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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.

Network205.232.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
205.232.0.0
Broadcast address
205.233.255.255
First usable
205.232.0.1
Last usable
205.233.255.254
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
C (default /24)
As numbers
Hex CDE80000 · Integer 3454533632 to 3454664703
Reverse DNS zones
232.205.in-addr.arpa
233.205.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
Address11001101.11101000.00000000.00000000205.232.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11001101.11101000.00000000.00000000205.232.0.0
Broadcast11001101.11101001.11111111.11111111205.233.255.255
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)

205.232.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1205.232.0.0/27205.232.0.1 to 205.232.0.30205.232.0.3130
2205.232.0.32/27205.232.0.33 to 205.232.0.62205.232.0.6330
3205.232.0.64/27205.232.0.65 to 205.232.0.94205.232.0.9530
4205.232.0.96/27205.232.0.97 to 205.232.0.126205.232.0.12730
5205.232.0.128/27205.232.0.129 to 205.232.0.158205.232.0.15930
6205.232.0.160/27205.232.0.161 to 205.232.0.190205.232.0.19130
7205.232.0.192/27205.232.0.193 to 205.232.0.222205.232.0.22330
8205.232.0.224/27205.232.0.225 to 205.232.0.254205.232.0.25530
9205.232.1.0/27205.232.1.1 to 205.232.1.30205.232.1.3130
10205.232.1.32/27205.232.1.33 to 205.232.1.62205.232.1.6330
11205.232.1.64/27205.232.1.65 to 205.232.1.94205.232.1.9530
12205.232.1.96/27205.232.1.97 to 205.232.1.126205.232.1.12730
13205.232.1.128/27205.232.1.129 to 205.232.1.158205.232.1.15930
14205.232.1.160/27205.232.1.161 to 205.232.1.190205.232.1.19130
15205.232.1.192/27205.232.1.193 to 205.232.1.222205.232.1.22330
16205.232.1.224/27205.232.1.225 to 205.232.1.254205.232.1.25530
17205.232.2.0/27205.232.2.1 to 205.232.2.30205.232.2.3130
18205.232.2.32/27205.232.2.33 to 205.232.2.62205.232.2.6330
19205.232.2.64/27205.232.2.65 to 205.232.2.94205.232.2.9530
20205.232.2.96/27205.232.2.97 to 205.232.2.126205.232.2.12730
21205.232.2.128/27205.232.2.129 to 205.232.2.158205.232.2.15930
22205.232.2.160/27205.232.2.161 to 205.232.2.190205.232.2.19130
23205.232.2.192/27205.232.2.193 to 205.232.2.222205.232.2.22330
24205.232.2.224/27205.232.2.225 to 205.232.2.254205.232.2.25530
25205.232.3.0/27205.232.3.1 to 205.232.3.30205.232.3.3130
26205.232.3.32/27205.232.3.33 to 205.232.3.62205.232.3.6330
27205.232.3.64/27205.232.3.65 to 205.232.3.94205.232.3.9530
28205.232.3.96/27205.232.3.97 to 205.232.3.126205.232.3.12730
29205.232.3.128/27205.232.3.129 to 205.232.3.158205.232.3.15930
30205.232.3.160/27205.232.3.161 to 205.232.3.190205.232.3.19130
31205.232.3.192/27205.232.3.193 to 205.232.3.222205.232.3.22330
32205.232.3.224/27205.232.3.225 to 205.232.3.254205.232.3.25530
33205.232.4.0/27205.232.4.1 to 205.232.4.30205.232.4.3130
34205.232.4.32/27205.232.4.33 to 205.232.4.62205.232.4.6330
35205.232.4.64/27205.232.4.65 to 205.232.4.94205.232.4.9530
36205.232.4.96/27205.232.4.97 to 205.232.4.126205.232.4.12730
37205.232.4.128/27205.232.4.129 to 205.232.4.158205.232.4.15930
38205.232.4.160/27205.232.4.161 to 205.232.4.190205.232.4.19130
39205.232.4.192/27205.232.4.193 to 205.232.4.222205.232.4.22330
40205.232.4.224/27205.232.4.225 to 205.232.4.254205.232.4.25530
41205.232.5.0/27205.232.5.1 to 205.232.5.30205.232.5.3130
42205.232.5.32/27205.232.5.33 to 205.232.5.62205.232.5.6330
43205.232.5.64/27205.232.5.65 to 205.232.5.94205.232.5.9530
44205.232.5.96/27205.232.5.97 to 205.232.5.126205.232.5.12730
45205.232.5.128/27205.232.5.129 to 205.232.5.158205.232.5.15930
46205.232.5.160/27205.232.5.161 to 205.232.5.190205.232.5.19130
47205.232.5.192/27205.232.5.193 to 205.232.5.222205.232.5.22330
48205.232.5.224/27205.232.5.225 to 205.232.5.254205.232.5.25530
49205.232.6.0/27205.232.6.1 to 205.232.6.30205.232.6.3130
50205.232.6.32/27205.232.6.33 to 205.232.6.62205.232.6.6330
51205.232.6.64/27205.232.6.65 to 205.232.6.94205.232.6.9530
52205.232.6.96/27205.232.6.97 to 205.232.6.126205.232.6.12730
53205.232.6.128/27205.232.6.129 to 205.232.6.158205.232.6.15930
54205.232.6.160/27205.232.6.161 to 205.232.6.190205.232.6.19130
55205.232.6.192/27205.232.6.193 to 205.232.6.222205.232.6.22330
56205.232.6.224/27205.232.6.225 to 205.232.6.254205.232.6.25530
57205.232.7.0/27205.232.7.1 to 205.232.7.30205.232.7.3130
58205.232.7.32/27205.232.7.33 to 205.232.7.62205.232.7.6330
59205.232.7.64/27205.232.7.65 to 205.232.7.94205.232.7.9530
60205.232.7.96/27205.232.7.97 to 205.232.7.126205.232.7.12730
61205.232.7.128/27205.232.7.129 to 205.232.7.158205.232.7.15930
62205.232.7.160/27205.232.7.161 to 205.232.7.190205.232.7.19130
63205.232.7.192/27205.232.7.193 to 205.232.7.222205.232.7.22330
64205.232.7.224/27205.232.7.225 to 205.232.7.254205.232.7.25530
65205.232.8.0/27205.232.8.1 to 205.232.8.30205.232.8.3130
66205.232.8.32/27205.232.8.33 to 205.232.8.62205.232.8.6330
67205.232.8.64/27205.232.8.65 to 205.232.8.94205.232.8.9530
68205.232.8.96/27205.232.8.97 to 205.232.8.126205.232.8.12730
69205.232.8.128/27205.232.8.129 to 205.232.8.158205.232.8.15930
70205.232.8.160/27205.232.8.161 to 205.232.8.190205.232.8.19130
71205.232.8.192/27205.232.8.193 to 205.232.8.222205.232.8.22330
72205.232.8.224/27205.232.8.225 to 205.232.8.254205.232.8.25530
73205.232.9.0/27205.232.9.1 to 205.232.9.30205.232.9.3130
74205.232.9.32/27205.232.9.33 to 205.232.9.62205.232.9.6330
75205.232.9.64/27205.232.9.65 to 205.232.9.94205.232.9.9530
76205.232.9.96/27205.232.9.97 to 205.232.9.126205.232.9.12730
77205.232.9.128/27205.232.9.129 to 205.232.9.158205.232.9.15930
78205.232.9.160/27205.232.9.161 to 205.232.9.190205.232.9.19130
79205.232.9.192/27205.232.9.193 to 205.232.9.222205.232.9.22330
80205.232.9.224/27205.232.9.225 to 205.232.9.254205.232.9.25530
81205.232.10.0/27205.232.10.1 to 205.232.10.30205.232.10.3130
82205.232.10.32/27205.232.10.33 to 205.232.10.62205.232.10.6330
83205.232.10.64/27205.232.10.65 to 205.232.10.94205.232.10.9530
84205.232.10.96/27205.232.10.97 to 205.232.10.126205.232.10.12730
85205.232.10.128/27205.232.10.129 to 205.232.10.158205.232.10.15930
86205.232.10.160/27205.232.10.161 to 205.232.10.190205.232.10.19130
87205.232.10.192/27205.232.10.193 to 205.232.10.222205.232.10.22330
88205.232.10.224/27205.232.10.225 to 205.232.10.254205.232.10.25530
89205.232.11.0/27205.232.11.1 to 205.232.11.30205.232.11.3130
90205.232.11.32/27205.232.11.33 to 205.232.11.62205.232.11.6330
91205.232.11.64/27205.232.11.65 to 205.232.11.94205.232.11.9530
92205.232.11.96/27205.232.11.97 to 205.232.11.126205.232.11.12730
93205.232.11.128/27205.232.11.129 to 205.232.11.158205.232.11.15930
94205.232.11.160/27205.232.11.161 to 205.232.11.190205.232.11.19130
95205.232.11.192/27205.232.11.193 to 205.232.11.222205.232.11.22330
96205.232.11.224/27205.232.11.225 to 205.232.11.254205.232.11.25530
97205.232.12.0/27205.232.12.1 to 205.232.12.30205.232.12.3130
98205.232.12.32/27205.232.12.33 to 205.232.12.62205.232.12.6330
99205.232.12.64/27205.232.12.65 to 205.232.12.94205.232.12.9530
100205.232.12.96/27205.232.12.97 to 205.232.12.126205.232.12.12730
101205.232.12.128/27205.232.12.129 to 205.232.12.158205.232.12.15930
102205.232.12.160/27205.232.12.161 to 205.232.12.190205.232.12.19130
103205.232.12.192/27205.232.12.193 to 205.232.12.222205.232.12.22330
104205.232.12.224/27205.232.12.225 to 205.232.12.254205.232.12.25530
105205.232.13.0/27205.232.13.1 to 205.232.13.30205.232.13.3130
106205.232.13.32/27205.232.13.33 to 205.232.13.62205.232.13.6330
107205.232.13.64/27205.232.13.65 to 205.232.13.94205.232.13.9530
108205.232.13.96/27205.232.13.97 to 205.232.13.126205.232.13.12730
109205.232.13.128/27205.232.13.129 to 205.232.13.158205.232.13.15930
110205.232.13.160/27205.232.13.161 to 205.232.13.190205.232.13.19130
111205.232.13.192/27205.232.13.193 to 205.232.13.222205.232.13.22330
112205.232.13.224/27205.232.13.225 to 205.232.13.254205.232.13.25530
113205.232.14.0/27205.232.14.1 to 205.232.14.30205.232.14.3130
114205.232.14.32/27205.232.14.33 to 205.232.14.62205.232.14.6330
115205.232.14.64/27205.232.14.65 to 205.232.14.94205.232.14.9530
116205.232.14.96/27205.232.14.97 to 205.232.14.126205.232.14.12730
117205.232.14.128/27205.232.14.129 to 205.232.14.158205.232.14.15930
118205.232.14.160/27205.232.14.161 to 205.232.14.190205.232.14.19130
119205.232.14.192/27205.232.14.193 to 205.232.14.222205.232.14.22330
120205.232.14.224/27205.232.14.225 to 205.232.14.254205.232.14.25530
121205.232.15.0/27205.232.15.1 to 205.232.15.30205.232.15.3130
122205.232.15.32/27205.232.15.33 to 205.232.15.62205.232.15.6330
123205.232.15.64/27205.232.15.65 to 205.232.15.94205.232.15.9530
124205.232.15.96/27205.232.15.97 to 205.232.15.126205.232.15.12730
125205.232.15.128/27205.232.15.129 to 205.232.15.158205.232.15.15930
126205.232.15.160/27205.232.15.161 to 205.232.15.190205.232.15.19130
127205.232.15.192/27205.232.15.193 to 205.232.15.222205.232.15.22330
128205.232.15.224/27205.232.15.225 to 205.232.15.254205.232.15.25530
129205.232.16.0/27205.232.16.1 to 205.232.16.30205.232.16.3130
130205.232.16.32/27205.232.16.33 to 205.232.16.62205.232.16.6330
131205.232.16.64/27205.232.16.65 to 205.232.16.94205.232.16.9530
132205.232.16.96/27205.232.16.97 to 205.232.16.126205.232.16.12730
133205.232.16.128/27205.232.16.129 to 205.232.16.158205.232.16.15930
134205.232.16.160/27205.232.16.161 to 205.232.16.190205.232.16.19130
135205.232.16.192/27205.232.16.193 to 205.232.16.222205.232.16.22330
136205.232.16.224/27205.232.16.225 to 205.232.16.254205.232.16.25530
137205.232.17.0/27205.232.17.1 to 205.232.17.30205.232.17.3130
138205.232.17.32/27205.232.17.33 to 205.232.17.62205.232.17.6330
139205.232.17.64/27205.232.17.65 to 205.232.17.94205.232.17.9530
140205.232.17.96/27205.232.17.97 to 205.232.17.126205.232.17.12730
141205.232.17.128/27205.232.17.129 to 205.232.17.158205.232.17.15930
142205.232.17.160/27205.232.17.161 to 205.232.17.190205.232.17.19130
143205.232.17.192/27205.232.17.193 to 205.232.17.222205.232.17.22330
144205.232.17.224/27205.232.17.225 to 205.232.17.254205.232.17.25530
145205.232.18.0/27205.232.18.1 to 205.232.18.30205.232.18.3130
146205.232.18.32/27205.232.18.33 to 205.232.18.62205.232.18.6330
147205.232.18.64/27205.232.18.65 to 205.232.18.94205.232.18.9530
148205.232.18.96/27205.232.18.97 to 205.232.18.126205.232.18.12730
149205.232.18.128/27205.232.18.129 to 205.232.18.158205.232.18.15930
150205.232.18.160/27205.232.18.161 to 205.232.18.190205.232.18.19130
151205.232.18.192/27205.232.18.193 to 205.232.18.222205.232.18.22330
152205.232.18.224/27205.232.18.225 to 205.232.18.254205.232.18.25530
153205.232.19.0/27205.232.19.1 to 205.232.19.30205.232.19.3130
154205.232.19.32/27205.232.19.33 to 205.232.19.62205.232.19.6330
155205.232.19.64/27205.232.19.65 to 205.232.19.94205.232.19.9530
156205.232.19.96/27205.232.19.97 to 205.232.19.126205.232.19.12730
157205.232.19.128/27205.232.19.129 to 205.232.19.158205.232.19.15930
158205.232.19.160/27205.232.19.161 to 205.232.19.190205.232.19.19130
159205.232.19.192/27205.232.19.193 to 205.232.19.222205.232.19.22330
160205.232.19.224/27205.232.19.225 to 205.232.19.254205.232.19.25530
161205.232.20.0/27205.232.20.1 to 205.232.20.30205.232.20.3130
162205.232.20.32/27205.232.20.33 to 205.232.20.62205.232.20.6330
163205.232.20.64/27205.232.20.65 to 205.232.20.94205.232.20.9530
164205.232.20.96/27205.232.20.97 to 205.232.20.126205.232.20.12730
165205.232.20.128/27205.232.20.129 to 205.232.20.158205.232.20.15930
166205.232.20.160/27205.232.20.161 to 205.232.20.190205.232.20.19130
167205.232.20.192/27205.232.20.193 to 205.232.20.222205.232.20.22330
168205.232.20.224/27205.232.20.225 to 205.232.20.254205.232.20.25530
169205.232.21.0/27205.232.21.1 to 205.232.21.30205.232.21.3130
170205.232.21.32/27205.232.21.33 to 205.232.21.62205.232.21.6330
171205.232.21.64/27205.232.21.65 to 205.232.21.94205.232.21.9530
172205.232.21.96/27205.232.21.97 to 205.232.21.126205.232.21.12730
173205.232.21.128/27205.232.21.129 to 205.232.21.158205.232.21.15930
174205.232.21.160/27205.232.21.161 to 205.232.21.190205.232.21.19130
175205.232.21.192/27205.232.21.193 to 205.232.21.222205.232.21.22330
176205.232.21.224/27205.232.21.225 to 205.232.21.254205.232.21.25530
177205.232.22.0/27205.232.22.1 to 205.232.22.30205.232.22.3130
178205.232.22.32/27205.232.22.33 to 205.232.22.62205.232.22.6330
179205.232.22.64/27205.232.22.65 to 205.232.22.94205.232.22.9530
180205.232.22.96/27205.232.22.97 to 205.232.22.126205.232.22.12730
181205.232.22.128/27205.232.22.129 to 205.232.22.158205.232.22.15930
182205.232.22.160/27205.232.22.161 to 205.232.22.190205.232.22.19130
183205.232.22.192/27205.232.22.193 to 205.232.22.222205.232.22.22330
184205.232.22.224/27205.232.22.225 to 205.232.22.254205.232.22.25530
185205.232.23.0/27205.232.23.1 to 205.232.23.30205.232.23.3130
186205.232.23.32/27205.232.23.33 to 205.232.23.62205.232.23.6330
187205.232.23.64/27205.232.23.65 to 205.232.23.94205.232.23.9530
188205.232.23.96/27205.232.23.97 to 205.232.23.126205.232.23.12730
189205.232.23.128/27205.232.23.129 to 205.232.23.158205.232.23.15930
190205.232.23.160/27205.232.23.161 to 205.232.23.190205.232.23.19130
191205.232.23.192/27205.232.23.193 to 205.232.23.222205.232.23.22330
192205.232.23.224/27205.232.23.225 to 205.232.23.254205.232.23.25530
193205.232.24.0/27205.232.24.1 to 205.232.24.30205.232.24.3130
194205.232.24.32/27205.232.24.33 to 205.232.24.62205.232.24.6330
195205.232.24.64/27205.232.24.65 to 205.232.24.94205.232.24.9530
196205.232.24.96/27205.232.24.97 to 205.232.24.126205.232.24.12730
197205.232.24.128/27205.232.24.129 to 205.232.24.158205.232.24.15930
198205.232.24.160/27205.232.24.161 to 205.232.24.190205.232.24.19130
199205.232.24.192/27205.232.24.193 to 205.232.24.222205.232.24.22330
200205.232.24.224/27205.232.24.225 to 205.232.24.254205.232.24.25530
201205.232.25.0/27205.232.25.1 to 205.232.25.30205.232.25.3130
202205.232.25.32/27205.232.25.33 to 205.232.25.62205.232.25.6330
203205.232.25.64/27205.232.25.65 to 205.232.25.94205.232.25.9530
204205.232.25.96/27205.232.25.97 to 205.232.25.126205.232.25.12730
205205.232.25.128/27205.232.25.129 to 205.232.25.158205.232.25.15930
206205.232.25.160/27205.232.25.161 to 205.232.25.190205.232.25.19130
207205.232.25.192/27205.232.25.193 to 205.232.25.222205.232.25.22330
208205.232.25.224/27205.232.25.225 to 205.232.25.254205.232.25.25530
209205.232.26.0/27205.232.26.1 to 205.232.26.30205.232.26.3130
210205.232.26.32/27205.232.26.33 to 205.232.26.62205.232.26.6330
211205.232.26.64/27205.232.26.65 to 205.232.26.94205.232.26.9530
212205.232.26.96/27205.232.26.97 to 205.232.26.126205.232.26.12730
213205.232.26.128/27205.232.26.129 to 205.232.26.158205.232.26.15930
214205.232.26.160/27205.232.26.161 to 205.232.26.190205.232.26.19130
215205.232.26.192/27205.232.26.193 to 205.232.26.222205.232.26.22330
216205.232.26.224/27205.232.26.225 to 205.232.26.254205.232.26.25530
217205.232.27.0/27205.232.27.1 to 205.232.27.30205.232.27.3130
218205.232.27.32/27205.232.27.33 to 205.232.27.62205.232.27.6330
219205.232.27.64/27205.232.27.65 to 205.232.27.94205.232.27.9530
220205.232.27.96/27205.232.27.97 to 205.232.27.126205.232.27.12730
221205.232.27.128/27205.232.27.129 to 205.232.27.158205.232.27.15930
222205.232.27.160/27205.232.27.161 to 205.232.27.190205.232.27.19130
223205.232.27.192/27205.232.27.193 to 205.232.27.222205.232.27.22330
224205.232.27.224/27205.232.27.225 to 205.232.27.254205.232.27.25530
225205.232.28.0/27205.232.28.1 to 205.232.28.30205.232.28.3130
226205.232.28.32/27205.232.28.33 to 205.232.28.62205.232.28.6330
227205.232.28.64/27205.232.28.65 to 205.232.28.94205.232.28.9530
228205.232.28.96/27205.232.28.97 to 205.232.28.126205.232.28.12730
229205.232.28.128/27205.232.28.129 to 205.232.28.158205.232.28.15930
230205.232.28.160/27205.232.28.161 to 205.232.28.190205.232.28.19130
231205.232.28.192/27205.232.28.193 to 205.232.28.222205.232.28.22330
232205.232.28.224/27205.232.28.225 to 205.232.28.254205.232.28.25530
233205.232.29.0/27205.232.29.1 to 205.232.29.30205.232.29.3130
234205.232.29.32/27205.232.29.33 to 205.232.29.62205.232.29.6330
235205.232.29.64/27205.232.29.65 to 205.232.29.94205.232.29.9530
236205.232.29.96/27205.232.29.97 to 205.232.29.126205.232.29.12730
237205.232.29.128/27205.232.29.129 to 205.232.29.158205.232.29.15930
238205.232.29.160/27205.232.29.161 to 205.232.29.190205.232.29.19130
239205.232.29.192/27205.232.29.193 to 205.232.29.222205.232.29.22330
240205.232.29.224/27205.232.29.225 to 205.232.29.254205.232.29.25530
241205.232.30.0/27205.232.30.1 to 205.232.30.30205.232.30.3130
242205.232.30.32/27205.232.30.33 to 205.232.30.62205.232.30.6330
243205.232.30.64/27205.232.30.65 to 205.232.30.94205.232.30.9530
244205.232.30.96/27205.232.30.97 to 205.232.30.126205.232.30.12730
245205.232.30.128/27205.232.30.129 to 205.232.30.158205.232.30.15930
246205.232.30.160/27205.232.30.161 to 205.232.30.190205.232.30.19130
247205.232.30.192/27205.232.30.193 to 205.232.30.222205.232.30.22330
248205.232.30.224/27205.232.30.225 to 205.232.30.254205.232.30.25530
249205.232.31.0/27205.232.31.1 to 205.232.31.30205.232.31.3130
250205.232.31.32/27205.232.31.33 to 205.232.31.62205.232.31.6330
251205.232.31.64/27205.232.31.65 to 205.232.31.94205.232.31.9530
252205.232.31.96/27205.232.31.97 to 205.232.31.126205.232.31.12730
253205.232.31.128/27205.232.31.129 to 205.232.31.158205.232.31.15930
254205.232.31.160/27205.232.31.161 to 205.232.31.190205.232.31.19130
255205.232.31.192/27205.232.31.193 to 205.232.31.222205.232.31.22330
256205.232.31.224/27205.232.31.225 to 205.232.31.254205.232.31.25530

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.