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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.

Network138.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
138.0.0.0
Broadcast address
138.63.255.255
First usable
138.0.0.1
Last usable
138.63.255.254
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 8A000000 · Integer 2315255808 to 2319450111
Reverse DNS zones
0.138.in-addr.arpa
1.138.in-addr.arpa
2.138.in-addr.arpa
3.138.in-addr.arpa
4.138.in-addr.arpa
5.138.in-addr.arpa
6.138.in-addr.arpa
7.138.in-addr.arpa
8.138.in-addr.arpa
9.138.in-addr.arpa
10.138.in-addr.arpa
11.138.in-addr.arpa
12.138.in-addr.arpa
13.138.in-addr.arpa
14.138.in-addr.arpa
15.138.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
Address10001010.00000000.00000000.00000000138.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10001010.00000000.00000000.00000000138.0.0.0
Broadcast10001010.00111111.11111111.11111111138.63.255.255
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)

138.0.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1138.0.0.0/22138.0.0.1 to 138.0.3.254138.0.3.2551,022
2138.0.4.0/22138.0.4.1 to 138.0.7.254138.0.7.2551,022
3138.0.8.0/22138.0.8.1 to 138.0.11.254138.0.11.2551,022
4138.0.12.0/22138.0.12.1 to 138.0.15.254138.0.15.2551,022
5138.0.16.0/22138.0.16.1 to 138.0.19.254138.0.19.2551,022
6138.0.20.0/22138.0.20.1 to 138.0.23.254138.0.23.2551,022
7138.0.24.0/22138.0.24.1 to 138.0.27.254138.0.27.2551,022
8138.0.28.0/22138.0.28.1 to 138.0.31.254138.0.31.2551,022
9138.0.32.0/22138.0.32.1 to 138.0.35.254138.0.35.2551,022
10138.0.36.0/22138.0.36.1 to 138.0.39.254138.0.39.2551,022
11138.0.40.0/22138.0.40.1 to 138.0.43.254138.0.43.2551,022
12138.0.44.0/22138.0.44.1 to 138.0.47.254138.0.47.2551,022
13138.0.48.0/22138.0.48.1 to 138.0.51.254138.0.51.2551,022
14138.0.52.0/22138.0.52.1 to 138.0.55.254138.0.55.2551,022
15138.0.56.0/22138.0.56.1 to 138.0.59.254138.0.59.2551,022
16138.0.60.0/22138.0.60.1 to 138.0.63.254138.0.63.2551,022
17138.0.64.0/22138.0.64.1 to 138.0.67.254138.0.67.2551,022
18138.0.68.0/22138.0.68.1 to 138.0.71.254138.0.71.2551,022
19138.0.72.0/22138.0.72.1 to 138.0.75.254138.0.75.2551,022
20138.0.76.0/22138.0.76.1 to 138.0.79.254138.0.79.2551,022
21138.0.80.0/22138.0.80.1 to 138.0.83.254138.0.83.2551,022
22138.0.84.0/22138.0.84.1 to 138.0.87.254138.0.87.2551,022
23138.0.88.0/22138.0.88.1 to 138.0.91.254138.0.91.2551,022
24138.0.92.0/22138.0.92.1 to 138.0.95.254138.0.95.2551,022
25138.0.96.0/22138.0.96.1 to 138.0.99.254138.0.99.2551,022
26138.0.100.0/22138.0.100.1 to 138.0.103.254138.0.103.2551,022
27138.0.104.0/22138.0.104.1 to 138.0.107.254138.0.107.2551,022
28138.0.108.0/22138.0.108.1 to 138.0.111.254138.0.111.2551,022
29138.0.112.0/22138.0.112.1 to 138.0.115.254138.0.115.2551,022
30138.0.116.0/22138.0.116.1 to 138.0.119.254138.0.119.2551,022
31138.0.120.0/22138.0.120.1 to 138.0.123.254138.0.123.2551,022
32138.0.124.0/22138.0.124.1 to 138.0.127.254138.0.127.2551,022
33138.0.128.0/22138.0.128.1 to 138.0.131.254138.0.131.2551,022
34138.0.132.0/22138.0.132.1 to 138.0.135.254138.0.135.2551,022
35138.0.136.0/22138.0.136.1 to 138.0.139.254138.0.139.2551,022
36138.0.140.0/22138.0.140.1 to 138.0.143.254138.0.143.2551,022
37138.0.144.0/22138.0.144.1 to 138.0.147.254138.0.147.2551,022
38138.0.148.0/22138.0.148.1 to 138.0.151.254138.0.151.2551,022
39138.0.152.0/22138.0.152.1 to 138.0.155.254138.0.155.2551,022
40138.0.156.0/22138.0.156.1 to 138.0.159.254138.0.159.2551,022
41138.0.160.0/22138.0.160.1 to 138.0.163.254138.0.163.2551,022
42138.0.164.0/22138.0.164.1 to 138.0.167.254138.0.167.2551,022
43138.0.168.0/22138.0.168.1 to 138.0.171.254138.0.171.2551,022
44138.0.172.0/22138.0.172.1 to 138.0.175.254138.0.175.2551,022
45138.0.176.0/22138.0.176.1 to 138.0.179.254138.0.179.2551,022
46138.0.180.0/22138.0.180.1 to 138.0.183.254138.0.183.2551,022
47138.0.184.0/22138.0.184.1 to 138.0.187.254138.0.187.2551,022
48138.0.188.0/22138.0.188.1 to 138.0.191.254138.0.191.2551,022
49138.0.192.0/22138.0.192.1 to 138.0.195.254138.0.195.2551,022
50138.0.196.0/22138.0.196.1 to 138.0.199.254138.0.199.2551,022
51138.0.200.0/22138.0.200.1 to 138.0.203.254138.0.203.2551,022
52138.0.204.0/22138.0.204.1 to 138.0.207.254138.0.207.2551,022
53138.0.208.0/22138.0.208.1 to 138.0.211.254138.0.211.2551,022
54138.0.212.0/22138.0.212.1 to 138.0.215.254138.0.215.2551,022
55138.0.216.0/22138.0.216.1 to 138.0.219.254138.0.219.2551,022
56138.0.220.0/22138.0.220.1 to 138.0.223.254138.0.223.2551,022
57138.0.224.0/22138.0.224.1 to 138.0.227.254138.0.227.2551,022
58138.0.228.0/22138.0.228.1 to 138.0.231.254138.0.231.2551,022
59138.0.232.0/22138.0.232.1 to 138.0.235.254138.0.235.2551,022
60138.0.236.0/22138.0.236.1 to 138.0.239.254138.0.239.2551,022
61138.0.240.0/22138.0.240.1 to 138.0.243.254138.0.243.2551,022
62138.0.244.0/22138.0.244.1 to 138.0.247.254138.0.247.2551,022
63138.0.248.0/22138.0.248.1 to 138.0.251.254138.0.251.2551,022
64138.0.252.0/22138.0.252.1 to 138.0.255.254138.0.255.2551,022
65138.1.0.0/22138.1.0.1 to 138.1.3.254138.1.3.2551,022
66138.1.4.0/22138.1.4.1 to 138.1.7.254138.1.7.2551,022
67138.1.8.0/22138.1.8.1 to 138.1.11.254138.1.11.2551,022
68138.1.12.0/22138.1.12.1 to 138.1.15.254138.1.15.2551,022
69138.1.16.0/22138.1.16.1 to 138.1.19.254138.1.19.2551,022
70138.1.20.0/22138.1.20.1 to 138.1.23.254138.1.23.2551,022
71138.1.24.0/22138.1.24.1 to 138.1.27.254138.1.27.2551,022
72138.1.28.0/22138.1.28.1 to 138.1.31.254138.1.31.2551,022
73138.1.32.0/22138.1.32.1 to 138.1.35.254138.1.35.2551,022
74138.1.36.0/22138.1.36.1 to 138.1.39.254138.1.39.2551,022
75138.1.40.0/22138.1.40.1 to 138.1.43.254138.1.43.2551,022
76138.1.44.0/22138.1.44.1 to 138.1.47.254138.1.47.2551,022
77138.1.48.0/22138.1.48.1 to 138.1.51.254138.1.51.2551,022
78138.1.52.0/22138.1.52.1 to 138.1.55.254138.1.55.2551,022
79138.1.56.0/22138.1.56.1 to 138.1.59.254138.1.59.2551,022
80138.1.60.0/22138.1.60.1 to 138.1.63.254138.1.63.2551,022
81138.1.64.0/22138.1.64.1 to 138.1.67.254138.1.67.2551,022
82138.1.68.0/22138.1.68.1 to 138.1.71.254138.1.71.2551,022
83138.1.72.0/22138.1.72.1 to 138.1.75.254138.1.75.2551,022
84138.1.76.0/22138.1.76.1 to 138.1.79.254138.1.79.2551,022
85138.1.80.0/22138.1.80.1 to 138.1.83.254138.1.83.2551,022
86138.1.84.0/22138.1.84.1 to 138.1.87.254138.1.87.2551,022
87138.1.88.0/22138.1.88.1 to 138.1.91.254138.1.91.2551,022
88138.1.92.0/22138.1.92.1 to 138.1.95.254138.1.95.2551,022
89138.1.96.0/22138.1.96.1 to 138.1.99.254138.1.99.2551,022
90138.1.100.0/22138.1.100.1 to 138.1.103.254138.1.103.2551,022
91138.1.104.0/22138.1.104.1 to 138.1.107.254138.1.107.2551,022
92138.1.108.0/22138.1.108.1 to 138.1.111.254138.1.111.2551,022
93138.1.112.0/22138.1.112.1 to 138.1.115.254138.1.115.2551,022
94138.1.116.0/22138.1.116.1 to 138.1.119.254138.1.119.2551,022
95138.1.120.0/22138.1.120.1 to 138.1.123.254138.1.123.2551,022
96138.1.124.0/22138.1.124.1 to 138.1.127.254138.1.127.2551,022
97138.1.128.0/22138.1.128.1 to 138.1.131.254138.1.131.2551,022
98138.1.132.0/22138.1.132.1 to 138.1.135.254138.1.135.2551,022
99138.1.136.0/22138.1.136.1 to 138.1.139.254138.1.139.2551,022
100138.1.140.0/22138.1.140.1 to 138.1.143.254138.1.143.2551,022
101138.1.144.0/22138.1.144.1 to 138.1.147.254138.1.147.2551,022
102138.1.148.0/22138.1.148.1 to 138.1.151.254138.1.151.2551,022
103138.1.152.0/22138.1.152.1 to 138.1.155.254138.1.155.2551,022
104138.1.156.0/22138.1.156.1 to 138.1.159.254138.1.159.2551,022
105138.1.160.0/22138.1.160.1 to 138.1.163.254138.1.163.2551,022
106138.1.164.0/22138.1.164.1 to 138.1.167.254138.1.167.2551,022
107138.1.168.0/22138.1.168.1 to 138.1.171.254138.1.171.2551,022
108138.1.172.0/22138.1.172.1 to 138.1.175.254138.1.175.2551,022
109138.1.176.0/22138.1.176.1 to 138.1.179.254138.1.179.2551,022
110138.1.180.0/22138.1.180.1 to 138.1.183.254138.1.183.2551,022
111138.1.184.0/22138.1.184.1 to 138.1.187.254138.1.187.2551,022
112138.1.188.0/22138.1.188.1 to 138.1.191.254138.1.191.2551,022
113138.1.192.0/22138.1.192.1 to 138.1.195.254138.1.195.2551,022
114138.1.196.0/22138.1.196.1 to 138.1.199.254138.1.199.2551,022
115138.1.200.0/22138.1.200.1 to 138.1.203.254138.1.203.2551,022
116138.1.204.0/22138.1.204.1 to 138.1.207.254138.1.207.2551,022
117138.1.208.0/22138.1.208.1 to 138.1.211.254138.1.211.2551,022
118138.1.212.0/22138.1.212.1 to 138.1.215.254138.1.215.2551,022
119138.1.216.0/22138.1.216.1 to 138.1.219.254138.1.219.2551,022
120138.1.220.0/22138.1.220.1 to 138.1.223.254138.1.223.2551,022
121138.1.224.0/22138.1.224.1 to 138.1.227.254138.1.227.2551,022
122138.1.228.0/22138.1.228.1 to 138.1.231.254138.1.231.2551,022
123138.1.232.0/22138.1.232.1 to 138.1.235.254138.1.235.2551,022
124138.1.236.0/22138.1.236.1 to 138.1.239.254138.1.239.2551,022
125138.1.240.0/22138.1.240.1 to 138.1.243.254138.1.243.2551,022
126138.1.244.0/22138.1.244.1 to 138.1.247.254138.1.247.2551,022
127138.1.248.0/22138.1.248.1 to 138.1.251.254138.1.251.2551,022
128138.1.252.0/22138.1.252.1 to 138.1.255.254138.1.255.2551,022
129138.2.0.0/22138.2.0.1 to 138.2.3.254138.2.3.2551,022
130138.2.4.0/22138.2.4.1 to 138.2.7.254138.2.7.2551,022
131138.2.8.0/22138.2.8.1 to 138.2.11.254138.2.11.2551,022
132138.2.12.0/22138.2.12.1 to 138.2.15.254138.2.15.2551,022
133138.2.16.0/22138.2.16.1 to 138.2.19.254138.2.19.2551,022
134138.2.20.0/22138.2.20.1 to 138.2.23.254138.2.23.2551,022
135138.2.24.0/22138.2.24.1 to 138.2.27.254138.2.27.2551,022
136138.2.28.0/22138.2.28.1 to 138.2.31.254138.2.31.2551,022
137138.2.32.0/22138.2.32.1 to 138.2.35.254138.2.35.2551,022
138138.2.36.0/22138.2.36.1 to 138.2.39.254138.2.39.2551,022
139138.2.40.0/22138.2.40.1 to 138.2.43.254138.2.43.2551,022
140138.2.44.0/22138.2.44.1 to 138.2.47.254138.2.47.2551,022
141138.2.48.0/22138.2.48.1 to 138.2.51.254138.2.51.2551,022
142138.2.52.0/22138.2.52.1 to 138.2.55.254138.2.55.2551,022
143138.2.56.0/22138.2.56.1 to 138.2.59.254138.2.59.2551,022
144138.2.60.0/22138.2.60.1 to 138.2.63.254138.2.63.2551,022
145138.2.64.0/22138.2.64.1 to 138.2.67.254138.2.67.2551,022
146138.2.68.0/22138.2.68.1 to 138.2.71.254138.2.71.2551,022
147138.2.72.0/22138.2.72.1 to 138.2.75.254138.2.75.2551,022
148138.2.76.0/22138.2.76.1 to 138.2.79.254138.2.79.2551,022
149138.2.80.0/22138.2.80.1 to 138.2.83.254138.2.83.2551,022
150138.2.84.0/22138.2.84.1 to 138.2.87.254138.2.87.2551,022
151138.2.88.0/22138.2.88.1 to 138.2.91.254138.2.91.2551,022
152138.2.92.0/22138.2.92.1 to 138.2.95.254138.2.95.2551,022
153138.2.96.0/22138.2.96.1 to 138.2.99.254138.2.99.2551,022
154138.2.100.0/22138.2.100.1 to 138.2.103.254138.2.103.2551,022
155138.2.104.0/22138.2.104.1 to 138.2.107.254138.2.107.2551,022
156138.2.108.0/22138.2.108.1 to 138.2.111.254138.2.111.2551,022
157138.2.112.0/22138.2.112.1 to 138.2.115.254138.2.115.2551,022
158138.2.116.0/22138.2.116.1 to 138.2.119.254138.2.119.2551,022
159138.2.120.0/22138.2.120.1 to 138.2.123.254138.2.123.2551,022
160138.2.124.0/22138.2.124.1 to 138.2.127.254138.2.127.2551,022
161138.2.128.0/22138.2.128.1 to 138.2.131.254138.2.131.2551,022
162138.2.132.0/22138.2.132.1 to 138.2.135.254138.2.135.2551,022
163138.2.136.0/22138.2.136.1 to 138.2.139.254138.2.139.2551,022
164138.2.140.0/22138.2.140.1 to 138.2.143.254138.2.143.2551,022
165138.2.144.0/22138.2.144.1 to 138.2.147.254138.2.147.2551,022
166138.2.148.0/22138.2.148.1 to 138.2.151.254138.2.151.2551,022
167138.2.152.0/22138.2.152.1 to 138.2.155.254138.2.155.2551,022
168138.2.156.0/22138.2.156.1 to 138.2.159.254138.2.159.2551,022
169138.2.160.0/22138.2.160.1 to 138.2.163.254138.2.163.2551,022
170138.2.164.0/22138.2.164.1 to 138.2.167.254138.2.167.2551,022
171138.2.168.0/22138.2.168.1 to 138.2.171.254138.2.171.2551,022
172138.2.172.0/22138.2.172.1 to 138.2.175.254138.2.175.2551,022
173138.2.176.0/22138.2.176.1 to 138.2.179.254138.2.179.2551,022
174138.2.180.0/22138.2.180.1 to 138.2.183.254138.2.183.2551,022
175138.2.184.0/22138.2.184.1 to 138.2.187.254138.2.187.2551,022
176138.2.188.0/22138.2.188.1 to 138.2.191.254138.2.191.2551,022
177138.2.192.0/22138.2.192.1 to 138.2.195.254138.2.195.2551,022
178138.2.196.0/22138.2.196.1 to 138.2.199.254138.2.199.2551,022
179138.2.200.0/22138.2.200.1 to 138.2.203.254138.2.203.2551,022
180138.2.204.0/22138.2.204.1 to 138.2.207.254138.2.207.2551,022
181138.2.208.0/22138.2.208.1 to 138.2.211.254138.2.211.2551,022
182138.2.212.0/22138.2.212.1 to 138.2.215.254138.2.215.2551,022
183138.2.216.0/22138.2.216.1 to 138.2.219.254138.2.219.2551,022
184138.2.220.0/22138.2.220.1 to 138.2.223.254138.2.223.2551,022
185138.2.224.0/22138.2.224.1 to 138.2.227.254138.2.227.2551,022
186138.2.228.0/22138.2.228.1 to 138.2.231.254138.2.231.2551,022
187138.2.232.0/22138.2.232.1 to 138.2.235.254138.2.235.2551,022
188138.2.236.0/22138.2.236.1 to 138.2.239.254138.2.239.2551,022
189138.2.240.0/22138.2.240.1 to 138.2.243.254138.2.243.2551,022
190138.2.244.0/22138.2.244.1 to 138.2.247.254138.2.247.2551,022
191138.2.248.0/22138.2.248.1 to 138.2.251.254138.2.251.2551,022
192138.2.252.0/22138.2.252.1 to 138.2.255.254138.2.255.2551,022
193138.3.0.0/22138.3.0.1 to 138.3.3.254138.3.3.2551,022
194138.3.4.0/22138.3.4.1 to 138.3.7.254138.3.7.2551,022
195138.3.8.0/22138.3.8.1 to 138.3.11.254138.3.11.2551,022
196138.3.12.0/22138.3.12.1 to 138.3.15.254138.3.15.2551,022
197138.3.16.0/22138.3.16.1 to 138.3.19.254138.3.19.2551,022
198138.3.20.0/22138.3.20.1 to 138.3.23.254138.3.23.2551,022
199138.3.24.0/22138.3.24.1 to 138.3.27.254138.3.27.2551,022
200138.3.28.0/22138.3.28.1 to 138.3.31.254138.3.31.2551,022
201138.3.32.0/22138.3.32.1 to 138.3.35.254138.3.35.2551,022
202138.3.36.0/22138.3.36.1 to 138.3.39.254138.3.39.2551,022
203138.3.40.0/22138.3.40.1 to 138.3.43.254138.3.43.2551,022
204138.3.44.0/22138.3.44.1 to 138.3.47.254138.3.47.2551,022
205138.3.48.0/22138.3.48.1 to 138.3.51.254138.3.51.2551,022
206138.3.52.0/22138.3.52.1 to 138.3.55.254138.3.55.2551,022
207138.3.56.0/22138.3.56.1 to 138.3.59.254138.3.59.2551,022
208138.3.60.0/22138.3.60.1 to 138.3.63.254138.3.63.2551,022
209138.3.64.0/22138.3.64.1 to 138.3.67.254138.3.67.2551,022
210138.3.68.0/22138.3.68.1 to 138.3.71.254138.3.71.2551,022
211138.3.72.0/22138.3.72.1 to 138.3.75.254138.3.75.2551,022
212138.3.76.0/22138.3.76.1 to 138.3.79.254138.3.79.2551,022
213138.3.80.0/22138.3.80.1 to 138.3.83.254138.3.83.2551,022
214138.3.84.0/22138.3.84.1 to 138.3.87.254138.3.87.2551,022
215138.3.88.0/22138.3.88.1 to 138.3.91.254138.3.91.2551,022
216138.3.92.0/22138.3.92.1 to 138.3.95.254138.3.95.2551,022
217138.3.96.0/22138.3.96.1 to 138.3.99.254138.3.99.2551,022
218138.3.100.0/22138.3.100.1 to 138.3.103.254138.3.103.2551,022
219138.3.104.0/22138.3.104.1 to 138.3.107.254138.3.107.2551,022
220138.3.108.0/22138.3.108.1 to 138.3.111.254138.3.111.2551,022
221138.3.112.0/22138.3.112.1 to 138.3.115.254138.3.115.2551,022
222138.3.116.0/22138.3.116.1 to 138.3.119.254138.3.119.2551,022
223138.3.120.0/22138.3.120.1 to 138.3.123.254138.3.123.2551,022
224138.3.124.0/22138.3.124.1 to 138.3.127.254138.3.127.2551,022
225138.3.128.0/22138.3.128.1 to 138.3.131.254138.3.131.2551,022
226138.3.132.0/22138.3.132.1 to 138.3.135.254138.3.135.2551,022
227138.3.136.0/22138.3.136.1 to 138.3.139.254138.3.139.2551,022
228138.3.140.0/22138.3.140.1 to 138.3.143.254138.3.143.2551,022
229138.3.144.0/22138.3.144.1 to 138.3.147.254138.3.147.2551,022
230138.3.148.0/22138.3.148.1 to 138.3.151.254138.3.151.2551,022
231138.3.152.0/22138.3.152.1 to 138.3.155.254138.3.155.2551,022
232138.3.156.0/22138.3.156.1 to 138.3.159.254138.3.159.2551,022
233138.3.160.0/22138.3.160.1 to 138.3.163.254138.3.163.2551,022
234138.3.164.0/22138.3.164.1 to 138.3.167.254138.3.167.2551,022
235138.3.168.0/22138.3.168.1 to 138.3.171.254138.3.171.2551,022
236138.3.172.0/22138.3.172.1 to 138.3.175.254138.3.175.2551,022
237138.3.176.0/22138.3.176.1 to 138.3.179.254138.3.179.2551,022
238138.3.180.0/22138.3.180.1 to 138.3.183.254138.3.183.2551,022
239138.3.184.0/22138.3.184.1 to 138.3.187.254138.3.187.2551,022
240138.3.188.0/22138.3.188.1 to 138.3.191.254138.3.191.2551,022
241138.3.192.0/22138.3.192.1 to 138.3.195.254138.3.195.2551,022
242138.3.196.0/22138.3.196.1 to 138.3.199.254138.3.199.2551,022
243138.3.200.0/22138.3.200.1 to 138.3.203.254138.3.203.2551,022
244138.3.204.0/22138.3.204.1 to 138.3.207.254138.3.207.2551,022
245138.3.208.0/22138.3.208.1 to 138.3.211.254138.3.211.2551,022
246138.3.212.0/22138.3.212.1 to 138.3.215.254138.3.215.2551,022
247138.3.216.0/22138.3.216.1 to 138.3.219.254138.3.219.2551,022
248138.3.220.0/22138.3.220.1 to 138.3.223.254138.3.223.2551,022
249138.3.224.0/22138.3.224.1 to 138.3.227.254138.3.227.2551,022
250138.3.228.0/22138.3.228.1 to 138.3.231.254138.3.231.2551,022
251138.3.232.0/22138.3.232.1 to 138.3.235.254138.3.235.2551,022
252138.3.236.0/22138.3.236.1 to 138.3.239.254138.3.239.2551,022
253138.3.240.0/22138.3.240.1 to 138.3.243.254138.3.243.2551,022
254138.3.244.0/22138.3.244.1 to 138.3.247.254138.3.247.2551,022
255138.3.248.0/22138.3.248.1 to 138.3.251.254138.3.251.2551,022
256138.3.252.0/22138.3.252.1 to 138.3.255.254138.3.255.2551,022

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.