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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.

Network165.136.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
165.136.0.0
Broadcast address
165.143.255.255
First usable
165.136.0.1
Last usable
165.143.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
B (default /16)
As numbers
Hex A5880000 · Integer 2777153536 to 2777677823
Reverse DNS zones
136.165.in-addr.arpa
137.165.in-addr.arpa
138.165.in-addr.arpa
139.165.in-addr.arpa
140.165.in-addr.arpa
141.165.in-addr.arpa
142.165.in-addr.arpa
143.165.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100101.10001000.00000000.00000000165.136.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10100101.10001000.00000000.00000000165.136.0.0
Broadcast10100101.10001111.11111111.11111111165.143.255.255
Split into smaller subnets/21
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

165.136.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1165.136.0.0/21165.136.0.1 to 165.136.7.254165.136.7.2552,046
2165.136.8.0/21165.136.8.1 to 165.136.15.254165.136.15.2552,046
3165.136.16.0/21165.136.16.1 to 165.136.23.254165.136.23.2552,046
4165.136.24.0/21165.136.24.1 to 165.136.31.254165.136.31.2552,046
5165.136.32.0/21165.136.32.1 to 165.136.39.254165.136.39.2552,046
6165.136.40.0/21165.136.40.1 to 165.136.47.254165.136.47.2552,046
7165.136.48.0/21165.136.48.1 to 165.136.55.254165.136.55.2552,046
8165.136.56.0/21165.136.56.1 to 165.136.63.254165.136.63.2552,046
9165.136.64.0/21165.136.64.1 to 165.136.71.254165.136.71.2552,046
10165.136.72.0/21165.136.72.1 to 165.136.79.254165.136.79.2552,046
11165.136.80.0/21165.136.80.1 to 165.136.87.254165.136.87.2552,046
12165.136.88.0/21165.136.88.1 to 165.136.95.254165.136.95.2552,046
13165.136.96.0/21165.136.96.1 to 165.136.103.254165.136.103.2552,046
14165.136.104.0/21165.136.104.1 to 165.136.111.254165.136.111.2552,046
15165.136.112.0/21165.136.112.1 to 165.136.119.254165.136.119.2552,046
16165.136.120.0/21165.136.120.1 to 165.136.127.254165.136.127.2552,046
17165.136.128.0/21165.136.128.1 to 165.136.135.254165.136.135.2552,046
18165.136.136.0/21165.136.136.1 to 165.136.143.254165.136.143.2552,046
19165.136.144.0/21165.136.144.1 to 165.136.151.254165.136.151.2552,046
20165.136.152.0/21165.136.152.1 to 165.136.159.254165.136.159.2552,046
21165.136.160.0/21165.136.160.1 to 165.136.167.254165.136.167.2552,046
22165.136.168.0/21165.136.168.1 to 165.136.175.254165.136.175.2552,046
23165.136.176.0/21165.136.176.1 to 165.136.183.254165.136.183.2552,046
24165.136.184.0/21165.136.184.1 to 165.136.191.254165.136.191.2552,046
25165.136.192.0/21165.136.192.1 to 165.136.199.254165.136.199.2552,046
26165.136.200.0/21165.136.200.1 to 165.136.207.254165.136.207.2552,046
27165.136.208.0/21165.136.208.1 to 165.136.215.254165.136.215.2552,046
28165.136.216.0/21165.136.216.1 to 165.136.223.254165.136.223.2552,046
29165.136.224.0/21165.136.224.1 to 165.136.231.254165.136.231.2552,046
30165.136.232.0/21165.136.232.1 to 165.136.239.254165.136.239.2552,046
31165.136.240.0/21165.136.240.1 to 165.136.247.254165.136.247.2552,046
32165.136.248.0/21165.136.248.1 to 165.136.255.254165.136.255.2552,046
33165.137.0.0/21165.137.0.1 to 165.137.7.254165.137.7.2552,046
34165.137.8.0/21165.137.8.1 to 165.137.15.254165.137.15.2552,046
35165.137.16.0/21165.137.16.1 to 165.137.23.254165.137.23.2552,046
36165.137.24.0/21165.137.24.1 to 165.137.31.254165.137.31.2552,046
37165.137.32.0/21165.137.32.1 to 165.137.39.254165.137.39.2552,046
38165.137.40.0/21165.137.40.1 to 165.137.47.254165.137.47.2552,046
39165.137.48.0/21165.137.48.1 to 165.137.55.254165.137.55.2552,046
40165.137.56.0/21165.137.56.1 to 165.137.63.254165.137.63.2552,046
41165.137.64.0/21165.137.64.1 to 165.137.71.254165.137.71.2552,046
42165.137.72.0/21165.137.72.1 to 165.137.79.254165.137.79.2552,046
43165.137.80.0/21165.137.80.1 to 165.137.87.254165.137.87.2552,046
44165.137.88.0/21165.137.88.1 to 165.137.95.254165.137.95.2552,046
45165.137.96.0/21165.137.96.1 to 165.137.103.254165.137.103.2552,046
46165.137.104.0/21165.137.104.1 to 165.137.111.254165.137.111.2552,046
47165.137.112.0/21165.137.112.1 to 165.137.119.254165.137.119.2552,046
48165.137.120.0/21165.137.120.1 to 165.137.127.254165.137.127.2552,046
49165.137.128.0/21165.137.128.1 to 165.137.135.254165.137.135.2552,046
50165.137.136.0/21165.137.136.1 to 165.137.143.254165.137.143.2552,046
51165.137.144.0/21165.137.144.1 to 165.137.151.254165.137.151.2552,046
52165.137.152.0/21165.137.152.1 to 165.137.159.254165.137.159.2552,046
53165.137.160.0/21165.137.160.1 to 165.137.167.254165.137.167.2552,046
54165.137.168.0/21165.137.168.1 to 165.137.175.254165.137.175.2552,046
55165.137.176.0/21165.137.176.1 to 165.137.183.254165.137.183.2552,046
56165.137.184.0/21165.137.184.1 to 165.137.191.254165.137.191.2552,046
57165.137.192.0/21165.137.192.1 to 165.137.199.254165.137.199.2552,046
58165.137.200.0/21165.137.200.1 to 165.137.207.254165.137.207.2552,046
59165.137.208.0/21165.137.208.1 to 165.137.215.254165.137.215.2552,046
60165.137.216.0/21165.137.216.1 to 165.137.223.254165.137.223.2552,046
61165.137.224.0/21165.137.224.1 to 165.137.231.254165.137.231.2552,046
62165.137.232.0/21165.137.232.1 to 165.137.239.254165.137.239.2552,046
63165.137.240.0/21165.137.240.1 to 165.137.247.254165.137.247.2552,046
64165.137.248.0/21165.137.248.1 to 165.137.255.254165.137.255.2552,046
65165.138.0.0/21165.138.0.1 to 165.138.7.254165.138.7.2552,046
66165.138.8.0/21165.138.8.1 to 165.138.15.254165.138.15.2552,046
67165.138.16.0/21165.138.16.1 to 165.138.23.254165.138.23.2552,046
68165.138.24.0/21165.138.24.1 to 165.138.31.254165.138.31.2552,046
69165.138.32.0/21165.138.32.1 to 165.138.39.254165.138.39.2552,046
70165.138.40.0/21165.138.40.1 to 165.138.47.254165.138.47.2552,046
71165.138.48.0/21165.138.48.1 to 165.138.55.254165.138.55.2552,046
72165.138.56.0/21165.138.56.1 to 165.138.63.254165.138.63.2552,046
73165.138.64.0/21165.138.64.1 to 165.138.71.254165.138.71.2552,046
74165.138.72.0/21165.138.72.1 to 165.138.79.254165.138.79.2552,046
75165.138.80.0/21165.138.80.1 to 165.138.87.254165.138.87.2552,046
76165.138.88.0/21165.138.88.1 to 165.138.95.254165.138.95.2552,046
77165.138.96.0/21165.138.96.1 to 165.138.103.254165.138.103.2552,046
78165.138.104.0/21165.138.104.1 to 165.138.111.254165.138.111.2552,046
79165.138.112.0/21165.138.112.1 to 165.138.119.254165.138.119.2552,046
80165.138.120.0/21165.138.120.1 to 165.138.127.254165.138.127.2552,046
81165.138.128.0/21165.138.128.1 to 165.138.135.254165.138.135.2552,046
82165.138.136.0/21165.138.136.1 to 165.138.143.254165.138.143.2552,046
83165.138.144.0/21165.138.144.1 to 165.138.151.254165.138.151.2552,046
84165.138.152.0/21165.138.152.1 to 165.138.159.254165.138.159.2552,046
85165.138.160.0/21165.138.160.1 to 165.138.167.254165.138.167.2552,046
86165.138.168.0/21165.138.168.1 to 165.138.175.254165.138.175.2552,046
87165.138.176.0/21165.138.176.1 to 165.138.183.254165.138.183.2552,046
88165.138.184.0/21165.138.184.1 to 165.138.191.254165.138.191.2552,046
89165.138.192.0/21165.138.192.1 to 165.138.199.254165.138.199.2552,046
90165.138.200.0/21165.138.200.1 to 165.138.207.254165.138.207.2552,046
91165.138.208.0/21165.138.208.1 to 165.138.215.254165.138.215.2552,046
92165.138.216.0/21165.138.216.1 to 165.138.223.254165.138.223.2552,046
93165.138.224.0/21165.138.224.1 to 165.138.231.254165.138.231.2552,046
94165.138.232.0/21165.138.232.1 to 165.138.239.254165.138.239.2552,046
95165.138.240.0/21165.138.240.1 to 165.138.247.254165.138.247.2552,046
96165.138.248.0/21165.138.248.1 to 165.138.255.254165.138.255.2552,046
97165.139.0.0/21165.139.0.1 to 165.139.7.254165.139.7.2552,046
98165.139.8.0/21165.139.8.1 to 165.139.15.254165.139.15.2552,046
99165.139.16.0/21165.139.16.1 to 165.139.23.254165.139.23.2552,046
100165.139.24.0/21165.139.24.1 to 165.139.31.254165.139.31.2552,046
101165.139.32.0/21165.139.32.1 to 165.139.39.254165.139.39.2552,046
102165.139.40.0/21165.139.40.1 to 165.139.47.254165.139.47.2552,046
103165.139.48.0/21165.139.48.1 to 165.139.55.254165.139.55.2552,046
104165.139.56.0/21165.139.56.1 to 165.139.63.254165.139.63.2552,046
105165.139.64.0/21165.139.64.1 to 165.139.71.254165.139.71.2552,046
106165.139.72.0/21165.139.72.1 to 165.139.79.254165.139.79.2552,046
107165.139.80.0/21165.139.80.1 to 165.139.87.254165.139.87.2552,046
108165.139.88.0/21165.139.88.1 to 165.139.95.254165.139.95.2552,046
109165.139.96.0/21165.139.96.1 to 165.139.103.254165.139.103.2552,046
110165.139.104.0/21165.139.104.1 to 165.139.111.254165.139.111.2552,046
111165.139.112.0/21165.139.112.1 to 165.139.119.254165.139.119.2552,046
112165.139.120.0/21165.139.120.1 to 165.139.127.254165.139.127.2552,046
113165.139.128.0/21165.139.128.1 to 165.139.135.254165.139.135.2552,046
114165.139.136.0/21165.139.136.1 to 165.139.143.254165.139.143.2552,046
115165.139.144.0/21165.139.144.1 to 165.139.151.254165.139.151.2552,046
116165.139.152.0/21165.139.152.1 to 165.139.159.254165.139.159.2552,046
117165.139.160.0/21165.139.160.1 to 165.139.167.254165.139.167.2552,046
118165.139.168.0/21165.139.168.1 to 165.139.175.254165.139.175.2552,046
119165.139.176.0/21165.139.176.1 to 165.139.183.254165.139.183.2552,046
120165.139.184.0/21165.139.184.1 to 165.139.191.254165.139.191.2552,046
121165.139.192.0/21165.139.192.1 to 165.139.199.254165.139.199.2552,046
122165.139.200.0/21165.139.200.1 to 165.139.207.254165.139.207.2552,046
123165.139.208.0/21165.139.208.1 to 165.139.215.254165.139.215.2552,046
124165.139.216.0/21165.139.216.1 to 165.139.223.254165.139.223.2552,046
125165.139.224.0/21165.139.224.1 to 165.139.231.254165.139.231.2552,046
126165.139.232.0/21165.139.232.1 to 165.139.239.254165.139.239.2552,046
127165.139.240.0/21165.139.240.1 to 165.139.247.254165.139.247.2552,046
128165.139.248.0/21165.139.248.1 to 165.139.255.254165.139.255.2552,046
129165.140.0.0/21165.140.0.1 to 165.140.7.254165.140.7.2552,046
130165.140.8.0/21165.140.8.1 to 165.140.15.254165.140.15.2552,046
131165.140.16.0/21165.140.16.1 to 165.140.23.254165.140.23.2552,046
132165.140.24.0/21165.140.24.1 to 165.140.31.254165.140.31.2552,046
133165.140.32.0/21165.140.32.1 to 165.140.39.254165.140.39.2552,046
134165.140.40.0/21165.140.40.1 to 165.140.47.254165.140.47.2552,046
135165.140.48.0/21165.140.48.1 to 165.140.55.254165.140.55.2552,046
136165.140.56.0/21165.140.56.1 to 165.140.63.254165.140.63.2552,046
137165.140.64.0/21165.140.64.1 to 165.140.71.254165.140.71.2552,046
138165.140.72.0/21165.140.72.1 to 165.140.79.254165.140.79.2552,046
139165.140.80.0/21165.140.80.1 to 165.140.87.254165.140.87.2552,046
140165.140.88.0/21165.140.88.1 to 165.140.95.254165.140.95.2552,046
141165.140.96.0/21165.140.96.1 to 165.140.103.254165.140.103.2552,046
142165.140.104.0/21165.140.104.1 to 165.140.111.254165.140.111.2552,046
143165.140.112.0/21165.140.112.1 to 165.140.119.254165.140.119.2552,046
144165.140.120.0/21165.140.120.1 to 165.140.127.254165.140.127.2552,046
145165.140.128.0/21165.140.128.1 to 165.140.135.254165.140.135.2552,046
146165.140.136.0/21165.140.136.1 to 165.140.143.254165.140.143.2552,046
147165.140.144.0/21165.140.144.1 to 165.140.151.254165.140.151.2552,046
148165.140.152.0/21165.140.152.1 to 165.140.159.254165.140.159.2552,046
149165.140.160.0/21165.140.160.1 to 165.140.167.254165.140.167.2552,046
150165.140.168.0/21165.140.168.1 to 165.140.175.254165.140.175.2552,046
151165.140.176.0/21165.140.176.1 to 165.140.183.254165.140.183.2552,046
152165.140.184.0/21165.140.184.1 to 165.140.191.254165.140.191.2552,046
153165.140.192.0/21165.140.192.1 to 165.140.199.254165.140.199.2552,046
154165.140.200.0/21165.140.200.1 to 165.140.207.254165.140.207.2552,046
155165.140.208.0/21165.140.208.1 to 165.140.215.254165.140.215.2552,046
156165.140.216.0/21165.140.216.1 to 165.140.223.254165.140.223.2552,046
157165.140.224.0/21165.140.224.1 to 165.140.231.254165.140.231.2552,046
158165.140.232.0/21165.140.232.1 to 165.140.239.254165.140.239.2552,046
159165.140.240.0/21165.140.240.1 to 165.140.247.254165.140.247.2552,046
160165.140.248.0/21165.140.248.1 to 165.140.255.254165.140.255.2552,046
161165.141.0.0/21165.141.0.1 to 165.141.7.254165.141.7.2552,046
162165.141.8.0/21165.141.8.1 to 165.141.15.254165.141.15.2552,046
163165.141.16.0/21165.141.16.1 to 165.141.23.254165.141.23.2552,046
164165.141.24.0/21165.141.24.1 to 165.141.31.254165.141.31.2552,046
165165.141.32.0/21165.141.32.1 to 165.141.39.254165.141.39.2552,046
166165.141.40.0/21165.141.40.1 to 165.141.47.254165.141.47.2552,046
167165.141.48.0/21165.141.48.1 to 165.141.55.254165.141.55.2552,046
168165.141.56.0/21165.141.56.1 to 165.141.63.254165.141.63.2552,046
169165.141.64.0/21165.141.64.1 to 165.141.71.254165.141.71.2552,046
170165.141.72.0/21165.141.72.1 to 165.141.79.254165.141.79.2552,046
171165.141.80.0/21165.141.80.1 to 165.141.87.254165.141.87.2552,046
172165.141.88.0/21165.141.88.1 to 165.141.95.254165.141.95.2552,046
173165.141.96.0/21165.141.96.1 to 165.141.103.254165.141.103.2552,046
174165.141.104.0/21165.141.104.1 to 165.141.111.254165.141.111.2552,046
175165.141.112.0/21165.141.112.1 to 165.141.119.254165.141.119.2552,046
176165.141.120.0/21165.141.120.1 to 165.141.127.254165.141.127.2552,046
177165.141.128.0/21165.141.128.1 to 165.141.135.254165.141.135.2552,046
178165.141.136.0/21165.141.136.1 to 165.141.143.254165.141.143.2552,046
179165.141.144.0/21165.141.144.1 to 165.141.151.254165.141.151.2552,046
180165.141.152.0/21165.141.152.1 to 165.141.159.254165.141.159.2552,046
181165.141.160.0/21165.141.160.1 to 165.141.167.254165.141.167.2552,046
182165.141.168.0/21165.141.168.1 to 165.141.175.254165.141.175.2552,046
183165.141.176.0/21165.141.176.1 to 165.141.183.254165.141.183.2552,046
184165.141.184.0/21165.141.184.1 to 165.141.191.254165.141.191.2552,046
185165.141.192.0/21165.141.192.1 to 165.141.199.254165.141.199.2552,046
186165.141.200.0/21165.141.200.1 to 165.141.207.254165.141.207.2552,046
187165.141.208.0/21165.141.208.1 to 165.141.215.254165.141.215.2552,046
188165.141.216.0/21165.141.216.1 to 165.141.223.254165.141.223.2552,046
189165.141.224.0/21165.141.224.1 to 165.141.231.254165.141.231.2552,046
190165.141.232.0/21165.141.232.1 to 165.141.239.254165.141.239.2552,046
191165.141.240.0/21165.141.240.1 to 165.141.247.254165.141.247.2552,046
192165.141.248.0/21165.141.248.1 to 165.141.255.254165.141.255.2552,046
193165.142.0.0/21165.142.0.1 to 165.142.7.254165.142.7.2552,046
194165.142.8.0/21165.142.8.1 to 165.142.15.254165.142.15.2552,046
195165.142.16.0/21165.142.16.1 to 165.142.23.254165.142.23.2552,046
196165.142.24.0/21165.142.24.1 to 165.142.31.254165.142.31.2552,046
197165.142.32.0/21165.142.32.1 to 165.142.39.254165.142.39.2552,046
198165.142.40.0/21165.142.40.1 to 165.142.47.254165.142.47.2552,046
199165.142.48.0/21165.142.48.1 to 165.142.55.254165.142.55.2552,046
200165.142.56.0/21165.142.56.1 to 165.142.63.254165.142.63.2552,046
201165.142.64.0/21165.142.64.1 to 165.142.71.254165.142.71.2552,046
202165.142.72.0/21165.142.72.1 to 165.142.79.254165.142.79.2552,046
203165.142.80.0/21165.142.80.1 to 165.142.87.254165.142.87.2552,046
204165.142.88.0/21165.142.88.1 to 165.142.95.254165.142.95.2552,046
205165.142.96.0/21165.142.96.1 to 165.142.103.254165.142.103.2552,046
206165.142.104.0/21165.142.104.1 to 165.142.111.254165.142.111.2552,046
207165.142.112.0/21165.142.112.1 to 165.142.119.254165.142.119.2552,046
208165.142.120.0/21165.142.120.1 to 165.142.127.254165.142.127.2552,046
209165.142.128.0/21165.142.128.1 to 165.142.135.254165.142.135.2552,046
210165.142.136.0/21165.142.136.1 to 165.142.143.254165.142.143.2552,046
211165.142.144.0/21165.142.144.1 to 165.142.151.254165.142.151.2552,046
212165.142.152.0/21165.142.152.1 to 165.142.159.254165.142.159.2552,046
213165.142.160.0/21165.142.160.1 to 165.142.167.254165.142.167.2552,046
214165.142.168.0/21165.142.168.1 to 165.142.175.254165.142.175.2552,046
215165.142.176.0/21165.142.176.1 to 165.142.183.254165.142.183.2552,046
216165.142.184.0/21165.142.184.1 to 165.142.191.254165.142.191.2552,046
217165.142.192.0/21165.142.192.1 to 165.142.199.254165.142.199.2552,046
218165.142.200.0/21165.142.200.1 to 165.142.207.254165.142.207.2552,046
219165.142.208.0/21165.142.208.1 to 165.142.215.254165.142.215.2552,046
220165.142.216.0/21165.142.216.1 to 165.142.223.254165.142.223.2552,046
221165.142.224.0/21165.142.224.1 to 165.142.231.254165.142.231.2552,046
222165.142.232.0/21165.142.232.1 to 165.142.239.254165.142.239.2552,046
223165.142.240.0/21165.142.240.1 to 165.142.247.254165.142.247.2552,046
224165.142.248.0/21165.142.248.1 to 165.142.255.254165.142.255.2552,046
225165.143.0.0/21165.143.0.1 to 165.143.7.254165.143.7.2552,046
226165.143.8.0/21165.143.8.1 to 165.143.15.254165.143.15.2552,046
227165.143.16.0/21165.143.16.1 to 165.143.23.254165.143.23.2552,046
228165.143.24.0/21165.143.24.1 to 165.143.31.254165.143.31.2552,046
229165.143.32.0/21165.143.32.1 to 165.143.39.254165.143.39.2552,046
230165.143.40.0/21165.143.40.1 to 165.143.47.254165.143.47.2552,046
231165.143.48.0/21165.143.48.1 to 165.143.55.254165.143.55.2552,046
232165.143.56.0/21165.143.56.1 to 165.143.63.254165.143.63.2552,046
233165.143.64.0/21165.143.64.1 to 165.143.71.254165.143.71.2552,046
234165.143.72.0/21165.143.72.1 to 165.143.79.254165.143.79.2552,046
235165.143.80.0/21165.143.80.1 to 165.143.87.254165.143.87.2552,046
236165.143.88.0/21165.143.88.1 to 165.143.95.254165.143.95.2552,046
237165.143.96.0/21165.143.96.1 to 165.143.103.254165.143.103.2552,046
238165.143.104.0/21165.143.104.1 to 165.143.111.254165.143.111.2552,046
239165.143.112.0/21165.143.112.1 to 165.143.119.254165.143.119.2552,046
240165.143.120.0/21165.143.120.1 to 165.143.127.254165.143.127.2552,046
241165.143.128.0/21165.143.128.1 to 165.143.135.254165.143.135.2552,046
242165.143.136.0/21165.143.136.1 to 165.143.143.254165.143.143.2552,046
243165.143.144.0/21165.143.144.1 to 165.143.151.254165.143.151.2552,046
244165.143.152.0/21165.143.152.1 to 165.143.159.254165.143.159.2552,046
245165.143.160.0/21165.143.160.1 to 165.143.167.254165.143.167.2552,046
246165.143.168.0/21165.143.168.1 to 165.143.175.254165.143.175.2552,046
247165.143.176.0/21165.143.176.1 to 165.143.183.254165.143.183.2552,046
248165.143.184.0/21165.143.184.1 to 165.143.191.254165.143.191.2552,046
249165.143.192.0/21165.143.192.1 to 165.143.199.254165.143.199.2552,046
250165.143.200.0/21165.143.200.1 to 165.143.207.254165.143.207.2552,046
251165.143.208.0/21165.143.208.1 to 165.143.215.254165.143.215.2552,046
252165.143.216.0/21165.143.216.1 to 165.143.223.254165.143.223.2552,046
253165.143.224.0/21165.143.224.1 to 165.143.231.254165.143.231.2552,046
254165.143.232.0/21165.143.232.1 to 165.143.239.254165.143.239.2552,046
255165.143.240.0/21165.143.240.1 to 165.143.247.254165.143.247.2552,046
256165.143.248.0/21165.143.248.1 to 165.143.255.254165.143.255.2552,046

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.