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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.

Network216.7.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
216.7.0.0
Broadcast address
216.7.31.255
First usable
216.7.0.1
Last usable
216.7.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
C (default /24)
As numbers
Hex D8070000 · Integer 3624337408 to 3624345599
Reverse DNS zones
0.7.216.in-addr.arpa
1.7.216.in-addr.arpa
2.7.216.in-addr.arpa
3.7.216.in-addr.arpa
4.7.216.in-addr.arpa
5.7.216.in-addr.arpa
6.7.216.in-addr.arpa
7.7.216.in-addr.arpa
8.7.216.in-addr.arpa
9.7.216.in-addr.arpa
10.7.216.in-addr.arpa
11.7.216.in-addr.arpa
12.7.216.in-addr.arpa
13.7.216.in-addr.arpa
14.7.216.in-addr.arpa
15.7.216.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011000.00000111.00000000.00000000216.7.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11011000.00000111.00000000.00000000216.7.0.0
Broadcast11011000.00000111.00011111.11111111216.7.31.255
Split into smaller subnets/27
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

216.7.0.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1216.7.0.0/27216.7.0.1 to 216.7.0.30216.7.0.3130
2216.7.0.32/27216.7.0.33 to 216.7.0.62216.7.0.6330
3216.7.0.64/27216.7.0.65 to 216.7.0.94216.7.0.9530
4216.7.0.96/27216.7.0.97 to 216.7.0.126216.7.0.12730
5216.7.0.128/27216.7.0.129 to 216.7.0.158216.7.0.15930
6216.7.0.160/27216.7.0.161 to 216.7.0.190216.7.0.19130
7216.7.0.192/27216.7.0.193 to 216.7.0.222216.7.0.22330
8216.7.0.224/27216.7.0.225 to 216.7.0.254216.7.0.25530
9216.7.1.0/27216.7.1.1 to 216.7.1.30216.7.1.3130
10216.7.1.32/27216.7.1.33 to 216.7.1.62216.7.1.6330
11216.7.1.64/27216.7.1.65 to 216.7.1.94216.7.1.9530
12216.7.1.96/27216.7.1.97 to 216.7.1.126216.7.1.12730
13216.7.1.128/27216.7.1.129 to 216.7.1.158216.7.1.15930
14216.7.1.160/27216.7.1.161 to 216.7.1.190216.7.1.19130
15216.7.1.192/27216.7.1.193 to 216.7.1.222216.7.1.22330
16216.7.1.224/27216.7.1.225 to 216.7.1.254216.7.1.25530
17216.7.2.0/27216.7.2.1 to 216.7.2.30216.7.2.3130
18216.7.2.32/27216.7.2.33 to 216.7.2.62216.7.2.6330
19216.7.2.64/27216.7.2.65 to 216.7.2.94216.7.2.9530
20216.7.2.96/27216.7.2.97 to 216.7.2.126216.7.2.12730
21216.7.2.128/27216.7.2.129 to 216.7.2.158216.7.2.15930
22216.7.2.160/27216.7.2.161 to 216.7.2.190216.7.2.19130
23216.7.2.192/27216.7.2.193 to 216.7.2.222216.7.2.22330
24216.7.2.224/27216.7.2.225 to 216.7.2.254216.7.2.25530
25216.7.3.0/27216.7.3.1 to 216.7.3.30216.7.3.3130
26216.7.3.32/27216.7.3.33 to 216.7.3.62216.7.3.6330
27216.7.3.64/27216.7.3.65 to 216.7.3.94216.7.3.9530
28216.7.3.96/27216.7.3.97 to 216.7.3.126216.7.3.12730
29216.7.3.128/27216.7.3.129 to 216.7.3.158216.7.3.15930
30216.7.3.160/27216.7.3.161 to 216.7.3.190216.7.3.19130
31216.7.3.192/27216.7.3.193 to 216.7.3.222216.7.3.22330
32216.7.3.224/27216.7.3.225 to 216.7.3.254216.7.3.25530
33216.7.4.0/27216.7.4.1 to 216.7.4.30216.7.4.3130
34216.7.4.32/27216.7.4.33 to 216.7.4.62216.7.4.6330
35216.7.4.64/27216.7.4.65 to 216.7.4.94216.7.4.9530
36216.7.4.96/27216.7.4.97 to 216.7.4.126216.7.4.12730
37216.7.4.128/27216.7.4.129 to 216.7.4.158216.7.4.15930
38216.7.4.160/27216.7.4.161 to 216.7.4.190216.7.4.19130
39216.7.4.192/27216.7.4.193 to 216.7.4.222216.7.4.22330
40216.7.4.224/27216.7.4.225 to 216.7.4.254216.7.4.25530
41216.7.5.0/27216.7.5.1 to 216.7.5.30216.7.5.3130
42216.7.5.32/27216.7.5.33 to 216.7.5.62216.7.5.6330
43216.7.5.64/27216.7.5.65 to 216.7.5.94216.7.5.9530
44216.7.5.96/27216.7.5.97 to 216.7.5.126216.7.5.12730
45216.7.5.128/27216.7.5.129 to 216.7.5.158216.7.5.15930
46216.7.5.160/27216.7.5.161 to 216.7.5.190216.7.5.19130
47216.7.5.192/27216.7.5.193 to 216.7.5.222216.7.5.22330
48216.7.5.224/27216.7.5.225 to 216.7.5.254216.7.5.25530
49216.7.6.0/27216.7.6.1 to 216.7.6.30216.7.6.3130
50216.7.6.32/27216.7.6.33 to 216.7.6.62216.7.6.6330
51216.7.6.64/27216.7.6.65 to 216.7.6.94216.7.6.9530
52216.7.6.96/27216.7.6.97 to 216.7.6.126216.7.6.12730
53216.7.6.128/27216.7.6.129 to 216.7.6.158216.7.6.15930
54216.7.6.160/27216.7.6.161 to 216.7.6.190216.7.6.19130
55216.7.6.192/27216.7.6.193 to 216.7.6.222216.7.6.22330
56216.7.6.224/27216.7.6.225 to 216.7.6.254216.7.6.25530
57216.7.7.0/27216.7.7.1 to 216.7.7.30216.7.7.3130
58216.7.7.32/27216.7.7.33 to 216.7.7.62216.7.7.6330
59216.7.7.64/27216.7.7.65 to 216.7.7.94216.7.7.9530
60216.7.7.96/27216.7.7.97 to 216.7.7.126216.7.7.12730
61216.7.7.128/27216.7.7.129 to 216.7.7.158216.7.7.15930
62216.7.7.160/27216.7.7.161 to 216.7.7.190216.7.7.19130
63216.7.7.192/27216.7.7.193 to 216.7.7.222216.7.7.22330
64216.7.7.224/27216.7.7.225 to 216.7.7.254216.7.7.25530
65216.7.8.0/27216.7.8.1 to 216.7.8.30216.7.8.3130
66216.7.8.32/27216.7.8.33 to 216.7.8.62216.7.8.6330
67216.7.8.64/27216.7.8.65 to 216.7.8.94216.7.8.9530
68216.7.8.96/27216.7.8.97 to 216.7.8.126216.7.8.12730
69216.7.8.128/27216.7.8.129 to 216.7.8.158216.7.8.15930
70216.7.8.160/27216.7.8.161 to 216.7.8.190216.7.8.19130
71216.7.8.192/27216.7.8.193 to 216.7.8.222216.7.8.22330
72216.7.8.224/27216.7.8.225 to 216.7.8.254216.7.8.25530
73216.7.9.0/27216.7.9.1 to 216.7.9.30216.7.9.3130
74216.7.9.32/27216.7.9.33 to 216.7.9.62216.7.9.6330
75216.7.9.64/27216.7.9.65 to 216.7.9.94216.7.9.9530
76216.7.9.96/27216.7.9.97 to 216.7.9.126216.7.9.12730
77216.7.9.128/27216.7.9.129 to 216.7.9.158216.7.9.15930
78216.7.9.160/27216.7.9.161 to 216.7.9.190216.7.9.19130
79216.7.9.192/27216.7.9.193 to 216.7.9.222216.7.9.22330
80216.7.9.224/27216.7.9.225 to 216.7.9.254216.7.9.25530
81216.7.10.0/27216.7.10.1 to 216.7.10.30216.7.10.3130
82216.7.10.32/27216.7.10.33 to 216.7.10.62216.7.10.6330
83216.7.10.64/27216.7.10.65 to 216.7.10.94216.7.10.9530
84216.7.10.96/27216.7.10.97 to 216.7.10.126216.7.10.12730
85216.7.10.128/27216.7.10.129 to 216.7.10.158216.7.10.15930
86216.7.10.160/27216.7.10.161 to 216.7.10.190216.7.10.19130
87216.7.10.192/27216.7.10.193 to 216.7.10.222216.7.10.22330
88216.7.10.224/27216.7.10.225 to 216.7.10.254216.7.10.25530
89216.7.11.0/27216.7.11.1 to 216.7.11.30216.7.11.3130
90216.7.11.32/27216.7.11.33 to 216.7.11.62216.7.11.6330
91216.7.11.64/27216.7.11.65 to 216.7.11.94216.7.11.9530
92216.7.11.96/27216.7.11.97 to 216.7.11.126216.7.11.12730
93216.7.11.128/27216.7.11.129 to 216.7.11.158216.7.11.15930
94216.7.11.160/27216.7.11.161 to 216.7.11.190216.7.11.19130
95216.7.11.192/27216.7.11.193 to 216.7.11.222216.7.11.22330
96216.7.11.224/27216.7.11.225 to 216.7.11.254216.7.11.25530
97216.7.12.0/27216.7.12.1 to 216.7.12.30216.7.12.3130
98216.7.12.32/27216.7.12.33 to 216.7.12.62216.7.12.6330
99216.7.12.64/27216.7.12.65 to 216.7.12.94216.7.12.9530
100216.7.12.96/27216.7.12.97 to 216.7.12.126216.7.12.12730
101216.7.12.128/27216.7.12.129 to 216.7.12.158216.7.12.15930
102216.7.12.160/27216.7.12.161 to 216.7.12.190216.7.12.19130
103216.7.12.192/27216.7.12.193 to 216.7.12.222216.7.12.22330
104216.7.12.224/27216.7.12.225 to 216.7.12.254216.7.12.25530
105216.7.13.0/27216.7.13.1 to 216.7.13.30216.7.13.3130
106216.7.13.32/27216.7.13.33 to 216.7.13.62216.7.13.6330
107216.7.13.64/27216.7.13.65 to 216.7.13.94216.7.13.9530
108216.7.13.96/27216.7.13.97 to 216.7.13.126216.7.13.12730
109216.7.13.128/27216.7.13.129 to 216.7.13.158216.7.13.15930
110216.7.13.160/27216.7.13.161 to 216.7.13.190216.7.13.19130
111216.7.13.192/27216.7.13.193 to 216.7.13.222216.7.13.22330
112216.7.13.224/27216.7.13.225 to 216.7.13.254216.7.13.25530
113216.7.14.0/27216.7.14.1 to 216.7.14.30216.7.14.3130
114216.7.14.32/27216.7.14.33 to 216.7.14.62216.7.14.6330
115216.7.14.64/27216.7.14.65 to 216.7.14.94216.7.14.9530
116216.7.14.96/27216.7.14.97 to 216.7.14.126216.7.14.12730
117216.7.14.128/27216.7.14.129 to 216.7.14.158216.7.14.15930
118216.7.14.160/27216.7.14.161 to 216.7.14.190216.7.14.19130
119216.7.14.192/27216.7.14.193 to 216.7.14.222216.7.14.22330
120216.7.14.224/27216.7.14.225 to 216.7.14.254216.7.14.25530
121216.7.15.0/27216.7.15.1 to 216.7.15.30216.7.15.3130
122216.7.15.32/27216.7.15.33 to 216.7.15.62216.7.15.6330
123216.7.15.64/27216.7.15.65 to 216.7.15.94216.7.15.9530
124216.7.15.96/27216.7.15.97 to 216.7.15.126216.7.15.12730
125216.7.15.128/27216.7.15.129 to 216.7.15.158216.7.15.15930
126216.7.15.160/27216.7.15.161 to 216.7.15.190216.7.15.19130
127216.7.15.192/27216.7.15.193 to 216.7.15.222216.7.15.22330
128216.7.15.224/27216.7.15.225 to 216.7.15.254216.7.15.25530
129216.7.16.0/27216.7.16.1 to 216.7.16.30216.7.16.3130
130216.7.16.32/27216.7.16.33 to 216.7.16.62216.7.16.6330
131216.7.16.64/27216.7.16.65 to 216.7.16.94216.7.16.9530
132216.7.16.96/27216.7.16.97 to 216.7.16.126216.7.16.12730
133216.7.16.128/27216.7.16.129 to 216.7.16.158216.7.16.15930
134216.7.16.160/27216.7.16.161 to 216.7.16.190216.7.16.19130
135216.7.16.192/27216.7.16.193 to 216.7.16.222216.7.16.22330
136216.7.16.224/27216.7.16.225 to 216.7.16.254216.7.16.25530
137216.7.17.0/27216.7.17.1 to 216.7.17.30216.7.17.3130
138216.7.17.32/27216.7.17.33 to 216.7.17.62216.7.17.6330
139216.7.17.64/27216.7.17.65 to 216.7.17.94216.7.17.9530
140216.7.17.96/27216.7.17.97 to 216.7.17.126216.7.17.12730
141216.7.17.128/27216.7.17.129 to 216.7.17.158216.7.17.15930
142216.7.17.160/27216.7.17.161 to 216.7.17.190216.7.17.19130
143216.7.17.192/27216.7.17.193 to 216.7.17.222216.7.17.22330
144216.7.17.224/27216.7.17.225 to 216.7.17.254216.7.17.25530
145216.7.18.0/27216.7.18.1 to 216.7.18.30216.7.18.3130
146216.7.18.32/27216.7.18.33 to 216.7.18.62216.7.18.6330
147216.7.18.64/27216.7.18.65 to 216.7.18.94216.7.18.9530
148216.7.18.96/27216.7.18.97 to 216.7.18.126216.7.18.12730
149216.7.18.128/27216.7.18.129 to 216.7.18.158216.7.18.15930
150216.7.18.160/27216.7.18.161 to 216.7.18.190216.7.18.19130
151216.7.18.192/27216.7.18.193 to 216.7.18.222216.7.18.22330
152216.7.18.224/27216.7.18.225 to 216.7.18.254216.7.18.25530
153216.7.19.0/27216.7.19.1 to 216.7.19.30216.7.19.3130
154216.7.19.32/27216.7.19.33 to 216.7.19.62216.7.19.6330
155216.7.19.64/27216.7.19.65 to 216.7.19.94216.7.19.9530
156216.7.19.96/27216.7.19.97 to 216.7.19.126216.7.19.12730
157216.7.19.128/27216.7.19.129 to 216.7.19.158216.7.19.15930
158216.7.19.160/27216.7.19.161 to 216.7.19.190216.7.19.19130
159216.7.19.192/27216.7.19.193 to 216.7.19.222216.7.19.22330
160216.7.19.224/27216.7.19.225 to 216.7.19.254216.7.19.25530
161216.7.20.0/27216.7.20.1 to 216.7.20.30216.7.20.3130
162216.7.20.32/27216.7.20.33 to 216.7.20.62216.7.20.6330
163216.7.20.64/27216.7.20.65 to 216.7.20.94216.7.20.9530
164216.7.20.96/27216.7.20.97 to 216.7.20.126216.7.20.12730
165216.7.20.128/27216.7.20.129 to 216.7.20.158216.7.20.15930
166216.7.20.160/27216.7.20.161 to 216.7.20.190216.7.20.19130
167216.7.20.192/27216.7.20.193 to 216.7.20.222216.7.20.22330
168216.7.20.224/27216.7.20.225 to 216.7.20.254216.7.20.25530
169216.7.21.0/27216.7.21.1 to 216.7.21.30216.7.21.3130
170216.7.21.32/27216.7.21.33 to 216.7.21.62216.7.21.6330
171216.7.21.64/27216.7.21.65 to 216.7.21.94216.7.21.9530
172216.7.21.96/27216.7.21.97 to 216.7.21.126216.7.21.12730
173216.7.21.128/27216.7.21.129 to 216.7.21.158216.7.21.15930
174216.7.21.160/27216.7.21.161 to 216.7.21.190216.7.21.19130
175216.7.21.192/27216.7.21.193 to 216.7.21.222216.7.21.22330
176216.7.21.224/27216.7.21.225 to 216.7.21.254216.7.21.25530
177216.7.22.0/27216.7.22.1 to 216.7.22.30216.7.22.3130
178216.7.22.32/27216.7.22.33 to 216.7.22.62216.7.22.6330
179216.7.22.64/27216.7.22.65 to 216.7.22.94216.7.22.9530
180216.7.22.96/27216.7.22.97 to 216.7.22.126216.7.22.12730
181216.7.22.128/27216.7.22.129 to 216.7.22.158216.7.22.15930
182216.7.22.160/27216.7.22.161 to 216.7.22.190216.7.22.19130
183216.7.22.192/27216.7.22.193 to 216.7.22.222216.7.22.22330
184216.7.22.224/27216.7.22.225 to 216.7.22.254216.7.22.25530
185216.7.23.0/27216.7.23.1 to 216.7.23.30216.7.23.3130
186216.7.23.32/27216.7.23.33 to 216.7.23.62216.7.23.6330
187216.7.23.64/27216.7.23.65 to 216.7.23.94216.7.23.9530
188216.7.23.96/27216.7.23.97 to 216.7.23.126216.7.23.12730
189216.7.23.128/27216.7.23.129 to 216.7.23.158216.7.23.15930
190216.7.23.160/27216.7.23.161 to 216.7.23.190216.7.23.19130
191216.7.23.192/27216.7.23.193 to 216.7.23.222216.7.23.22330
192216.7.23.224/27216.7.23.225 to 216.7.23.254216.7.23.25530
193216.7.24.0/27216.7.24.1 to 216.7.24.30216.7.24.3130
194216.7.24.32/27216.7.24.33 to 216.7.24.62216.7.24.6330
195216.7.24.64/27216.7.24.65 to 216.7.24.94216.7.24.9530
196216.7.24.96/27216.7.24.97 to 216.7.24.126216.7.24.12730
197216.7.24.128/27216.7.24.129 to 216.7.24.158216.7.24.15930
198216.7.24.160/27216.7.24.161 to 216.7.24.190216.7.24.19130
199216.7.24.192/27216.7.24.193 to 216.7.24.222216.7.24.22330
200216.7.24.224/27216.7.24.225 to 216.7.24.254216.7.24.25530
201216.7.25.0/27216.7.25.1 to 216.7.25.30216.7.25.3130
202216.7.25.32/27216.7.25.33 to 216.7.25.62216.7.25.6330
203216.7.25.64/27216.7.25.65 to 216.7.25.94216.7.25.9530
204216.7.25.96/27216.7.25.97 to 216.7.25.126216.7.25.12730
205216.7.25.128/27216.7.25.129 to 216.7.25.158216.7.25.15930
206216.7.25.160/27216.7.25.161 to 216.7.25.190216.7.25.19130
207216.7.25.192/27216.7.25.193 to 216.7.25.222216.7.25.22330
208216.7.25.224/27216.7.25.225 to 216.7.25.254216.7.25.25530
209216.7.26.0/27216.7.26.1 to 216.7.26.30216.7.26.3130
210216.7.26.32/27216.7.26.33 to 216.7.26.62216.7.26.6330
211216.7.26.64/27216.7.26.65 to 216.7.26.94216.7.26.9530
212216.7.26.96/27216.7.26.97 to 216.7.26.126216.7.26.12730
213216.7.26.128/27216.7.26.129 to 216.7.26.158216.7.26.15930
214216.7.26.160/27216.7.26.161 to 216.7.26.190216.7.26.19130
215216.7.26.192/27216.7.26.193 to 216.7.26.222216.7.26.22330
216216.7.26.224/27216.7.26.225 to 216.7.26.254216.7.26.25530
217216.7.27.0/27216.7.27.1 to 216.7.27.30216.7.27.3130
218216.7.27.32/27216.7.27.33 to 216.7.27.62216.7.27.6330
219216.7.27.64/27216.7.27.65 to 216.7.27.94216.7.27.9530
220216.7.27.96/27216.7.27.97 to 216.7.27.126216.7.27.12730
221216.7.27.128/27216.7.27.129 to 216.7.27.158216.7.27.15930
222216.7.27.160/27216.7.27.161 to 216.7.27.190216.7.27.19130
223216.7.27.192/27216.7.27.193 to 216.7.27.222216.7.27.22330
224216.7.27.224/27216.7.27.225 to 216.7.27.254216.7.27.25530
225216.7.28.0/27216.7.28.1 to 216.7.28.30216.7.28.3130
226216.7.28.32/27216.7.28.33 to 216.7.28.62216.7.28.6330
227216.7.28.64/27216.7.28.65 to 216.7.28.94216.7.28.9530
228216.7.28.96/27216.7.28.97 to 216.7.28.126216.7.28.12730
229216.7.28.128/27216.7.28.129 to 216.7.28.158216.7.28.15930
230216.7.28.160/27216.7.28.161 to 216.7.28.190216.7.28.19130
231216.7.28.192/27216.7.28.193 to 216.7.28.222216.7.28.22330
232216.7.28.224/27216.7.28.225 to 216.7.28.254216.7.28.25530
233216.7.29.0/27216.7.29.1 to 216.7.29.30216.7.29.3130
234216.7.29.32/27216.7.29.33 to 216.7.29.62216.7.29.6330
235216.7.29.64/27216.7.29.65 to 216.7.29.94216.7.29.9530
236216.7.29.96/27216.7.29.97 to 216.7.29.126216.7.29.12730
237216.7.29.128/27216.7.29.129 to 216.7.29.158216.7.29.15930
238216.7.29.160/27216.7.29.161 to 216.7.29.190216.7.29.19130
239216.7.29.192/27216.7.29.193 to 216.7.29.222216.7.29.22330
240216.7.29.224/27216.7.29.225 to 216.7.29.254216.7.29.25530
241216.7.30.0/27216.7.30.1 to 216.7.30.30216.7.30.3130
242216.7.30.32/27216.7.30.33 to 216.7.30.62216.7.30.6330
243216.7.30.64/27216.7.30.65 to 216.7.30.94216.7.30.9530
244216.7.30.96/27216.7.30.97 to 216.7.30.126216.7.30.12730
245216.7.30.128/27216.7.30.129 to 216.7.30.158216.7.30.15930
246216.7.30.160/27216.7.30.161 to 216.7.30.190216.7.30.19130
247216.7.30.192/27216.7.30.193 to 216.7.30.222216.7.30.22330
248216.7.30.224/27216.7.30.225 to 216.7.30.254216.7.30.25530
249216.7.31.0/27216.7.31.1 to 216.7.31.30216.7.31.3130
250216.7.31.32/27216.7.31.33 to 216.7.31.62216.7.31.6330
251216.7.31.64/27216.7.31.65 to 216.7.31.94216.7.31.9530
252216.7.31.96/27216.7.31.97 to 216.7.31.126216.7.31.12730
253216.7.31.128/27216.7.31.129 to 216.7.31.158216.7.31.15930
254216.7.31.160/27216.7.31.161 to 216.7.31.190216.7.31.19130
255216.7.31.192/27216.7.31.193 to 216.7.31.222216.7.31.22330
256216.7.31.224/27216.7.31.225 to 216.7.31.254216.7.31.25530

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.