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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.

Network199.65.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
199.65.0.0
Broadcast address
199.65.255.255
First usable
199.65.0.1
Last usable
199.65.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
C (default /24)
As numbers
Hex C7410000 · Integer 3342925824 to 3342991359
Reverse DNS zone
65.199.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000111.01000001..00000000.00000000199.65.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11000111.01000001..00000000.00000000199.65.0.0
Broadcast11000111.01000001..11111111.11111111199.65.255.255
Split into smaller subnets/27
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

199.65.0.0/16 makes 2,048 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1199.65.0.0/27199.65.0.1 to 199.65.0.30199.65.0.3130
2199.65.0.32/27199.65.0.33 to 199.65.0.62199.65.0.6330
3199.65.0.64/27199.65.0.65 to 199.65.0.94199.65.0.9530
4199.65.0.96/27199.65.0.97 to 199.65.0.126199.65.0.12730
5199.65.0.128/27199.65.0.129 to 199.65.0.158199.65.0.15930
6199.65.0.160/27199.65.0.161 to 199.65.0.190199.65.0.19130
7199.65.0.192/27199.65.0.193 to 199.65.0.222199.65.0.22330
8199.65.0.224/27199.65.0.225 to 199.65.0.254199.65.0.25530
9199.65.1.0/27199.65.1.1 to 199.65.1.30199.65.1.3130
10199.65.1.32/27199.65.1.33 to 199.65.1.62199.65.1.6330
11199.65.1.64/27199.65.1.65 to 199.65.1.94199.65.1.9530
12199.65.1.96/27199.65.1.97 to 199.65.1.126199.65.1.12730
13199.65.1.128/27199.65.1.129 to 199.65.1.158199.65.1.15930
14199.65.1.160/27199.65.1.161 to 199.65.1.190199.65.1.19130
15199.65.1.192/27199.65.1.193 to 199.65.1.222199.65.1.22330
16199.65.1.224/27199.65.1.225 to 199.65.1.254199.65.1.25530
17199.65.2.0/27199.65.2.1 to 199.65.2.30199.65.2.3130
18199.65.2.32/27199.65.2.33 to 199.65.2.62199.65.2.6330
19199.65.2.64/27199.65.2.65 to 199.65.2.94199.65.2.9530
20199.65.2.96/27199.65.2.97 to 199.65.2.126199.65.2.12730
21199.65.2.128/27199.65.2.129 to 199.65.2.158199.65.2.15930
22199.65.2.160/27199.65.2.161 to 199.65.2.190199.65.2.19130
23199.65.2.192/27199.65.2.193 to 199.65.2.222199.65.2.22330
24199.65.2.224/27199.65.2.225 to 199.65.2.254199.65.2.25530
25199.65.3.0/27199.65.3.1 to 199.65.3.30199.65.3.3130
26199.65.3.32/27199.65.3.33 to 199.65.3.62199.65.3.6330
27199.65.3.64/27199.65.3.65 to 199.65.3.94199.65.3.9530
28199.65.3.96/27199.65.3.97 to 199.65.3.126199.65.3.12730
29199.65.3.128/27199.65.3.129 to 199.65.3.158199.65.3.15930
30199.65.3.160/27199.65.3.161 to 199.65.3.190199.65.3.19130
31199.65.3.192/27199.65.3.193 to 199.65.3.222199.65.3.22330
32199.65.3.224/27199.65.3.225 to 199.65.3.254199.65.3.25530
33199.65.4.0/27199.65.4.1 to 199.65.4.30199.65.4.3130
34199.65.4.32/27199.65.4.33 to 199.65.4.62199.65.4.6330
35199.65.4.64/27199.65.4.65 to 199.65.4.94199.65.4.9530
36199.65.4.96/27199.65.4.97 to 199.65.4.126199.65.4.12730
37199.65.4.128/27199.65.4.129 to 199.65.4.158199.65.4.15930
38199.65.4.160/27199.65.4.161 to 199.65.4.190199.65.4.19130
39199.65.4.192/27199.65.4.193 to 199.65.4.222199.65.4.22330
40199.65.4.224/27199.65.4.225 to 199.65.4.254199.65.4.25530
41199.65.5.0/27199.65.5.1 to 199.65.5.30199.65.5.3130
42199.65.5.32/27199.65.5.33 to 199.65.5.62199.65.5.6330
43199.65.5.64/27199.65.5.65 to 199.65.5.94199.65.5.9530
44199.65.5.96/27199.65.5.97 to 199.65.5.126199.65.5.12730
45199.65.5.128/27199.65.5.129 to 199.65.5.158199.65.5.15930
46199.65.5.160/27199.65.5.161 to 199.65.5.190199.65.5.19130
47199.65.5.192/27199.65.5.193 to 199.65.5.222199.65.5.22330
48199.65.5.224/27199.65.5.225 to 199.65.5.254199.65.5.25530
49199.65.6.0/27199.65.6.1 to 199.65.6.30199.65.6.3130
50199.65.6.32/27199.65.6.33 to 199.65.6.62199.65.6.6330
51199.65.6.64/27199.65.6.65 to 199.65.6.94199.65.6.9530
52199.65.6.96/27199.65.6.97 to 199.65.6.126199.65.6.12730
53199.65.6.128/27199.65.6.129 to 199.65.6.158199.65.6.15930
54199.65.6.160/27199.65.6.161 to 199.65.6.190199.65.6.19130
55199.65.6.192/27199.65.6.193 to 199.65.6.222199.65.6.22330
56199.65.6.224/27199.65.6.225 to 199.65.6.254199.65.6.25530
57199.65.7.0/27199.65.7.1 to 199.65.7.30199.65.7.3130
58199.65.7.32/27199.65.7.33 to 199.65.7.62199.65.7.6330
59199.65.7.64/27199.65.7.65 to 199.65.7.94199.65.7.9530
60199.65.7.96/27199.65.7.97 to 199.65.7.126199.65.7.12730
61199.65.7.128/27199.65.7.129 to 199.65.7.158199.65.7.15930
62199.65.7.160/27199.65.7.161 to 199.65.7.190199.65.7.19130
63199.65.7.192/27199.65.7.193 to 199.65.7.222199.65.7.22330
64199.65.7.224/27199.65.7.225 to 199.65.7.254199.65.7.25530
65199.65.8.0/27199.65.8.1 to 199.65.8.30199.65.8.3130
66199.65.8.32/27199.65.8.33 to 199.65.8.62199.65.8.6330
67199.65.8.64/27199.65.8.65 to 199.65.8.94199.65.8.9530
68199.65.8.96/27199.65.8.97 to 199.65.8.126199.65.8.12730
69199.65.8.128/27199.65.8.129 to 199.65.8.158199.65.8.15930
70199.65.8.160/27199.65.8.161 to 199.65.8.190199.65.8.19130
71199.65.8.192/27199.65.8.193 to 199.65.8.222199.65.8.22330
72199.65.8.224/27199.65.8.225 to 199.65.8.254199.65.8.25530
73199.65.9.0/27199.65.9.1 to 199.65.9.30199.65.9.3130
74199.65.9.32/27199.65.9.33 to 199.65.9.62199.65.9.6330
75199.65.9.64/27199.65.9.65 to 199.65.9.94199.65.9.9530
76199.65.9.96/27199.65.9.97 to 199.65.9.126199.65.9.12730
77199.65.9.128/27199.65.9.129 to 199.65.9.158199.65.9.15930
78199.65.9.160/27199.65.9.161 to 199.65.9.190199.65.9.19130
79199.65.9.192/27199.65.9.193 to 199.65.9.222199.65.9.22330
80199.65.9.224/27199.65.9.225 to 199.65.9.254199.65.9.25530
81199.65.10.0/27199.65.10.1 to 199.65.10.30199.65.10.3130
82199.65.10.32/27199.65.10.33 to 199.65.10.62199.65.10.6330
83199.65.10.64/27199.65.10.65 to 199.65.10.94199.65.10.9530
84199.65.10.96/27199.65.10.97 to 199.65.10.126199.65.10.12730
85199.65.10.128/27199.65.10.129 to 199.65.10.158199.65.10.15930
86199.65.10.160/27199.65.10.161 to 199.65.10.190199.65.10.19130
87199.65.10.192/27199.65.10.193 to 199.65.10.222199.65.10.22330
88199.65.10.224/27199.65.10.225 to 199.65.10.254199.65.10.25530
89199.65.11.0/27199.65.11.1 to 199.65.11.30199.65.11.3130
90199.65.11.32/27199.65.11.33 to 199.65.11.62199.65.11.6330
91199.65.11.64/27199.65.11.65 to 199.65.11.94199.65.11.9530
92199.65.11.96/27199.65.11.97 to 199.65.11.126199.65.11.12730
93199.65.11.128/27199.65.11.129 to 199.65.11.158199.65.11.15930
94199.65.11.160/27199.65.11.161 to 199.65.11.190199.65.11.19130
95199.65.11.192/27199.65.11.193 to 199.65.11.222199.65.11.22330
96199.65.11.224/27199.65.11.225 to 199.65.11.254199.65.11.25530
97199.65.12.0/27199.65.12.1 to 199.65.12.30199.65.12.3130
98199.65.12.32/27199.65.12.33 to 199.65.12.62199.65.12.6330
99199.65.12.64/27199.65.12.65 to 199.65.12.94199.65.12.9530
100199.65.12.96/27199.65.12.97 to 199.65.12.126199.65.12.12730
101199.65.12.128/27199.65.12.129 to 199.65.12.158199.65.12.15930
102199.65.12.160/27199.65.12.161 to 199.65.12.190199.65.12.19130
103199.65.12.192/27199.65.12.193 to 199.65.12.222199.65.12.22330
104199.65.12.224/27199.65.12.225 to 199.65.12.254199.65.12.25530
105199.65.13.0/27199.65.13.1 to 199.65.13.30199.65.13.3130
106199.65.13.32/27199.65.13.33 to 199.65.13.62199.65.13.6330
107199.65.13.64/27199.65.13.65 to 199.65.13.94199.65.13.9530
108199.65.13.96/27199.65.13.97 to 199.65.13.126199.65.13.12730
109199.65.13.128/27199.65.13.129 to 199.65.13.158199.65.13.15930
110199.65.13.160/27199.65.13.161 to 199.65.13.190199.65.13.19130
111199.65.13.192/27199.65.13.193 to 199.65.13.222199.65.13.22330
112199.65.13.224/27199.65.13.225 to 199.65.13.254199.65.13.25530
113199.65.14.0/27199.65.14.1 to 199.65.14.30199.65.14.3130
114199.65.14.32/27199.65.14.33 to 199.65.14.62199.65.14.6330
115199.65.14.64/27199.65.14.65 to 199.65.14.94199.65.14.9530
116199.65.14.96/27199.65.14.97 to 199.65.14.126199.65.14.12730
117199.65.14.128/27199.65.14.129 to 199.65.14.158199.65.14.15930
118199.65.14.160/27199.65.14.161 to 199.65.14.190199.65.14.19130
119199.65.14.192/27199.65.14.193 to 199.65.14.222199.65.14.22330
120199.65.14.224/27199.65.14.225 to 199.65.14.254199.65.14.25530
121199.65.15.0/27199.65.15.1 to 199.65.15.30199.65.15.3130
122199.65.15.32/27199.65.15.33 to 199.65.15.62199.65.15.6330
123199.65.15.64/27199.65.15.65 to 199.65.15.94199.65.15.9530
124199.65.15.96/27199.65.15.97 to 199.65.15.126199.65.15.12730
125199.65.15.128/27199.65.15.129 to 199.65.15.158199.65.15.15930
126199.65.15.160/27199.65.15.161 to 199.65.15.190199.65.15.19130
127199.65.15.192/27199.65.15.193 to 199.65.15.222199.65.15.22330
128199.65.15.224/27199.65.15.225 to 199.65.15.254199.65.15.25530
129199.65.16.0/27199.65.16.1 to 199.65.16.30199.65.16.3130
130199.65.16.32/27199.65.16.33 to 199.65.16.62199.65.16.6330
131199.65.16.64/27199.65.16.65 to 199.65.16.94199.65.16.9530
132199.65.16.96/27199.65.16.97 to 199.65.16.126199.65.16.12730
133199.65.16.128/27199.65.16.129 to 199.65.16.158199.65.16.15930
134199.65.16.160/27199.65.16.161 to 199.65.16.190199.65.16.19130
135199.65.16.192/27199.65.16.193 to 199.65.16.222199.65.16.22330
136199.65.16.224/27199.65.16.225 to 199.65.16.254199.65.16.25530
137199.65.17.0/27199.65.17.1 to 199.65.17.30199.65.17.3130
138199.65.17.32/27199.65.17.33 to 199.65.17.62199.65.17.6330
139199.65.17.64/27199.65.17.65 to 199.65.17.94199.65.17.9530
140199.65.17.96/27199.65.17.97 to 199.65.17.126199.65.17.12730
141199.65.17.128/27199.65.17.129 to 199.65.17.158199.65.17.15930
142199.65.17.160/27199.65.17.161 to 199.65.17.190199.65.17.19130
143199.65.17.192/27199.65.17.193 to 199.65.17.222199.65.17.22330
144199.65.17.224/27199.65.17.225 to 199.65.17.254199.65.17.25530
145199.65.18.0/27199.65.18.1 to 199.65.18.30199.65.18.3130
146199.65.18.32/27199.65.18.33 to 199.65.18.62199.65.18.6330
147199.65.18.64/27199.65.18.65 to 199.65.18.94199.65.18.9530
148199.65.18.96/27199.65.18.97 to 199.65.18.126199.65.18.12730
149199.65.18.128/27199.65.18.129 to 199.65.18.158199.65.18.15930
150199.65.18.160/27199.65.18.161 to 199.65.18.190199.65.18.19130
151199.65.18.192/27199.65.18.193 to 199.65.18.222199.65.18.22330
152199.65.18.224/27199.65.18.225 to 199.65.18.254199.65.18.25530
153199.65.19.0/27199.65.19.1 to 199.65.19.30199.65.19.3130
154199.65.19.32/27199.65.19.33 to 199.65.19.62199.65.19.6330
155199.65.19.64/27199.65.19.65 to 199.65.19.94199.65.19.9530
156199.65.19.96/27199.65.19.97 to 199.65.19.126199.65.19.12730
157199.65.19.128/27199.65.19.129 to 199.65.19.158199.65.19.15930
158199.65.19.160/27199.65.19.161 to 199.65.19.190199.65.19.19130
159199.65.19.192/27199.65.19.193 to 199.65.19.222199.65.19.22330
160199.65.19.224/27199.65.19.225 to 199.65.19.254199.65.19.25530
161199.65.20.0/27199.65.20.1 to 199.65.20.30199.65.20.3130
162199.65.20.32/27199.65.20.33 to 199.65.20.62199.65.20.6330
163199.65.20.64/27199.65.20.65 to 199.65.20.94199.65.20.9530
164199.65.20.96/27199.65.20.97 to 199.65.20.126199.65.20.12730
165199.65.20.128/27199.65.20.129 to 199.65.20.158199.65.20.15930
166199.65.20.160/27199.65.20.161 to 199.65.20.190199.65.20.19130
167199.65.20.192/27199.65.20.193 to 199.65.20.222199.65.20.22330
168199.65.20.224/27199.65.20.225 to 199.65.20.254199.65.20.25530
169199.65.21.0/27199.65.21.1 to 199.65.21.30199.65.21.3130
170199.65.21.32/27199.65.21.33 to 199.65.21.62199.65.21.6330
171199.65.21.64/27199.65.21.65 to 199.65.21.94199.65.21.9530
172199.65.21.96/27199.65.21.97 to 199.65.21.126199.65.21.12730
173199.65.21.128/27199.65.21.129 to 199.65.21.158199.65.21.15930
174199.65.21.160/27199.65.21.161 to 199.65.21.190199.65.21.19130
175199.65.21.192/27199.65.21.193 to 199.65.21.222199.65.21.22330
176199.65.21.224/27199.65.21.225 to 199.65.21.254199.65.21.25530
177199.65.22.0/27199.65.22.1 to 199.65.22.30199.65.22.3130
178199.65.22.32/27199.65.22.33 to 199.65.22.62199.65.22.6330
179199.65.22.64/27199.65.22.65 to 199.65.22.94199.65.22.9530
180199.65.22.96/27199.65.22.97 to 199.65.22.126199.65.22.12730
181199.65.22.128/27199.65.22.129 to 199.65.22.158199.65.22.15930
182199.65.22.160/27199.65.22.161 to 199.65.22.190199.65.22.19130
183199.65.22.192/27199.65.22.193 to 199.65.22.222199.65.22.22330
184199.65.22.224/27199.65.22.225 to 199.65.22.254199.65.22.25530
185199.65.23.0/27199.65.23.1 to 199.65.23.30199.65.23.3130
186199.65.23.32/27199.65.23.33 to 199.65.23.62199.65.23.6330
187199.65.23.64/27199.65.23.65 to 199.65.23.94199.65.23.9530
188199.65.23.96/27199.65.23.97 to 199.65.23.126199.65.23.12730
189199.65.23.128/27199.65.23.129 to 199.65.23.158199.65.23.15930
190199.65.23.160/27199.65.23.161 to 199.65.23.190199.65.23.19130
191199.65.23.192/27199.65.23.193 to 199.65.23.222199.65.23.22330
192199.65.23.224/27199.65.23.225 to 199.65.23.254199.65.23.25530
193199.65.24.0/27199.65.24.1 to 199.65.24.30199.65.24.3130
194199.65.24.32/27199.65.24.33 to 199.65.24.62199.65.24.6330
195199.65.24.64/27199.65.24.65 to 199.65.24.94199.65.24.9530
196199.65.24.96/27199.65.24.97 to 199.65.24.126199.65.24.12730
197199.65.24.128/27199.65.24.129 to 199.65.24.158199.65.24.15930
198199.65.24.160/27199.65.24.161 to 199.65.24.190199.65.24.19130
199199.65.24.192/27199.65.24.193 to 199.65.24.222199.65.24.22330
200199.65.24.224/27199.65.24.225 to 199.65.24.254199.65.24.25530
201199.65.25.0/27199.65.25.1 to 199.65.25.30199.65.25.3130
202199.65.25.32/27199.65.25.33 to 199.65.25.62199.65.25.6330
203199.65.25.64/27199.65.25.65 to 199.65.25.94199.65.25.9530
204199.65.25.96/27199.65.25.97 to 199.65.25.126199.65.25.12730
205199.65.25.128/27199.65.25.129 to 199.65.25.158199.65.25.15930
206199.65.25.160/27199.65.25.161 to 199.65.25.190199.65.25.19130
207199.65.25.192/27199.65.25.193 to 199.65.25.222199.65.25.22330
208199.65.25.224/27199.65.25.225 to 199.65.25.254199.65.25.25530
209199.65.26.0/27199.65.26.1 to 199.65.26.30199.65.26.3130
210199.65.26.32/27199.65.26.33 to 199.65.26.62199.65.26.6330
211199.65.26.64/27199.65.26.65 to 199.65.26.94199.65.26.9530
212199.65.26.96/27199.65.26.97 to 199.65.26.126199.65.26.12730
213199.65.26.128/27199.65.26.129 to 199.65.26.158199.65.26.15930
214199.65.26.160/27199.65.26.161 to 199.65.26.190199.65.26.19130
215199.65.26.192/27199.65.26.193 to 199.65.26.222199.65.26.22330
216199.65.26.224/27199.65.26.225 to 199.65.26.254199.65.26.25530
217199.65.27.0/27199.65.27.1 to 199.65.27.30199.65.27.3130
218199.65.27.32/27199.65.27.33 to 199.65.27.62199.65.27.6330
219199.65.27.64/27199.65.27.65 to 199.65.27.94199.65.27.9530
220199.65.27.96/27199.65.27.97 to 199.65.27.126199.65.27.12730
221199.65.27.128/27199.65.27.129 to 199.65.27.158199.65.27.15930
222199.65.27.160/27199.65.27.161 to 199.65.27.190199.65.27.19130
223199.65.27.192/27199.65.27.193 to 199.65.27.222199.65.27.22330
224199.65.27.224/27199.65.27.225 to 199.65.27.254199.65.27.25530
225199.65.28.0/27199.65.28.1 to 199.65.28.30199.65.28.3130
226199.65.28.32/27199.65.28.33 to 199.65.28.62199.65.28.6330
227199.65.28.64/27199.65.28.65 to 199.65.28.94199.65.28.9530
228199.65.28.96/27199.65.28.97 to 199.65.28.126199.65.28.12730
229199.65.28.128/27199.65.28.129 to 199.65.28.158199.65.28.15930
230199.65.28.160/27199.65.28.161 to 199.65.28.190199.65.28.19130
231199.65.28.192/27199.65.28.193 to 199.65.28.222199.65.28.22330
232199.65.28.224/27199.65.28.225 to 199.65.28.254199.65.28.25530
233199.65.29.0/27199.65.29.1 to 199.65.29.30199.65.29.3130
234199.65.29.32/27199.65.29.33 to 199.65.29.62199.65.29.6330
235199.65.29.64/27199.65.29.65 to 199.65.29.94199.65.29.9530
236199.65.29.96/27199.65.29.97 to 199.65.29.126199.65.29.12730
237199.65.29.128/27199.65.29.129 to 199.65.29.158199.65.29.15930
238199.65.29.160/27199.65.29.161 to 199.65.29.190199.65.29.19130
239199.65.29.192/27199.65.29.193 to 199.65.29.222199.65.29.22330
240199.65.29.224/27199.65.29.225 to 199.65.29.254199.65.29.25530
241199.65.30.0/27199.65.30.1 to 199.65.30.30199.65.30.3130
242199.65.30.32/27199.65.30.33 to 199.65.30.62199.65.30.6330
243199.65.30.64/27199.65.30.65 to 199.65.30.94199.65.30.9530
244199.65.30.96/27199.65.30.97 to 199.65.30.126199.65.30.12730
245199.65.30.128/27199.65.30.129 to 199.65.30.158199.65.30.15930
246199.65.30.160/27199.65.30.161 to 199.65.30.190199.65.30.19130
247199.65.30.192/27199.65.30.193 to 199.65.30.222199.65.30.22330
248199.65.30.224/27199.65.30.225 to 199.65.30.254199.65.30.25530
249199.65.31.0/27199.65.31.1 to 199.65.31.30199.65.31.3130
250199.65.31.32/27199.65.31.33 to 199.65.31.62199.65.31.6330
251199.65.31.64/27199.65.31.65 to 199.65.31.94199.65.31.9530
252199.65.31.96/27199.65.31.97 to 199.65.31.126199.65.31.12730
253199.65.31.128/27199.65.31.129 to 199.65.31.158199.65.31.15930
254199.65.31.160/27199.65.31.161 to 199.65.31.190199.65.31.19130
255199.65.31.192/27199.65.31.193 to 199.65.31.222199.65.31.22330
256199.65.31.224/27199.65.31.225 to 199.65.31.254199.65.31.25530

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.