.65 to 188.136.32.126188.136.32.12762
131188.136.32.128/26188.136.32.129 to 188.136.32.190188.136.32.19162
132188.136.32.192/26188.136.32.193 to 188.136.32.254188.136.32.25562
133188.136.33.0/26188.136.33.1 to 188.136.33.62188.136.33.6362
134188.136.33.64/26188.136.33.65 to 188.136.33.126188.136.33.12762
135188.136.33.128/26188.136.33.129 to 188.136.33.190188.136.33.19162
136188.136.33.192/26188.136.33.193 to 188.136.33.254188.136.33.25562
137188.136.34.0/26188.136.34.1 to 188.136.34.62188.136.34.6362
138188.136.34.64/26188.136.34.65 to 188.136.34.126188.136.34.12762
139188.136.34.128/26188.136.34.129 to 188.136.34.190188.136.34.19162
140188.136.34.192/26188.136.34.193 to 188.136.34.254188.136.34.25562
141188.136.35.0/26188.136.35.1 to 188.136.35.62188.136.35.6362
142188.136.35.64/26188.136.35.65 to 188.136.35.126188.136.35.12762
143188.136.35.128/26188.136.35.129 to 188.136.35.190188.136.35.19162
144188.136.35.192/26188.136.35.193 to 188.136.35.254188.136.35.25562
145188.136.36.0/26188.136.36.1 to 188.136.36.62188.136.36.6362
146188.136.36.64/26188.136.36.65 to 188.136.36.126188.136.36.12762
147188.136.36.128/26188.136.36.129 to 188.136.36.190188.136.36.19162
148188.136.36.192/26188.136.36.193 to 188.136.36.254188.136.36.25562
149188.136.37.0/26188.136.37.1 to 188.136.37.62188.136.37.6362
150188.136.37.64/26188.136.37.65 to 188.136.37.126188.136.37.12762
151188.136.37.128/26188.136.37.129 to 188.136.37.190188.136.37.19162
152188.136.37.192/26188.136.37.193 to 188.136.37.254188.136.37.25562
153188.136.38.0/26188.136.38.1 to 188.136.38.62188.136.38.6362
154188.136.38.64/26188.136.38.65 to 188.136.38.126188.136.38.12762
155188.136.38.128/26188.136.38.129 to 188.136.38.190188.136.38.19162
156188.136.38.192/26188.136.38.193 to 188.136.38.254188.136.38.25562
157188.136.39.0/26188.136.39.1 to 188.136.39.62188.136.39.6362
158188.136.39.64/26188.136.39.65 to 188.136.39.126188.136.39.12762
159188.136.39.128/26188.136.39.129 to 188.136.39.190188.136.39.19162
160188.136.39.192/26188.136.39.193 to 188.136.39.254188.136.39.25562
161188.136.40.0/26188.136.40.1 to 188.136.40.62188.136.40.6362
162188.136.40.64/26188.136.40.65 to 188.136.40.126188.136.40.12762
163188.136.40.128/26188.136.40.129 to 188.136.40.190188.136.40.19162
164188.136.40.192/26188.136.40.193 to 188.136.40.254188.136.40.25562
165188.136.41.0/26188.136.41.1 to 188.136.41.62188.136.41.6362
166188.136.41.64/26188.136.41.65 to 188.136.41.126188.136.41.12762
167188.136.41.128/26188.136.41.129 to 188.136.41.190188.136.41.19162
168188.136.41.192/26188.136.41.193 to 188.136.41.254188.136.41.25562
169188.136.42.0/26188.136.42.1 to 188.136.42.62188.136.42.6362
170188.136.42.64/26188.136.42.65 to 188.136.42.126188.136.42.12762
171188.136.42.128/26188.136.42.129 to 188.136.42.190188.136.42.19162
172188.136.42.192/26188.136.42.193 to 188.136.42.254188.136.42.25562
173188.136.43.0/26188.136.43.1 to 188.136.43.62188.136.43.6362
174188.136.43.64/26188.136.43.65 to 188.136.43.126188.136.43.12762
175188.136.43.128/26188.136.43.129 to 188.136.43.190188.136.43.19162
176188.136.43.192/26188.136.43.193 to 188.136.43.254188.136.43.25562
177188.136.44.0/26188.136.44.1 to 188.136.44.62188.136.44.6362
178188.136.44.64/26188.136.44.65 to 188.136.44.126188.136.44.12762
179188.136.44.128/26188.136.44.129 to 188.136.44.190188.136.44.19162
180188.136.44.192/26188.136.44.193 to 188.136.44.254188.136.44.25562
181188.136.45.0/26188.136.45.1 to 188.136.45.62188.136.45.6362
182188.136.45.64/26188.136.45.65 to 188.136.45.126188.136.45.12762
183188.136.45.128/26188.136.45.129 to 188.136.45.190188.136.45.19162
184188.136.45.192/26188.136.45.193 to 188.136.45.254188.136.45.25562
185188.136.46.0/26188.136.46.1 to 188.136.46.62188.136.46.6362
186188.136.46.64/26188.136.46.65 to 188.136.46.126188.136.46.12762
187188.136.46.128/26188.136.46.129 to 188.136.46.190188.136.46.19162
188188.136.46.192/26188.136.46.193 to 188.136.46.254188.136.46.25562
189188.136.47.0/26188.136.47.1 to 188.136.47.62188.136.47.6362
190188.136.47.64/26188.136.47.65 to 188.136.47.126188.136.47.12762
191188.136.47.128/26188.136.47.129 to 188.136.47.190188.136.47.19162
192188.136.47.192/26188.136.47.193 to 188.136.47.254188.136.47.25562
193188.136.48.0/26188.136.48.1 to 188.136.48.62188.136.48.6362
194188.136.48.64/26188.136.48.65 to 188.136.48.126188.136.48.12762
195188.136.48.128/26188.136.48.129 to 188.136.48.190188.136.48.19162
196188.136.48.192/26188.136.48.193 to 188.136.48.254188.136.48.25562
197188.136.49.0/26188.136.49.1 to 188.136.49.62188.136.49.6362
198188.136.49.64/26188.136.49.65 to 188.136.49.126188.136.49.12762
199188.136.49.128/26188.136.49.129 to 188.136.49.190188.136.49.19162
200188.136.49.192/26188.136.49.193 to 188.136.49.254188.136.49.25562
201188.136.50.0/26188.136.50.1 to 188.136.50.62188.136.50.6362
202188.136.50.64/26188.136.50.65 to 188.136.50.126188.136.50.12762
203188.136.50.128/26188.136.50.129 to 188.136.50.190188.136.50.19162
204188.136.50.192/26188.136.50.193 to 188.136.50.254188.136.50.25562
205188.136.51.0/26188.136.51.1 to 188.136.51.62188.136.51.6362
206188.136.51.64/26188.136.51.65 to 188.136.51.126188.136.51.12762
207188.136.51.128/26188.136.51.129 to 188.136.51.190188.136.51.19162
208188.136.51.192/26188.136.51.193 to 188.136.51.254188.136.51.25562
209188.136.52.0/26188.136.52.1 to 188.136.52.62188.136.52.6362
210188.136.52.64/26188.136.52.65 to 188.136.52.126188.136.52.12762
211188.136.52.128/26188.136.52.129 to 188.136.52.190188.136.52.19162
212188.136.52.192/26188.136.52.193 to 188.136.52.254188.136.52.25562
213188.136.53.0/26188.136.53.1 to 188.136.53.62188.136.53.6362
214188.136.53.64/26188.136.53.65 to 188.136.53.126188.136.53.12762
215188.136.53.128/26188.136.53.129 to 188.136.53.190188.136.53.19162
216188.136.53.192/26188.136.53.193 to 188.136.53.254188.136.53.25562
217188.136.54.0/26188.136.54.1 to 188.136.54.62188.136.54.6362
218188.136.54.64/26188.136.54.65 to 188.136.54.126188.136.54.12762
219188.136.54.128/26188.136.54.129 to 188.136.54.190188.136.54.19162
220188.136.54.192/26188.136.54.193 to 188.136.54.254188.136.54.25562
221188.136.55.0/26188.136.55.1 to 188.136.55.62188.136.55.6362
222188.136.55.64/26188.136.55.65 to 188.136.55.126188.136.55.12762
223188.136.55.128/26188.136.55.129 to 188.136.55.190188.136.55.19162
224188.136.55.192/26188.136.55.193 to 188.136.55.254188.136.55.25562
225188.136.56.0/26188.136.56.1 to 188.136.56.62188.136.56.6362
226188.136.56.64/26188.136.56.65 to 188.136.56.126188.136.56.12762
227188.136.56.128/26188.136.56.129 to 188.136.56.190188.136.56.19162
228188.136.56.192/26188.136.56.193 to 188.136.56.254188.136.56.25562
229188.136.57.0/26188.136.57.1 to 188.136.57.62188.136.57.6362
230188.136.57.64/26188.136.57.65 to 188.136.57.126188.136.57.12762
231188.136.57.128/26188.136.57.129 to 188.136.57.190188.136.57.19162
232188.136.57.192/26188.136.57.193 to 188.136.57.254188.136.57.25562
233188.136.58.0/26188.136.58.1 to 188.136.58.62188.136.58.6362
234188.136.58.64/26188.136.58.65 to 188.136.58.126188.136.58.12762
235188.136.58.128/26188.136.58.129 to 188.136.58.190188.136.58.19162
236188.136.58.192/26188.136.58.193 to 188.136.58.254188.136.58.25562
237188.136.59.0/26188.136.59.1 to 188.136.59.62188.136.59.6362
238188.136.59.64/26188.136.59.65 to 188.136.59.126188.136.59.12762
239188.136.59.128/26188.136.59.129 to 188.136.59.190188.136.59.19162
240188.136.59.192/26188.136.59.193 to 188.136.59.254188.136.59.25562
241188.136.60.0/26188.136.60.1 to 188.136.60.62188.136.60.6362
242188.136.60.64/26188.136.60.65 to 188.136.60.126188.136.60.12762
243188.136.60.128/26188.136.60.129 to 188.136.60.190188.136.60.19162
244188.136.60.192/26188.136.60.193 to 188.136.60.254188.136.60.25562
245188.136.61.0/26188.136.61.1 to 188.136.61.62188.136.61.6362
246188.136.61.64/26188.136.61.65 to 188.136.61.126188.136.61.12762
247188.136.61.128/26188.136.61.129 to 188.136.61.190188.136.61.19162
248188.136.61.192/26188.136.61.193 to 188.136.61.254188.136.61.25562
249188.136.62.0/26188.136.62.1 to 188.136.62.62188.136.62.6362
250188.136.62.64/26188.136.62.65 to 188.136.62.126188.136.62.12762
251188.136.62.128/26188.136.62.129 to 188.136.62.190188.136.62.19162
252188.136.62.192/26188.136.62.193 to 188.136.62.254188.136.62.25562
253188.136.63.0/26188.136.63.1 to 188.136.63.62188.136.63.6362
254188.136.63.64/26188.136.63.65 to 188.136.63.126188.136.63.12762
255188.136.63.128/26188.136.63.129 to 188.136.63.190188.136.63.19162
256188.136.63.192/26188.136.63.193 to 188.136.63.254188.136.63.25562

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.