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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.

Network183.8.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
183.8.0.0
Broadcast address
183.15.255.255
First usable
183.8.0.1
Last usable
183.15.255.254
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 B7080000 · Integer 3070754816 to 3071279103
Reverse DNS zones
8.183.in-addr.arpa
9.183.in-addr.arpa
10.183.in-addr.arpa
11.183.in-addr.arpa
12.183.in-addr.arpa
13.183.in-addr.arpa
14.183.in-addr.arpa
15.183.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
Address10110111.00001000.00000000.00000000183.8.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10110111.00001000.00000000.00000000183.8.0.0
Broadcast10110111.00001111.11111111.11111111183.15.255.255
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)

183.8.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.8.0.0/21183.8.0.1 to 183.8.7.254183.8.7.2552,046
2183.8.8.0/21183.8.8.1 to 183.8.15.254183.8.15.2552,046
3183.8.16.0/21183.8.16.1 to 183.8.23.254183.8.23.2552,046
4183.8.24.0/21183.8.24.1 to 183.8.31.254183.8.31.2552,046
5183.8.32.0/21183.8.32.1 to 183.8.39.254183.8.39.2552,046
6183.8.40.0/21183.8.40.1 to 183.8.47.254183.8.47.2552,046
7183.8.48.0/21183.8.48.1 to 183.8.55.254183.8.55.2552,046
8183.8.56.0/21183.8.56.1 to 183.8.63.254183.8.63.2552,046
9183.8.64.0/21183.8.64.1 to 183.8.71.254183.8.71.2552,046
10183.8.72.0/21183.8.72.1 to 183.8.79.254183.8.79.2552,046
11183.8.80.0/21183.8.80.1 to 183.8.87.254183.8.87.2552,046
12183.8.88.0/21183.8.88.1 to 183.8.95.254183.8.95.2552,046
13183.8.96.0/21183.8.96.1 to 183.8.103.254183.8.103.2552,046
14183.8.104.0/21183.8.104.1 to 183.8.111.254183.8.111.2552,046
15183.8.112.0/21183.8.112.1 to 183.8.119.254183.8.119.2552,046
16183.8.120.0/21183.8.120.1 to 183.8.127.254183.8.127.2552,046
17183.8.128.0/21183.8.128.1 to 183.8.135.254183.8.135.2552,046
18183.8.136.0/21183.8.136.1 to 183.8.143.254183.8.143.2552,046
19183.8.144.0/21183.8.144.1 to 183.8.151.254183.8.151.2552,046
20183.8.152.0/21183.8.152.1 to 183.8.159.254183.8.159.2552,046
21183.8.160.0/21183.8.160.1 to 183.8.167.254183.8.167.2552,046
22183.8.168.0/21183.8.168.1 to 183.8.175.254183.8.175.2552,046
23183.8.176.0/21183.8.176.1 to 183.8.183.254183.8.183.2552,046
24183.8.184.0/21183.8.184.1 to 183.8.191.254183.8.191.2552,046
25183.8.192.0/21183.8.192.1 to 183.8.199.254183.8.199.2552,046
26183.8.200.0/21183.8.200.1 to 183.8.207.254183.8.207.2552,046
27183.8.208.0/21183.8.208.1 to 183.8.215.254183.8.215.2552,046
28183.8.216.0/21183.8.216.1 to 183.8.223.254183.8.223.2552,046
29183.8.224.0/21183.8.224.1 to 183.8.231.254183.8.231.2552,046
30183.8.232.0/21183.8.232.1 to 183.8.239.254183.8.239.2552,046
31183.8.240.0/21183.8.240.1 to 183.8.247.254183.8.247.2552,046
32183.8.248.0/21183.8.248.1 to 183.8.255.254183.8.255.2552,046
33183.9.0.0/21183.9.0.1 to 183.9.7.254183.9.7.2552,046
34183.9.8.0/21183.9.8.1 to 183.9.15.254183.9.15.2552,046
35183.9.16.0/21183.9.16.1 to 183.9.23.254183.9.23.2552,046
36183.9.24.0/21183.9.24.1 to 183.9.31.254183.9.31.2552,046
37183.9.32.0/21183.9.32.1 to 183.9.39.254183.9.39.2552,046
38183.9.40.0/21183.9.40.1 to 183.9.47.254183.9.47.2552,046
39183.9.48.0/21183.9.48.1 to 183.9.55.254183.9.55.2552,046
40183.9.56.0/21183.9.56.1 to 183.9.63.254183.9.63.2552,046
41183.9.64.0/21183.9.64.1 to 183.9.71.254183.9.71.2552,046
42183.9.72.0/21183.9.72.1 to 183.9.79.254183.9.79.2552,046
43183.9.80.0/21183.9.80.1 to 183.9.87.254183.9.87.2552,046
44183.9.88.0/21183.9.88.1 to 183.9.95.254183.9.95.2552,046
45183.9.96.0/21183.9.96.1 to 183.9.103.254183.9.103.2552,046
46183.9.104.0/21183.9.104.1 to 183.9.111.254183.9.111.2552,046
47183.9.112.0/21183.9.112.1 to 183.9.119.254183.9.119.2552,046
48183.9.120.0/21183.9.120.1 to 183.9.127.254183.9.127.2552,046
49183.9.128.0/21183.9.128.1 to 183.9.135.254183.9.135.2552,046
50183.9.136.0/21183.9.136.1 to 183.9.143.254183.9.143.2552,046
51183.9.144.0/21183.9.144.1 to 183.9.151.254183.9.151.2552,046
52183.9.152.0/21183.9.152.1 to 183.9.159.254183.9.159.2552,046
53183.9.160.0/21183.9.160.1 to 183.9.167.254183.9.167.2552,046
54183.9.168.0/21183.9.168.1 to 183.9.175.254183.9.175.2552,046
55183.9.176.0/21183.9.176.1 to 183.9.183.254183.9.183.2552,046
56183.9.184.0/21183.9.184.1 to 183.9.191.254183.9.191.2552,046
57183.9.192.0/21183.9.192.1 to 183.9.199.254183.9.199.2552,046
58183.9.200.0/21183.9.200.1 to 183.9.207.254183.9.207.2552,046
59183.9.208.0/21183.9.208.1 to 183.9.215.254183.9.215.2552,046
60183.9.216.0/21183.9.216.1 to 183.9.223.254183.9.223.2552,046
61183.9.224.0/21183.9.224.1 to 183.9.231.254183.9.231.2552,046
62183.9.232.0/21183.9.232.1 to 183.9.239.254183.9.239.2552,046
63183.9.240.0/21183.9.240.1 to 183.9.247.254183.9.247.2552,046
64183.9.248.0/21183.9.248.1 to 183.9.255.254183.9.255.2552,046
65183.10.0.0/21183.10.0.1 to 183.10.7.254183.10.7.2552,046
66183.10.8.0/21183.10.8.1 to 183.10.15.254183.10.15.2552,046
67183.10.16.0/21183.10.16.1 to 183.10.23.254183.10.23.2552,046
68183.10.24.0/21183.10.24.1 to 183.10.31.254183.10.31.2552,046
69183.10.32.0/21183.10.32.1 to 183.10.39.254183.10.39.2552,046
70183.10.40.0/21183.10.40.1 to 183.10.47.254183.10.47.2552,046
71183.10.48.0/21183.10.48.1 to 183.10.55.254183.10.55.2552,046
72183.10.56.0/21183.10.56.1 to 183.10.63.254183.10.63.2552,046
73183.10.64.0/21183.10.64.1 to 183.10.71.254183.10.71.2552,046
74183.10.72.0/21183.10.72.1 to 183.10.79.254183.10.79.2552,046
75183.10.80.0/21183.10.80.1 to 183.10.87.254183.10.87.2552,046
76183.10.88.0/21183.10.88.1 to 183.10.95.254183.10.95.2552,046
77183.10.96.0/21183.10.96.1 to 183.10.103.254183.10.103.2552,046
78183.10.104.0/21183.10.104.1 to 183.10.111.254183.10.111.2552,046
79183.10.112.0/21183.10.112.1 to 183.10.119.254183.10.119.2552,046
80183.10.120.0/21183.10.120.1 to 183.10.127.254183.10.127.2552,046
81183.10.128.0/21183.10.128.1 to 183.10.135.254183.10.135.2552,046
82183.10.136.0/21183.10.136.1 to 183.10.143.254183.10.143.2552,046
83183.10.144.0/21183.10.144.1 to 183.10.151.254183.10.151.2552,046
84183.10.152.0/21183.10.152.1 to 183.10.159.254183.10.159.2552,046
85183.10.160.0/21183.10.160.1 to 183.10.167.254183.10.167.2552,046
86183.10.168.0/21183.10.168.1 to 183.10.175.254183.10.175.2552,046
87183.10.176.0/21183.10.176.1 to 183.10.183.254183.10.183.2552,046
88183.10.184.0/21183.10.184.1 to 183.10.191.254183.10.191.2552,046
89183.10.192.0/21183.10.192.1 to 183.10.199.254183.10.199.2552,046
90183.10.200.0/21183.10.200.1 to 183.10.207.254183.10.207.2552,046
91183.10.208.0/21183.10.208.1 to 183.10.215.254183.10.215.2552,046
92183.10.216.0/21183.10.216.1 to 183.10.223.254183.10.223.2552,046
93183.10.224.0/21183.10.224.1 to 183.10.231.254183.10.231.2552,046
94183.10.232.0/21183.10.232.1 to 183.10.239.254183.10.239.2552,046
95183.10.240.0/21183.10.240.1 to 183.10.247.254183.10.247.2552,046
96183.10.248.0/21183.10.248.1 to 183.10.255.254183.10.255.2552,046
97183.11.0.0/21183.11.0.1 to 183.11.7.254183.11.7.2552,046
98183.11.8.0/21183.11.8.1 to 183.11.15.254183.11.15.2552,046
99183.11.16.0/21183.11.16.1 to 183.11.23.254183.11.23.2552,046
100183.11.24.0/21183.11.24.1 to 183.11.31.254183.11.31.2552,046
101183.11.32.0/21183.11.32.1 to 183.11.39.254183.11.39.2552,046
102183.11.40.0/21183.11.40.1 to 183.11.47.254183.11.47.2552,046
103183.11.48.0/21183.11.48.1 to 183.11.55.254183.11.55.2552,046
104183.11.56.0/21183.11.56.1 to 183.11.63.254183.11.63.2552,046
105183.11.64.0/21183.11.64.1 to 183.11.71.254183.11.71.2552,046
106183.11.72.0/21183.11.72.1 to 183.11.79.254183.11.79.2552,046
107183.11.80.0/21183.11.80.1 to 183.11.87.254183.11.87.2552,046
108183.11.88.0/21183.11.88.1 to 183.11.95.254183.11.95.2552,046
109183.11.96.0/21183.11.96.1 to 183.11.103.254183.11.103.2552,046
110183.11.104.0/21183.11.104.1 to 183.11.111.254183.11.111.2552,046
111183.11.112.0/21183.11.112.1 to 183.11.119.254183.11.119.2552,046
112183.11.120.0/21183.11.120.1 to 183.11.127.254183.11.127.2552,046
113183.11.128.0/21183.11.128.1 to 183.11.135.254183.11.135.2552,046
114183.11.136.0/21183.11.136.1 to 183.11.143.254183.11.143.2552,046
115183.11.144.0/21183.11.144.1 to 183.11.151.254183.11.151.2552,046
116183.11.152.0/21183.11.152.1 to 183.11.159.254183.11.159.2552,046
117183.11.160.0/21183.11.160.1 to 183.11.167.254183.11.167.2552,046
118183.11.168.0/21183.11.168.1 to 183.11.175.254183.11.175.2552,046
119183.11.176.0/21183.11.176.1 to 183.11.183.254183.11.183.2552,046
120183.11.184.0/21183.11.184.1 to 183.11.191.254183.11.191.2552,046
121183.11.192.0/21183.11.192.1 to 183.11.199.254183.11.199.2552,046
122183.11.200.0/21183.11.200.1 to 183.11.207.254183.11.207.2552,046
123183.11.208.0/21183.11.208.1 to 183.11.215.254183.11.215.2552,046
124183.11.216.0/21183.11.216.1 to 183.11.223.254183.11.223.2552,046
125183.11.224.0/21183.11.224.1 to 183.11.231.254183.11.231.2552,046
126183.11.232.0/21183.11.232.1 to 183.11.239.254183.11.239.2552,046
127183.11.240.0/21183.11.240.1 to 183.11.247.254183.11.247.2552,046
128183.11.248.0/21183.11.248.1 to 183.11.255.254183.11.255.2552,046
129183.12.0.0/21183.12.0.1 to 183.12.7.254183.12.7.2552,046
130183.12.8.0/21183.12.8.1 to 183.12.15.254183.12.15.2552,046
131183.12.16.0/21183.12.16.1 to 183.12.23.254183.12.23.2552,046
132183.12.24.0/21183.12.24.1 to 183.12.31.254183.12.31.2552,046
133183.12.32.0/21183.12.32.1 to 183.12.39.254183.12.39.2552,046
134183.12.40.0/21183.12.40.1 to 183.12.47.254183.12.47.2552,046
135183.12.48.0/21183.12.48.1 to 183.12.55.254183.12.55.2552,046
136183.12.56.0/21183.12.56.1 to 183.12.63.254183.12.63.2552,046
137183.12.64.0/21183.12.64.1 to 183.12.71.254183.12.71.2552,046
138183.12.72.0/21183.12.72.1 to 183.12.79.254183.12.79.2552,046
139183.12.80.0/21183.12.80.1 to 183.12.87.254183.12.87.2552,046
140183.12.88.0/21183.12.88.1 to 183.12.95.254183.12.95.2552,046
141183.12.96.0/21183.12.96.1 to 183.12.103.254183.12.103.2552,046
142183.12.104.0/21183.12.104.1 to 183.12.111.254183.12.111.2552,046
143183.12.112.0/21183.12.112.1 to 183.12.119.254183.12.119.2552,046
144183.12.120.0/21183.12.120.1 to 183.12.127.254183.12.127.2552,046
145183.12.128.0/21183.12.128.1 to 183.12.135.254183.12.135.2552,046
146183.12.136.0/21183.12.136.1 to 183.12.143.254183.12.143.2552,046
147183.12.144.0/21183.12.144.1 to 183.12.151.254183.12.151.2552,046
148183.12.152.0/21183.12.152.1 to 183.12.159.254183.12.159.2552,046
149183.12.160.0/21183.12.160.1 to 183.12.167.254183.12.167.2552,046
150183.12.168.0/21183.12.168.1 to 183.12.175.254183.12.175.2552,046
151183.12.176.0/21183.12.176.1 to 183.12.183.254183.12.183.2552,046
152183.12.184.0/21183.12.184.1 to 183.12.191.254183.12.191.2552,046
153183.12.192.0/21183.12.192.1 to 183.12.199.254183.12.199.2552,046
154183.12.200.0/21183.12.200.1 to 183.12.207.254183.12.207.2552,046
155183.12.208.0/21183.12.208.1 to 183.12.215.254183.12.215.2552,046
156183.12.216.0/21183.12.216.1 to 183.12.223.254183.12.223.2552,046
157183.12.224.0/21183.12.224.1 to 183.12.231.254183.12.231.2552,046
158183.12.232.0/21183.12.232.1 to 183.12.239.254183.12.239.2552,046
159183.12.240.0/21183.12.240.1 to 183.12.247.254183.12.247.2552,046
160183.12.248.0/21183.12.248.1 to 183.12.255.254183.12.255.2552,046
161183.13.0.0/21183.13.0.1 to 183.13.7.254183.13.7.2552,046
162183.13.8.0/21183.13.8.1 to 183.13.15.254183.13.15.2552,046
163183.13.16.0/21183.13.16.1 to 183.13.23.254183.13.23.2552,046
164183.13.24.0/21183.13.24.1 to 183.13.31.254183.13.31.2552,046
165183.13.32.0/21183.13.32.1 to 183.13.39.254183.13.39.2552,046
166183.13.40.0/21183.13.40.1 to 183.13.47.254183.13.47.2552,046
167183.13.48.0/21183.13.48.1 to 183.13.55.254183.13.55.2552,046
168183.13.56.0/21183.13.56.1 to 183.13.63.254183.13.63.2552,046
169183.13.64.0/21183.13.64.1 to 183.13.71.254183.13.71.2552,046
170183.13.72.0/21183.13.72.1 to 183.13.79.254183.13.79.2552,046
171183.13.80.0/21183.13.80.1 to 183.13.87.254183.13.87.2552,046
172183.13.88.0/21183.13.88.1 to 183.13.95.254183.13.95.2552,046
173183.13.96.0/21183.13.96.1 to 183.13.103.254183.13.103.2552,046
174183.13.104.0/21183.13.104.1 to 183.13.111.254183.13.111.2552,046
175183.13.112.0/21183.13.112.1 to 183.13.119.254183.13.119.2552,046
176183.13.120.0/21183.13.120.1 to 183.13.127.254183.13.127.2552,046
177183.13.128.0/21183.13.128.1 to 183.13.135.254183.13.135.2552,046
178183.13.136.0/21183.13.136.1 to 183.13.143.254183.13.143.2552,046
179183.13.144.0/21183.13.144.1 to 183.13.151.254183.13.151.2552,046
180183.13.152.0/21183.13.152.1 to 183.13.159.254183.13.159.2552,046
181183.13.160.0/21183.13.160.1 to 183.13.167.254183.13.167.2552,046
182183.13.168.0/21183.13.168.1 to 183.13.175.254183.13.175.2552,046
183183.13.176.0/21183.13.176.1 to 183.13.183.254183.13.183.2552,046
184183.13.184.0/21183.13.184.1 to 183.13.191.254183.13.191.2552,046
185183.13.192.0/21183.13.192.1 to 183.13.199.254183.13.199.2552,046
186183.13.200.0/21183.13.200.1 to 183.13.207.254183.13.207.2552,046
187183.13.208.0/21183.13.208.1 to 183.13.215.254183.13.215.2552,046
188183.13.216.0/21183.13.216.1 to 183.13.223.254183.13.223.2552,046
189183.13.224.0/21183.13.224.1 to 183.13.231.254183.13.231.2552,046
190183.13.232.0/21183.13.232.1 to 183.13.239.254183.13.239.2552,046
191183.13.240.0/21183.13.240.1 to 183.13.247.254183.13.247.2552,046
192183.13.248.0/21183.13.248.1 to 183.13.255.254183.13.255.2552,046
193183.14.0.0/21183.14.0.1 to 183.14.7.254183.14.7.2552,046
194183.14.8.0/21183.14.8.1 to 183.14.15.254183.14.15.2552,046
195183.14.16.0/21183.14.16.1 to 183.14.23.254183.14.23.2552,046
196183.14.24.0/21183.14.24.1 to 183.14.31.254183.14.31.2552,046
197183.14.32.0/21183.14.32.1 to 183.14.39.254183.14.39.2552,046
198183.14.40.0/21183.14.40.1 to 183.14.47.254183.14.47.2552,046
199183.14.48.0/21183.14.48.1 to 183.14.55.254183.14.55.2552,046
200183.14.56.0/21183.14.56.1 to 183.14.63.254183.14.63.2552,046
201183.14.64.0/21183.14.64.1 to 183.14.71.254183.14.71.2552,046
202183.14.72.0/21183.14.72.1 to 183.14.79.254183.14.79.2552,046
203183.14.80.0/21183.14.80.1 to 183.14.87.254183.14.87.2552,046
204183.14.88.0/21183.14.88.1 to 183.14.95.254183.14.95.2552,046
205183.14.96.0/21183.14.96.1 to 183.14.103.254183.14.103.2552,046
206183.14.104.0/21183.14.104.1 to 183.14.111.254183.14.111.2552,046
207183.14.112.0/21183.14.112.1 to 183.14.119.254183.14.119.2552,046
208183.14.120.0/21183.14.120.1 to 183.14.127.254183.14.127.2552,046
209183.14.128.0/21183.14.128.1 to 183.14.135.254183.14.135.2552,046
210183.14.136.0/21183.14.136.1 to 183.14.143.254183.14.143.2552,046
211183.14.144.0/21183.14.144.1 to 183.14.151.254183.14.151.2552,046
212183.14.152.0/21183.14.152.1 to 183.14.159.254183.14.159.2552,046
213183.14.160.0/21183.14.160.1 to 183.14.167.254183.14.167.2552,046
214183.14.168.0/21183.14.168.1 to 183.14.175.254183.14.175.2552,046
215183.14.176.0/21183.14.176.1 to 183.14.183.254183.14.183.2552,046
216183.14.184.0/21183.14.184.1 to 183.14.191.254183.14.191.2552,046
217183.14.192.0/21183.14.192.1 to 183.14.199.254183.14.199.2552,046
218183.14.200.0/21183.14.200.1 to 183.14.207.254183.14.207.2552,046
219183.14.208.0/21183.14.208.1 to 183.14.215.254183.14.215.2552,046
220183.14.216.0/21183.14.216.1 to 183.14.223.254183.14.223.2552,046
221183.14.224.0/21183.14.224.1 to 183.14.231.254183.14.231.2552,046
222183.14.232.0/21183.14.232.1 to 183.14.239.254183.14.239.2552,046
223183.14.240.0/21183.14.240.1 to 183.14.247.254183.14.247.2552,046
224183.14.248.0/21183.14.248.1 to 183.14.255.254183.14.255.2552,046
225183.15.0.0/21183.15.0.1 to 183.15.7.254183.15.7.2552,046
226183.15.8.0/21183.15.8.1 to 183.15.15.254183.15.15.2552,046
227183.15.16.0/21183.15.16.1 to 183.15.23.254183.15.23.2552,046
228183.15.24.0/21183.15.24.1 to 183.15.31.254183.15.31.2552,046
229183.15.32.0/21183.15.32.1 to 183.15.39.254183.15.39.2552,046
230183.15.40.0/21183.15.40.1 to 183.15.47.254183.15.47.2552,046
231183.15.48.0/21183.15.48.1 to 183.15.55.254183.15.55.2552,046
232183.15.56.0/21183.15.56.1 to 183.15.63.254183.15.63.2552,046
233183.15.64.0/21183.15.64.1 to 183.15.71.254183.15.71.2552,046
234183.15.72.0/21183.15.72.1 to 183.15.79.254183.15.79.2552,046
235183.15.80.0/21183.15.80.1 to 183.15.87.254183.15.87.2552,046
236183.15.88.0/21183.15.88.1 to 183.15.95.254183.15.95.2552,046
237183.15.96.0/21183.15.96.1 to 183.15.103.254183.15.103.2552,046
238183.15.104.0/21183.15.104.1 to 183.15.111.254183.15.111.2552,046
239183.15.112.0/21183.15.112.1 to 183.15.119.254183.15.119.2552,046
240183.15.120.0/21183.15.120.1 to 183.15.127.254183.15.127.2552,046
241183.15.128.0/21183.15.128.1 to 183.15.135.254183.15.135.2552,046
242183.15.136.0/21183.15.136.1 to 183.15.143.254183.15.143.2552,046
243183.15.144.0/21183.15.144.1 to 183.15.151.254183.15.151.2552,046
244183.15.152.0/21183.15.152.1 to 183.15.159.254183.15.159.2552,046
245183.15.160.0/21183.15.160.1 to 183.15.167.254183.15.167.2552,046
246183.15.168.0/21183.15.168.1 to 183.15.175.254183.15.175.2552,046
247183.15.176.0/21183.15.176.1 to 183.15.183.254183.15.183.2552,046
248183.15.184.0/21183.15.184.1 to 183.15.191.254183.15.191.2552,046
249183.15.192.0/21183.15.192.1 to 183.15.199.254183.15.199.2552,046
250183.15.200.0/21183.15.200.1 to 183.15.207.254183.15.207.2552,046
251183.15.208.0/21183.15.208.1 to 183.15.215.254183.15.215.2552,046
252183.15.216.0/21183.15.216.1 to 183.15.223.254183.15.223.2552,046
253183.15.224.0/21183.15.224.1 to 183.15.231.254183.15.231.2552,046
254183.15.232.0/21183.15.232.1 to 183.15.239.254183.15.239.2552,046
255183.15.240.0/21183.15.240.1 to 183.15.247.254183.15.247.2552,046
256183.15.248.0/21183.15.248.1 to 183.15.255.254183.15.255.2552,046

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.