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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.

Network183.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
183.166.0.0
Broadcast address
183.167.255.255
First usable
183.166.0.1
Last usable
183.167.255.254
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 B7A60000 · Integer 3081109504 to 3081240575
Reverse DNS zones
166.183.in-addr.arpa
167.183.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
Address10110111.10100110.00000000.00000000183.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10110111.10100110.00000000.00000000183.166.0.0
Broadcast10110111.10100111.11111111.11111111183.167.255.255
Split into smaller subnets/27
/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)

183.166.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.166.0.0/27183.166.0.1 to 183.166.0.30183.166.0.3130
2183.166.0.32/27183.166.0.33 to 183.166.0.62183.166.0.6330
3183.166.0.64/27183.166.0.65 to 183.166.0.94183.166.0.9530
4183.166.0.96/27183.166.0.97 to 183.166.0.126183.166.0.12730
5183.166.0.128/27183.166.0.129 to 183.166.0.158183.166.0.15930
6183.166.0.160/27183.166.0.161 to 183.166.0.190183.166.0.19130
7183.166.0.192/27183.166.0.193 to 183.166.0.222183.166.0.22330
8183.166.0.224/27183.166.0.225 to 183.166.0.254183.166.0.25530
9183.166.1.0/27183.166.1.1 to 183.166.1.30183.166.1.3130
10183.166.1.32/27183.166.1.33 to 183.166.1.62183.166.1.6330
11183.166.1.64/27183.166.1.65 to 183.166.1.94183.166.1.9530
12183.166.1.96/27183.166.1.97 to 183.166.1.126183.166.1.12730
13183.166.1.128/27183.166.1.129 to 183.166.1.158183.166.1.15930
14183.166.1.160/27183.166.1.161 to 183.166.1.190183.166.1.19130
15183.166.1.192/27183.166.1.193 to 183.166.1.222183.166.1.22330
16183.166.1.224/27183.166.1.225 to 183.166.1.254183.166.1.25530
17183.166.2.0/27183.166.2.1 to 183.166.2.30183.166.2.3130
18183.166.2.32/27183.166.2.33 to 183.166.2.62183.166.2.6330
19183.166.2.64/27183.166.2.65 to 183.166.2.94183.166.2.9530
20183.166.2.96/27183.166.2.97 to 183.166.2.126183.166.2.12730
21183.166.2.128/27183.166.2.129 to 183.166.2.158183.166.2.15930
22183.166.2.160/27183.166.2.161 to 183.166.2.190183.166.2.19130
23183.166.2.192/27183.166.2.193 to 183.166.2.222183.166.2.22330
24183.166.2.224/27183.166.2.225 to 183.166.2.254183.166.2.25530
25183.166.3.0/27183.166.3.1 to 183.166.3.30183.166.3.3130
26183.166.3.32/27183.166.3.33 to 183.166.3.62183.166.3.6330
27183.166.3.64/27183.166.3.65 to 183.166.3.94183.166.3.9530
28183.166.3.96/27183.166.3.97 to 183.166.3.126183.166.3.12730
29183.166.3.128/27183.166.3.129 to 183.166.3.158183.166.3.15930
30183.166.3.160/27183.166.3.161 to 183.166.3.190183.166.3.19130
31183.166.3.192/27183.166.3.193 to 183.166.3.222183.166.3.22330
32183.166.3.224/27183.166.3.225 to 183.166.3.254183.166.3.25530
33183.166.4.0/27183.166.4.1 to 183.166.4.30183.166.4.3130
34183.166.4.32/27183.166.4.33 to 183.166.4.62183.166.4.6330
35183.166.4.64/27183.166.4.65 to 183.166.4.94183.166.4.9530
36183.166.4.96/27183.166.4.97 to 183.166.4.126183.166.4.12730
37183.166.4.128/27183.166.4.129 to 183.166.4.158183.166.4.15930
38183.166.4.160/27183.166.4.161 to 183.166.4.190183.166.4.19130
39183.166.4.192/27183.166.4.193 to 183.166.4.222183.166.4.22330
40183.166.4.224/27183.166.4.225 to 183.166.4.254183.166.4.25530
41183.166.5.0/27183.166.5.1 to 183.166.5.30183.166.5.3130
42183.166.5.32/27183.166.5.33 to 183.166.5.62183.166.5.6330
43183.166.5.64/27183.166.5.65 to 183.166.5.94183.166.5.9530
44183.166.5.96/27183.166.5.97 to 183.166.5.126183.166.5.12730
45183.166.5.128/27183.166.5.129 to 183.166.5.158183.166.5.15930
46183.166.5.160/27183.166.5.161 to 183.166.5.190183.166.5.19130
47183.166.5.192/27183.166.5.193 to 183.166.5.222183.166.5.22330
48183.166.5.224/27183.166.5.225 to 183.166.5.254183.166.5.25530
49183.166.6.0/27183.166.6.1 to 183.166.6.30183.166.6.3130
50183.166.6.32/27183.166.6.33 to 183.166.6.62183.166.6.6330
51183.166.6.64/27183.166.6.65 to 183.166.6.94183.166.6.9530
52183.166.6.96/27183.166.6.97 to 183.166.6.126183.166.6.12730
53183.166.6.128/27183.166.6.129 to 183.166.6.158183.166.6.15930
54183.166.6.160/27183.166.6.161 to 183.166.6.190183.166.6.19130
55183.166.6.192/27183.166.6.193 to 183.166.6.222183.166.6.22330
56183.166.6.224/27183.166.6.225 to 183.166.6.254183.166.6.25530
57183.166.7.0/27183.166.7.1 to 183.166.7.30183.166.7.3130
58183.166.7.32/27183.166.7.33 to 183.166.7.62183.166.7.6330
59183.166.7.64/27183.166.7.65 to 183.166.7.94183.166.7.9530
60183.166.7.96/27183.166.7.97 to 183.166.7.126183.166.7.12730
61183.166.7.128/27183.166.7.129 to 183.166.7.158183.166.7.15930
62183.166.7.160/27183.166.7.161 to 183.166.7.190183.166.7.19130
63183.166.7.192/27183.166.7.193 to 183.166.7.222183.166.7.22330
64183.166.7.224/27183.166.7.225 to 183.166.7.254183.166.7.25530
65183.166.8.0/27183.166.8.1 to 183.166.8.30183.166.8.3130
66183.166.8.32/27183.166.8.33 to 183.166.8.62183.166.8.6330
67183.166.8.64/27183.166.8.65 to 183.166.8.94183.166.8.9530
68183.166.8.96/27183.166.8.97 to 183.166.8.126183.166.8.12730
69183.166.8.128/27183.166.8.129 to 183.166.8.158183.166.8.15930
70183.166.8.160/27183.166.8.161 to 183.166.8.190183.166.8.19130
71183.166.8.192/27183.166.8.193 to 183.166.8.222183.166.8.22330
72183.166.8.224/27183.166.8.225 to 183.166.8.254183.166.8.25530
73183.166.9.0/27183.166.9.1 to 183.166.9.30183.166.9.3130
74183.166.9.32/27183.166.9.33 to 183.166.9.62183.166.9.6330
75183.166.9.64/27183.166.9.65 to 183.166.9.94183.166.9.9530
76183.166.9.96/27183.166.9.97 to 183.166.9.126183.166.9.12730
77183.166.9.128/27183.166.9.129 to 183.166.9.158183.166.9.15930
78183.166.9.160/27183.166.9.161 to 183.166.9.190183.166.9.19130
79183.166.9.192/27183.166.9.193 to 183.166.9.222183.166.9.22330
80183.166.9.224/27183.166.9.225 to 183.166.9.254183.166.9.25530
81183.166.10.0/27183.166.10.1 to 183.166.10.30183.166.10.3130
82183.166.10.32/27183.166.10.33 to 183.166.10.62183.166.10.6330
83183.166.10.64/27183.166.10.65 to 183.166.10.94183.166.10.9530
84183.166.10.96/27183.166.10.97 to 183.166.10.126183.166.10.12730
85183.166.10.128/27183.166.10.129 to 183.166.10.158183.166.10.15930
86183.166.10.160/27183.166.10.161 to 183.166.10.190183.166.10.19130
87183.166.10.192/27183.166.10.193 to 183.166.10.222183.166.10.22330
88183.166.10.224/27183.166.10.225 to 183.166.10.254183.166.10.25530
89183.166.11.0/27183.166.11.1 to 183.166.11.30183.166.11.3130
90183.166.11.32/27183.166.11.33 to 183.166.11.62183.166.11.6330
91183.166.11.64/27183.166.11.65 to 183.166.11.94183.166.11.9530
92183.166.11.96/27183.166.11.97 to 183.166.11.126183.166.11.12730
93183.166.11.128/27183.166.11.129 to 183.166.11.158183.166.11.15930
94183.166.11.160/27183.166.11.161 to 183.166.11.190183.166.11.19130
95183.166.11.192/27183.166.11.193 to 183.166.11.222183.166.11.22330
96183.166.11.224/27183.166.11.225 to 183.166.11.254183.166.11.25530
97183.166.12.0/27183.166.12.1 to 183.166.12.30183.166.12.3130
98183.166.12.32/27183.166.12.33 to 183.166.12.62183.166.12.6330
99183.166.12.64/27183.166.12.65 to 183.166.12.94183.166.12.9530
100183.166.12.96/27183.166.12.97 to 183.166.12.126183.166.12.12730
101183.166.12.128/27183.166.12.129 to 183.166.12.158183.166.12.15930
102183.166.12.160/27183.166.12.161 to 183.166.12.190183.166.12.19130
103183.166.12.192/27183.166.12.193 to 183.166.12.222183.166.12.22330
104183.166.12.224/27183.166.12.225 to 183.166.12.254183.166.12.25530
105183.166.13.0/27183.166.13.1 to 183.166.13.30183.166.13.3130
106183.166.13.32/27183.166.13.33 to 183.166.13.62183.166.13.6330
107183.166.13.64/27183.166.13.65 to 183.166.13.94183.166.13.9530
108183.166.13.96/27183.166.13.97 to 183.166.13.126183.166.13.12730
109183.166.13.128/27183.166.13.129 to 183.166.13.158183.166.13.15930
110183.166.13.160/27183.166.13.161 to 183.166.13.190183.166.13.19130
111183.166.13.192/27183.166.13.193 to 183.166.13.222183.166.13.22330
112183.166.13.224/27183.166.13.225 to 183.166.13.254183.166.13.25530
113183.166.14.0/27183.166.14.1 to 183.166.14.30183.166.14.3130
114183.166.14.32/27183.166.14.33 to 183.166.14.62183.166.14.6330
115183.166.14.64/27183.166.14.65 to 183.166.14.94183.166.14.9530
116183.166.14.96/27183.166.14.97 to 183.166.14.126183.166.14.12730
117183.166.14.128/27183.166.14.129 to 183.166.14.158183.166.14.15930
118183.166.14.160/27183.166.14.161 to 183.166.14.190183.166.14.19130
119183.166.14.192/27183.166.14.193 to 183.166.14.222183.166.14.22330
120183.166.14.224/27183.166.14.225 to 183.166.14.254183.166.14.25530
121183.166.15.0/27183.166.15.1 to 183.166.15.30183.166.15.3130
122183.166.15.32/27183.166.15.33 to 183.166.15.62183.166.15.6330
123183.166.15.64/27183.166.15.65 to 183.166.15.94183.166.15.9530
124183.166.15.96/27183.166.15.97 to 183.166.15.126183.166.15.12730
125183.166.15.128/27183.166.15.129 to 183.166.15.158183.166.15.15930
126183.166.15.160/27183.166.15.161 to 183.166.15.190183.166.15.19130
127183.166.15.192/27183.166.15.193 to 183.166.15.222183.166.15.22330
128183.166.15.224/27183.166.15.225 to 183.166.15.254183.166.15.25530
129183.166.16.0/27183.166.16.1 to 183.166.16.30183.166.16.3130
130183.166.16.32/27183.166.16.33 to 183.166.16.62183.166.16.6330
131183.166.16.64/27183.166.16.65 to 183.166.16.94183.166.16.9530
132183.166.16.96/27183.166.16.97 to 183.166.16.126183.166.16.12730
133183.166.16.128/27183.166.16.129 to 183.166.16.158183.166.16.15930
134183.166.16.160/27183.166.16.161 to 183.166.16.190183.166.16.19130
135183.166.16.192/27183.166.16.193 to 183.166.16.222183.166.16.22330
136183.166.16.224/27183.166.16.225 to 183.166.16.254183.166.16.25530
137183.166.17.0/27183.166.17.1 to 183.166.17.30183.166.17.3130
138183.166.17.32/27183.166.17.33 to 183.166.17.62183.166.17.6330
139183.166.17.64/27183.166.17.65 to 183.166.17.94183.166.17.9530
140183.166.17.96/27183.166.17.97 to 183.166.17.126183.166.17.12730
141183.166.17.128/27183.166.17.129 to 183.166.17.158183.166.17.15930
142183.166.17.160/27183.166.17.161 to 183.166.17.190183.166.17.19130
143183.166.17.192/27183.166.17.193 to 183.166.17.222183.166.17.22330
144183.166.17.224/27183.166.17.225 to 183.166.17.254183.166.17.25530
145183.166.18.0/27183.166.18.1 to 183.166.18.30183.166.18.3130
146183.166.18.32/27183.166.18.33 to 183.166.18.62183.166.18.6330
147183.166.18.64/27183.166.18.65 to 183.166.18.94183.166.18.9530
148183.166.18.96/27183.166.18.97 to 183.166.18.126183.166.18.12730
149183.166.18.128/27183.166.18.129 to 183.166.18.158183.166.18.15930
150183.166.18.160/27183.166.18.161 to 183.166.18.190183.166.18.19130
151183.166.18.192/27183.166.18.193 to 183.166.18.222183.166.18.22330
152183.166.18.224/27183.166.18.225 to 183.166.18.254183.166.18.25530
153183.166.19.0/27183.166.19.1 to 183.166.19.30183.166.19.3130
154183.166.19.32/27183.166.19.33 to 183.166.19.62183.166.19.6330
155183.166.19.64/27183.166.19.65 to 183.166.19.94183.166.19.9530
156183.166.19.96/27183.166.19.97 to 183.166.19.126183.166.19.12730
157183.166.19.128/27183.166.19.129 to 183.166.19.158183.166.19.15930
158183.166.19.160/27183.166.19.161 to 183.166.19.190183.166.19.19130
159183.166.19.192/27183.166.19.193 to 183.166.19.222183.166.19.22330
160183.166.19.224/27183.166.19.225 to 183.166.19.254183.166.19.25530
161183.166.20.0/27183.166.20.1 to 183.166.20.30183.166.20.3130
162183.166.20.32/27183.166.20.33 to 183.166.20.62183.166.20.6330
163183.166.20.64/27183.166.20.65 to 183.166.20.94183.166.20.9530
164183.166.20.96/27183.166.20.97 to 183.166.20.126183.166.20.12730
165183.166.20.128/27183.166.20.129 to 183.166.20.158183.166.20.15930
166183.166.20.160/27183.166.20.161 to 183.166.20.190183.166.20.19130
167183.166.20.192/27183.166.20.193 to 183.166.20.222183.166.20.22330
168183.166.20.224/27183.166.20.225 to 183.166.20.254183.166.20.25530
169183.166.21.0/27183.166.21.1 to 183.166.21.30183.166.21.3130
170183.166.21.32/27183.166.21.33 to 183.166.21.62183.166.21.6330
171183.166.21.64/27183.166.21.65 to 183.166.21.94183.166.21.9530
172183.166.21.96/27183.166.21.97 to 183.166.21.126183.166.21.12730
173183.166.21.128/27183.166.21.129 to 183.166.21.158183.166.21.15930
174183.166.21.160/27183.166.21.161 to 183.166.21.190183.166.21.19130
175183.166.21.192/27183.166.21.193 to 183.166.21.222183.166.21.22330
176183.166.21.224/27183.166.21.225 to 183.166.21.254183.166.21.25530
177183.166.22.0/27183.166.22.1 to 183.166.22.30183.166.22.3130
178183.166.22.32/27183.166.22.33 to 183.166.22.62183.166.22.6330
179183.166.22.64/27183.166.22.65 to 183.166.22.94183.166.22.9530
180183.166.22.96/27183.166.22.97 to 183.166.22.126183.166.22.12730
181183.166.22.128/27183.166.22.129 to 183.166.22.158183.166.22.15930
182183.166.22.160/27183.166.22.161 to 183.166.22.190183.166.22.19130
183183.166.22.192/27183.166.22.193 to 183.166.22.222183.166.22.22330
184183.166.22.224/27183.166.22.225 to 183.166.22.254183.166.22.25530
185183.166.23.0/27183.166.23.1 to 183.166.23.30183.166.23.3130
186183.166.23.32/27183.166.23.33 to 183.166.23.62183.166.23.6330
187183.166.23.64/27183.166.23.65 to 183.166.23.94183.166.23.9530
188183.166.23.96/27183.166.23.97 to 183.166.23.126183.166.23.12730
189183.166.23.128/27183.166.23.129 to 183.166.23.158183.166.23.15930
190183.166.23.160/27183.166.23.161 to 183.166.23.190183.166.23.19130
191183.166.23.192/27183.166.23.193 to 183.166.23.222183.166.23.22330
192183.166.23.224/27183.166.23.225 to 183.166.23.254183.166.23.25530
193183.166.24.0/27183.166.24.1 to 183.166.24.30183.166.24.3130
194183.166.24.32/27183.166.24.33 to 183.166.24.62183.166.24.6330
195183.166.24.64/27183.166.24.65 to 183.166.24.94183.166.24.9530
196183.166.24.96/27183.166.24.97 to 183.166.24.126183.166.24.12730
197183.166.24.128/27183.166.24.129 to 183.166.24.158183.166.24.15930
198183.166.24.160/27183.166.24.161 to 183.166.24.190183.166.24.19130
199183.166.24.192/27183.166.24.193 to 183.166.24.222183.166.24.22330
200183.166.24.224/27183.166.24.225 to 183.166.24.254183.166.24.25530
201183.166.25.0/27183.166.25.1 to 183.166.25.30183.166.25.3130
202183.166.25.32/27183.166.25.33 to 183.166.25.62183.166.25.6330
203183.166.25.64/27183.166.25.65 to 183.166.25.94183.166.25.9530
204183.166.25.96/27183.166.25.97 to 183.166.25.126183.166.25.12730
205183.166.25.128/27183.166.25.129 to 183.166.25.158183.166.25.15930
206183.166.25.160/27183.166.25.161 to 183.166.25.190183.166.25.19130
207183.166.25.192/27183.166.25.193 to 183.166.25.222183.166.25.22330
208183.166.25.224/27183.166.25.225 to 183.166.25.254183.166.25.25530
209183.166.26.0/27183.166.26.1 to 183.166.26.30183.166.26.3130
210183.166.26.32/27183.166.26.33 to 183.166.26.62183.166.26.6330
211183.166.26.64/27183.166.26.65 to 183.166.26.94183.166.26.9530
212183.166.26.96/27183.166.26.97 to 183.166.26.126183.166.26.12730
213183.166.26.128/27183.166.26.129 to 183.166.26.158183.166.26.15930
214183.166.26.160/27183.166.26.161 to 183.166.26.190183.166.26.19130
215183.166.26.192/27183.166.26.193 to 183.166.26.222183.166.26.22330
216183.166.26.224/27183.166.26.225 to 183.166.26.254183.166.26.25530
217183.166.27.0/27183.166.27.1 to 183.166.27.30183.166.27.3130
218183.166.27.32/27183.166.27.33 to 183.166.27.62183.166.27.6330
219183.166.27.64/27183.166.27.65 to 183.166.27.94183.166.27.9530
220183.166.27.96/27183.166.27.97 to 183.166.27.126183.166.27.12730
221183.166.27.128/27183.166.27.129 to 183.166.27.158183.166.27.15930
222183.166.27.160/27183.166.27.161 to 183.166.27.190183.166.27.19130
223183.166.27.192/27183.166.27.193 to 183.166.27.222183.166.27.22330
224183.166.27.224/27183.166.27.225 to 183.166.27.254183.166.27.25530
225183.166.28.0/27183.166.28.1 to 183.166.28.30183.166.28.3130
226183.166.28.32/27183.166.28.33 to 183.166.28.62183.166.28.6330
227183.166.28.64/27183.166.28.65 to 183.166.28.94183.166.28.9530
228183.166.28.96/27183.166.28.97 to 183.166.28.126183.166.28.12730
229183.166.28.128/27183.166.28.129 to 183.166.28.158183.166.28.15930
230183.166.28.160/27183.166.28.161 to 183.166.28.190183.166.28.19130
231183.166.28.192/27183.166.28.193 to 183.166.28.222183.166.28.22330
232183.166.28.224/27183.166.28.225 to 183.166.28.254183.166.28.25530
233183.166.29.0/27183.166.29.1 to 183.166.29.30183.166.29.3130
234183.166.29.32/27183.166.29.33 to 183.166.29.62183.166.29.6330
235183.166.29.64/27183.166.29.65 to 183.166.29.94183.166.29.9530
236183.166.29.96/27183.166.29.97 to 183.166.29.126183.166.29.12730
237183.166.29.128/27183.166.29.129 to 183.166.29.158183.166.29.15930
238183.166.29.160/27183.166.29.161 to 183.166.29.190183.166.29.19130
239183.166.29.192/27183.166.29.193 to 183.166.29.222183.166.29.22330
240183.166.29.224/27183.166.29.225 to 183.166.29.254183.166.29.25530
241183.166.30.0/27183.166.30.1 to 183.166.30.30183.166.30.3130
242183.166.30.32/27183.166.30.33 to 183.166.30.62183.166.30.6330
243183.166.30.64/27183.166.30.65 to 183.166.30.94183.166.30.9530
244183.166.30.96/27183.166.30.97 to 183.166.30.126183.166.30.12730
245183.166.30.128/27183.166.30.129 to 183.166.30.158183.166.30.15930
246183.166.30.160/27183.166.30.161 to 183.166.30.190183.166.30.19130
247183.166.30.192/27183.166.30.193 to 183.166.30.222183.166.30.22330
248183.166.30.224/27183.166.30.225 to 183.166.30.254183.166.30.25530
249183.166.31.0/27183.166.31.1 to 183.166.31.30183.166.31.3130
250183.166.31.32/27183.166.31.33 to 183.166.31.62183.166.31.6330
251183.166.31.64/27183.166.31.65 to 183.166.31.94183.166.31.9530
252183.166.31.96/27183.166.31.97 to 183.166.31.126183.166.31.12730
253183.166.31.128/27183.166.31.129 to 183.166.31.158183.166.31.15930
254183.166.31.160/27183.166.31.161 to 183.166.31.190183.166.31.19130
255183.166.31.192/27183.166.31.193 to 183.166.31.222183.166.31.22330
256183.166.31.224/27183.166.31.225 to 183.166.31.254183.166.31.25530

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.