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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.

Network104.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
104.0.0.0
Broadcast address
104.127.255.255
First usable
104.0.0.1
Last usable
104.127.255.254
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 68000000 · Integer 1744830464 to 1753219071
Reverse DNS zones
0.104.in-addr.arpa
1.104.in-addr.arpa
2.104.in-addr.arpa
3.104.in-addr.arpa
4.104.in-addr.arpa
5.104.in-addr.arpa
6.104.in-addr.arpa
7.104.in-addr.arpa
8.104.in-addr.arpa
9.104.in-addr.arpa
10.104.in-addr.arpa
11.104.in-addr.arpa
12.104.in-addr.arpa
13.104.in-addr.arpa
14.104.in-addr.arpa
15.104.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
Address01101000.00000000.00000000.00000000104.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101000.00000000.00000000.00000000104.0.0.0
Broadcast01101000.01111111.11111111.11111111104.127.255.255
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)

104.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1104.0.0.0/19104.0.0.1 to 104.0.31.254104.0.31.2558,190
2104.0.32.0/19104.0.32.1 to 104.0.63.254104.0.63.2558,190
3104.0.64.0/19104.0.64.1 to 104.0.95.254104.0.95.2558,190
4104.0.96.0/19104.0.96.1 to 104.0.127.254104.0.127.2558,190
5104.0.128.0/19104.0.128.1 to 104.0.159.254104.0.159.2558,190
6104.0.160.0/19104.0.160.1 to 104.0.191.254104.0.191.2558,190
7104.0.192.0/19104.0.192.1 to 104.0.223.254104.0.223.2558,190
8104.0.224.0/19104.0.224.1 to 104.0.255.254104.0.255.2558,190
9104.1.0.0/19104.1.0.1 to 104.1.31.254104.1.31.2558,190
10104.1.32.0/19104.1.32.1 to 104.1.63.254104.1.63.2558,190
11104.1.64.0/19104.1.64.1 to 104.1.95.254104.1.95.2558,190
12104.1.96.0/19104.1.96.1 to 104.1.127.254104.1.127.2558,190
13104.1.128.0/19104.1.128.1 to 104.1.159.254104.1.159.2558,190
14104.1.160.0/19104.1.160.1 to 104.1.191.254104.1.191.2558,190
15104.1.192.0/19104.1.192.1 to 104.1.223.254104.1.223.2558,190
16104.1.224.0/19104.1.224.1 to 104.1.255.254104.1.255.2558,190
17104.2.0.0/19104.2.0.1 to 104.2.31.254104.2.31.2558,190
18104.2.32.0/19104.2.32.1 to 104.2.63.254104.2.63.2558,190
19104.2.64.0/19104.2.64.1 to 104.2.95.254104.2.95.2558,190
20104.2.96.0/19104.2.96.1 to 104.2.127.254104.2.127.2558,190
21104.2.128.0/19104.2.128.1 to 104.2.159.254104.2.159.2558,190
22104.2.160.0/19104.2.160.1 to 104.2.191.254104.2.191.2558,190
23104.2.192.0/19104.2.192.1 to 104.2.223.254104.2.223.2558,190
24104.2.224.0/19104.2.224.1 to 104.2.255.254104.2.255.2558,190
25104.3.0.0/19104.3.0.1 to 104.3.31.254104.3.31.2558,190
26104.3.32.0/19104.3.32.1 to 104.3.63.254104.3.63.2558,190
27104.3.64.0/19104.3.64.1 to 104.3.95.254104.3.95.2558,190
28104.3.96.0/19104.3.96.1 to 104.3.127.254104.3.127.2558,190
29104.3.128.0/19104.3.128.1 to 104.3.159.254104.3.159.2558,190
30104.3.160.0/19104.3.160.1 to 104.3.191.254104.3.191.2558,190
31104.3.192.0/19104.3.192.1 to 104.3.223.254104.3.223.2558,190
32104.3.224.0/19104.3.224.1 to 104.3.255.254104.3.255.2558,190
33104.4.0.0/19104.4.0.1 to 104.4.31.254104.4.31.2558,190
34104.4.32.0/19104.4.32.1 to 104.4.63.254104.4.63.2558,190
35104.4.64.0/19104.4.64.1 to 104.4.95.254104.4.95.2558,190
36104.4.96.0/19104.4.96.1 to 104.4.127.254104.4.127.2558,190
37104.4.128.0/19104.4.128.1 to 104.4.159.254104.4.159.2558,190
38104.4.160.0/19104.4.160.1 to 104.4.191.254104.4.191.2558,190
39104.4.192.0/19104.4.192.1 to 104.4.223.254104.4.223.2558,190
40104.4.224.0/19104.4.224.1 to 104.4.255.254104.4.255.2558,190
41104.5.0.0/19104.5.0.1 to 104.5.31.254104.5.31.2558,190
42104.5.32.0/19104.5.32.1 to 104.5.63.254104.5.63.2558,190
43104.5.64.0/19104.5.64.1 to 104.5.95.254104.5.95.2558,190
44104.5.96.0/19104.5.96.1 to 104.5.127.254104.5.127.2558,190
45104.5.128.0/19104.5.128.1 to 104.5.159.254104.5.159.2558,190
46104.5.160.0/19104.5.160.1 to 104.5.191.254104.5.191.2558,190
47104.5.192.0/19104.5.192.1 to 104.5.223.254104.5.223.2558,190
48104.5.224.0/19104.5.224.1 to 104.5.255.254104.5.255.2558,190
49104.6.0.0/19104.6.0.1 to 104.6.31.254104.6.31.2558,190
50104.6.32.0/19104.6.32.1 to 104.6.63.254104.6.63.2558,190
51104.6.64.0/19104.6.64.1 to 104.6.95.254104.6.95.2558,190
52104.6.96.0/19104.6.96.1 to 104.6.127.254104.6.127.2558,190
53104.6.128.0/19104.6.128.1 to 104.6.159.254104.6.159.2558,190
54104.6.160.0/19104.6.160.1 to 104.6.191.254104.6.191.2558,190
55104.6.192.0/19104.6.192.1 to 104.6.223.254104.6.223.2558,190
56104.6.224.0/19104.6.224.1 to 104.6.255.254104.6.255.2558,190
57104.7.0.0/19104.7.0.1 to 104.7.31.254104.7.31.2558,190
58104.7.32.0/19104.7.32.1 to 104.7.63.254104.7.63.2558,190
59104.7.64.0/19104.7.64.1 to 104.7.95.254104.7.95.2558,190
60104.7.96.0/19104.7.96.1 to 104.7.127.254104.7.127.2558,190
61104.7.128.0/19104.7.128.1 to 104.7.159.254104.7.159.2558,190
62104.7.160.0/19104.7.160.1 to 104.7.191.254104.7.191.2558,190
63104.7.192.0/19104.7.192.1 to 104.7.223.254104.7.223.2558,190
64104.7.224.0/19104.7.224.1 to 104.7.255.254104.7.255.2558,190
65104.8.0.0/19104.8.0.1 to 104.8.31.254104.8.31.2558,190
66104.8.32.0/19104.8.32.1 to 104.8.63.254104.8.63.2558,190
67104.8.64.0/19104.8.64.1 to 104.8.95.254104.8.95.2558,190
68104.8.96.0/19104.8.96.1 to 104.8.127.254104.8.127.2558,190
69104.8.128.0/19104.8.128.1 to 104.8.159.254104.8.159.2558,190
70104.8.160.0/19104.8.160.1 to 104.8.191.254104.8.191.2558,190
71104.8.192.0/19104.8.192.1 to 104.8.223.254104.8.223.2558,190
72104.8.224.0/19104.8.224.1 to 104.8.255.254104.8.255.2558,190
73104.9.0.0/19104.9.0.1 to 104.9.31.254104.9.31.2558,190
74104.9.32.0/19104.9.32.1 to 104.9.63.254104.9.63.2558,190
75104.9.64.0/19104.9.64.1 to 104.9.95.254104.9.95.2558,190
76104.9.96.0/19104.9.96.1 to 104.9.127.254104.9.127.2558,190
77104.9.128.0/19104.9.128.1 to 104.9.159.254104.9.159.2558,190
78104.9.160.0/19104.9.160.1 to 104.9.191.254104.9.191.2558,190
79104.9.192.0/19104.9.192.1 to 104.9.223.254104.9.223.2558,190
80104.9.224.0/19104.9.224.1 to 104.9.255.254104.9.255.2558,190
81104.10.0.0/19104.10.0.1 to 104.10.31.254104.10.31.2558,190
82104.10.32.0/19104.10.32.1 to 104.10.63.254104.10.63.2558,190
83104.10.64.0/19104.10.64.1 to 104.10.95.254104.10.95.2558,190
84104.10.96.0/19104.10.96.1 to 104.10.127.254104.10.127.2558,190
85104.10.128.0/19104.10.128.1 to 104.10.159.254104.10.159.2558,190
86104.10.160.0/19104.10.160.1 to 104.10.191.254104.10.191.2558,190
87104.10.192.0/19104.10.192.1 to 104.10.223.254104.10.223.2558,190
88104.10.224.0/19104.10.224.1 to 104.10.255.254104.10.255.2558,190
89104.11.0.0/19104.11.0.1 to 104.11.31.254104.11.31.2558,190
90104.11.32.0/19104.11.32.1 to 104.11.63.254104.11.63.2558,190
91104.11.64.0/19104.11.64.1 to 104.11.95.254104.11.95.2558,190
92104.11.96.0/19104.11.96.1 to 104.11.127.254104.11.127.2558,190
93104.11.128.0/19104.11.128.1 to 104.11.159.254104.11.159.2558,190
94104.11.160.0/19104.11.160.1 to 104.11.191.254104.11.191.2558,190
95104.11.192.0/19104.11.192.1 to 104.11.223.254104.11.223.2558,190
96104.11.224.0/19104.11.224.1 to 104.11.255.254104.11.255.2558,190
97104.12.0.0/19104.12.0.1 to 104.12.31.254104.12.31.2558,190
98104.12.32.0/19104.12.32.1 to 104.12.63.254104.12.63.2558,190
99104.12.64.0/19104.12.64.1 to 104.12.95.254104.12.95.2558,190
100104.12.96.0/19104.12.96.1 to 104.12.127.254104.12.127.2558,190
101104.12.128.0/19104.12.128.1 to 104.12.159.254104.12.159.2558,190
102104.12.160.0/19104.12.160.1 to 104.12.191.254104.12.191.2558,190
103104.12.192.0/19104.12.192.1 to 104.12.223.254104.12.223.2558,190
104104.12.224.0/19104.12.224.1 to 104.12.255.254104.12.255.2558,190
105104.13.0.0/19104.13.0.1 to 104.13.31.254104.13.31.2558,190
106104.13.32.0/19104.13.32.1 to 104.13.63.254104.13.63.2558,190
107104.13.64.0/19104.13.64.1 to 104.13.95.254104.13.95.2558,190
108104.13.96.0/19104.13.96.1 to 104.13.127.254104.13.127.2558,190
109104.13.128.0/19104.13.128.1 to 104.13.159.254104.13.159.2558,190
110104.13.160.0/19104.13.160.1 to 104.13.191.254104.13.191.2558,190
111104.13.192.0/19104.13.192.1 to 104.13.223.254104.13.223.2558,190
112104.13.224.0/19104.13.224.1 to 104.13.255.254104.13.255.2558,190
113104.14.0.0/19104.14.0.1 to 104.14.31.254104.14.31.2558,190
114104.14.32.0/19104.14.32.1 to 104.14.63.254104.14.63.2558,190
115104.14.64.0/19104.14.64.1 to 104.14.95.254104.14.95.2558,190
116104.14.96.0/19104.14.96.1 to 104.14.127.254104.14.127.2558,190
117104.14.128.0/19104.14.128.1 to 104.14.159.254104.14.159.2558,190
118104.14.160.0/19104.14.160.1 to 104.14.191.254104.14.191.2558,190
119104.14.192.0/19104.14.192.1 to 104.14.223.254104.14.223.2558,190
120104.14.224.0/19104.14.224.1 to 104.14.255.254104.14.255.2558,190
121104.15.0.0/19104.15.0.1 to 104.15.31.254104.15.31.2558,190
122104.15.32.0/19104.15.32.1 to 104.15.63.254104.15.63.2558,190
123104.15.64.0/19104.15.64.1 to 104.15.95.254104.15.95.2558,190
124104.15.96.0/19104.15.96.1 to 104.15.127.254104.15.127.2558,190
125104.15.128.0/19104.15.128.1 to 104.15.159.254104.15.159.2558,190
126104.15.160.0/19104.15.160.1 to 104.15.191.254104.15.191.2558,190
127104.15.192.0/19104.15.192.1 to 104.15.223.254104.15.223.2558,190
128104.15.224.0/19104.15.224.1 to 104.15.255.254104.15.255.2558,190
129104.16.0.0/19104.16.0.1 to 104.16.31.254104.16.31.2558,190
130104.16.32.0/19104.16.32.1 to 104.16.63.254104.16.63.2558,190
131104.16.64.0/19104.16.64.1 to 104.16.95.254104.16.95.2558,190
132104.16.96.0/19104.16.96.1 to 104.16.127.254104.16.127.2558,190
133104.16.128.0/19104.16.128.1 to 104.16.159.254104.16.159.2558,190
134104.16.160.0/19104.16.160.1 to 104.16.191.254104.16.191.2558,190
135104.16.192.0/19104.16.192.1 to 104.16.223.254104.16.223.2558,190
136104.16.224.0/19104.16.224.1 to 104.16.255.254104.16.255.2558,190
137104.17.0.0/19104.17.0.1 to 104.17.31.254104.17.31.2558,190
138104.17.32.0/19104.17.32.1 to 104.17.63.254104.17.63.2558,190
139104.17.64.0/19104.17.64.1 to 104.17.95.254104.17.95.2558,190
140104.17.96.0/19104.17.96.1 to 104.17.127.254104.17.127.2558,190
141104.17.128.0/19104.17.128.1 to 104.17.159.254104.17.159.2558,190
142104.17.160.0/19104.17.160.1 to 104.17.191.254104.17.191.2558,190
143104.17.192.0/19104.17.192.1 to 104.17.223.254104.17.223.2558,190
144104.17.224.0/19104.17.224.1 to 104.17.255.254104.17.255.2558,190
145104.18.0.0/19104.18.0.1 to 104.18.31.254104.18.31.2558,190
146104.18.32.0/19104.18.32.1 to 104.18.63.254104.18.63.2558,190
147104.18.64.0/19104.18.64.1 to 104.18.95.254104.18.95.2558,190
148104.18.96.0/19104.18.96.1 to 104.18.127.254104.18.127.2558,190
149104.18.128.0/19104.18.128.1 to 104.18.159.254104.18.159.2558,190
150104.18.160.0/19104.18.160.1 to 104.18.191.254104.18.191.2558,190
151104.18.192.0/19104.18.192.1 to 104.18.223.254104.18.223.2558,190
152104.18.224.0/19104.18.224.1 to 104.18.255.254104.18.255.2558,190
153104.19.0.0/19104.19.0.1 to 104.19.31.254104.19.31.2558,190
154104.19.32.0/19104.19.32.1 to 104.19.63.254104.19.63.2558,190
155104.19.64.0/19104.19.64.1 to 104.19.95.254104.19.95.2558,190
156104.19.96.0/19104.19.96.1 to 104.19.127.254104.19.127.2558,190
157104.19.128.0/19104.19.128.1 to 104.19.159.254104.19.159.2558,190
158104.19.160.0/19104.19.160.1 to 104.19.191.254104.19.191.2558,190
159104.19.192.0/19104.19.192.1 to 104.19.223.254104.19.223.2558,190
160104.19.224.0/19104.19.224.1 to 104.19.255.254104.19.255.2558,190
161104.20.0.0/19104.20.0.1 to 104.20.31.254104.20.31.2558,190
162104.20.32.0/19104.20.32.1 to 104.20.63.254104.20.63.2558,190
163104.20.64.0/19104.20.64.1 to 104.20.95.254104.20.95.2558,190
164104.20.96.0/19104.20.96.1 to 104.20.127.254104.20.127.2558,190
165104.20.128.0/19104.20.128.1 to 104.20.159.254104.20.159.2558,190
166104.20.160.0/19104.20.160.1 to 104.20.191.254104.20.191.2558,190
167104.20.192.0/19104.20.192.1 to 104.20.223.254104.20.223.2558,190
168104.20.224.0/19104.20.224.1 to 104.20.255.254104.20.255.2558,190
169104.21.0.0/19104.21.0.1 to 104.21.31.254104.21.31.2558,190
170104.21.32.0/19104.21.32.1 to 104.21.63.254104.21.63.2558,190
171104.21.64.0/19104.21.64.1 to 104.21.95.254104.21.95.2558,190
172104.21.96.0/19104.21.96.1 to 104.21.127.254104.21.127.2558,190
173104.21.128.0/19104.21.128.1 to 104.21.159.254104.21.159.2558,190
174104.21.160.0/19104.21.160.1 to 104.21.191.254104.21.191.2558,190
175104.21.192.0/19104.21.192.1 to 104.21.223.254104.21.223.2558,190
176104.21.224.0/19104.21.224.1 to 104.21.255.254104.21.255.2558,190
177104.22.0.0/19104.22.0.1 to 104.22.31.254104.22.31.2558,190
178104.22.32.0/19104.22.32.1 to 104.22.63.254104.22.63.2558,190
179104.22.64.0/19104.22.64.1 to 104.22.95.254104.22.95.2558,190
180104.22.96.0/19104.22.96.1 to 104.22.127.254104.22.127.2558,190
181104.22.128.0/19104.22.128.1 to 104.22.159.254104.22.159.2558,190
182104.22.160.0/19104.22.160.1 to 104.22.191.254104.22.191.2558,190
183104.22.192.0/19104.22.192.1 to 104.22.223.254104.22.223.2558,190
184104.22.224.0/19104.22.224.1 to 104.22.255.254104.22.255.2558,190
185104.23.0.0/19104.23.0.1 to 104.23.31.254104.23.31.2558,190
186104.23.32.0/19104.23.32.1 to 104.23.63.254104.23.63.2558,190
187104.23.64.0/19104.23.64.1 to 104.23.95.254104.23.95.2558,190
188104.23.96.0/19104.23.96.1 to 104.23.127.254104.23.127.2558,190
189104.23.128.0/19104.23.128.1 to 104.23.159.254104.23.159.2558,190
190104.23.160.0/19104.23.160.1 to 104.23.191.254104.23.191.2558,190
191104.23.192.0/19104.23.192.1 to 104.23.223.254104.23.223.2558,190
192104.23.224.0/19104.23.224.1 to 104.23.255.254104.23.255.2558,190
193104.24.0.0/19104.24.0.1 to 104.24.31.254104.24.31.2558,190
194104.24.32.0/19104.24.32.1 to 104.24.63.254104.24.63.2558,190
195104.24.64.0/19104.24.64.1 to 104.24.95.254104.24.95.2558,190
196104.24.96.0/19104.24.96.1 to 104.24.127.254104.24.127.2558,190
197104.24.128.0/19104.24.128.1 to 104.24.159.254104.24.159.2558,190
198104.24.160.0/19104.24.160.1 to 104.24.191.254104.24.191.2558,190
199104.24.192.0/19104.24.192.1 to 104.24.223.254104.24.223.2558,190
200104.24.224.0/19104.24.224.1 to 104.24.255.254104.24.255.2558,190
201104.25.0.0/19104.25.0.1 to 104.25.31.254104.25.31.2558,190
202104.25.32.0/19104.25.32.1 to 104.25.63.254104.25.63.2558,190
203104.25.64.0/19104.25.64.1 to 104.25.95.254104.25.95.2558,190
204104.25.96.0/19104.25.96.1 to 104.25.127.254104.25.127.2558,190
205104.25.128.0/19104.25.128.1 to 104.25.159.254104.25.159.2558,190
206104.25.160.0/19104.25.160.1 to 104.25.191.254104.25.191.2558,190
207104.25.192.0/19104.25.192.1 to 104.25.223.254104.25.223.2558,190
208104.25.224.0/19104.25.224.1 to 104.25.255.254104.25.255.2558,190
209104.26.0.0/19104.26.0.1 to 104.26.31.254104.26.31.2558,190
210104.26.32.0/19104.26.32.1 to 104.26.63.254104.26.63.2558,190
211104.26.64.0/19104.26.64.1 to 104.26.95.254104.26.95.2558,190
212104.26.96.0/19104.26.96.1 to 104.26.127.254104.26.127.2558,190
213104.26.128.0/19104.26.128.1 to 104.26.159.254104.26.159.2558,190
214104.26.160.0/19104.26.160.1 to 104.26.191.254104.26.191.2558,190
215104.26.192.0/19104.26.192.1 to 104.26.223.254104.26.223.2558,190
216104.26.224.0/19104.26.224.1 to 104.26.255.254104.26.255.2558,190
217104.27.0.0/19104.27.0.1 to 104.27.31.254104.27.31.2558,190
218104.27.32.0/19104.27.32.1 to 104.27.63.254104.27.63.2558,190
219104.27.64.0/19104.27.64.1 to 104.27.95.254104.27.95.2558,190
220104.27.96.0/19104.27.96.1 to 104.27.127.254104.27.127.2558,190
221104.27.128.0/19104.27.128.1 to 104.27.159.254104.27.159.2558,190
222104.27.160.0/19104.27.160.1 to 104.27.191.254104.27.191.2558,190
223104.27.192.0/19104.27.192.1 to 104.27.223.254104.27.223.2558,190
224104.27.224.0/19104.27.224.1 to 104.27.255.254104.27.255.2558,190
225104.28.0.0/19104.28.0.1 to 104.28.31.254104.28.31.2558,190
226104.28.32.0/19104.28.32.1 to 104.28.63.254104.28.63.2558,190
227104.28.64.0/19104.28.64.1 to 104.28.95.254104.28.95.2558,190
228104.28.96.0/19104.28.96.1 to 104.28.127.254104.28.127.2558,190
229104.28.128.0/19104.28.128.1 to 104.28.159.254104.28.159.2558,190
230104.28.160.0/19104.28.160.1 to 104.28.191.254104.28.191.2558,190
231104.28.192.0/19104.28.192.1 to 104.28.223.254104.28.223.2558,190
232104.28.224.0/19104.28.224.1 to 104.28.255.254104.28.255.2558,190
233104.29.0.0/19104.29.0.1 to 104.29.31.254104.29.31.2558,190
234104.29.32.0/19104.29.32.1 to 104.29.63.254104.29.63.2558,190
235104.29.64.0/19104.29.64.1 to 104.29.95.254104.29.95.2558,190
236104.29.96.0/19104.29.96.1 to 104.29.127.254104.29.127.2558,190
237104.29.128.0/19104.29.128.1 to 104.29.159.254104.29.159.2558,190
238104.29.160.0/19104.29.160.1 to 104.29.191.254104.29.191.2558,190
239104.29.192.0/19104.29.192.1 to 104.29.223.254104.29.223.2558,190
240104.29.224.0/19104.29.224.1 to 104.29.255.254104.29.255.2558,190
241104.30.0.0/19104.30.0.1 to 104.30.31.254104.30.31.2558,190
242104.30.32.0/19104.30.32.1 to 104.30.63.254104.30.63.2558,190
243104.30.64.0/19104.30.64.1 to 104.30.95.254104.30.95.2558,190
244104.30.96.0/19104.30.96.1 to 104.30.127.254104.30.127.2558,190
245104.30.128.0/19104.30.128.1 to 104.30.159.254104.30.159.2558,190
246104.30.160.0/19104.30.160.1 to 104.30.191.254104.30.191.2558,190
247104.30.192.0/19104.30.192.1 to 104.30.223.254104.30.223.2558,190
248104.30.224.0/19104.30.224.1 to 104.30.255.254104.30.255.2558,190
249104.31.0.0/19104.31.0.1 to 104.31.31.254104.31.31.2558,190
250104.31.32.0/19104.31.32.1 to 104.31.63.254104.31.63.2558,190
251104.31.64.0/19104.31.64.1 to 104.31.95.254104.31.95.2558,190
252104.31.96.0/19104.31.96.1 to 104.31.127.254104.31.127.2558,190
253104.31.128.0/19104.31.128.1 to 104.31.159.254104.31.159.2558,190
254104.31.160.0/19104.31.160.1 to 104.31.191.254104.31.191.2558,190
255104.31.192.0/19104.31.192.1 to 104.31.223.254104.31.223.2558,190
256104.31.224.0/19104.31.224.1 to 104.31.255.254104.31.255.2558,190

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.