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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.

Network103.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
103.0.0.0
Broadcast address
103.127.255.255
First usable
103.0.0.1
Last usable
103.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 67000000 · Integer 1728053248 to 1736441855
Reverse DNS zones
0.103.in-addr.arpa
1.103.in-addr.arpa
2.103.in-addr.arpa
3.103.in-addr.arpa
4.103.in-addr.arpa
5.103.in-addr.arpa
6.103.in-addr.arpa
7.103.in-addr.arpa
8.103.in-addr.arpa
9.103.in-addr.arpa
10.103.in-addr.arpa
11.103.in-addr.arpa
12.103.in-addr.arpa
13.103.in-addr.arpa
14.103.in-addr.arpa
15.103.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100111.00000000.00000000.00000000103.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01100111.00000000.00000000.00000000103.0.0.0
Broadcast01100111.01111111.11111111.11111111103.127.255.255
Split into smaller subnets/19
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

103.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1103.0.0.0/19103.0.0.1 to 103.0.31.254103.0.31.2558,190
2103.0.32.0/19103.0.32.1 to 103.0.63.254103.0.63.2558,190
3103.0.64.0/19103.0.64.1 to 103.0.95.254103.0.95.2558,190
4103.0.96.0/19103.0.96.1 to 103.0.127.254103.0.127.2558,190
5103.0.128.0/19103.0.128.1 to 103.0.159.254103.0.159.2558,190
6103.0.160.0/19103.0.160.1 to 103.0.191.254103.0.191.2558,190
7103.0.192.0/19103.0.192.1 to 103.0.223.254103.0.223.2558,190
8103.0.224.0/19103.0.224.1 to 103.0.255.254103.0.255.2558,190
9103.1.0.0/19103.1.0.1 to 103.1.31.254103.1.31.2558,190
10103.1.32.0/19103.1.32.1 to 103.1.63.254103.1.63.2558,190
11103.1.64.0/19103.1.64.1 to 103.1.95.254103.1.95.2558,190
12103.1.96.0/19103.1.96.1 to 103.1.127.254103.1.127.2558,190
13103.1.128.0/19103.1.128.1 to 103.1.159.254103.1.159.2558,190
14103.1.160.0/19103.1.160.1 to 103.1.191.254103.1.191.2558,190
15103.1.192.0/19103.1.192.1 to 103.1.223.254103.1.223.2558,190
16103.1.224.0/19103.1.224.1 to 103.1.255.254103.1.255.2558,190
17103.2.0.0/19103.2.0.1 to 103.2.31.254103.2.31.2558,190
18103.2.32.0/19103.2.32.1 to 103.2.63.254103.2.63.2558,190
19103.2.64.0/19103.2.64.1 to 103.2.95.254103.2.95.2558,190
20103.2.96.0/19103.2.96.1 to 103.2.127.254103.2.127.2558,190
21103.2.128.0/19103.2.128.1 to 103.2.159.254103.2.159.2558,190
22103.2.160.0/19103.2.160.1 to 103.2.191.254103.2.191.2558,190
23103.2.192.0/19103.2.192.1 to 103.2.223.254103.2.223.2558,190
24103.2.224.0/19103.2.224.1 to 103.2.255.254103.2.255.2558,190
25103.3.0.0/19103.3.0.1 to 103.3.31.254103.3.31.2558,190
26103.3.32.0/19103.3.32.1 to 103.3.63.254103.3.63.2558,190
27103.3.64.0/19103.3.64.1 to 103.3.95.254103.3.95.2558,190
28103.3.96.0/19103.3.96.1 to 103.3.127.254103.3.127.2558,190
29103.3.128.0/19103.3.128.1 to 103.3.159.254103.3.159.2558,190
30103.3.160.0/19103.3.160.1 to 103.3.191.254103.3.191.2558,190
31103.3.192.0/19103.3.192.1 to 103.3.223.254103.3.223.2558,190
32103.3.224.0/19103.3.224.1 to 103.3.255.254103.3.255.2558,190
33103.4.0.0/19103.4.0.1 to 103.4.31.254103.4.31.2558,190
34103.4.32.0/19103.4.32.1 to 103.4.63.254103.4.63.2558,190
35103.4.64.0/19103.4.64.1 to 103.4.95.254103.4.95.2558,190
36103.4.96.0/19103.4.96.1 to 103.4.127.254103.4.127.2558,190
37103.4.128.0/19103.4.128.1 to 103.4.159.254103.4.159.2558,190
38103.4.160.0/19103.4.160.1 to 103.4.191.254103.4.191.2558,190
39103.4.192.0/19103.4.192.1 to 103.4.223.254103.4.223.2558,190
40103.4.224.0/19103.4.224.1 to 103.4.255.254103.4.255.2558,190
41103.5.0.0/19103.5.0.1 to 103.5.31.254103.5.31.2558,190
42103.5.32.0/19103.5.32.1 to 103.5.63.254103.5.63.2558,190
43103.5.64.0/19103.5.64.1 to 103.5.95.254103.5.95.2558,190
44103.5.96.0/19103.5.96.1 to 103.5.127.254103.5.127.2558,190
45103.5.128.0/19103.5.128.1 to 103.5.159.254103.5.159.2558,190
46103.5.160.0/19103.5.160.1 to 103.5.191.254103.5.191.2558,190
47103.5.192.0/19103.5.192.1 to 103.5.223.254103.5.223.2558,190
48103.5.224.0/19103.5.224.1 to 103.5.255.254103.5.255.2558,190
49103.6.0.0/19103.6.0.1 to 103.6.31.254103.6.31.2558,190
50103.6.32.0/19103.6.32.1 to 103.6.63.254103.6.63.2558,190
51103.6.64.0/19103.6.64.1 to 103.6.95.254103.6.95.2558,190
52103.6.96.0/19103.6.96.1 to 103.6.127.254103.6.127.2558,190
53103.6.128.0/19103.6.128.1 to 103.6.159.254103.6.159.2558,190
54103.6.160.0/19103.6.160.1 to 103.6.191.254103.6.191.2558,190
55103.6.192.0/19103.6.192.1 to 103.6.223.254103.6.223.2558,190
56103.6.224.0/19103.6.224.1 to 103.6.255.254103.6.255.2558,190
57103.7.0.0/19103.7.0.1 to 103.7.31.254103.7.31.2558,190
58103.7.32.0/19103.7.32.1 to 103.7.63.254103.7.63.2558,190
59103.7.64.0/19103.7.64.1 to 103.7.95.254103.7.95.2558,190
60103.7.96.0/19103.7.96.1 to 103.7.127.254103.7.127.2558,190
61103.7.128.0/19103.7.128.1 to 103.7.159.254103.7.159.2558,190
62103.7.160.0/19103.7.160.1 to 103.7.191.254103.7.191.2558,190
63103.7.192.0/19103.7.192.1 to 103.7.223.254103.7.223.2558,190
64103.7.224.0/19103.7.224.1 to 103.7.255.254103.7.255.2558,190
65103.8.0.0/19103.8.0.1 to 103.8.31.254103.8.31.2558,190
66103.8.32.0/19103.8.32.1 to 103.8.63.254103.8.63.2558,190
67103.8.64.0/19103.8.64.1 to 103.8.95.254103.8.95.2558,190
68103.8.96.0/19103.8.96.1 to 103.8.127.254103.8.127.2558,190
69103.8.128.0/19103.8.128.1 to 103.8.159.254103.8.159.2558,190
70103.8.160.0/19103.8.160.1 to 103.8.191.254103.8.191.2558,190
71103.8.192.0/19103.8.192.1 to 103.8.223.254103.8.223.2558,190
72103.8.224.0/19103.8.224.1 to 103.8.255.254103.8.255.2558,190
73103.9.0.0/19103.9.0.1 to 103.9.31.254103.9.31.2558,190
74103.9.32.0/19103.9.32.1 to 103.9.63.254103.9.63.2558,190
75103.9.64.0/19103.9.64.1 to 103.9.95.254103.9.95.2558,190
76103.9.96.0/19103.9.96.1 to 103.9.127.254103.9.127.2558,190
77103.9.128.0/19103.9.128.1 to 103.9.159.254103.9.159.2558,190
78103.9.160.0/19103.9.160.1 to 103.9.191.254103.9.191.2558,190
79103.9.192.0/19103.9.192.1 to 103.9.223.254103.9.223.2558,190
80103.9.224.0/19103.9.224.1 to 103.9.255.254103.9.255.2558,190
81103.10.0.0/19103.10.0.1 to 103.10.31.254103.10.31.2558,190
82103.10.32.0/19103.10.32.1 to 103.10.63.254103.10.63.2558,190
83103.10.64.0/19103.10.64.1 to 103.10.95.254103.10.95.2558,190
84103.10.96.0/19103.10.96.1 to 103.10.127.254103.10.127.2558,190
85103.10.128.0/19103.10.128.1 to 103.10.159.254103.10.159.2558,190
86103.10.160.0/19103.10.160.1 to 103.10.191.254103.10.191.2558,190
87103.10.192.0/19103.10.192.1 to 103.10.223.254103.10.223.2558,190
88103.10.224.0/19103.10.224.1 to 103.10.255.254103.10.255.2558,190
89103.11.0.0/19103.11.0.1 to 103.11.31.254103.11.31.2558,190
90103.11.32.0/19103.11.32.1 to 103.11.63.254103.11.63.2558,190
91103.11.64.0/19103.11.64.1 to 103.11.95.254103.11.95.2558,190
92103.11.96.0/19103.11.96.1 to 103.11.127.254103.11.127.2558,190
93103.11.128.0/19103.11.128.1 to 103.11.159.254103.11.159.2558,190
94103.11.160.0/19103.11.160.1 to 103.11.191.254103.11.191.2558,190
95103.11.192.0/19103.11.192.1 to 103.11.223.254103.11.223.2558,190
96103.11.224.0/19103.11.224.1 to 103.11.255.254103.11.255.2558,190
97103.12.0.0/19103.12.0.1 to 103.12.31.254103.12.31.2558,190
98103.12.32.0/19103.12.32.1 to 103.12.63.254103.12.63.2558,190
99103.12.64.0/19103.12.64.1 to 103.12.95.254103.12.95.2558,190
100103.12.96.0/19103.12.96.1 to 103.12.127.254103.12.127.2558,190
101103.12.128.0/19103.12.128.1 to 103.12.159.254103.12.159.2558,190
102103.12.160.0/19103.12.160.1 to 103.12.191.254103.12.191.2558,190
103103.12.192.0/19103.12.192.1 to 103.12.223.254103.12.223.2558,190
104103.12.224.0/19103.12.224.1 to 103.12.255.254103.12.255.2558,190
105103.13.0.0/19103.13.0.1 to 103.13.31.254103.13.31.2558,190
106103.13.32.0/19103.13.32.1 to 103.13.63.254103.13.63.2558,190
107103.13.64.0/19103.13.64.1 to 103.13.95.254103.13.95.2558,190
108103.13.96.0/19103.13.96.1 to 103.13.127.254103.13.127.2558,190
109103.13.128.0/19103.13.128.1 to 103.13.159.254103.13.159.2558,190
110103.13.160.0/19103.13.160.1 to 103.13.191.254103.13.191.2558,190
111103.13.192.0/19103.13.192.1 to 103.13.223.254103.13.223.2558,190
112103.13.224.0/19103.13.224.1 to 103.13.255.254103.13.255.2558,190
113103.14.0.0/19103.14.0.1 to 103.14.31.254103.14.31.2558,190
114103.14.32.0/19103.14.32.1 to 103.14.63.254103.14.63.2558,190
115103.14.64.0/19103.14.64.1 to 103.14.95.254103.14.95.2558,190
116103.14.96.0/19103.14.96.1 to 103.14.127.254103.14.127.2558,190
117103.14.128.0/19103.14.128.1 to 103.14.159.254103.14.159.2558,190
118103.14.160.0/19103.14.160.1 to 103.14.191.254103.14.191.2558,190
119103.14.192.0/19103.14.192.1 to 103.14.223.254103.14.223.2558,190
120103.14.224.0/19103.14.224.1 to 103.14.255.254103.14.255.2558,190
121103.15.0.0/19103.15.0.1 to 103.15.31.254103.15.31.2558,190
122103.15.32.0/19103.15.32.1 to 103.15.63.254103.15.63.2558,190
123103.15.64.0/19103.15.64.1 to 103.15.95.254103.15.95.2558,190
124103.15.96.0/19103.15.96.1 to 103.15.127.254103.15.127.2558,190
125103.15.128.0/19103.15.128.1 to 103.15.159.254103.15.159.2558,190
126103.15.160.0/19103.15.160.1 to 103.15.191.254103.15.191.2558,190
127103.15.192.0/19103.15.192.1 to 103.15.223.254103.15.223.2558,190
128103.15.224.0/19103.15.224.1 to 103.15.255.254103.15.255.2558,190
129103.16.0.0/19103.16.0.1 to 103.16.31.254103.16.31.2558,190
130103.16.32.0/19103.16.32.1 to 103.16.63.254103.16.63.2558,190
131103.16.64.0/19103.16.64.1 to 103.16.95.254103.16.95.2558,190
132103.16.96.0/19103.16.96.1 to 103.16.127.254103.16.127.2558,190
133103.16.128.0/19103.16.128.1 to 103.16.159.254103.16.159.2558,190
134103.16.160.0/19103.16.160.1 to 103.16.191.254103.16.191.2558,190
135103.16.192.0/19103.16.192.1 to 103.16.223.254103.16.223.2558,190
136103.16.224.0/19103.16.224.1 to 103.16.255.254103.16.255.2558,190
137103.17.0.0/19103.17.0.1 to 103.17.31.254103.17.31.2558,190
138103.17.32.0/19103.17.32.1 to 103.17.63.254103.17.63.2558,190
139103.17.64.0/19103.17.64.1 to 103.17.95.254103.17.95.2558,190
140103.17.96.0/19103.17.96.1 to 103.17.127.254103.17.127.2558,190
141103.17.128.0/19103.17.128.1 to 103.17.159.254103.17.159.2558,190
142103.17.160.0/19103.17.160.1 to 103.17.191.254103.17.191.2558,190
143103.17.192.0/19103.17.192.1 to 103.17.223.254103.17.223.2558,190
144103.17.224.0/19103.17.224.1 to 103.17.255.254103.17.255.2558,190
145103.18.0.0/19103.18.0.1 to 103.18.31.254103.18.31.2558,190
146103.18.32.0/19103.18.32.1 to 103.18.63.254103.18.63.2558,190
147103.18.64.0/19103.18.64.1 to 103.18.95.254103.18.95.2558,190
148103.18.96.0/19103.18.96.1 to 103.18.127.254103.18.127.2558,190
149103.18.128.0/19103.18.128.1 to 103.18.159.254103.18.159.2558,190
150103.18.160.0/19103.18.160.1 to 103.18.191.254103.18.191.2558,190
151103.18.192.0/19103.18.192.1 to 103.18.223.254103.18.223.2558,190
152103.18.224.0/19103.18.224.1 to 103.18.255.254103.18.255.2558,190
153103.19.0.0/19103.19.0.1 to 103.19.31.254103.19.31.2558,190
154103.19.32.0/19103.19.32.1 to 103.19.63.254103.19.63.2558,190
155103.19.64.0/19103.19.64.1 to 103.19.95.254103.19.95.2558,190
156103.19.96.0/19103.19.96.1 to 103.19.127.254103.19.127.2558,190
157103.19.128.0/19103.19.128.1 to 103.19.159.254103.19.159.2558,190
158103.19.160.0/19103.19.160.1 to 103.19.191.254103.19.191.2558,190
159103.19.192.0/19103.19.192.1 to 103.19.223.254103.19.223.2558,190
160103.19.224.0/19103.19.224.1 to 103.19.255.254103.19.255.2558,190
161103.20.0.0/19103.20.0.1 to 103.20.31.254103.20.31.2558,190
162103.20.32.0/19103.20.32.1 to 103.20.63.254103.20.63.2558,190
163103.20.64.0/19103.20.64.1 to 103.20.95.254103.20.95.2558,190
164103.20.96.0/19103.20.96.1 to 103.20.127.254103.20.127.2558,190
165103.20.128.0/19103.20.128.1 to 103.20.159.254103.20.159.2558,190
166103.20.160.0/19103.20.160.1 to 103.20.191.254103.20.191.2558,190
167103.20.192.0/19103.20.192.1 to 103.20.223.254103.20.223.2558,190
168103.20.224.0/19103.20.224.1 to 103.20.255.254103.20.255.2558,190
169103.21.0.0/19103.21.0.1 to 103.21.31.254103.21.31.2558,190
170103.21.32.0/19103.21.32.1 to 103.21.63.254103.21.63.2558,190
171103.21.64.0/19103.21.64.1 to 103.21.95.254103.21.95.2558,190
172103.21.96.0/19103.21.96.1 to 103.21.127.254103.21.127.2558,190
173103.21.128.0/19103.21.128.1 to 103.21.159.254103.21.159.2558,190
174103.21.160.0/19103.21.160.1 to 103.21.191.254103.21.191.2558,190
175103.21.192.0/19103.21.192.1 to 103.21.223.254103.21.223.2558,190
176103.21.224.0/19103.21.224.1 to 103.21.255.254103.21.255.2558,190
177103.22.0.0/19103.22.0.1 to 103.22.31.254103.22.31.2558,190
178103.22.32.0/19103.22.32.1 to 103.22.63.254103.22.63.2558,190
179103.22.64.0/19103.22.64.1 to 103.22.95.254103.22.95.2558,190
180103.22.96.0/19103.22.96.1 to 103.22.127.254103.22.127.2558,190
181103.22.128.0/19103.22.128.1 to 103.22.159.254103.22.159.2558,190
182103.22.160.0/19103.22.160.1 to 103.22.191.254103.22.191.2558,190
183103.22.192.0/19103.22.192.1 to 103.22.223.254103.22.223.2558,190
184103.22.224.0/19103.22.224.1 to 103.22.255.254103.22.255.2558,190
185103.23.0.0/19103.23.0.1 to 103.23.31.254103.23.31.2558,190
186103.23.32.0/19103.23.32.1 to 103.23.63.254103.23.63.2558,190
187103.23.64.0/19103.23.64.1 to 103.23.95.254103.23.95.2558,190
188103.23.96.0/19103.23.96.1 to 103.23.127.254103.23.127.2558,190
189103.23.128.0/19103.23.128.1 to 103.23.159.254103.23.159.2558,190
190103.23.160.0/19103.23.160.1 to 103.23.191.254103.23.191.2558,190
191103.23.192.0/19103.23.192.1 to 103.23.223.254103.23.223.2558,190
192103.23.224.0/19103.23.224.1 to 103.23.255.254103.23.255.2558,190
193103.24.0.0/19103.24.0.1 to 103.24.31.254103.24.31.2558,190
194103.24.32.0/19103.24.32.1 to 103.24.63.254103.24.63.2558,190
195103.24.64.0/19103.24.64.1 to 103.24.95.254103.24.95.2558,190
196103.24.96.0/19103.24.96.1 to 103.24.127.254103.24.127.2558,190
197103.24.128.0/19103.24.128.1 to 103.24.159.254103.24.159.2558,190
198103.24.160.0/19103.24.160.1 to 103.24.191.254103.24.191.2558,190
199103.24.192.0/19103.24.192.1 to 103.24.223.254103.24.223.2558,190
200103.24.224.0/19103.24.224.1 to 103.24.255.254103.24.255.2558,190
201103.25.0.0/19103.25.0.1 to 103.25.31.254103.25.31.2558,190
202103.25.32.0/19103.25.32.1 to 103.25.63.254103.25.63.2558,190
203103.25.64.0/19103.25.64.1 to 103.25.95.254103.25.95.2558,190
204103.25.96.0/19103.25.96.1 to 103.25.127.254103.25.127.2558,190
205103.25.128.0/19103.25.128.1 to 103.25.159.254103.25.159.2558,190
206103.25.160.0/19103.25.160.1 to 103.25.191.254103.25.191.2558,190
207103.25.192.0/19103.25.192.1 to 103.25.223.254103.25.223.2558,190
208103.25.224.0/19103.25.224.1 to 103.25.255.254103.25.255.2558,190
209103.26.0.0/19103.26.0.1 to 103.26.31.254103.26.31.2558,190
210103.26.32.0/19103.26.32.1 to 103.26.63.254103.26.63.2558,190
211103.26.64.0/19103.26.64.1 to 103.26.95.254103.26.95.2558,190
212103.26.96.0/19103.26.96.1 to 103.26.127.254103.26.127.2558,190
213103.26.128.0/19103.26.128.1 to 103.26.159.254103.26.159.2558,190
214103.26.160.0/19103.26.160.1 to 103.26.191.254103.26.191.2558,190
215103.26.192.0/19103.26.192.1 to 103.26.223.254103.26.223.2558,190
216103.26.224.0/19103.26.224.1 to 103.26.255.254103.26.255.2558,190
217103.27.0.0/19103.27.0.1 to 103.27.31.254103.27.31.2558,190
218103.27.32.0/19103.27.32.1 to 103.27.63.254103.27.63.2558,190
219103.27.64.0/19103.27.64.1 to 103.27.95.254103.27.95.2558,190
220103.27.96.0/19103.27.96.1 to 103.27.127.254103.27.127.2558,190
221103.27.128.0/19103.27.128.1 to 103.27.159.254103.27.159.2558,190
222103.27.160.0/19103.27.160.1 to 103.27.191.254103.27.191.2558,190
223103.27.192.0/19103.27.192.1 to 103.27.223.254103.27.223.2558,190
224103.27.224.0/19103.27.224.1 to 103.27.255.254103.27.255.2558,190
225103.28.0.0/19103.28.0.1 to 103.28.31.254103.28.31.2558,190
226103.28.32.0/19103.28.32.1 to 103.28.63.254103.28.63.2558,190
227103.28.64.0/19103.28.64.1 to 103.28.95.254103.28.95.2558,190
228103.28.96.0/19103.28.96.1 to 103.28.127.254103.28.127.2558,190
229103.28.128.0/19103.28.128.1 to 103.28.159.254103.28.159.2558,190
230103.28.160.0/19103.28.160.1 to 103.28.191.254103.28.191.2558,190
231103.28.192.0/19103.28.192.1 to 103.28.223.254103.28.223.2558,190
232103.28.224.0/19103.28.224.1 to 103.28.255.254103.28.255.2558,190
233103.29.0.0/19103.29.0.1 to 103.29.31.254103.29.31.2558,190
234103.29.32.0/19103.29.32.1 to 103.29.63.254103.29.63.2558,190
235103.29.64.0/19103.29.64.1 to 103.29.95.254103.29.95.2558,190
236103.29.96.0/19103.29.96.1 to 103.29.127.254103.29.127.2558,190
237103.29.128.0/19103.29.128.1 to 103.29.159.254103.29.159.2558,190
238103.29.160.0/19103.29.160.1 to 103.29.191.254103.29.191.2558,190
239103.29.192.0/19103.29.192.1 to 103.29.223.254103.29.223.2558,190
240103.29.224.0/19103.29.224.1 to 103.29.255.254103.29.255.2558,190
241103.30.0.0/19103.30.0.1 to 103.30.31.254103.30.31.2558,190
242103.30.32.0/19103.30.32.1 to 103.30.63.254103.30.63.2558,190
243103.30.64.0/19103.30.64.1 to 103.30.95.254103.30.95.2558,190
244103.30.96.0/19103.30.96.1 to 103.30.127.254103.30.127.2558,190
245103.30.128.0/19103.30.128.1 to 103.30.159.254103.30.159.2558,190
246103.30.160.0/19103.30.160.1 to 103.30.191.254103.30.191.2558,190
247103.30.192.0/19103.30.192.1 to 103.30.223.254103.30.223.2558,190
248103.30.224.0/19103.30.224.1 to 103.30.255.254103.30.255.2558,190
249103.31.0.0/19103.31.0.1 to 103.31.31.254103.31.31.2558,190
250103.31.32.0/19103.31.32.1 to 103.31.63.254103.31.63.2558,190
251103.31.64.0/19103.31.64.1 to 103.31.95.254103.31.95.2558,190
252103.31.96.0/19103.31.96.1 to 103.31.127.254103.31.127.2558,190
253103.31.128.0/19103.31.128.1 to 103.31.159.254103.31.159.2558,190
254103.31.160.0/19103.31.160.1 to 103.31.191.254103.31.191.2558,190
255103.31.192.0/19103.31.192.1 to 103.31.223.254103.31.223.2558,190
256103.31.224.0/19103.31.224.1 to 103.31.255.254103.31.255.2558,190

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.