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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.

Network165.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
165.0.0.0
Broadcast address
165.63.255.255
First usable
165.0.0.1
Last usable
165.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex A5000000 · Integer 2768240640 to 2772434943
Reverse DNS zones
0.165.in-addr.arpa
1.165.in-addr.arpa
2.165.in-addr.arpa
3.165.in-addr.arpa
4.165.in-addr.arpa
5.165.in-addr.arpa
6.165.in-addr.arpa
7.165.in-addr.arpa
8.165.in-addr.arpa
9.165.in-addr.arpa
10.165.in-addr.arpa
11.165.in-addr.arpa
12.165.in-addr.arpa
13.165.in-addr.arpa
14.165.in-addr.arpa
15.165.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100101.00000000.00000000.00000000165.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10100101.00000000.00000000.00000000165.0.0.0
Broadcast10100101.00111111.11111111.11111111165.63.255.255
Split into smaller subnets/22
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

165.0.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1165.0.0.0/22165.0.0.1 to 165.0.3.254165.0.3.2551,022
2165.0.4.0/22165.0.4.1 to 165.0.7.254165.0.7.2551,022
3165.0.8.0/22165.0.8.1 to 165.0.11.254165.0.11.2551,022
4165.0.12.0/22165.0.12.1 to 165.0.15.254165.0.15.2551,022
5165.0.16.0/22165.0.16.1 to 165.0.19.254165.0.19.2551,022
6165.0.20.0/22165.0.20.1 to 165.0.23.254165.0.23.2551,022
7165.0.24.0/22165.0.24.1 to 165.0.27.254165.0.27.2551,022
8165.0.28.0/22165.0.28.1 to 165.0.31.254165.0.31.2551,022
9165.0.32.0/22165.0.32.1 to 165.0.35.254165.0.35.2551,022
10165.0.36.0/22165.0.36.1 to 165.0.39.254165.0.39.2551,022
11165.0.40.0/22165.0.40.1 to 165.0.43.254165.0.43.2551,022
12165.0.44.0/22165.0.44.1 to 165.0.47.254165.0.47.2551,022
13165.0.48.0/22165.0.48.1 to 165.0.51.254165.0.51.2551,022
14165.0.52.0/22165.0.52.1 to 165.0.55.254165.0.55.2551,022
15165.0.56.0/22165.0.56.1 to 165.0.59.254165.0.59.2551,022
16165.0.60.0/22165.0.60.1 to 165.0.63.254165.0.63.2551,022
17165.0.64.0/22165.0.64.1 to 165.0.67.254165.0.67.2551,022
18165.0.68.0/22165.0.68.1 to 165.0.71.254165.0.71.2551,022
19165.0.72.0/22165.0.72.1 to 165.0.75.254165.0.75.2551,022
20165.0.76.0/22165.0.76.1 to 165.0.79.254165.0.79.2551,022
21165.0.80.0/22165.0.80.1 to 165.0.83.254165.0.83.2551,022
22165.0.84.0/22165.0.84.1 to 165.0.87.254165.0.87.2551,022
23165.0.88.0/22165.0.88.1 to 165.0.91.254165.0.91.2551,022
24165.0.92.0/22165.0.92.1 to 165.0.95.254165.0.95.2551,022
25165.0.96.0/22165.0.96.1 to 165.0.99.254165.0.99.2551,022
26165.0.100.0/22165.0.100.1 to 165.0.103.254165.0.103.2551,022
27165.0.104.0/22165.0.104.1 to 165.0.107.254165.0.107.2551,022
28165.0.108.0/22165.0.108.1 to 165.0.111.254165.0.111.2551,022
29165.0.112.0/22165.0.112.1 to 165.0.115.254165.0.115.2551,022
30165.0.116.0/22165.0.116.1 to 165.0.119.254165.0.119.2551,022
31165.0.120.0/22165.0.120.1 to 165.0.123.254165.0.123.2551,022
32165.0.124.0/22165.0.124.1 to 165.0.127.254165.0.127.2551,022
33165.0.128.0/22165.0.128.1 to 165.0.131.254165.0.131.2551,022
34165.0.132.0/22165.0.132.1 to 165.0.135.254165.0.135.2551,022
35165.0.136.0/22165.0.136.1 to 165.0.139.254165.0.139.2551,022
36165.0.140.0/22165.0.140.1 to 165.0.143.254165.0.143.2551,022
37165.0.144.0/22165.0.144.1 to 165.0.147.254165.0.147.2551,022
38165.0.148.0/22165.0.148.1 to 165.0.151.254165.0.151.2551,022
39165.0.152.0/22165.0.152.1 to 165.0.155.254165.0.155.2551,022
40165.0.156.0/22165.0.156.1 to 165.0.159.254165.0.159.2551,022
41165.0.160.0/22165.0.160.1 to 165.0.163.254165.0.163.2551,022
42165.0.164.0/22165.0.164.1 to 165.0.167.254165.0.167.2551,022
43165.0.168.0/22165.0.168.1 to 165.0.171.254165.0.171.2551,022
44165.0.172.0/22165.0.172.1 to 165.0.175.254165.0.175.2551,022
45165.0.176.0/22165.0.176.1 to 165.0.179.254165.0.179.2551,022
46165.0.180.0/22165.0.180.1 to 165.0.183.254165.0.183.2551,022
47165.0.184.0/22165.0.184.1 to 165.0.187.254165.0.187.2551,022
48165.0.188.0/22165.0.188.1 to 165.0.191.254165.0.191.2551,022
49165.0.192.0/22165.0.192.1 to 165.0.195.254165.0.195.2551,022
50165.0.196.0/22165.0.196.1 to 165.0.199.254165.0.199.2551,022
51165.0.200.0/22165.0.200.1 to 165.0.203.254165.0.203.2551,022
52165.0.204.0/22165.0.204.1 to 165.0.207.254165.0.207.2551,022
53165.0.208.0/22165.0.208.1 to 165.0.211.254165.0.211.2551,022
54165.0.212.0/22165.0.212.1 to 165.0.215.254165.0.215.2551,022
55165.0.216.0/22165.0.216.1 to 165.0.219.254165.0.219.2551,022
56165.0.220.0/22165.0.220.1 to 165.0.223.254165.0.223.2551,022
57165.0.224.0/22165.0.224.1 to 165.0.227.254165.0.227.2551,022
58165.0.228.0/22165.0.228.1 to 165.0.231.254165.0.231.2551,022
59165.0.232.0/22165.0.232.1 to 165.0.235.254165.0.235.2551,022
60165.0.236.0/22165.0.236.1 to 165.0.239.254165.0.239.2551,022
61165.0.240.0/22165.0.240.1 to 165.0.243.254165.0.243.2551,022
62165.0.244.0/22165.0.244.1 to 165.0.247.254165.0.247.2551,022
63165.0.248.0/22165.0.248.1 to 165.0.251.254165.0.251.2551,022
64165.0.252.0/22165.0.252.1 to 165.0.255.254165.0.255.2551,022
65165.1.0.0/22165.1.0.1 to 165.1.3.254165.1.3.2551,022
66165.1.4.0/22165.1.4.1 to 165.1.7.254165.1.7.2551,022
67165.1.8.0/22165.1.8.1 to 165.1.11.254165.1.11.2551,022
68165.1.12.0/22165.1.12.1 to 165.1.15.254165.1.15.2551,022
69165.1.16.0/22165.1.16.1 to 165.1.19.254165.1.19.2551,022
70165.1.20.0/22165.1.20.1 to 165.1.23.254165.1.23.2551,022
71165.1.24.0/22165.1.24.1 to 165.1.27.254165.1.27.2551,022
72165.1.28.0/22165.1.28.1 to 165.1.31.254165.1.31.2551,022
73165.1.32.0/22165.1.32.1 to 165.1.35.254165.1.35.2551,022
74165.1.36.0/22165.1.36.1 to 165.1.39.254165.1.39.2551,022
75165.1.40.0/22165.1.40.1 to 165.1.43.254165.1.43.2551,022
76165.1.44.0/22165.1.44.1 to 165.1.47.254165.1.47.2551,022
77165.1.48.0/22165.1.48.1 to 165.1.51.254165.1.51.2551,022
78165.1.52.0/22165.1.52.1 to 165.1.55.254165.1.55.2551,022
79165.1.56.0/22165.1.56.1 to 165.1.59.254165.1.59.2551,022
80165.1.60.0/22165.1.60.1 to 165.1.63.254165.1.63.2551,022
81165.1.64.0/22165.1.64.1 to 165.1.67.254165.1.67.2551,022
82165.1.68.0/22165.1.68.1 to 165.1.71.254165.1.71.2551,022
83165.1.72.0/22165.1.72.1 to 165.1.75.254165.1.75.2551,022
84165.1.76.0/22165.1.76.1 to 165.1.79.254165.1.79.2551,022
85165.1.80.0/22165.1.80.1 to 165.1.83.254165.1.83.2551,022
86165.1.84.0/22165.1.84.1 to 165.1.87.254165.1.87.2551,022
87165.1.88.0/22165.1.88.1 to 165.1.91.254165.1.91.2551,022
88165.1.92.0/22165.1.92.1 to 165.1.95.254165.1.95.2551,022
89165.1.96.0/22165.1.96.1 to 165.1.99.254165.1.99.2551,022
90165.1.100.0/22165.1.100.1 to 165.1.103.254165.1.103.2551,022
91165.1.104.0/22165.1.104.1 to 165.1.107.254165.1.107.2551,022
92165.1.108.0/22165.1.108.1 to 165.1.111.254165.1.111.2551,022
93165.1.112.0/22165.1.112.1 to 165.1.115.254165.1.115.2551,022
94165.1.116.0/22165.1.116.1 to 165.1.119.254165.1.119.2551,022
95165.1.120.0/22165.1.120.1 to 165.1.123.254165.1.123.2551,022
96165.1.124.0/22165.1.124.1 to 165.1.127.254165.1.127.2551,022
97165.1.128.0/22165.1.128.1 to 165.1.131.254165.1.131.2551,022
98165.1.132.0/22165.1.132.1 to 165.1.135.254165.1.135.2551,022
99165.1.136.0/22165.1.136.1 to 165.1.139.254165.1.139.2551,022
100165.1.140.0/22165.1.140.1 to 165.1.143.254165.1.143.2551,022
101165.1.144.0/22165.1.144.1 to 165.1.147.254165.1.147.2551,022
102165.1.148.0/22165.1.148.1 to 165.1.151.254165.1.151.2551,022
103165.1.152.0/22165.1.152.1 to 165.1.155.254165.1.155.2551,022
104165.1.156.0/22165.1.156.1 to 165.1.159.254165.1.159.2551,022
105165.1.160.0/22165.1.160.1 to 165.1.163.254165.1.163.2551,022
106165.1.164.0/22165.1.164.1 to 165.1.167.254165.1.167.2551,022
107165.1.168.0/22165.1.168.1 to 165.1.171.254165.1.171.2551,022
108165.1.172.0/22165.1.172.1 to 165.1.175.254165.1.175.2551,022
109165.1.176.0/22165.1.176.1 to 165.1.179.254165.1.179.2551,022
110165.1.180.0/22165.1.180.1 to 165.1.183.254165.1.183.2551,022
111165.1.184.0/22165.1.184.1 to 165.1.187.254165.1.187.2551,022
112165.1.188.0/22165.1.188.1 to 165.1.191.254165.1.191.2551,022
113165.1.192.0/22165.1.192.1 to 165.1.195.254165.1.195.2551,022
114165.1.196.0/22165.1.196.1 to 165.1.199.254165.1.199.2551,022
115165.1.200.0/22165.1.200.1 to 165.1.203.254165.1.203.2551,022
116165.1.204.0/22165.1.204.1 to 165.1.207.254165.1.207.2551,022
117165.1.208.0/22165.1.208.1 to 165.1.211.254165.1.211.2551,022
118165.1.212.0/22165.1.212.1 to 165.1.215.254165.1.215.2551,022
119165.1.216.0/22165.1.216.1 to 165.1.219.254165.1.219.2551,022
120165.1.220.0/22165.1.220.1 to 165.1.223.254165.1.223.2551,022
121165.1.224.0/22165.1.224.1 to 165.1.227.254165.1.227.2551,022
122165.1.228.0/22165.1.228.1 to 165.1.231.254165.1.231.2551,022
123165.1.232.0/22165.1.232.1 to 165.1.235.254165.1.235.2551,022
124165.1.236.0/22165.1.236.1 to 165.1.239.254165.1.239.2551,022
125165.1.240.0/22165.1.240.1 to 165.1.243.254165.1.243.2551,022
126165.1.244.0/22165.1.244.1 to 165.1.247.254165.1.247.2551,022
127165.1.248.0/22165.1.248.1 to 165.1.251.254165.1.251.2551,022
128165.1.252.0/22165.1.252.1 to 165.1.255.254165.1.255.2551,022
129165.2.0.0/22165.2.0.1 to 165.2.3.254165.2.3.2551,022
130165.2.4.0/22165.2.4.1 to 165.2.7.254165.2.7.2551,022
131165.2.8.0/22165.2.8.1 to 165.2.11.254165.2.11.2551,022
132165.2.12.0/22165.2.12.1 to 165.2.15.254165.2.15.2551,022
133165.2.16.0/22165.2.16.1 to 165.2.19.254165.2.19.2551,022
134165.2.20.0/22165.2.20.1 to 165.2.23.254165.2.23.2551,022
135165.2.24.0/22165.2.24.1 to 165.2.27.254165.2.27.2551,022
136165.2.28.0/22165.2.28.1 to 165.2.31.254165.2.31.2551,022
137165.2.32.0/22165.2.32.1 to 165.2.35.254165.2.35.2551,022
138165.2.36.0/22165.2.36.1 to 165.2.39.254165.2.39.2551,022
139165.2.40.0/22165.2.40.1 to 165.2.43.254165.2.43.2551,022
140165.2.44.0/22165.2.44.1 to 165.2.47.254165.2.47.2551,022
141165.2.48.0/22165.2.48.1 to 165.2.51.254165.2.51.2551,022
142165.2.52.0/22165.2.52.1 to 165.2.55.254165.2.55.2551,022
143165.2.56.0/22165.2.56.1 to 165.2.59.254165.2.59.2551,022
144165.2.60.0/22165.2.60.1 to 165.2.63.254165.2.63.2551,022
145165.2.64.0/22165.2.64.1 to 165.2.67.254165.2.67.2551,022
146165.2.68.0/22165.2.68.1 to 165.2.71.254165.2.71.2551,022
147165.2.72.0/22165.2.72.1 to 165.2.75.254165.2.75.2551,022
148165.2.76.0/22165.2.76.1 to 165.2.79.254165.2.79.2551,022
149165.2.80.0/22165.2.80.1 to 165.2.83.254165.2.83.2551,022
150165.2.84.0/22165.2.84.1 to 165.2.87.254165.2.87.2551,022
151165.2.88.0/22165.2.88.1 to 165.2.91.254165.2.91.2551,022
152165.2.92.0/22165.2.92.1 to 165.2.95.254165.2.95.2551,022
153165.2.96.0/22165.2.96.1 to 165.2.99.254165.2.99.2551,022
154165.2.100.0/22165.2.100.1 to 165.2.103.254165.2.103.2551,022
155165.2.104.0/22165.2.104.1 to 165.2.107.254165.2.107.2551,022
156165.2.108.0/22165.2.108.1 to 165.2.111.254165.2.111.2551,022
157165.2.112.0/22165.2.112.1 to 165.2.115.254165.2.115.2551,022
158165.2.116.0/22165.2.116.1 to 165.2.119.254165.2.119.2551,022
159165.2.120.0/22165.2.120.1 to 165.2.123.254165.2.123.2551,022
160165.2.124.0/22165.2.124.1 to 165.2.127.254165.2.127.2551,022
161165.2.128.0/22165.2.128.1 to 165.2.131.254165.2.131.2551,022
162165.2.132.0/22165.2.132.1 to 165.2.135.254165.2.135.2551,022
163165.2.136.0/22165.2.136.1 to 165.2.139.254165.2.139.2551,022
164165.2.140.0/22165.2.140.1 to 165.2.143.254165.2.143.2551,022
165165.2.144.0/22165.2.144.1 to 165.2.147.254165.2.147.2551,022
166165.2.148.0/22165.2.148.1 to 165.2.151.254165.2.151.2551,022
167165.2.152.0/22165.2.152.1 to 165.2.155.254165.2.155.2551,022
168165.2.156.0/22165.2.156.1 to 165.2.159.254165.2.159.2551,022
169165.2.160.0/22165.2.160.1 to 165.2.163.254165.2.163.2551,022
170165.2.164.0/22165.2.164.1 to 165.2.167.254165.2.167.2551,022
171165.2.168.0/22165.2.168.1 to 165.2.171.254165.2.171.2551,022
172165.2.172.0/22165.2.172.1 to 165.2.175.254165.2.175.2551,022
173165.2.176.0/22165.2.176.1 to 165.2.179.254165.2.179.2551,022
174165.2.180.0/22165.2.180.1 to 165.2.183.254165.2.183.2551,022
175165.2.184.0/22165.2.184.1 to 165.2.187.254165.2.187.2551,022
176165.2.188.0/22165.2.188.1 to 165.2.191.254165.2.191.2551,022
177165.2.192.0/22165.2.192.1 to 165.2.195.254165.2.195.2551,022
178165.2.196.0/22165.2.196.1 to 165.2.199.254165.2.199.2551,022
179165.2.200.0/22165.2.200.1 to 165.2.203.254165.2.203.2551,022
180165.2.204.0/22165.2.204.1 to 165.2.207.254165.2.207.2551,022
181165.2.208.0/22165.2.208.1 to 165.2.211.254165.2.211.2551,022
182165.2.212.0/22165.2.212.1 to 165.2.215.254165.2.215.2551,022
183165.2.216.0/22165.2.216.1 to 165.2.219.254165.2.219.2551,022
184165.2.220.0/22165.2.220.1 to 165.2.223.254165.2.223.2551,022
185165.2.224.0/22165.2.224.1 to 165.2.227.254165.2.227.2551,022
186165.2.228.0/22165.2.228.1 to 165.2.231.254165.2.231.2551,022
187165.2.232.0/22165.2.232.1 to 165.2.235.254165.2.235.2551,022
188165.2.236.0/22165.2.236.1 to 165.2.239.254165.2.239.2551,022
189165.2.240.0/22165.2.240.1 to 165.2.243.254165.2.243.2551,022
190165.2.244.0/22165.2.244.1 to 165.2.247.254165.2.247.2551,022
191165.2.248.0/22165.2.248.1 to 165.2.251.254165.2.251.2551,022
192165.2.252.0/22165.2.252.1 to 165.2.255.254165.2.255.2551,022
193165.3.0.0/22165.3.0.1 to 165.3.3.254165.3.3.2551,022
194165.3.4.0/22165.3.4.1 to 165.3.7.254165.3.7.2551,022
195165.3.8.0/22165.3.8.1 to 165.3.11.254165.3.11.2551,022
196165.3.12.0/22165.3.12.1 to 165.3.15.254165.3.15.2551,022
197165.3.16.0/22165.3.16.1 to 165.3.19.254165.3.19.2551,022
198165.3.20.0/22165.3.20.1 to 165.3.23.254165.3.23.2551,022
199165.3.24.0/22165.3.24.1 to 165.3.27.254165.3.27.2551,022
200165.3.28.0/22165.3.28.1 to 165.3.31.254165.3.31.2551,022
201165.3.32.0/22165.3.32.1 to 165.3.35.254165.3.35.2551,022
202165.3.36.0/22165.3.36.1 to 165.3.39.254165.3.39.2551,022
203165.3.40.0/22165.3.40.1 to 165.3.43.254165.3.43.2551,022
204165.3.44.0/22165.3.44.1 to 165.3.47.254165.3.47.2551,022
205165.3.48.0/22165.3.48.1 to 165.3.51.254165.3.51.2551,022
206165.3.52.0/22165.3.52.1 to 165.3.55.254165.3.55.2551,022
207165.3.56.0/22165.3.56.1 to 165.3.59.254165.3.59.2551,022
208165.3.60.0/22165.3.60.1 to 165.3.63.254165.3.63.2551,022
209165.3.64.0/22165.3.64.1 to 165.3.67.254165.3.67.2551,022
210165.3.68.0/22165.3.68.1 to 165.3.71.254165.3.71.2551,022
211165.3.72.0/22165.3.72.1 to 165.3.75.254165.3.75.2551,022
212165.3.76.0/22165.3.76.1 to 165.3.79.254165.3.79.2551,022
213165.3.80.0/22165.3.80.1 to 165.3.83.254165.3.83.2551,022
214165.3.84.0/22165.3.84.1 to 165.3.87.254165.3.87.2551,022
215165.3.88.0/22165.3.88.1 to 165.3.91.254165.3.91.2551,022
216165.3.92.0/22165.3.92.1 to 165.3.95.254165.3.95.2551,022
217165.3.96.0/22165.3.96.1 to 165.3.99.254165.3.99.2551,022
218165.3.100.0/22165.3.100.1 to 165.3.103.254165.3.103.2551,022
219165.3.104.0/22165.3.104.1 to 165.3.107.254165.3.107.2551,022
220165.3.108.0/22165.3.108.1 to 165.3.111.254165.3.111.2551,022
221165.3.112.0/22165.3.112.1 to 165.3.115.254165.3.115.2551,022
222165.3.116.0/22165.3.116.1 to 165.3.119.254165.3.119.2551,022
223165.3.120.0/22165.3.120.1 to 165.3.123.254165.3.123.2551,022
224165.3.124.0/22165.3.124.1 to 165.3.127.254165.3.127.2551,022
225165.3.128.0/22165.3.128.1 to 165.3.131.254165.3.131.2551,022
226165.3.132.0/22165.3.132.1 to 165.3.135.254165.3.135.2551,022
227165.3.136.0/22165.3.136.1 to 165.3.139.254165.3.139.2551,022
228165.3.140.0/22165.3.140.1 to 165.3.143.254165.3.143.2551,022
229165.3.144.0/22165.3.144.1 to 165.3.147.254165.3.147.2551,022
230165.3.148.0/22165.3.148.1 to 165.3.151.254165.3.151.2551,022
231165.3.152.0/22165.3.152.1 to 165.3.155.254165.3.155.2551,022
232165.3.156.0/22165.3.156.1 to 165.3.159.254165.3.159.2551,022
233165.3.160.0/22165.3.160.1 to 165.3.163.254165.3.163.2551,022
234165.3.164.0/22165.3.164.1 to 165.3.167.254165.3.167.2551,022
235165.3.168.0/22165.3.168.1 to 165.3.171.254165.3.171.2551,022
236165.3.172.0/22165.3.172.1 to 165.3.175.254165.3.175.2551,022
237165.3.176.0/22165.3.176.1 to 165.3.179.254165.3.179.2551,022
238165.3.180.0/22165.3.180.1 to 165.3.183.254165.3.183.2551,022
239165.3.184.0/22165.3.184.1 to 165.3.187.254165.3.187.2551,022
240165.3.188.0/22165.3.188.1 to 165.3.191.254165.3.191.2551,022
241165.3.192.0/22165.3.192.1 to 165.3.195.254165.3.195.2551,022
242165.3.196.0/22165.3.196.1 to 165.3.199.254165.3.199.2551,022
243165.3.200.0/22165.3.200.1 to 165.3.203.254165.3.203.2551,022
244165.3.204.0/22165.3.204.1 to 165.3.207.254165.3.207.2551,022
245165.3.208.0/22165.3.208.1 to 165.3.211.254165.3.211.2551,022
246165.3.212.0/22165.3.212.1 to 165.3.215.254165.3.215.2551,022
247165.3.216.0/22165.3.216.1 to 165.3.219.254165.3.219.2551,022
248165.3.220.0/22165.3.220.1 to 165.3.223.254165.3.223.2551,022
249165.3.224.0/22165.3.224.1 to 165.3.227.254165.3.227.2551,022
250165.3.228.0/22165.3.228.1 to 165.3.231.254165.3.231.2551,022
251165.3.232.0/22165.3.232.1 to 165.3.235.254165.3.235.2551,022
252165.3.236.0/22165.3.236.1 to 165.3.239.254165.3.239.2551,022
253165.3.240.0/22165.3.240.1 to 165.3.243.254165.3.243.2551,022
254165.3.244.0/22165.3.244.1 to 165.3.247.254165.3.247.2551,022
255165.3.248.0/22165.3.248.1 to 165.3.251.254165.3.251.2551,022
256165.3.252.0/22165.3.252.1 to 165.3.255.254165.3.255.2551,022

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.