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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.

Network245.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
245.232.0.0
Broadcast address
245.239.255.255
First usable
245.232.0.1
Last usable
245.239.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F5E80000 · Integer 4125622272 to 4126146559
Reverse DNS zones
232.245.in-addr.arpa
233.245.in-addr.arpa
234.245.in-addr.arpa
235.245.in-addr.arpa
236.245.in-addr.arpa
237.245.in-addr.arpa
238.245.in-addr.arpa
239.245.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
Address11110101.11101000.00000000.00000000245.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11110101.11101000.00000000.00000000245.232.0.0
Broadcast11110101.11101111.11111111.11111111245.239.255.255
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)

245.232.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1245.232.0.0/21245.232.0.1 to 245.232.7.254245.232.7.2552,046
2245.232.8.0/21245.232.8.1 to 245.232.15.254245.232.15.2552,046
3245.232.16.0/21245.232.16.1 to 245.232.23.254245.232.23.2552,046
4245.232.24.0/21245.232.24.1 to 245.232.31.254245.232.31.2552,046
5245.232.32.0/21245.232.32.1 to 245.232.39.254245.232.39.2552,046
6245.232.40.0/21245.232.40.1 to 245.232.47.254245.232.47.2552,046
7245.232.48.0/21245.232.48.1 to 245.232.55.254245.232.55.2552,046
8245.232.56.0/21245.232.56.1 to 245.232.63.254245.232.63.2552,046
9245.232.64.0/21245.232.64.1 to 245.232.71.254245.232.71.2552,046
10245.232.72.0/21245.232.72.1 to 245.232.79.254245.232.79.2552,046
11245.232.80.0/21245.232.80.1 to 245.232.87.254245.232.87.2552,046
12245.232.88.0/21245.232.88.1 to 245.232.95.254245.232.95.2552,046
13245.232.96.0/21245.232.96.1 to 245.232.103.254245.232.103.2552,046
14245.232.104.0/21245.232.104.1 to 245.232.111.254245.232.111.2552,046
15245.232.112.0/21245.232.112.1 to 245.232.119.254245.232.119.2552,046
16245.232.120.0/21245.232.120.1 to 245.232.127.254245.232.127.2552,046
17245.232.128.0/21245.232.128.1 to 245.232.135.254245.232.135.2552,046
18245.232.136.0/21245.232.136.1 to 245.232.143.254245.232.143.2552,046
19245.232.144.0/21245.232.144.1 to 245.232.151.254245.232.151.2552,046
20245.232.152.0/21245.232.152.1 to 245.232.159.254245.232.159.2552,046
21245.232.160.0/21245.232.160.1 to 245.232.167.254245.232.167.2552,046
22245.232.168.0/21245.232.168.1 to 245.232.175.254245.232.175.2552,046
23245.232.176.0/21245.232.176.1 to 245.232.183.254245.232.183.2552,046
24245.232.184.0/21245.232.184.1 to 245.232.191.254245.232.191.2552,046
25245.232.192.0/21245.232.192.1 to 245.232.199.254245.232.199.2552,046
26245.232.200.0/21245.232.200.1 to 245.232.207.254245.232.207.2552,046
27245.232.208.0/21245.232.208.1 to 245.232.215.254245.232.215.2552,046
28245.232.216.0/21245.232.216.1 to 245.232.223.254245.232.223.2552,046
29245.232.224.0/21245.232.224.1 to 245.232.231.254245.232.231.2552,046
30245.232.232.0/21245.232.232.1 to 245.232.239.254245.232.239.2552,046
31245.232.240.0/21245.232.240.1 to 245.232.247.254245.232.247.2552,046
32245.232.248.0/21245.232.248.1 to 245.232.255.254245.232.255.2552,046
33245.233.0.0/21245.233.0.1 to 245.233.7.254245.233.7.2552,046
34245.233.8.0/21245.233.8.1 to 245.233.15.254245.233.15.2552,046
35245.233.16.0/21245.233.16.1 to 245.233.23.254245.233.23.2552,046
36245.233.24.0/21245.233.24.1 to 245.233.31.254245.233.31.2552,046
37245.233.32.0/21245.233.32.1 to 245.233.39.254245.233.39.2552,046
38245.233.40.0/21245.233.40.1 to 245.233.47.254245.233.47.2552,046
39245.233.48.0/21245.233.48.1 to 245.233.55.254245.233.55.2552,046
40245.233.56.0/21245.233.56.1 to 245.233.63.254245.233.63.2552,046
41245.233.64.0/21245.233.64.1 to 245.233.71.254245.233.71.2552,046
42245.233.72.0/21245.233.72.1 to 245.233.79.254245.233.79.2552,046
43245.233.80.0/21245.233.80.1 to 245.233.87.254245.233.87.2552,046
44245.233.88.0/21245.233.88.1 to 245.233.95.254245.233.95.2552,046
45245.233.96.0/21245.233.96.1 to 245.233.103.254245.233.103.2552,046
46245.233.104.0/21245.233.104.1 to 245.233.111.254245.233.111.2552,046
47245.233.112.0/21245.233.112.1 to 245.233.119.254245.233.119.2552,046
48245.233.120.0/21245.233.120.1 to 245.233.127.254245.233.127.2552,046
49245.233.128.0/21245.233.128.1 to 245.233.135.254245.233.135.2552,046
50245.233.136.0/21245.233.136.1 to 245.233.143.254245.233.143.2552,046
51245.233.144.0/21245.233.144.1 to 245.233.151.254245.233.151.2552,046
52245.233.152.0/21245.233.152.1 to 245.233.159.254245.233.159.2552,046
53245.233.160.0/21245.233.160.1 to 245.233.167.254245.233.167.2552,046
54245.233.168.0/21245.233.168.1 to 245.233.175.254245.233.175.2552,046
55245.233.176.0/21245.233.176.1 to 245.233.183.254245.233.183.2552,046
56245.233.184.0/21245.233.184.1 to 245.233.191.254245.233.191.2552,046
57245.233.192.0/21245.233.192.1 to 245.233.199.254245.233.199.2552,046
58245.233.200.0/21245.233.200.1 to 245.233.207.254245.233.207.2552,046
59245.233.208.0/21245.233.208.1 to 245.233.215.254245.233.215.2552,046
60245.233.216.0/21245.233.216.1 to 245.233.223.254245.233.223.2552,046
61245.233.224.0/21245.233.224.1 to 245.233.231.254245.233.231.2552,046
62245.233.232.0/21245.233.232.1 to 245.233.239.254245.233.239.2552,046
63245.233.240.0/21245.233.240.1 to 245.233.247.254245.233.247.2552,046
64245.233.248.0/21245.233.248.1 to 245.233.255.254245.233.255.2552,046
65245.234.0.0/21245.234.0.1 to 245.234.7.254245.234.7.2552,046
66245.234.8.0/21245.234.8.1 to 245.234.15.254245.234.15.2552,046
67245.234.16.0/21245.234.16.1 to 245.234.23.254245.234.23.2552,046
68245.234.24.0/21245.234.24.1 to 245.234.31.254245.234.31.2552,046
69245.234.32.0/21245.234.32.1 to 245.234.39.254245.234.39.2552,046
70245.234.40.0/21245.234.40.1 to 245.234.47.254245.234.47.2552,046
71245.234.48.0/21245.234.48.1 to 245.234.55.254245.234.55.2552,046
72245.234.56.0/21245.234.56.1 to 245.234.63.254245.234.63.2552,046
73245.234.64.0/21245.234.64.1 to 245.234.71.254245.234.71.2552,046
74245.234.72.0/21245.234.72.1 to 245.234.79.254245.234.79.2552,046
75245.234.80.0/21245.234.80.1 to 245.234.87.254245.234.87.2552,046
76245.234.88.0/21245.234.88.1 to 245.234.95.254245.234.95.2552,046
77245.234.96.0/21245.234.96.1 to 245.234.103.254245.234.103.2552,046
78245.234.104.0/21245.234.104.1 to 245.234.111.254245.234.111.2552,046
79245.234.112.0/21245.234.112.1 to 245.234.119.254245.234.119.2552,046
80245.234.120.0/21245.234.120.1 to 245.234.127.254245.234.127.2552,046
81245.234.128.0/21245.234.128.1 to 245.234.135.254245.234.135.2552,046
82245.234.136.0/21245.234.136.1 to 245.234.143.254245.234.143.2552,046
83245.234.144.0/21245.234.144.1 to 245.234.151.254245.234.151.2552,046
84245.234.152.0/21245.234.152.1 to 245.234.159.254245.234.159.2552,046
85245.234.160.0/21245.234.160.1 to 245.234.167.254245.234.167.2552,046
86245.234.168.0/21245.234.168.1 to 245.234.175.254245.234.175.2552,046
87245.234.176.0/21245.234.176.1 to 245.234.183.254245.234.183.2552,046
88245.234.184.0/21245.234.184.1 to 245.234.191.254245.234.191.2552,046
89245.234.192.0/21245.234.192.1 to 245.234.199.254245.234.199.2552,046
90245.234.200.0/21245.234.200.1 to 245.234.207.254245.234.207.2552,046
91245.234.208.0/21245.234.208.1 to 245.234.215.254245.234.215.2552,046
92245.234.216.0/21245.234.216.1 to 245.234.223.254245.234.223.2552,046
93245.234.224.0/21245.234.224.1 to 245.234.231.254245.234.231.2552,046
94245.234.232.0/21245.234.232.1 to 245.234.239.254245.234.239.2552,046
95245.234.240.0/21245.234.240.1 to 245.234.247.254245.234.247.2552,046
96245.234.248.0/21245.234.248.1 to 245.234.255.254245.234.255.2552,046
97245.235.0.0/21245.235.0.1 to 245.235.7.254245.235.7.2552,046
98245.235.8.0/21245.235.8.1 to 245.235.15.254245.235.15.2552,046
99245.235.16.0/21245.235.16.1 to 245.235.23.254245.235.23.2552,046
100245.235.24.0/21245.235.24.1 to 245.235.31.254245.235.31.2552,046
101245.235.32.0/21245.235.32.1 to 245.235.39.254245.235.39.2552,046
102245.235.40.0/21245.235.40.1 to 245.235.47.254245.235.47.2552,046
103245.235.48.0/21245.235.48.1 to 245.235.55.254245.235.55.2552,046
104245.235.56.0/21245.235.56.1 to 245.235.63.254245.235.63.2552,046
105245.235.64.0/21245.235.64.1 to 245.235.71.254245.235.71.2552,046
106245.235.72.0/21245.235.72.1 to 245.235.79.254245.235.79.2552,046
107245.235.80.0/21245.235.80.1 to 245.235.87.254245.235.87.2552,046
108245.235.88.0/21245.235.88.1 to 245.235.95.254245.235.95.2552,046
109245.235.96.0/21245.235.96.1 to 245.235.103.254245.235.103.2552,046
110245.235.104.0/21245.235.104.1 to 245.235.111.254245.235.111.2552,046
111245.235.112.0/21245.235.112.1 to 245.235.119.254245.235.119.2552,046
112245.235.120.0/21245.235.120.1 to 245.235.127.254245.235.127.2552,046
113245.235.128.0/21245.235.128.1 to 245.235.135.254245.235.135.2552,046
114245.235.136.0/21245.235.136.1 to 245.235.143.254245.235.143.2552,046
115245.235.144.0/21245.235.144.1 to 245.235.151.254245.235.151.2552,046
116245.235.152.0/21245.235.152.1 to 245.235.159.254245.235.159.2552,046
117245.235.160.0/21245.235.160.1 to 245.235.167.254245.235.167.2552,046
118245.235.168.0/21245.235.168.1 to 245.235.175.254245.235.175.2552,046
119245.235.176.0/21245.235.176.1 to 245.235.183.254245.235.183.2552,046
120245.235.184.0/21245.235.184.1 to 245.235.191.254245.235.191.2552,046
121245.235.192.0/21245.235.192.1 to 245.235.199.254245.235.199.2552,046
122245.235.200.0/21245.235.200.1 to 245.235.207.254245.235.207.2552,046
123245.235.208.0/21245.235.208.1 to 245.235.215.254245.235.215.2552,046
124245.235.216.0/21245.235.216.1 to 245.235.223.254245.235.223.2552,046
125245.235.224.0/21245.235.224.1 to 245.235.231.254245.235.231.2552,046
126245.235.232.0/21245.235.232.1 to 245.235.239.254245.235.239.2552,046
127245.235.240.0/21245.235.240.1 to 245.235.247.254245.235.247.2552,046
128245.235.248.0/21245.235.248.1 to 245.235.255.254245.235.255.2552,046
129245.236.0.0/21245.236.0.1 to 245.236.7.254245.236.7.2552,046
130245.236.8.0/21245.236.8.1 to 245.236.15.254245.236.15.2552,046
131245.236.16.0/21245.236.16.1 to 245.236.23.254245.236.23.2552,046
132245.236.24.0/21245.236.24.1 to 245.236.31.254245.236.31.2552,046
133245.236.32.0/21245.236.32.1 to 245.236.39.254245.236.39.2552,046
134245.236.40.0/21245.236.40.1 to 245.236.47.254245.236.47.2552,046
135245.236.48.0/21245.236.48.1 to 245.236.55.254245.236.55.2552,046
136245.236.56.0/21245.236.56.1 to 245.236.63.254245.236.63.2552,046
137245.236.64.0/21245.236.64.1 to 245.236.71.254245.236.71.2552,046
138245.236.72.0/21245.236.72.1 to 245.236.79.254245.236.79.2552,046
139245.236.80.0/21245.236.80.1 to 245.236.87.254245.236.87.2552,046
140245.236.88.0/21245.236.88.1 to 245.236.95.254245.236.95.2552,046
141245.236.96.0/21245.236.96.1 to 245.236.103.254245.236.103.2552,046
142245.236.104.0/21245.236.104.1 to 245.236.111.254245.236.111.2552,046
143245.236.112.0/21245.236.112.1 to 245.236.119.254245.236.119.2552,046
144245.236.120.0/21245.236.120.1 to 245.236.127.254245.236.127.2552,046
145245.236.128.0/21245.236.128.1 to 245.236.135.254245.236.135.2552,046
146245.236.136.0/21245.236.136.1 to 245.236.143.254245.236.143.2552,046
147245.236.144.0/21245.236.144.1 to 245.236.151.254245.236.151.2552,046
148245.236.152.0/21245.236.152.1 to 245.236.159.254245.236.159.2552,046
149245.236.160.0/21245.236.160.1 to 245.236.167.254245.236.167.2552,046
150245.236.168.0/21245.236.168.1 to 245.236.175.254245.236.175.2552,046
151245.236.176.0/21245.236.176.1 to 245.236.183.254245.236.183.2552,046
152245.236.184.0/21245.236.184.1 to 245.236.191.254245.236.191.2552,046
153245.236.192.0/21245.236.192.1 to 245.236.199.254245.236.199.2552,046
154245.236.200.0/21245.236.200.1 to 245.236.207.254245.236.207.2552,046
155245.236.208.0/21245.236.208.1 to 245.236.215.254245.236.215.2552,046
156245.236.216.0/21245.236.216.1 to 245.236.223.254245.236.223.2552,046
157245.236.224.0/21245.236.224.1 to 245.236.231.254245.236.231.2552,046
158245.236.232.0/21245.236.232.1 to 245.236.239.254245.236.239.2552,046
159245.236.240.0/21245.236.240.1 to 245.236.247.254245.236.247.2552,046
160245.236.248.0/21245.236.248.1 to 245.236.255.254245.236.255.2552,046
161245.237.0.0/21245.237.0.1 to 245.237.7.254245.237.7.2552,046
162245.237.8.0/21245.237.8.1 to 245.237.15.254245.237.15.2552,046
163245.237.16.0/21245.237.16.1 to 245.237.23.254245.237.23.2552,046
164245.237.24.0/21245.237.24.1 to 245.237.31.254245.237.31.2552,046
165245.237.32.0/21245.237.32.1 to 245.237.39.254245.237.39.2552,046
166245.237.40.0/21245.237.40.1 to 245.237.47.254245.237.47.2552,046
167245.237.48.0/21245.237.48.1 to 245.237.55.254245.237.55.2552,046
168245.237.56.0/21245.237.56.1 to 245.237.63.254245.237.63.2552,046
169245.237.64.0/21245.237.64.1 to 245.237.71.254245.237.71.2552,046
170245.237.72.0/21245.237.72.1 to 245.237.79.254245.237.79.2552,046
171245.237.80.0/21245.237.80.1 to 245.237.87.254245.237.87.2552,046
172245.237.88.0/21245.237.88.1 to 245.237.95.254245.237.95.2552,046
173245.237.96.0/21245.237.96.1 to 245.237.103.254245.237.103.2552,046
174245.237.104.0/21245.237.104.1 to 245.237.111.254245.237.111.2552,046
175245.237.112.0/21245.237.112.1 to 245.237.119.254245.237.119.2552,046
176245.237.120.0/21245.237.120.1 to 245.237.127.254245.237.127.2552,046
177245.237.128.0/21245.237.128.1 to 245.237.135.254245.237.135.2552,046
178245.237.136.0/21245.237.136.1 to 245.237.143.254245.237.143.2552,046
179245.237.144.0/21245.237.144.1 to 245.237.151.254245.237.151.2552,046
180245.237.152.0/21245.237.152.1 to 245.237.159.254245.237.159.2552,046
181245.237.160.0/21245.237.160.1 to 245.237.167.254245.237.167.2552,046
182245.237.168.0/21245.237.168.1 to 245.237.175.254245.237.175.2552,046
183245.237.176.0/21245.237.176.1 to 245.237.183.254245.237.183.2552,046
184245.237.184.0/21245.237.184.1 to 245.237.191.254245.237.191.2552,046
185245.237.192.0/21245.237.192.1 to 245.237.199.254245.237.199.2552,046
186245.237.200.0/21245.237.200.1 to 245.237.207.254245.237.207.2552,046
187245.237.208.0/21245.237.208.1 to 245.237.215.254245.237.215.2552,046
188245.237.216.0/21245.237.216.1 to 245.237.223.254245.237.223.2552,046
189245.237.224.0/21245.237.224.1 to 245.237.231.254245.237.231.2552,046
190245.237.232.0/21245.237.232.1 to 245.237.239.254245.237.239.2552,046
191245.237.240.0/21245.237.240.1 to 245.237.247.254245.237.247.2552,046
192245.237.248.0/21245.237.248.1 to 245.237.255.254245.237.255.2552,046
193245.238.0.0/21245.238.0.1 to 245.238.7.254245.238.7.2552,046
194245.238.8.0/21245.238.8.1 to 245.238.15.254245.238.15.2552,046
195245.238.16.0/21245.238.16.1 to 245.238.23.254245.238.23.2552,046
196245.238.24.0/21245.238.24.1 to 245.238.31.254245.238.31.2552,046
197245.238.32.0/21245.238.32.1 to 245.238.39.254245.238.39.2552,046
198245.238.40.0/21245.238.40.1 to 245.238.47.254245.238.47.2552,046
199245.238.48.0/21245.238.48.1 to 245.238.55.254245.238.55.2552,046
200245.238.56.0/21245.238.56.1 to 245.238.63.254245.238.63.2552,046
201245.238.64.0/21245.238.64.1 to 245.238.71.254245.238.71.2552,046
202245.238.72.0/21245.238.72.1 to 245.238.79.254245.238.79.2552,046
203245.238.80.0/21245.238.80.1 to 245.238.87.254245.238.87.2552,046
204245.238.88.0/21245.238.88.1 to 245.238.95.254245.238.95.2552,046
205245.238.96.0/21245.238.96.1 to 245.238.103.254245.238.103.2552,046
206245.238.104.0/21245.238.104.1 to 245.238.111.254245.238.111.2552,046
207245.238.112.0/21245.238.112.1 to 245.238.119.254245.238.119.2552,046
208245.238.120.0/21245.238.120.1 to 245.238.127.254245.238.127.2552,046
209245.238.128.0/21245.238.128.1 to 245.238.135.254245.238.135.2552,046
210245.238.136.0/21245.238.136.1 to 245.238.143.254245.238.143.2552,046
211245.238.144.0/21245.238.144.1 to 245.238.151.254245.238.151.2552,046
212245.238.152.0/21245.238.152.1 to 245.238.159.254245.238.159.2552,046
213245.238.160.0/21245.238.160.1 to 245.238.167.254245.238.167.2552,046
214245.238.168.0/21245.238.168.1 to 245.238.175.254245.238.175.2552,046
215245.238.176.0/21245.238.176.1 to 245.238.183.254245.238.183.2552,046
216245.238.184.0/21245.238.184.1 to 245.238.191.254245.238.191.2552,046
217245.238.192.0/21245.238.192.1 to 245.238.199.254245.238.199.2552,046
218245.238.200.0/21245.238.200.1 to 245.238.207.254245.238.207.2552,046
219245.238.208.0/21245.238.208.1 to 245.238.215.254245.238.215.2552,046
220245.238.216.0/21245.238.216.1 to 245.238.223.254245.238.223.2552,046
221245.238.224.0/21245.238.224.1 to 245.238.231.254245.238.231.2552,046
222245.238.232.0/21245.238.232.1 to 245.238.239.254245.238.239.2552,046
223245.238.240.0/21245.238.240.1 to 245.238.247.254245.238.247.2552,046
224245.238.248.0/21245.238.248.1 to 245.238.255.254245.238.255.2552,046
225245.239.0.0/21245.239.0.1 to 245.239.7.254245.239.7.2552,046
226245.239.8.0/21245.239.8.1 to 245.239.15.254245.239.15.2552,046
227245.239.16.0/21245.239.16.1 to 245.239.23.254245.239.23.2552,046
228245.239.24.0/21245.239.24.1 to 245.239.31.254245.239.31.2552,046
229245.239.32.0/21245.239.32.1 to 245.239.39.254245.239.39.2552,046
230245.239.40.0/21245.239.40.1 to 245.239.47.254245.239.47.2552,046
231245.239.48.0/21245.239.48.1 to 245.239.55.254245.239.55.2552,046
232245.239.56.0/21245.239.56.1 to 245.239.63.254245.239.63.2552,046
233245.239.64.0/21245.239.64.1 to 245.239.71.254245.239.71.2552,046
234245.239.72.0/21245.239.72.1 to 245.239.79.254245.239.79.2552,046
235245.239.80.0/21245.239.80.1 to 245.239.87.254245.239.87.2552,046
236245.239.88.0/21245.239.88.1 to 245.239.95.254245.239.95.2552,046
237245.239.96.0/21245.239.96.1 to 245.239.103.254245.239.103.2552,046
238245.239.104.0/21245.239.104.1 to 245.239.111.254245.239.111.2552,046
239245.239.112.0/21245.239.112.1 to 245.239.119.254245.239.119.2552,046
240245.239.120.0/21245.239.120.1 to 245.239.127.254245.239.127.2552,046
241245.239.128.0/21245.239.128.1 to 245.239.135.254245.239.135.2552,046
242245.239.136.0/21245.239.136.1 to 245.239.143.254245.239.143.2552,046
243245.239.144.0/21245.239.144.1 to 245.239.151.254245.239.151.2552,046
244245.239.152.0/21245.239.152.1 to 245.239.159.254245.239.159.2552,046
245245.239.160.0/21245.239.160.1 to 245.239.167.254245.239.167.2552,046
246245.239.168.0/21245.239.168.1 to 245.239.175.254245.239.175.2552,046
247245.239.176.0/21245.239.176.1 to 245.239.183.254245.239.183.2552,046
248245.239.184.0/21245.239.184.1 to 245.239.191.254245.239.191.2552,046
249245.239.192.0/21245.239.192.1 to 245.239.199.254245.239.199.2552,046
250245.239.200.0/21245.239.200.1 to 245.239.207.254245.239.207.2552,046
251245.239.208.0/21245.239.208.1 to 245.239.215.254245.239.215.2552,046
252245.239.216.0/21245.239.216.1 to 245.239.223.254245.239.223.2552,046
253245.239.224.0/21245.239.224.1 to 245.239.231.254245.239.231.2552,046
254245.239.232.0/21245.239.232.1 to 245.239.239.254245.239.239.2552,046
255245.239.240.0/21245.239.240.1 to 245.239.247.254245.239.247.2552,046
256245.239.248.0/21245.239.248.1 to 245.239.255.254245.239.255.2552,046

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.