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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.

Network180.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
180.136.0.0
Broadcast address
180.137.255.255
First usable
180.136.0.1
Last usable
180.137.255.254
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 B4880000 · Integer 3028811776 to 3028942847
Reverse DNS zones
136.180.in-addr.arpa
137.180.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
Address10110100.10001000.00000000.00000000180.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10110100.10001000.00000000.00000000180.136.0.0
Broadcast10110100.10001001.11111111.11111111180.137.255.255
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)

180.136.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1180.136.0.0/27180.136.0.1 to 180.136.0.30180.136.0.3130
2180.136.0.32/27180.136.0.33 to 180.136.0.62180.136.0.6330
3180.136.0.64/27180.136.0.65 to 180.136.0.94180.136.0.9530
4180.136.0.96/27180.136.0.97 to 180.136.0.126180.136.0.12730
5180.136.0.128/27180.136.0.129 to 180.136.0.158180.136.0.15930
6180.136.0.160/27180.136.0.161 to 180.136.0.190180.136.0.19130
7180.136.0.192/27180.136.0.193 to 180.136.0.222180.136.0.22330
8180.136.0.224/27180.136.0.225 to 180.136.0.254180.136.0.25530
9180.136.1.0/27180.136.1.1 to 180.136.1.30180.136.1.3130
10180.136.1.32/27180.136.1.33 to 180.136.1.62180.136.1.6330
11180.136.1.64/27180.136.1.65 to 180.136.1.94180.136.1.9530
12180.136.1.96/27180.136.1.97 to 180.136.1.126180.136.1.12730
13180.136.1.128/27180.136.1.129 to 180.136.1.158180.136.1.15930
14180.136.1.160/27180.136.1.161 to 180.136.1.190180.136.1.19130
15180.136.1.192/27180.136.1.193 to 180.136.1.222180.136.1.22330
16180.136.1.224/27180.136.1.225 to 180.136.1.254180.136.1.25530
17180.136.2.0/27180.136.2.1 to 180.136.2.30180.136.2.3130
18180.136.2.32/27180.136.2.33 to 180.136.2.62180.136.2.6330
19180.136.2.64/27180.136.2.65 to 180.136.2.94180.136.2.9530
20180.136.2.96/27180.136.2.97 to 180.136.2.126180.136.2.12730
21180.136.2.128/27180.136.2.129 to 180.136.2.158180.136.2.15930
22180.136.2.160/27180.136.2.161 to 180.136.2.190180.136.2.19130
23180.136.2.192/27180.136.2.193 to 180.136.2.222180.136.2.22330
24180.136.2.224/27180.136.2.225 to 180.136.2.254180.136.2.25530
25180.136.3.0/27180.136.3.1 to 180.136.3.30180.136.3.3130
26180.136.3.32/27180.136.3.33 to 180.136.3.62180.136.3.6330
27180.136.3.64/27180.136.3.65 to 180.136.3.94180.136.3.9530
28180.136.3.96/27180.136.3.97 to 180.136.3.126180.136.3.12730
29180.136.3.128/27180.136.3.129 to 180.136.3.158180.136.3.15930
30180.136.3.160/27180.136.3.161 to 180.136.3.190180.136.3.19130
31180.136.3.192/27180.136.3.193 to 180.136.3.222180.136.3.22330
32180.136.3.224/27180.136.3.225 to 180.136.3.254180.136.3.25530
33180.136.4.0/27180.136.4.1 to 180.136.4.30180.136.4.3130
34180.136.4.32/27180.136.4.33 to 180.136.4.62180.136.4.6330
35180.136.4.64/27180.136.4.65 to 180.136.4.94180.136.4.9530
36180.136.4.96/27180.136.4.97 to 180.136.4.126180.136.4.12730
37180.136.4.128/27180.136.4.129 to 180.136.4.158180.136.4.15930
38180.136.4.160/27180.136.4.161 to 180.136.4.190180.136.4.19130
39180.136.4.192/27180.136.4.193 to 180.136.4.222180.136.4.22330
40180.136.4.224/27180.136.4.225 to 180.136.4.254180.136.4.25530
41180.136.5.0/27180.136.5.1 to 180.136.5.30180.136.5.3130
42180.136.5.32/27180.136.5.33 to 180.136.5.62180.136.5.6330
43180.136.5.64/27180.136.5.65 to 180.136.5.94180.136.5.9530
44180.136.5.96/27180.136.5.97 to 180.136.5.126180.136.5.12730
45180.136.5.128/27180.136.5.129 to 180.136.5.158180.136.5.15930
46180.136.5.160/27180.136.5.161 to 180.136.5.190180.136.5.19130
47180.136.5.192/27180.136.5.193 to 180.136.5.222180.136.5.22330
48180.136.5.224/27180.136.5.225 to 180.136.5.254180.136.5.25530
49180.136.6.0/27180.136.6.1 to 180.136.6.30180.136.6.3130
50180.136.6.32/27180.136.6.33 to 180.136.6.62180.136.6.6330
51180.136.6.64/27180.136.6.65 to 180.136.6.94180.136.6.9530
52180.136.6.96/27180.136.6.97 to 180.136.6.126180.136.6.12730
53180.136.6.128/27180.136.6.129 to 180.136.6.158180.136.6.15930
54180.136.6.160/27180.136.6.161 to 180.136.6.190180.136.6.19130
55180.136.6.192/27180.136.6.193 to 180.136.6.222180.136.6.22330
56180.136.6.224/27180.136.6.225 to 180.136.6.254180.136.6.25530
57180.136.7.0/27180.136.7.1 to 180.136.7.30180.136.7.3130
58180.136.7.32/27180.136.7.33 to 180.136.7.62180.136.7.6330
59180.136.7.64/27180.136.7.65 to 180.136.7.94180.136.7.9530
60180.136.7.96/27180.136.7.97 to 180.136.7.126180.136.7.12730
61180.136.7.128/27180.136.7.129 to 180.136.7.158180.136.7.15930
62180.136.7.160/27180.136.7.161 to 180.136.7.190180.136.7.19130
63180.136.7.192/27180.136.7.193 to 180.136.7.222180.136.7.22330
64180.136.7.224/27180.136.7.225 to 180.136.7.254180.136.7.25530
65180.136.8.0/27180.136.8.1 to 180.136.8.30180.136.8.3130
66180.136.8.32/27180.136.8.33 to 180.136.8.62180.136.8.6330
67180.136.8.64/27180.136.8.65 to 180.136.8.94180.136.8.9530
68180.136.8.96/27180.136.8.97 to 180.136.8.126180.136.8.12730
69180.136.8.128/27180.136.8.129 to 180.136.8.158180.136.8.15930
70180.136.8.160/27180.136.8.161 to 180.136.8.190180.136.8.19130
71180.136.8.192/27180.136.8.193 to 180.136.8.222180.136.8.22330
72180.136.8.224/27180.136.8.225 to 180.136.8.254180.136.8.25530
73180.136.9.0/27180.136.9.1 to 180.136.9.30180.136.9.3130
74180.136.9.32/27180.136.9.33 to 180.136.9.62180.136.9.6330
75180.136.9.64/27180.136.9.65 to 180.136.9.94180.136.9.9530
76180.136.9.96/27180.136.9.97 to 180.136.9.126180.136.9.12730
77180.136.9.128/27180.136.9.129 to 180.136.9.158180.136.9.15930
78180.136.9.160/27180.136.9.161 to 180.136.9.190180.136.9.19130
79180.136.9.192/27180.136.9.193 to 180.136.9.222180.136.9.22330
80180.136.9.224/27180.136.9.225 to 180.136.9.254180.136.9.25530
81180.136.10.0/27180.136.10.1 to 180.136.10.30180.136.10.3130
82180.136.10.32/27180.136.10.33 to 180.136.10.62180.136.10.6330
83180.136.10.64/27180.136.10.65 to 180.136.10.94180.136.10.9530
84180.136.10.96/27180.136.10.97 to 180.136.10.126180.136.10.12730
85180.136.10.128/27180.136.10.129 to 180.136.10.158180.136.10.15930
86180.136.10.160/27180.136.10.161 to 180.136.10.190180.136.10.19130
87180.136.10.192/27180.136.10.193 to 180.136.10.222180.136.10.22330
88180.136.10.224/27180.136.10.225 to 180.136.10.254180.136.10.25530
89180.136.11.0/27180.136.11.1 to 180.136.11.30180.136.11.3130
90180.136.11.32/27180.136.11.33 to 180.136.11.62180.136.11.6330
91180.136.11.64/27180.136.11.65 to 180.136.11.94180.136.11.9530
92180.136.11.96/27180.136.11.97 to 180.136.11.126180.136.11.12730
93180.136.11.128/27180.136.11.129 to 180.136.11.158180.136.11.15930
94180.136.11.160/27180.136.11.161 to 180.136.11.190180.136.11.19130
95180.136.11.192/27180.136.11.193 to 180.136.11.222180.136.11.22330
96180.136.11.224/27180.136.11.225 to 180.136.11.254180.136.11.25530
97180.136.12.0/27180.136.12.1 to 180.136.12.30180.136.12.3130
98180.136.12.32/27180.136.12.33 to 180.136.12.62180.136.12.6330
99180.136.12.64/27180.136.12.65 to 180.136.12.94180.136.12.9530
100180.136.12.96/27180.136.12.97 to 180.136.12.126180.136.12.12730
101180.136.12.128/27180.136.12.129 to 180.136.12.158180.136.12.15930
102180.136.12.160/27180.136.12.161 to 180.136.12.190180.136.12.19130
103180.136.12.192/27180.136.12.193 to 180.136.12.222180.136.12.22330
104180.136.12.224/27180.136.12.225 to 180.136.12.254180.136.12.25530
105180.136.13.0/27180.136.13.1 to 180.136.13.30180.136.13.3130
106180.136.13.32/27180.136.13.33 to 180.136.13.62180.136.13.6330
107180.136.13.64/27180.136.13.65 to 180.136.13.94180.136.13.9530
108180.136.13.96/27180.136.13.97 to 180.136.13.126180.136.13.12730
109180.136.13.128/27180.136.13.129 to 180.136.13.158180.136.13.15930
110180.136.13.160/27180.136.13.161 to 180.136.13.190180.136.13.19130
111180.136.13.192/27180.136.13.193 to 180.136.13.222180.136.13.22330
112180.136.13.224/27180.136.13.225 to 180.136.13.254180.136.13.25530
113180.136.14.0/27180.136.14.1 to 180.136.14.30180.136.14.3130
114180.136.14.32/27180.136.14.33 to 180.136.14.62180.136.14.6330
115180.136.14.64/27180.136.14.65 to 180.136.14.94180.136.14.9530
116180.136.14.96/27180.136.14.97 to 180.136.14.126180.136.14.12730
117180.136.14.128/27180.136.14.129 to 180.136.14.158180.136.14.15930
118180.136.14.160/27180.136.14.161 to 180.136.14.190180.136.14.19130
119180.136.14.192/27180.136.14.193 to 180.136.14.222180.136.14.22330
120180.136.14.224/27180.136.14.225 to 180.136.14.254180.136.14.25530
121180.136.15.0/27180.136.15.1 to 180.136.15.30180.136.15.3130
122180.136.15.32/27180.136.15.33 to 180.136.15.62180.136.15.6330
123180.136.15.64/27180.136.15.65 to 180.136.15.94180.136.15.9530
124180.136.15.96/27180.136.15.97 to 180.136.15.126180.136.15.12730
125180.136.15.128/27180.136.15.129 to 180.136.15.158180.136.15.15930
126180.136.15.160/27180.136.15.161 to 180.136.15.190180.136.15.19130
127180.136.15.192/27180.136.15.193 to 180.136.15.222180.136.15.22330
128180.136.15.224/27180.136.15.225 to 180.136.15.254180.136.15.25530
129180.136.16.0/27180.136.16.1 to 180.136.16.30180.136.16.3130
130180.136.16.32/27180.136.16.33 to 180.136.16.62180.136.16.6330
131180.136.16.64/27180.136.16.65 to 180.136.16.94180.136.16.9530
132180.136.16.96/27180.136.16.97 to 180.136.16.126180.136.16.12730
133180.136.16.128/27180.136.16.129 to 180.136.16.158180.136.16.15930
134180.136.16.160/27180.136.16.161 to 180.136.16.190180.136.16.19130
135180.136.16.192/27180.136.16.193 to 180.136.16.222180.136.16.22330
136180.136.16.224/27180.136.16.225 to 180.136.16.254180.136.16.25530
137180.136.17.0/27180.136.17.1 to 180.136.17.30180.136.17.3130
138180.136.17.32/27180.136.17.33 to 180.136.17.62180.136.17.6330
139180.136.17.64/27180.136.17.65 to 180.136.17.94180.136.17.9530
140180.136.17.96/27180.136.17.97 to 180.136.17.126180.136.17.12730
141180.136.17.128/27180.136.17.129 to 180.136.17.158180.136.17.15930
142180.136.17.160/27180.136.17.161 to 180.136.17.190180.136.17.19130
143180.136.17.192/27180.136.17.193 to 180.136.17.222180.136.17.22330
144180.136.17.224/27180.136.17.225 to 180.136.17.254180.136.17.25530
145180.136.18.0/27180.136.18.1 to 180.136.18.30180.136.18.3130
146180.136.18.32/27180.136.18.33 to 180.136.18.62180.136.18.6330
147180.136.18.64/27180.136.18.65 to 180.136.18.94180.136.18.9530
148180.136.18.96/27180.136.18.97 to 180.136.18.126180.136.18.12730
149180.136.18.128/27180.136.18.129 to 180.136.18.158180.136.18.15930
150180.136.18.160/27180.136.18.161 to 180.136.18.190180.136.18.19130
151180.136.18.192/27180.136.18.193 to 180.136.18.222180.136.18.22330
152180.136.18.224/27180.136.18.225 to 180.136.18.254180.136.18.25530
153180.136.19.0/27180.136.19.1 to 180.136.19.30180.136.19.3130
154180.136.19.32/27180.136.19.33 to 180.136.19.62180.136.19.6330
155180.136.19.64/27180.136.19.65 to 180.136.19.94180.136.19.9530
156180.136.19.96/27180.136.19.97 to 180.136.19.126180.136.19.12730
157180.136.19.128/27180.136.19.129 to 180.136.19.158180.136.19.15930
158180.136.19.160/27180.136.19.161 to 180.136.19.190180.136.19.19130
159180.136.19.192/27180.136.19.193 to 180.136.19.222180.136.19.22330
160180.136.19.224/27180.136.19.225 to 180.136.19.254180.136.19.25530
161180.136.20.0/27180.136.20.1 to 180.136.20.30180.136.20.3130
162180.136.20.32/27180.136.20.33 to 180.136.20.62180.136.20.6330
163180.136.20.64/27180.136.20.65 to 180.136.20.94180.136.20.9530
164180.136.20.96/27180.136.20.97 to 180.136.20.126180.136.20.12730
165180.136.20.128/27180.136.20.129 to 180.136.20.158180.136.20.15930
166180.136.20.160/27180.136.20.161 to 180.136.20.190180.136.20.19130
167180.136.20.192/27180.136.20.193 to 180.136.20.222180.136.20.22330
168180.136.20.224/27180.136.20.225 to 180.136.20.254180.136.20.25530
169180.136.21.0/27180.136.21.1 to 180.136.21.30180.136.21.3130
170180.136.21.32/27180.136.21.33 to 180.136.21.62180.136.21.6330
171180.136.21.64/27180.136.21.65 to 180.136.21.94180.136.21.9530
172180.136.21.96/27180.136.21.97 to 180.136.21.126180.136.21.12730
173180.136.21.128/27180.136.21.129 to 180.136.21.158180.136.21.15930
174180.136.21.160/27180.136.21.161 to 180.136.21.190180.136.21.19130
175180.136.21.192/27180.136.21.193 to 180.136.21.222180.136.21.22330
176180.136.21.224/27180.136.21.225 to 180.136.21.254180.136.21.25530
177180.136.22.0/27180.136.22.1 to 180.136.22.30180.136.22.3130
178180.136.22.32/27180.136.22.33 to 180.136.22.62180.136.22.6330
179180.136.22.64/27180.136.22.65 to 180.136.22.94180.136.22.9530
180180.136.22.96/27180.136.22.97 to 180.136.22.126180.136.22.12730
181180.136.22.128/27180.136.22.129 to 180.136.22.158180.136.22.15930
182180.136.22.160/27180.136.22.161 to 180.136.22.190180.136.22.19130
183180.136.22.192/27180.136.22.193 to 180.136.22.222180.136.22.22330
184180.136.22.224/27180.136.22.225 to 180.136.22.254180.136.22.25530
185180.136.23.0/27180.136.23.1 to 180.136.23.30180.136.23.3130
186180.136.23.32/27180.136.23.33 to 180.136.23.62180.136.23.6330
187180.136.23.64/27180.136.23.65 to 180.136.23.94180.136.23.9530
188180.136.23.96/27180.136.23.97 to 180.136.23.126180.136.23.12730
189180.136.23.128/27180.136.23.129 to 180.136.23.158180.136.23.15930
190180.136.23.160/27180.136.23.161 to 180.136.23.190180.136.23.19130
191180.136.23.192/27180.136.23.193 to 180.136.23.222180.136.23.22330
192180.136.23.224/27180.136.23.225 to 180.136.23.254180.136.23.25530
193180.136.24.0/27180.136.24.1 to 180.136.24.30180.136.24.3130
194180.136.24.32/27180.136.24.33 to 180.136.24.62180.136.24.6330
195180.136.24.64/27180.136.24.65 to 180.136.24.94180.136.24.9530
196180.136.24.96/27180.136.24.97 to 180.136.24.126180.136.24.12730
197180.136.24.128/27180.136.24.129 to 180.136.24.158180.136.24.15930
198180.136.24.160/27180.136.24.161 to 180.136.24.190180.136.24.19130
199180.136.24.192/27180.136.24.193 to 180.136.24.222180.136.24.22330
200180.136.24.224/27180.136.24.225 to 180.136.24.254180.136.24.25530
201180.136.25.0/27180.136.25.1 to 180.136.25.30180.136.25.3130
202180.136.25.32/27180.136.25.33 to 180.136.25.62180.136.25.6330
203180.136.25.64/27180.136.25.65 to 180.136.25.94180.136.25.9530
204180.136.25.96/27180.136.25.97 to 180.136.25.126180.136.25.12730
205180.136.25.128/27180.136.25.129 to 180.136.25.158180.136.25.15930
206180.136.25.160/27180.136.25.161 to 180.136.25.190180.136.25.19130
207180.136.25.192/27180.136.25.193 to 180.136.25.222180.136.25.22330
208180.136.25.224/27180.136.25.225 to 180.136.25.254180.136.25.25530
209180.136.26.0/27180.136.26.1 to 180.136.26.30180.136.26.3130
210180.136.26.32/27180.136.26.33 to 180.136.26.62180.136.26.6330
211180.136.26.64/27180.136.26.65 to 180.136.26.94180.136.26.9530
212180.136.26.96/27180.136.26.97 to 180.136.26.126180.136.26.12730
213180.136.26.128/27180.136.26.129 to 180.136.26.158180.136.26.15930
214180.136.26.160/27180.136.26.161 to 180.136.26.190180.136.26.19130
215180.136.26.192/27180.136.26.193 to 180.136.26.222180.136.26.22330
216180.136.26.224/27180.136.26.225 to 180.136.26.254180.136.26.25530
217180.136.27.0/27180.136.27.1 to 180.136.27.30180.136.27.3130
218180.136.27.32/27180.136.27.33 to 180.136.27.62180.136.27.6330
219180.136.27.64/27180.136.27.65 to 180.136.27.94180.136.27.9530
220180.136.27.96/27180.136.27.97 to 180.136.27.126180.136.27.12730
221180.136.27.128/27180.136.27.129 to 180.136.27.158180.136.27.15930
222180.136.27.160/27180.136.27.161 to 180.136.27.190180.136.27.19130
223180.136.27.192/27180.136.27.193 to 180.136.27.222180.136.27.22330
224180.136.27.224/27180.136.27.225 to 180.136.27.254180.136.27.25530
225180.136.28.0/27180.136.28.1 to 180.136.28.30180.136.28.3130
226180.136.28.32/27180.136.28.33 to 180.136.28.62180.136.28.6330
227180.136.28.64/27180.136.28.65 to 180.136.28.94180.136.28.9530
228180.136.28.96/27180.136.28.97 to 180.136.28.126180.136.28.12730
229180.136.28.128/27180.136.28.129 to 180.136.28.158180.136.28.15930
230180.136.28.160/27180.136.28.161 to 180.136.28.190180.136.28.19130
231180.136.28.192/27180.136.28.193 to 180.136.28.222180.136.28.22330
232180.136.28.224/27180.136.28.225 to 180.136.28.254180.136.28.25530
233180.136.29.0/27180.136.29.1 to 180.136.29.30180.136.29.3130
234180.136.29.32/27180.136.29.33 to 180.136.29.62180.136.29.6330
235180.136.29.64/27180.136.29.65 to 180.136.29.94180.136.29.9530
236180.136.29.96/27180.136.29.97 to 180.136.29.126180.136.29.12730
237180.136.29.128/27180.136.29.129 to 180.136.29.158180.136.29.15930
238180.136.29.160/27180.136.29.161 to 180.136.29.190180.136.29.19130
239180.136.29.192/27180.136.29.193 to 180.136.29.222180.136.29.22330
240180.136.29.224/27180.136.29.225 to 180.136.29.254180.136.29.25530
241180.136.30.0/27180.136.30.1 to 180.136.30.30180.136.30.3130
242180.136.30.32/27180.136.30.33 to 180.136.30.62180.136.30.6330
243180.136.30.64/27180.136.30.65 to 180.136.30.94180.136.30.9530
244180.136.30.96/27180.136.30.97 to 180.136.30.126180.136.30.12730
245180.136.30.128/27180.136.30.129 to 180.136.30.158180.136.30.15930
246180.136.30.160/27180.136.30.161 to 180.136.30.190180.136.30.19130
247180.136.30.192/27180.136.30.193 to 180.136.30.222180.136.30.22330
248180.136.30.224/27180.136.30.225 to 180.136.30.254180.136.30.25530
249180.136.31.0/27180.136.31.1 to 180.136.31.30180.136.31.3130
250180.136.31.32/27180.136.31.33 to 180.136.31.62180.136.31.6330
251180.136.31.64/27180.136.31.65 to 180.136.31.94180.136.31.9530
252180.136.31.96/27180.136.31.97 to 180.136.31.126180.136.31.12730
253180.136.31.128/27180.136.31.129 to 180.136.31.158180.136.31.15930
254180.136.31.160/27180.136.31.161 to 180.136.31.190180.136.31.19130
255180.136.31.192/27180.136.31.193 to 180.136.31.222180.136.31.22330
256180.136.31.224/27180.136.31.225 to 180.136.31.254180.136.31.25530

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.