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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.

Network122.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
122.128.0.0
Broadcast address
122.255.255.255
First usable
122.128.0.1
Last usable
122.255.255.254
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 7A800000 · Integer 2055208960 to 2063597567
Reverse DNS zones
128.122.in-addr.arpa
129.122.in-addr.arpa
130.122.in-addr.arpa
131.122.in-addr.arpa
132.122.in-addr.arpa
133.122.in-addr.arpa
134.122.in-addr.arpa
135.122.in-addr.arpa
136.122.in-addr.arpa
137.122.in-addr.arpa
138.122.in-addr.arpa
139.122.in-addr.arpa
140.122.in-addr.arpa
141.122.in-addr.arpa
142.122.in-addr.arpa
143.122.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
Address01111010.10000000.00000000.00000000122.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01111010.10000000.00000000.00000000122.128.0.0
Broadcast01111010.11111111.11111111.11111111122.255.255.255
Split into smaller subnets/21
/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)

122.128.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1122.128.0.0/21122.128.0.1 to 122.128.7.254122.128.7.2552,046
2122.128.8.0/21122.128.8.1 to 122.128.15.254122.128.15.2552,046
3122.128.16.0/21122.128.16.1 to 122.128.23.254122.128.23.2552,046
4122.128.24.0/21122.128.24.1 to 122.128.31.254122.128.31.2552,046
5122.128.32.0/21122.128.32.1 to 122.128.39.254122.128.39.2552,046
6122.128.40.0/21122.128.40.1 to 122.128.47.254122.128.47.2552,046
7122.128.48.0/21122.128.48.1 to 122.128.55.254122.128.55.2552,046
8122.128.56.0/21122.128.56.1 to 122.128.63.254122.128.63.2552,046
9122.128.64.0/21122.128.64.1 to 122.128.71.254122.128.71.2552,046
10122.128.72.0/21122.128.72.1 to 122.128.79.254122.128.79.2552,046
11122.128.80.0/21122.128.80.1 to 122.128.87.254122.128.87.2552,046
12122.128.88.0/21122.128.88.1 to 122.128.95.254122.128.95.2552,046
13122.128.96.0/21122.128.96.1 to 122.128.103.254122.128.103.2552,046
14122.128.104.0/21122.128.104.1 to 122.128.111.254122.128.111.2552,046
15122.128.112.0/21122.128.112.1 to 122.128.119.254122.128.119.2552,046
16122.128.120.0/21122.128.120.1 to 122.128.127.254122.128.127.2552,046
17122.128.128.0/21122.128.128.1 to 122.128.135.254122.128.135.2552,046
18122.128.136.0/21122.128.136.1 to 122.128.143.254122.128.143.2552,046
19122.128.144.0/21122.128.144.1 to 122.128.151.254122.128.151.2552,046
20122.128.152.0/21122.128.152.1 to 122.128.159.254122.128.159.2552,046
21122.128.160.0/21122.128.160.1 to 122.128.167.254122.128.167.2552,046
22122.128.168.0/21122.128.168.1 to 122.128.175.254122.128.175.2552,046
23122.128.176.0/21122.128.176.1 to 122.128.183.254122.128.183.2552,046
24122.128.184.0/21122.128.184.1 to 122.128.191.254122.128.191.2552,046
25122.128.192.0/21122.128.192.1 to 122.128.199.254122.128.199.2552,046
26122.128.200.0/21122.128.200.1 to 122.128.207.254122.128.207.2552,046
27122.128.208.0/21122.128.208.1 to 122.128.215.254122.128.215.2552,046
28122.128.216.0/21122.128.216.1 to 122.128.223.254122.128.223.2552,046
29122.128.224.0/21122.128.224.1 to 122.128.231.254122.128.231.2552,046
30122.128.232.0/21122.128.232.1 to 122.128.239.254122.128.239.2552,046
31122.128.240.0/21122.128.240.1 to 122.128.247.254122.128.247.2552,046
32122.128.248.0/21122.128.248.1 to 122.128.255.254122.128.255.2552,046
33122.129.0.0/21122.129.0.1 to 122.129.7.254122.129.7.2552,046
34122.129.8.0/21122.129.8.1 to 122.129.15.254122.129.15.2552,046
35122.129.16.0/21122.129.16.1 to 122.129.23.254122.129.23.2552,046
36122.129.24.0/21122.129.24.1 to 122.129.31.254122.129.31.2552,046
37122.129.32.0/21122.129.32.1 to 122.129.39.254122.129.39.2552,046
38122.129.40.0/21122.129.40.1 to 122.129.47.254122.129.47.2552,046
39122.129.48.0/21122.129.48.1 to 122.129.55.254122.129.55.2552,046
40122.129.56.0/21122.129.56.1 to 122.129.63.254122.129.63.2552,046
41122.129.64.0/21122.129.64.1 to 122.129.71.254122.129.71.2552,046
42122.129.72.0/21122.129.72.1 to 122.129.79.254122.129.79.2552,046
43122.129.80.0/21122.129.80.1 to 122.129.87.254122.129.87.2552,046
44122.129.88.0/21122.129.88.1 to 122.129.95.254122.129.95.2552,046
45122.129.96.0/21122.129.96.1 to 122.129.103.254122.129.103.2552,046
46122.129.104.0/21122.129.104.1 to 122.129.111.254122.129.111.2552,046
47122.129.112.0/21122.129.112.1 to 122.129.119.254122.129.119.2552,046
48122.129.120.0/21122.129.120.1 to 122.129.127.254122.129.127.2552,046
49122.129.128.0/21122.129.128.1 to 122.129.135.254122.129.135.2552,046
50122.129.136.0/21122.129.136.1 to 122.129.143.254122.129.143.2552,046
51122.129.144.0/21122.129.144.1 to 122.129.151.254122.129.151.2552,046
52122.129.152.0/21122.129.152.1 to 122.129.159.254122.129.159.2552,046
53122.129.160.0/21122.129.160.1 to 122.129.167.254122.129.167.2552,046
54122.129.168.0/21122.129.168.1 to 122.129.175.254122.129.175.2552,046
55122.129.176.0/21122.129.176.1 to 122.129.183.254122.129.183.2552,046
56122.129.184.0/21122.129.184.1 to 122.129.191.254122.129.191.2552,046
57122.129.192.0/21122.129.192.1 to 122.129.199.254122.129.199.2552,046
58122.129.200.0/21122.129.200.1 to 122.129.207.254122.129.207.2552,046
59122.129.208.0/21122.129.208.1 to 122.129.215.254122.129.215.2552,046
60122.129.216.0/21122.129.216.1 to 122.129.223.254122.129.223.2552,046
61122.129.224.0/21122.129.224.1 to 122.129.231.254122.129.231.2552,046
62122.129.232.0/21122.129.232.1 to 122.129.239.254122.129.239.2552,046
63122.129.240.0/21122.129.240.1 to 122.129.247.254122.129.247.2552,046
64122.129.248.0/21122.129.248.1 to 122.129.255.254122.129.255.2552,046
65122.130.0.0/21122.130.0.1 to 122.130.7.254122.130.7.2552,046
66122.130.8.0/21122.130.8.1 to 122.130.15.254122.130.15.2552,046
67122.130.16.0/21122.130.16.1 to 122.130.23.254122.130.23.2552,046
68122.130.24.0/21122.130.24.1 to 122.130.31.254122.130.31.2552,046
69122.130.32.0/21122.130.32.1 to 122.130.39.254122.130.39.2552,046
70122.130.40.0/21122.130.40.1 to 122.130.47.254122.130.47.2552,046
71122.130.48.0/21122.130.48.1 to 122.130.55.254122.130.55.2552,046
72122.130.56.0/21122.130.56.1 to 122.130.63.254122.130.63.2552,046
73122.130.64.0/21122.130.64.1 to 122.130.71.254122.130.71.2552,046
74122.130.72.0/21122.130.72.1 to 122.130.79.254122.130.79.2552,046
75122.130.80.0/21122.130.80.1 to 122.130.87.254122.130.87.2552,046
76122.130.88.0/21122.130.88.1 to 122.130.95.254122.130.95.2552,046
77122.130.96.0/21122.130.96.1 to 122.130.103.254122.130.103.2552,046
78122.130.104.0/21122.130.104.1 to 122.130.111.254122.130.111.2552,046
79122.130.112.0/21122.130.112.1 to 122.130.119.254122.130.119.2552,046
80122.130.120.0/21122.130.120.1 to 122.130.127.254122.130.127.2552,046
81122.130.128.0/21122.130.128.1 to 122.130.135.254122.130.135.2552,046
82122.130.136.0/21122.130.136.1 to 122.130.143.254122.130.143.2552,046
83122.130.144.0/21122.130.144.1 to 122.130.151.254122.130.151.2552,046
84122.130.152.0/21122.130.152.1 to 122.130.159.254122.130.159.2552,046
85122.130.160.0/21122.130.160.1 to 122.130.167.254122.130.167.2552,046
86122.130.168.0/21122.130.168.1 to 122.130.175.254122.130.175.2552,046
87122.130.176.0/21122.130.176.1 to 122.130.183.254122.130.183.2552,046
88122.130.184.0/21122.130.184.1 to 122.130.191.254122.130.191.2552,046
89122.130.192.0/21122.130.192.1 to 122.130.199.254122.130.199.2552,046
90122.130.200.0/21122.130.200.1 to 122.130.207.254122.130.207.2552,046
91122.130.208.0/21122.130.208.1 to 122.130.215.254122.130.215.2552,046
92122.130.216.0/21122.130.216.1 to 122.130.223.254122.130.223.2552,046
93122.130.224.0/21122.130.224.1 to 122.130.231.254122.130.231.2552,046
94122.130.232.0/21122.130.232.1 to 122.130.239.254122.130.239.2552,046
95122.130.240.0/21122.130.240.1 to 122.130.247.254122.130.247.2552,046
96122.130.248.0/21122.130.248.1 to 122.130.255.254122.130.255.2552,046
97122.131.0.0/21122.131.0.1 to 122.131.7.254122.131.7.2552,046
98122.131.8.0/21122.131.8.1 to 122.131.15.254122.131.15.2552,046
99122.131.16.0/21122.131.16.1 to 122.131.23.254122.131.23.2552,046
100122.131.24.0/21122.131.24.1 to 122.131.31.254122.131.31.2552,046
101122.131.32.0/21122.131.32.1 to 122.131.39.254122.131.39.2552,046
102122.131.40.0/21122.131.40.1 to 122.131.47.254122.131.47.2552,046
103122.131.48.0/21122.131.48.1 to 122.131.55.254122.131.55.2552,046
104122.131.56.0/21122.131.56.1 to 122.131.63.254122.131.63.2552,046
105122.131.64.0/21122.131.64.1 to 122.131.71.254122.131.71.2552,046
106122.131.72.0/21122.131.72.1 to 122.131.79.254122.131.79.2552,046
107122.131.80.0/21122.131.80.1 to 122.131.87.254122.131.87.2552,046
108122.131.88.0/21122.131.88.1 to 122.131.95.254122.131.95.2552,046
109122.131.96.0/21122.131.96.1 to 122.131.103.254122.131.103.2552,046
110122.131.104.0/21122.131.104.1 to 122.131.111.254122.131.111.2552,046
111122.131.112.0/21122.131.112.1 to 122.131.119.254122.131.119.2552,046
112122.131.120.0/21122.131.120.1 to 122.131.127.254122.131.127.2552,046
113122.131.128.0/21122.131.128.1 to 122.131.135.254122.131.135.2552,046
114122.131.136.0/21122.131.136.1 to 122.131.143.254122.131.143.2552,046
115122.131.144.0/21122.131.144.1 to 122.131.151.254122.131.151.2552,046
116122.131.152.0/21122.131.152.1 to 122.131.159.254122.131.159.2552,046
117122.131.160.0/21122.131.160.1 to 122.131.167.254122.131.167.2552,046
118122.131.168.0/21122.131.168.1 to 122.131.175.254122.131.175.2552,046
119122.131.176.0/21122.131.176.1 to 122.131.183.254122.131.183.2552,046
120122.131.184.0/21122.131.184.1 to 122.131.191.254122.131.191.2552,046
121122.131.192.0/21122.131.192.1 to 122.131.199.254122.131.199.2552,046
122122.131.200.0/21122.131.200.1 to 122.131.207.254122.131.207.2552,046
123122.131.208.0/21122.131.208.1 to 122.131.215.254122.131.215.2552,046
124122.131.216.0/21122.131.216.1 to 122.131.223.254122.131.223.2552,046
125122.131.224.0/21122.131.224.1 to 122.131.231.254122.131.231.2552,046
126122.131.232.0/21122.131.232.1 to 122.131.239.254122.131.239.2552,046
127122.131.240.0/21122.131.240.1 to 122.131.247.254122.131.247.2552,046
128122.131.248.0/21122.131.248.1 to 122.131.255.254122.131.255.2552,046
129122.132.0.0/21122.132.0.1 to 122.132.7.254122.132.7.2552,046
130122.132.8.0/21122.132.8.1 to 122.132.15.254122.132.15.2552,046
131122.132.16.0/21122.132.16.1 to 122.132.23.254122.132.23.2552,046
132122.132.24.0/21122.132.24.1 to 122.132.31.254122.132.31.2552,046
133122.132.32.0/21122.132.32.1 to 122.132.39.254122.132.39.2552,046
134122.132.40.0/21122.132.40.1 to 122.132.47.254122.132.47.2552,046
135122.132.48.0/21122.132.48.1 to 122.132.55.254122.132.55.2552,046
136122.132.56.0/21122.132.56.1 to 122.132.63.254122.132.63.2552,046
137122.132.64.0/21122.132.64.1 to 122.132.71.254122.132.71.2552,046
138122.132.72.0/21122.132.72.1 to 122.132.79.254122.132.79.2552,046
139122.132.80.0/21122.132.80.1 to 122.132.87.254122.132.87.2552,046
140122.132.88.0/21122.132.88.1 to 122.132.95.254122.132.95.2552,046
141122.132.96.0/21122.132.96.1 to 122.132.103.254122.132.103.2552,046
142122.132.104.0/21122.132.104.1 to 122.132.111.254122.132.111.2552,046
143122.132.112.0/21122.132.112.1 to 122.132.119.254122.132.119.2552,046
144122.132.120.0/21122.132.120.1 to 122.132.127.254122.132.127.2552,046
145122.132.128.0/21122.132.128.1 to 122.132.135.254122.132.135.2552,046
146122.132.136.0/21122.132.136.1 to 122.132.143.254122.132.143.2552,046
147122.132.144.0/21122.132.144.1 to 122.132.151.254122.132.151.2552,046
148122.132.152.0/21122.132.152.1 to 122.132.159.254122.132.159.2552,046
149122.132.160.0/21122.132.160.1 to 122.132.167.254122.132.167.2552,046
150122.132.168.0/21122.132.168.1 to 122.132.175.254122.132.175.2552,046
151122.132.176.0/21122.132.176.1 to 122.132.183.254122.132.183.2552,046
152122.132.184.0/21122.132.184.1 to 122.132.191.254122.132.191.2552,046
153122.132.192.0/21122.132.192.1 to 122.132.199.254122.132.199.2552,046
154122.132.200.0/21122.132.200.1 to 122.132.207.254122.132.207.2552,046
155122.132.208.0/21122.132.208.1 to 122.132.215.254122.132.215.2552,046
156122.132.216.0/21122.132.216.1 to 122.132.223.254122.132.223.2552,046
157122.132.224.0/21122.132.224.1 to 122.132.231.254122.132.231.2552,046
158122.132.232.0/21122.132.232.1 to 122.132.239.254122.132.239.2552,046
159122.132.240.0/21122.132.240.1 to 122.132.247.254122.132.247.2552,046
160122.132.248.0/21122.132.248.1 to 122.132.255.254122.132.255.2552,046
161122.133.0.0/21122.133.0.1 to 122.133.7.254122.133.7.2552,046
162122.133.8.0/21122.133.8.1 to 122.133.15.254122.133.15.2552,046
163122.133.16.0/21122.133.16.1 to 122.133.23.254122.133.23.2552,046
164122.133.24.0/21122.133.24.1 to 122.133.31.254122.133.31.2552,046
165122.133.32.0/21122.133.32.1 to 122.133.39.254122.133.39.2552,046
166122.133.40.0/21122.133.40.1 to 122.133.47.254122.133.47.2552,046
167122.133.48.0/21122.133.48.1 to 122.133.55.254122.133.55.2552,046
168122.133.56.0/21122.133.56.1 to 122.133.63.254122.133.63.2552,046
169122.133.64.0/21122.133.64.1 to 122.133.71.254122.133.71.2552,046
170122.133.72.0/21122.133.72.1 to 122.133.79.254122.133.79.2552,046
171122.133.80.0/21122.133.80.1 to 122.133.87.254122.133.87.2552,046
172122.133.88.0/21122.133.88.1 to 122.133.95.254122.133.95.2552,046
173122.133.96.0/21122.133.96.1 to 122.133.103.254122.133.103.2552,046
174122.133.104.0/21122.133.104.1 to 122.133.111.254122.133.111.2552,046
175122.133.112.0/21122.133.112.1 to 122.133.119.254122.133.119.2552,046
176122.133.120.0/21122.133.120.1 to 122.133.127.254122.133.127.2552,046
177122.133.128.0/21122.133.128.1 to 122.133.135.254122.133.135.2552,046
178122.133.136.0/21122.133.136.1 to 122.133.143.254122.133.143.2552,046
179122.133.144.0/21122.133.144.1 to 122.133.151.254122.133.151.2552,046
180122.133.152.0/21122.133.152.1 to 122.133.159.254122.133.159.2552,046
181122.133.160.0/21122.133.160.1 to 122.133.167.254122.133.167.2552,046
182122.133.168.0/21122.133.168.1 to 122.133.175.254122.133.175.2552,046
183122.133.176.0/21122.133.176.1 to 122.133.183.254122.133.183.2552,046
184122.133.184.0/21122.133.184.1 to 122.133.191.254122.133.191.2552,046
185122.133.192.0/21122.133.192.1 to 122.133.199.254122.133.199.2552,046
186122.133.200.0/21122.133.200.1 to 122.133.207.254122.133.207.2552,046
187122.133.208.0/21122.133.208.1 to 122.133.215.254122.133.215.2552,046
188122.133.216.0/21122.133.216.1 to 122.133.223.254122.133.223.2552,046
189122.133.224.0/21122.133.224.1 to 122.133.231.254122.133.231.2552,046
190122.133.232.0/21122.133.232.1 to 122.133.239.254122.133.239.2552,046
191122.133.240.0/21122.133.240.1 to 122.133.247.254122.133.247.2552,046
192122.133.248.0/21122.133.248.1 to 122.133.255.254122.133.255.2552,046
193122.134.0.0/21122.134.0.1 to 122.134.7.254122.134.7.2552,046
194122.134.8.0/21122.134.8.1 to 122.134.15.254122.134.15.2552,046
195122.134.16.0/21122.134.16.1 to 122.134.23.254122.134.23.2552,046
196122.134.24.0/21122.134.24.1 to 122.134.31.254122.134.31.2552,046
197122.134.32.0/21122.134.32.1 to 122.134.39.254122.134.39.2552,046
198122.134.40.0/21122.134.40.1 to 122.134.47.254122.134.47.2552,046
199122.134.48.0/21122.134.48.1 to 122.134.55.254122.134.55.2552,046
200122.134.56.0/21122.134.56.1 to 122.134.63.254122.134.63.2552,046
201122.134.64.0/21122.134.64.1 to 122.134.71.254122.134.71.2552,046
202122.134.72.0/21122.134.72.1 to 122.134.79.254122.134.79.2552,046
203122.134.80.0/21122.134.80.1 to 122.134.87.254122.134.87.2552,046
204122.134.88.0/21122.134.88.1 to 122.134.95.254122.134.95.2552,046
205122.134.96.0/21122.134.96.1 to 122.134.103.254122.134.103.2552,046
206122.134.104.0/21122.134.104.1 to 122.134.111.254122.134.111.2552,046
207122.134.112.0/21122.134.112.1 to 122.134.119.254122.134.119.2552,046
208122.134.120.0/21122.134.120.1 to 122.134.127.254122.134.127.2552,046
209122.134.128.0/21122.134.128.1 to 122.134.135.254122.134.135.2552,046
210122.134.136.0/21122.134.136.1 to 122.134.143.254122.134.143.2552,046
211122.134.144.0/21122.134.144.1 to 122.134.151.254122.134.151.2552,046
212122.134.152.0/21122.134.152.1 to 122.134.159.254122.134.159.2552,046
213122.134.160.0/21122.134.160.1 to 122.134.167.254122.134.167.2552,046
214122.134.168.0/21122.134.168.1 to 122.134.175.254122.134.175.2552,046
215122.134.176.0/21122.134.176.1 to 122.134.183.254122.134.183.2552,046
216122.134.184.0/21122.134.184.1 to 122.134.191.254122.134.191.2552,046
217122.134.192.0/21122.134.192.1 to 122.134.199.254122.134.199.2552,046
218122.134.200.0/21122.134.200.1 to 122.134.207.254122.134.207.2552,046
219122.134.208.0/21122.134.208.1 to 122.134.215.254122.134.215.2552,046
220122.134.216.0/21122.134.216.1 to 122.134.223.254122.134.223.2552,046
221122.134.224.0/21122.134.224.1 to 122.134.231.254122.134.231.2552,046
222122.134.232.0/21122.134.232.1 to 122.134.239.254122.134.239.2552,046
223122.134.240.0/21122.134.240.1 to 122.134.247.254122.134.247.2552,046
224122.134.248.0/21122.134.248.1 to 122.134.255.254122.134.255.2552,046
225122.135.0.0/21122.135.0.1 to 122.135.7.254122.135.7.2552,046
226122.135.8.0/21122.135.8.1 to 122.135.15.254122.135.15.2552,046
227122.135.16.0/21122.135.16.1 to 122.135.23.254122.135.23.2552,046
228122.135.24.0/21122.135.24.1 to 122.135.31.254122.135.31.2552,046
229122.135.32.0/21122.135.32.1 to 122.135.39.254122.135.39.2552,046
230122.135.40.0/21122.135.40.1 to 122.135.47.254122.135.47.2552,046
231122.135.48.0/21122.135.48.1 to 122.135.55.254122.135.55.2552,046
232122.135.56.0/21122.135.56.1 to 122.135.63.254122.135.63.2552,046
233122.135.64.0/21122.135.64.1 to 122.135.71.254122.135.71.2552,046
234122.135.72.0/21122.135.72.1 to 122.135.79.254122.135.79.2552,046
235122.135.80.0/21122.135.80.1 to 122.135.87.254122.135.87.2552,046
236122.135.88.0/21122.135.88.1 to 122.135.95.254122.135.95.2552,046
237122.135.96.0/21122.135.96.1 to 122.135.103.254122.135.103.2552,046
238122.135.104.0/21122.135.104.1 to 122.135.111.254122.135.111.2552,046
239122.135.112.0/21122.135.112.1 to 122.135.119.254122.135.119.2552,046
240122.135.120.0/21122.135.120.1 to 122.135.127.254122.135.127.2552,046
241122.135.128.0/21122.135.128.1 to 122.135.135.254122.135.135.2552,046
242122.135.136.0/21122.135.136.1 to 122.135.143.254122.135.143.2552,046
243122.135.144.0/21122.135.144.1 to 122.135.151.254122.135.151.2552,046
244122.135.152.0/21122.135.152.1 to 122.135.159.254122.135.159.2552,046
245122.135.160.0/21122.135.160.1 to 122.135.167.254122.135.167.2552,046
246122.135.168.0/21122.135.168.1 to 122.135.175.254122.135.175.2552,046
247122.135.176.0/21122.135.176.1 to 122.135.183.254122.135.183.2552,046
248122.135.184.0/21122.135.184.1 to 122.135.191.254122.135.191.2552,046
249122.135.192.0/21122.135.192.1 to 122.135.199.254122.135.199.2552,046
250122.135.200.0/21122.135.200.1 to 122.135.207.254122.135.207.2552,046
251122.135.208.0/21122.135.208.1 to 122.135.215.254122.135.215.2552,046
252122.135.216.0/21122.135.216.1 to 122.135.223.254122.135.223.2552,046
253122.135.224.0/21122.135.224.1 to 122.135.231.254122.135.231.2552,046
254122.135.232.0/21122.135.232.1 to 122.135.239.254122.135.239.2552,046
255122.135.240.0/21122.135.240.1 to 122.135.247.254122.135.247.2552,046
256122.135.248.0/21122.135.248.1 to 122.135.255.254122.135.255.2552,046

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.