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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.

Network120.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
120.128.0.0
Broadcast address
120.255.255.255
First usable
120.128.0.1
Last usable
120.255.255.254
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 78800000 · Integer 2021654528 to 2030043135
Reverse DNS zones
128.120.in-addr.arpa
129.120.in-addr.arpa
130.120.in-addr.arpa
131.120.in-addr.arpa
132.120.in-addr.arpa
133.120.in-addr.arpa
134.120.in-addr.arpa
135.120.in-addr.arpa
136.120.in-addr.arpa
137.120.in-addr.arpa
138.120.in-addr.arpa
139.120.in-addr.arpa
140.120.in-addr.arpa
141.120.in-addr.arpa
142.120.in-addr.arpa
143.120.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
Address01111000.10000000.00000000.00000000120.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01111000.10000000.00000000.00000000120.128.0.0
Broadcast01111000.11111111.11111111.11111111120.255.255.255
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)

120.128.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1120.128.0.0/21120.128.0.1 to 120.128.7.254120.128.7.2552,046
2120.128.8.0/21120.128.8.1 to 120.128.15.254120.128.15.2552,046
3120.128.16.0/21120.128.16.1 to 120.128.23.254120.128.23.2552,046
4120.128.24.0/21120.128.24.1 to 120.128.31.254120.128.31.2552,046
5120.128.32.0/21120.128.32.1 to 120.128.39.254120.128.39.2552,046
6120.128.40.0/21120.128.40.1 to 120.128.47.254120.128.47.2552,046
7120.128.48.0/21120.128.48.1 to 120.128.55.254120.128.55.2552,046
8120.128.56.0/21120.128.56.1 to 120.128.63.254120.128.63.2552,046
9120.128.64.0/21120.128.64.1 to 120.128.71.254120.128.71.2552,046
10120.128.72.0/21120.128.72.1 to 120.128.79.254120.128.79.2552,046
11120.128.80.0/21120.128.80.1 to 120.128.87.254120.128.87.2552,046
12120.128.88.0/21120.128.88.1 to 120.128.95.254120.128.95.2552,046
13120.128.96.0/21120.128.96.1 to 120.128.103.254120.128.103.2552,046
14120.128.104.0/21120.128.104.1 to 120.128.111.254120.128.111.2552,046
15120.128.112.0/21120.128.112.1 to 120.128.119.254120.128.119.2552,046
16120.128.120.0/21120.128.120.1 to 120.128.127.254120.128.127.2552,046
17120.128.128.0/21120.128.128.1 to 120.128.135.254120.128.135.2552,046
18120.128.136.0/21120.128.136.1 to 120.128.143.254120.128.143.2552,046
19120.128.144.0/21120.128.144.1 to 120.128.151.254120.128.151.2552,046
20120.128.152.0/21120.128.152.1 to 120.128.159.254120.128.159.2552,046
21120.128.160.0/21120.128.160.1 to 120.128.167.254120.128.167.2552,046
22120.128.168.0/21120.128.168.1 to 120.128.175.254120.128.175.2552,046
23120.128.176.0/21120.128.176.1 to 120.128.183.254120.128.183.2552,046
24120.128.184.0/21120.128.184.1 to 120.128.191.254120.128.191.2552,046
25120.128.192.0/21120.128.192.1 to 120.128.199.254120.128.199.2552,046
26120.128.200.0/21120.128.200.1 to 120.128.207.254120.128.207.2552,046
27120.128.208.0/21120.128.208.1 to 120.128.215.254120.128.215.2552,046
28120.128.216.0/21120.128.216.1 to 120.128.223.254120.128.223.2552,046
29120.128.224.0/21120.128.224.1 to 120.128.231.254120.128.231.2552,046
30120.128.232.0/21120.128.232.1 to 120.128.239.254120.128.239.2552,046
31120.128.240.0/21120.128.240.1 to 120.128.247.254120.128.247.2552,046
32120.128.248.0/21120.128.248.1 to 120.128.255.254120.128.255.2552,046
33120.129.0.0/21120.129.0.1 to 120.129.7.254120.129.7.2552,046
34120.129.8.0/21120.129.8.1 to 120.129.15.254120.129.15.2552,046
35120.129.16.0/21120.129.16.1 to 120.129.23.254120.129.23.2552,046
36120.129.24.0/21120.129.24.1 to 120.129.31.254120.129.31.2552,046
37120.129.32.0/21120.129.32.1 to 120.129.39.254120.129.39.2552,046
38120.129.40.0/21120.129.40.1 to 120.129.47.254120.129.47.2552,046
39120.129.48.0/21120.129.48.1 to 120.129.55.254120.129.55.2552,046
40120.129.56.0/21120.129.56.1 to 120.129.63.254120.129.63.2552,046
41120.129.64.0/21120.129.64.1 to 120.129.71.254120.129.71.2552,046
42120.129.72.0/21120.129.72.1 to 120.129.79.254120.129.79.2552,046
43120.129.80.0/21120.129.80.1 to 120.129.87.254120.129.87.2552,046
44120.129.88.0/21120.129.88.1 to 120.129.95.254120.129.95.2552,046
45120.129.96.0/21120.129.96.1 to 120.129.103.254120.129.103.2552,046
46120.129.104.0/21120.129.104.1 to 120.129.111.254120.129.111.2552,046
47120.129.112.0/21120.129.112.1 to 120.129.119.254120.129.119.2552,046
48120.129.120.0/21120.129.120.1 to 120.129.127.254120.129.127.2552,046
49120.129.128.0/21120.129.128.1 to 120.129.135.254120.129.135.2552,046
50120.129.136.0/21120.129.136.1 to 120.129.143.254120.129.143.2552,046
51120.129.144.0/21120.129.144.1 to 120.129.151.254120.129.151.2552,046
52120.129.152.0/21120.129.152.1 to 120.129.159.254120.129.159.2552,046
53120.129.160.0/21120.129.160.1 to 120.129.167.254120.129.167.2552,046
54120.129.168.0/21120.129.168.1 to 120.129.175.254120.129.175.2552,046
55120.129.176.0/21120.129.176.1 to 120.129.183.254120.129.183.2552,046
56120.129.184.0/21120.129.184.1 to 120.129.191.254120.129.191.2552,046
57120.129.192.0/21120.129.192.1 to 120.129.199.254120.129.199.2552,046
58120.129.200.0/21120.129.200.1 to 120.129.207.254120.129.207.2552,046
59120.129.208.0/21120.129.208.1 to 120.129.215.254120.129.215.2552,046
60120.129.216.0/21120.129.216.1 to 120.129.223.254120.129.223.2552,046
61120.129.224.0/21120.129.224.1 to 120.129.231.254120.129.231.2552,046
62120.129.232.0/21120.129.232.1 to 120.129.239.254120.129.239.2552,046
63120.129.240.0/21120.129.240.1 to 120.129.247.254120.129.247.2552,046
64120.129.248.0/21120.129.248.1 to 120.129.255.254120.129.255.2552,046
65120.130.0.0/21120.130.0.1 to 120.130.7.254120.130.7.2552,046
66120.130.8.0/21120.130.8.1 to 120.130.15.254120.130.15.2552,046
67120.130.16.0/21120.130.16.1 to 120.130.23.254120.130.23.2552,046
68120.130.24.0/21120.130.24.1 to 120.130.31.254120.130.31.2552,046
69120.130.32.0/21120.130.32.1 to 120.130.39.254120.130.39.2552,046
70120.130.40.0/21120.130.40.1 to 120.130.47.254120.130.47.2552,046
71120.130.48.0/21120.130.48.1 to 120.130.55.254120.130.55.2552,046
72120.130.56.0/21120.130.56.1 to 120.130.63.254120.130.63.2552,046
73120.130.64.0/21120.130.64.1 to 120.130.71.254120.130.71.2552,046
74120.130.72.0/21120.130.72.1 to 120.130.79.254120.130.79.2552,046
75120.130.80.0/21120.130.80.1 to 120.130.87.254120.130.87.2552,046
76120.130.88.0/21120.130.88.1 to 120.130.95.254120.130.95.2552,046
77120.130.96.0/21120.130.96.1 to 120.130.103.254120.130.103.2552,046
78120.130.104.0/21120.130.104.1 to 120.130.111.254120.130.111.2552,046
79120.130.112.0/21120.130.112.1 to 120.130.119.254120.130.119.2552,046
80120.130.120.0/21120.130.120.1 to 120.130.127.254120.130.127.2552,046
81120.130.128.0/21120.130.128.1 to 120.130.135.254120.130.135.2552,046
82120.130.136.0/21120.130.136.1 to 120.130.143.254120.130.143.2552,046
83120.130.144.0/21120.130.144.1 to 120.130.151.254120.130.151.2552,046
84120.130.152.0/21120.130.152.1 to 120.130.159.254120.130.159.2552,046
85120.130.160.0/21120.130.160.1 to 120.130.167.254120.130.167.2552,046
86120.130.168.0/21120.130.168.1 to 120.130.175.254120.130.175.2552,046
87120.130.176.0/21120.130.176.1 to 120.130.183.254120.130.183.2552,046
88120.130.184.0/21120.130.184.1 to 120.130.191.254120.130.191.2552,046
89120.130.192.0/21120.130.192.1 to 120.130.199.254120.130.199.2552,046
90120.130.200.0/21120.130.200.1 to 120.130.207.254120.130.207.2552,046
91120.130.208.0/21120.130.208.1 to 120.130.215.254120.130.215.2552,046
92120.130.216.0/21120.130.216.1 to 120.130.223.254120.130.223.2552,046
93120.130.224.0/21120.130.224.1 to 120.130.231.254120.130.231.2552,046
94120.130.232.0/21120.130.232.1 to 120.130.239.254120.130.239.2552,046
95120.130.240.0/21120.130.240.1 to 120.130.247.254120.130.247.2552,046
96120.130.248.0/21120.130.248.1 to 120.130.255.254120.130.255.2552,046
97120.131.0.0/21120.131.0.1 to 120.131.7.254120.131.7.2552,046
98120.131.8.0/21120.131.8.1 to 120.131.15.254120.131.15.2552,046
99120.131.16.0/21120.131.16.1 to 120.131.23.254120.131.23.2552,046
100120.131.24.0/21120.131.24.1 to 120.131.31.254120.131.31.2552,046
101120.131.32.0/21120.131.32.1 to 120.131.39.254120.131.39.2552,046
102120.131.40.0/21120.131.40.1 to 120.131.47.254120.131.47.2552,046
103120.131.48.0/21120.131.48.1 to 120.131.55.254120.131.55.2552,046
104120.131.56.0/21120.131.56.1 to 120.131.63.254120.131.63.2552,046
105120.131.64.0/21120.131.64.1 to 120.131.71.254120.131.71.2552,046
106120.131.72.0/21120.131.72.1 to 120.131.79.254120.131.79.2552,046
107120.131.80.0/21120.131.80.1 to 120.131.87.254120.131.87.2552,046
108120.131.88.0/21120.131.88.1 to 120.131.95.254120.131.95.2552,046
109120.131.96.0/21120.131.96.1 to 120.131.103.254120.131.103.2552,046
110120.131.104.0/21120.131.104.1 to 120.131.111.254120.131.111.2552,046
111120.131.112.0/21120.131.112.1 to 120.131.119.254120.131.119.2552,046
112120.131.120.0/21120.131.120.1 to 120.131.127.254120.131.127.2552,046
113120.131.128.0/21120.131.128.1 to 120.131.135.254120.131.135.2552,046
114120.131.136.0/21120.131.136.1 to 120.131.143.254120.131.143.2552,046
115120.131.144.0/21120.131.144.1 to 120.131.151.254120.131.151.2552,046
116120.131.152.0/21120.131.152.1 to 120.131.159.254120.131.159.2552,046
117120.131.160.0/21120.131.160.1 to 120.131.167.254120.131.167.2552,046
118120.131.168.0/21120.131.168.1 to 120.131.175.254120.131.175.2552,046
119120.131.176.0/21120.131.176.1 to 120.131.183.254120.131.183.2552,046
120120.131.184.0/21120.131.184.1 to 120.131.191.254120.131.191.2552,046
121120.131.192.0/21120.131.192.1 to 120.131.199.254120.131.199.2552,046
122120.131.200.0/21120.131.200.1 to 120.131.207.254120.131.207.2552,046
123120.131.208.0/21120.131.208.1 to 120.131.215.254120.131.215.2552,046
124120.131.216.0/21120.131.216.1 to 120.131.223.254120.131.223.2552,046
125120.131.224.0/21120.131.224.1 to 120.131.231.254120.131.231.2552,046
126120.131.232.0/21120.131.232.1 to 120.131.239.254120.131.239.2552,046
127120.131.240.0/21120.131.240.1 to 120.131.247.254120.131.247.2552,046
128120.131.248.0/21120.131.248.1 to 120.131.255.254120.131.255.2552,046
129120.132.0.0/21120.132.0.1 to 120.132.7.254120.132.7.2552,046
130120.132.8.0/21120.132.8.1 to 120.132.15.254120.132.15.2552,046
131120.132.16.0/21120.132.16.1 to 120.132.23.254120.132.23.2552,046
132120.132.24.0/21120.132.24.1 to 120.132.31.254120.132.31.2552,046
133120.132.32.0/21120.132.32.1 to 120.132.39.254120.132.39.2552,046
134120.132.40.0/21120.132.40.1 to 120.132.47.254120.132.47.2552,046
135120.132.48.0/21120.132.48.1 to 120.132.55.254120.132.55.2552,046
136120.132.56.0/21120.132.56.1 to 120.132.63.254120.132.63.2552,046
137120.132.64.0/21120.132.64.1 to 120.132.71.254120.132.71.2552,046
138120.132.72.0/21120.132.72.1 to 120.132.79.254120.132.79.2552,046
139120.132.80.0/21120.132.80.1 to 120.132.87.254120.132.87.2552,046
140120.132.88.0/21120.132.88.1 to 120.132.95.254120.132.95.2552,046
141120.132.96.0/21120.132.96.1 to 120.132.103.254120.132.103.2552,046
142120.132.104.0/21120.132.104.1 to 120.132.111.254120.132.111.2552,046
143120.132.112.0/21120.132.112.1 to 120.132.119.254120.132.119.2552,046
144120.132.120.0/21120.132.120.1 to 120.132.127.254120.132.127.2552,046
145120.132.128.0/21120.132.128.1 to 120.132.135.254120.132.135.2552,046
146120.132.136.0/21120.132.136.1 to 120.132.143.254120.132.143.2552,046
147120.132.144.0/21120.132.144.1 to 120.132.151.254120.132.151.2552,046
148120.132.152.0/21120.132.152.1 to 120.132.159.254120.132.159.2552,046
149120.132.160.0/21120.132.160.1 to 120.132.167.254120.132.167.2552,046
150120.132.168.0/21120.132.168.1 to 120.132.175.254120.132.175.2552,046
151120.132.176.0/21120.132.176.1 to 120.132.183.254120.132.183.2552,046
152120.132.184.0/21120.132.184.1 to 120.132.191.254120.132.191.2552,046
153120.132.192.0/21120.132.192.1 to 120.132.199.254120.132.199.2552,046
154120.132.200.0/21120.132.200.1 to 120.132.207.254120.132.207.2552,046
155120.132.208.0/21120.132.208.1 to 120.132.215.254120.132.215.2552,046
156120.132.216.0/21120.132.216.1 to 120.132.223.254120.132.223.2552,046
157120.132.224.0/21120.132.224.1 to 120.132.231.254120.132.231.2552,046
158120.132.232.0/21120.132.232.1 to 120.132.239.254120.132.239.2552,046
159120.132.240.0/21120.132.240.1 to 120.132.247.254120.132.247.2552,046
160120.132.248.0/21120.132.248.1 to 120.132.255.254120.132.255.2552,046
161120.133.0.0/21120.133.0.1 to 120.133.7.254120.133.7.2552,046
162120.133.8.0/21120.133.8.1 to 120.133.15.254120.133.15.2552,046
163120.133.16.0/21120.133.16.1 to 120.133.23.254120.133.23.2552,046
164120.133.24.0/21120.133.24.1 to 120.133.31.254120.133.31.2552,046
165120.133.32.0/21120.133.32.1 to 120.133.39.254120.133.39.2552,046
166120.133.40.0/21120.133.40.1 to 120.133.47.254120.133.47.2552,046
167120.133.48.0/21120.133.48.1 to 120.133.55.254120.133.55.2552,046
168120.133.56.0/21120.133.56.1 to 120.133.63.254120.133.63.2552,046
169120.133.64.0/21120.133.64.1 to 120.133.71.254120.133.71.2552,046
170120.133.72.0/21120.133.72.1 to 120.133.79.254120.133.79.2552,046
171120.133.80.0/21120.133.80.1 to 120.133.87.254120.133.87.2552,046
172120.133.88.0/21120.133.88.1 to 120.133.95.254120.133.95.2552,046
173120.133.96.0/21120.133.96.1 to 120.133.103.254120.133.103.2552,046
174120.133.104.0/21120.133.104.1 to 120.133.111.254120.133.111.2552,046
175120.133.112.0/21120.133.112.1 to 120.133.119.254120.133.119.2552,046
176120.133.120.0/21120.133.120.1 to 120.133.127.254120.133.127.2552,046
177120.133.128.0/21120.133.128.1 to 120.133.135.254120.133.135.2552,046
178120.133.136.0/21120.133.136.1 to 120.133.143.254120.133.143.2552,046
179120.133.144.0/21120.133.144.1 to 120.133.151.254120.133.151.2552,046
180120.133.152.0/21120.133.152.1 to 120.133.159.254120.133.159.2552,046
181120.133.160.0/21120.133.160.1 to 120.133.167.254120.133.167.2552,046
182120.133.168.0/21120.133.168.1 to 120.133.175.254120.133.175.2552,046
183120.133.176.0/21120.133.176.1 to 120.133.183.254120.133.183.2552,046
184120.133.184.0/21120.133.184.1 to 120.133.191.254120.133.191.2552,046
185120.133.192.0/21120.133.192.1 to 120.133.199.254120.133.199.2552,046
186120.133.200.0/21120.133.200.1 to 120.133.207.254120.133.207.2552,046
187120.133.208.0/21120.133.208.1 to 120.133.215.254120.133.215.2552,046
188120.133.216.0/21120.133.216.1 to 120.133.223.254120.133.223.2552,046
189120.133.224.0/21120.133.224.1 to 120.133.231.254120.133.231.2552,046
190120.133.232.0/21120.133.232.1 to 120.133.239.254120.133.239.2552,046
191120.133.240.0/21120.133.240.1 to 120.133.247.254120.133.247.2552,046
192120.133.248.0/21120.133.248.1 to 120.133.255.254120.133.255.2552,046
193120.134.0.0/21120.134.0.1 to 120.134.7.254120.134.7.2552,046
194120.134.8.0/21120.134.8.1 to 120.134.15.254120.134.15.2552,046
195120.134.16.0/21120.134.16.1 to 120.134.23.254120.134.23.2552,046
196120.134.24.0/21120.134.24.1 to 120.134.31.254120.134.31.2552,046
197120.134.32.0/21120.134.32.1 to 120.134.39.254120.134.39.2552,046
198120.134.40.0/21120.134.40.1 to 120.134.47.254120.134.47.2552,046
199120.134.48.0/21120.134.48.1 to 120.134.55.254120.134.55.2552,046
200120.134.56.0/21120.134.56.1 to 120.134.63.254120.134.63.2552,046
201120.134.64.0/21120.134.64.1 to 120.134.71.254120.134.71.2552,046
202120.134.72.0/21120.134.72.1 to 120.134.79.254120.134.79.2552,046
203120.134.80.0/21120.134.80.1 to 120.134.87.254120.134.87.2552,046
204120.134.88.0/21120.134.88.1 to 120.134.95.254120.134.95.2552,046
205120.134.96.0/21120.134.96.1 to 120.134.103.254120.134.103.2552,046
206120.134.104.0/21120.134.104.1 to 120.134.111.254120.134.111.2552,046
207120.134.112.0/21120.134.112.1 to 120.134.119.254120.134.119.2552,046
208120.134.120.0/21120.134.120.1 to 120.134.127.254120.134.127.2552,046
209120.134.128.0/21120.134.128.1 to 120.134.135.254120.134.135.2552,046
210120.134.136.0/21120.134.136.1 to 120.134.143.254120.134.143.2552,046
211120.134.144.0/21120.134.144.1 to 120.134.151.254120.134.151.2552,046
212120.134.152.0/21120.134.152.1 to 120.134.159.254120.134.159.2552,046
213120.134.160.0/21120.134.160.1 to 120.134.167.254120.134.167.2552,046
214120.134.168.0/21120.134.168.1 to 120.134.175.254120.134.175.2552,046
215120.134.176.0/21120.134.176.1 to 120.134.183.254120.134.183.2552,046
216120.134.184.0/21120.134.184.1 to 120.134.191.254120.134.191.2552,046
217120.134.192.0/21120.134.192.1 to 120.134.199.254120.134.199.2552,046
218120.134.200.0/21120.134.200.1 to 120.134.207.254120.134.207.2552,046
219120.134.208.0/21120.134.208.1 to 120.134.215.254120.134.215.2552,046
220120.134.216.0/21120.134.216.1 to 120.134.223.254120.134.223.2552,046
221120.134.224.0/21120.134.224.1 to 120.134.231.254120.134.231.2552,046
222120.134.232.0/21120.134.232.1 to 120.134.239.254120.134.239.2552,046
223120.134.240.0/21120.134.240.1 to 120.134.247.254120.134.247.2552,046
224120.134.248.0/21120.134.248.1 to 120.134.255.254120.134.255.2552,046
225120.135.0.0/21120.135.0.1 to 120.135.7.254120.135.7.2552,046
226120.135.8.0/21120.135.8.1 to 120.135.15.254120.135.15.2552,046
227120.135.16.0/21120.135.16.1 to 120.135.23.254120.135.23.2552,046
228120.135.24.0/21120.135.24.1 to 120.135.31.254120.135.31.2552,046
229120.135.32.0/21120.135.32.1 to 120.135.39.254120.135.39.2552,046
230120.135.40.0/21120.135.40.1 to 120.135.47.254120.135.47.2552,046
231120.135.48.0/21120.135.48.1 to 120.135.55.254120.135.55.2552,046
232120.135.56.0/21120.135.56.1 to 120.135.63.254120.135.63.2552,046
233120.135.64.0/21120.135.64.1 to 120.135.71.254120.135.71.2552,046
234120.135.72.0/21120.135.72.1 to 120.135.79.254120.135.79.2552,046
235120.135.80.0/21120.135.80.1 to 120.135.87.254120.135.87.2552,046
236120.135.88.0/21120.135.88.1 to 120.135.95.254120.135.95.2552,046
237120.135.96.0/21120.135.96.1 to 120.135.103.254120.135.103.2552,046
238120.135.104.0/21120.135.104.1 to 120.135.111.254120.135.111.2552,046
239120.135.112.0/21120.135.112.1 to 120.135.119.254120.135.119.2552,046
240120.135.120.0/21120.135.120.1 to 120.135.127.254120.135.127.2552,046
241120.135.128.0/21120.135.128.1 to 120.135.135.254120.135.135.2552,046
242120.135.136.0/21120.135.136.1 to 120.135.143.254120.135.143.2552,046
243120.135.144.0/21120.135.144.1 to 120.135.151.254120.135.151.2552,046
244120.135.152.0/21120.135.152.1 to 120.135.159.254120.135.159.2552,046
245120.135.160.0/21120.135.160.1 to 120.135.167.254120.135.167.2552,046
246120.135.168.0/21120.135.168.1 to 120.135.175.254120.135.175.2552,046
247120.135.176.0/21120.135.176.1 to 120.135.183.254120.135.183.2552,046
248120.135.184.0/21120.135.184.1 to 120.135.191.254120.135.191.2552,046
249120.135.192.0/21120.135.192.1 to 120.135.199.254120.135.199.2552,046
250120.135.200.0/21120.135.200.1 to 120.135.207.254120.135.207.2552,046
251120.135.208.0/21120.135.208.1 to 120.135.215.254120.135.215.2552,046
252120.135.216.0/21120.135.216.1 to 120.135.223.254120.135.223.2552,046
253120.135.224.0/21120.135.224.1 to 120.135.231.254120.135.231.2552,046
254120.135.232.0/21120.135.232.1 to 120.135.239.254120.135.239.2552,046
255120.135.240.0/21120.135.240.1 to 120.135.247.254120.135.247.2552,046
256120.135.248.0/21120.135.248.1 to 120.135.255.254120.135.255.2552,046

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.