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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.

Network240.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
240.232.0.0
Broadcast address
240.239.255.255
First usable
240.232.0.1
Last usable
240.239.255.254
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 F0E80000 · Integer 4041736192 to 4042260479
Reverse DNS zones
232.240.in-addr.arpa
233.240.in-addr.arpa
234.240.in-addr.arpa
235.240.in-addr.arpa
236.240.in-addr.arpa
237.240.in-addr.arpa
238.240.in-addr.arpa
239.240.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
Address11110000.11101000.00000000.00000000240.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11110000.11101000.00000000.00000000240.232.0.0
Broadcast11110000.11101111.11111111.11111111240.239.255.255
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)

240.232.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1240.232.0.0/21240.232.0.1 to 240.232.7.254240.232.7.2552,046
2240.232.8.0/21240.232.8.1 to 240.232.15.254240.232.15.2552,046
3240.232.16.0/21240.232.16.1 to 240.232.23.254240.232.23.2552,046
4240.232.24.0/21240.232.24.1 to 240.232.31.254240.232.31.2552,046
5240.232.32.0/21240.232.32.1 to 240.232.39.254240.232.39.2552,046
6240.232.40.0/21240.232.40.1 to 240.232.47.254240.232.47.2552,046
7240.232.48.0/21240.232.48.1 to 240.232.55.254240.232.55.2552,046
8240.232.56.0/21240.232.56.1 to 240.232.63.254240.232.63.2552,046
9240.232.64.0/21240.232.64.1 to 240.232.71.254240.232.71.2552,046
10240.232.72.0/21240.232.72.1 to 240.232.79.254240.232.79.2552,046
11240.232.80.0/21240.232.80.1 to 240.232.87.254240.232.87.2552,046
12240.232.88.0/21240.232.88.1 to 240.232.95.254240.232.95.2552,046
13240.232.96.0/21240.232.96.1 to 240.232.103.254240.232.103.2552,046
14240.232.104.0/21240.232.104.1 to 240.232.111.254240.232.111.2552,046
15240.232.112.0/21240.232.112.1 to 240.232.119.254240.232.119.2552,046
16240.232.120.0/21240.232.120.1 to 240.232.127.254240.232.127.2552,046
17240.232.128.0/21240.232.128.1 to 240.232.135.254240.232.135.2552,046
18240.232.136.0/21240.232.136.1 to 240.232.143.254240.232.143.2552,046
19240.232.144.0/21240.232.144.1 to 240.232.151.254240.232.151.2552,046
20240.232.152.0/21240.232.152.1 to 240.232.159.254240.232.159.2552,046
21240.232.160.0/21240.232.160.1 to 240.232.167.254240.232.167.2552,046
22240.232.168.0/21240.232.168.1 to 240.232.175.254240.232.175.2552,046
23240.232.176.0/21240.232.176.1 to 240.232.183.254240.232.183.2552,046
24240.232.184.0/21240.232.184.1 to 240.232.191.254240.232.191.2552,046
25240.232.192.0/21240.232.192.1 to 240.232.199.254240.232.199.2552,046
26240.232.200.0/21240.232.200.1 to 240.232.207.254240.232.207.2552,046
27240.232.208.0/21240.232.208.1 to 240.232.215.254240.232.215.2552,046
28240.232.216.0/21240.232.216.1 to 240.232.223.254240.232.223.2552,046
29240.232.224.0/21240.232.224.1 to 240.232.231.254240.232.231.2552,046
30240.232.232.0/21240.232.232.1 to 240.232.239.254240.232.239.2552,046
31240.232.240.0/21240.232.240.1 to 240.232.247.254240.232.247.2552,046
32240.232.248.0/21240.232.248.1 to 240.232.255.254240.232.255.2552,046
33240.233.0.0/21240.233.0.1 to 240.233.7.254240.233.7.2552,046
34240.233.8.0/21240.233.8.1 to 240.233.15.254240.233.15.2552,046
35240.233.16.0/21240.233.16.1 to 240.233.23.254240.233.23.2552,046
36240.233.24.0/21240.233.24.1 to 240.233.31.254240.233.31.2552,046
37240.233.32.0/21240.233.32.1 to 240.233.39.254240.233.39.2552,046
38240.233.40.0/21240.233.40.1 to 240.233.47.254240.233.47.2552,046
39240.233.48.0/21240.233.48.1 to 240.233.55.254240.233.55.2552,046
40240.233.56.0/21240.233.56.1 to 240.233.63.254240.233.63.2552,046
41240.233.64.0/21240.233.64.1 to 240.233.71.254240.233.71.2552,046
42240.233.72.0/21240.233.72.1 to 240.233.79.254240.233.79.2552,046
43240.233.80.0/21240.233.80.1 to 240.233.87.254240.233.87.2552,046
44240.233.88.0/21240.233.88.1 to 240.233.95.254240.233.95.2552,046
45240.233.96.0/21240.233.96.1 to 240.233.103.254240.233.103.2552,046
46240.233.104.0/21240.233.104.1 to 240.233.111.254240.233.111.2552,046
47240.233.112.0/21240.233.112.1 to 240.233.119.254240.233.119.2552,046
48240.233.120.0/21240.233.120.1 to 240.233.127.254240.233.127.2552,046
49240.233.128.0/21240.233.128.1 to 240.233.135.254240.233.135.2552,046
50240.233.136.0/21240.233.136.1 to 240.233.143.254240.233.143.2552,046
51240.233.144.0/21240.233.144.1 to 240.233.151.254240.233.151.2552,046
52240.233.152.0/21240.233.152.1 to 240.233.159.254240.233.159.2552,046
53240.233.160.0/21240.233.160.1 to 240.233.167.254240.233.167.2552,046
54240.233.168.0/21240.233.168.1 to 240.233.175.254240.233.175.2552,046
55240.233.176.0/21240.233.176.1 to 240.233.183.254240.233.183.2552,046
56240.233.184.0/21240.233.184.1 to 240.233.191.254240.233.191.2552,046
57240.233.192.0/21240.233.192.1 to 240.233.199.254240.233.199.2552,046
58240.233.200.0/21240.233.200.1 to 240.233.207.254240.233.207.2552,046
59240.233.208.0/21240.233.208.1 to 240.233.215.254240.233.215.2552,046
60240.233.216.0/21240.233.216.1 to 240.233.223.254240.233.223.2552,046
61240.233.224.0/21240.233.224.1 to 240.233.231.254240.233.231.2552,046
62240.233.232.0/21240.233.232.1 to 240.233.239.254240.233.239.2552,046
63240.233.240.0/21240.233.240.1 to 240.233.247.254240.233.247.2552,046
64240.233.248.0/21240.233.248.1 to 240.233.255.254240.233.255.2552,046
65240.234.0.0/21240.234.0.1 to 240.234.7.254240.234.7.2552,046
66240.234.8.0/21240.234.8.1 to 240.234.15.254240.234.15.2552,046
67240.234.16.0/21240.234.16.1 to 240.234.23.254240.234.23.2552,046
68240.234.24.0/21240.234.24.1 to 240.234.31.254240.234.31.2552,046
69240.234.32.0/21240.234.32.1 to 240.234.39.254240.234.39.2552,046
70240.234.40.0/21240.234.40.1 to 240.234.47.254240.234.47.2552,046
71240.234.48.0/21240.234.48.1 to 240.234.55.254240.234.55.2552,046
72240.234.56.0/21240.234.56.1 to 240.234.63.254240.234.63.2552,046
73240.234.64.0/21240.234.64.1 to 240.234.71.254240.234.71.2552,046
74240.234.72.0/21240.234.72.1 to 240.234.79.254240.234.79.2552,046
75240.234.80.0/21240.234.80.1 to 240.234.87.254240.234.87.2552,046
76240.234.88.0/21240.234.88.1 to 240.234.95.254240.234.95.2552,046
77240.234.96.0/21240.234.96.1 to 240.234.103.254240.234.103.2552,046
78240.234.104.0/21240.234.104.1 to 240.234.111.254240.234.111.2552,046
79240.234.112.0/21240.234.112.1 to 240.234.119.254240.234.119.2552,046
80240.234.120.0/21240.234.120.1 to 240.234.127.254240.234.127.2552,046
81240.234.128.0/21240.234.128.1 to 240.234.135.254240.234.135.2552,046
82240.234.136.0/21240.234.136.1 to 240.234.143.254240.234.143.2552,046
83240.234.144.0/21240.234.144.1 to 240.234.151.254240.234.151.2552,046
84240.234.152.0/21240.234.152.1 to 240.234.159.254240.234.159.2552,046
85240.234.160.0/21240.234.160.1 to 240.234.167.254240.234.167.2552,046
86240.234.168.0/21240.234.168.1 to 240.234.175.254240.234.175.2552,046
87240.234.176.0/21240.234.176.1 to 240.234.183.254240.234.183.2552,046
88240.234.184.0/21240.234.184.1 to 240.234.191.254240.234.191.2552,046
89240.234.192.0/21240.234.192.1 to 240.234.199.254240.234.199.2552,046
90240.234.200.0/21240.234.200.1 to 240.234.207.254240.234.207.2552,046
91240.234.208.0/21240.234.208.1 to 240.234.215.254240.234.215.2552,046
92240.234.216.0/21240.234.216.1 to 240.234.223.254240.234.223.2552,046
93240.234.224.0/21240.234.224.1 to 240.234.231.254240.234.231.2552,046
94240.234.232.0/21240.234.232.1 to 240.234.239.254240.234.239.2552,046
95240.234.240.0/21240.234.240.1 to 240.234.247.254240.234.247.2552,046
96240.234.248.0/21240.234.248.1 to 240.234.255.254240.234.255.2552,046
97240.235.0.0/21240.235.0.1 to 240.235.7.254240.235.7.2552,046
98240.235.8.0/21240.235.8.1 to 240.235.15.254240.235.15.2552,046
99240.235.16.0/21240.235.16.1 to 240.235.23.254240.235.23.2552,046
100240.235.24.0/21240.235.24.1 to 240.235.31.254240.235.31.2552,046
101240.235.32.0/21240.235.32.1 to 240.235.39.254240.235.39.2552,046
102240.235.40.0/21240.235.40.1 to 240.235.47.254240.235.47.2552,046
103240.235.48.0/21240.235.48.1 to 240.235.55.254240.235.55.2552,046
104240.235.56.0/21240.235.56.1 to 240.235.63.254240.235.63.2552,046
105240.235.64.0/21240.235.64.1 to 240.235.71.254240.235.71.2552,046
106240.235.72.0/21240.235.72.1 to 240.235.79.254240.235.79.2552,046
107240.235.80.0/21240.235.80.1 to 240.235.87.254240.235.87.2552,046
108240.235.88.0/21240.235.88.1 to 240.235.95.254240.235.95.2552,046
109240.235.96.0/21240.235.96.1 to 240.235.103.254240.235.103.2552,046
110240.235.104.0/21240.235.104.1 to 240.235.111.254240.235.111.2552,046
111240.235.112.0/21240.235.112.1 to 240.235.119.254240.235.119.2552,046
112240.235.120.0/21240.235.120.1 to 240.235.127.254240.235.127.2552,046
113240.235.128.0/21240.235.128.1 to 240.235.135.254240.235.135.2552,046
114240.235.136.0/21240.235.136.1 to 240.235.143.254240.235.143.2552,046
115240.235.144.0/21240.235.144.1 to 240.235.151.254240.235.151.2552,046
116240.235.152.0/21240.235.152.1 to 240.235.159.254240.235.159.2552,046
117240.235.160.0/21240.235.160.1 to 240.235.167.254240.235.167.2552,046
118240.235.168.0/21240.235.168.1 to 240.235.175.254240.235.175.2552,046
119240.235.176.0/21240.235.176.1 to 240.235.183.254240.235.183.2552,046
120240.235.184.0/21240.235.184.1 to 240.235.191.254240.235.191.2552,046
121240.235.192.0/21240.235.192.1 to 240.235.199.254240.235.199.2552,046
122240.235.200.0/21240.235.200.1 to 240.235.207.254240.235.207.2552,046
123240.235.208.0/21240.235.208.1 to 240.235.215.254240.235.215.2552,046
124240.235.216.0/21240.235.216.1 to 240.235.223.254240.235.223.2552,046
125240.235.224.0/21240.235.224.1 to 240.235.231.254240.235.231.2552,046
126240.235.232.0/21240.235.232.1 to 240.235.239.254240.235.239.2552,046
127240.235.240.0/21240.235.240.1 to 240.235.247.254240.235.247.2552,046
128240.235.248.0/21240.235.248.1 to 240.235.255.254240.235.255.2552,046
129240.236.0.0/21240.236.0.1 to 240.236.7.254240.236.7.2552,046
130240.236.8.0/21240.236.8.1 to 240.236.15.254240.236.15.2552,046
131240.236.16.0/21240.236.16.1 to 240.236.23.254240.236.23.2552,046
132240.236.24.0/21240.236.24.1 to 240.236.31.254240.236.31.2552,046
133240.236.32.0/21240.236.32.1 to 240.236.39.254240.236.39.2552,046
134240.236.40.0/21240.236.40.1 to 240.236.47.254240.236.47.2552,046
135240.236.48.0/21240.236.48.1 to 240.236.55.254240.236.55.2552,046
136240.236.56.0/21240.236.56.1 to 240.236.63.254240.236.63.2552,046
137240.236.64.0/21240.236.64.1 to 240.236.71.254240.236.71.2552,046
138240.236.72.0/21240.236.72.1 to 240.236.79.254240.236.79.2552,046
139240.236.80.0/21240.236.80.1 to 240.236.87.254240.236.87.2552,046
140240.236.88.0/21240.236.88.1 to 240.236.95.254240.236.95.2552,046
141240.236.96.0/21240.236.96.1 to 240.236.103.254240.236.103.2552,046
142240.236.104.0/21240.236.104.1 to 240.236.111.254240.236.111.2552,046
143240.236.112.0/21240.236.112.1 to 240.236.119.254240.236.119.2552,046
144240.236.120.0/21240.236.120.1 to 240.236.127.254240.236.127.2552,046
145240.236.128.0/21240.236.128.1 to 240.236.135.254240.236.135.2552,046
146240.236.136.0/21240.236.136.1 to 240.236.143.254240.236.143.2552,046
147240.236.144.0/21240.236.144.1 to 240.236.151.254240.236.151.2552,046
148240.236.152.0/21240.236.152.1 to 240.236.159.254240.236.159.2552,046
149240.236.160.0/21240.236.160.1 to 240.236.167.254240.236.167.2552,046
150240.236.168.0/21240.236.168.1 to 240.236.175.254240.236.175.2552,046
151240.236.176.0/21240.236.176.1 to 240.236.183.254240.236.183.2552,046
152240.236.184.0/21240.236.184.1 to 240.236.191.254240.236.191.2552,046
153240.236.192.0/21240.236.192.1 to 240.236.199.254240.236.199.2552,046
154240.236.200.0/21240.236.200.1 to 240.236.207.254240.236.207.2552,046
155240.236.208.0/21240.236.208.1 to 240.236.215.254240.236.215.2552,046
156240.236.216.0/21240.236.216.1 to 240.236.223.254240.236.223.2552,046
157240.236.224.0/21240.236.224.1 to 240.236.231.254240.236.231.2552,046
158240.236.232.0/21240.236.232.1 to 240.236.239.254240.236.239.2552,046
159240.236.240.0/21240.236.240.1 to 240.236.247.254240.236.247.2552,046
160240.236.248.0/21240.236.248.1 to 240.236.255.254240.236.255.2552,046
161240.237.0.0/21240.237.0.1 to 240.237.7.254240.237.7.2552,046
162240.237.8.0/21240.237.8.1 to 240.237.15.254240.237.15.2552,046
163240.237.16.0/21240.237.16.1 to 240.237.23.254240.237.23.2552,046
164240.237.24.0/21240.237.24.1 to 240.237.31.254240.237.31.2552,046
165240.237.32.0/21240.237.32.1 to 240.237.39.254240.237.39.2552,046
166240.237.40.0/21240.237.40.1 to 240.237.47.254240.237.47.2552,046
167240.237.48.0/21240.237.48.1 to 240.237.55.254240.237.55.2552,046
168240.237.56.0/21240.237.56.1 to 240.237.63.254240.237.63.2552,046
169240.237.64.0/21240.237.64.1 to 240.237.71.254240.237.71.2552,046
170240.237.72.0/21240.237.72.1 to 240.237.79.254240.237.79.2552,046
171240.237.80.0/21240.237.80.1 to 240.237.87.254240.237.87.2552,046
172240.237.88.0/21240.237.88.1 to 240.237.95.254240.237.95.2552,046
173240.237.96.0/21240.237.96.1 to 240.237.103.254240.237.103.2552,046
174240.237.104.0/21240.237.104.1 to 240.237.111.254240.237.111.2552,046
175240.237.112.0/21240.237.112.1 to 240.237.119.254240.237.119.2552,046
176240.237.120.0/21240.237.120.1 to 240.237.127.254240.237.127.2552,046
177240.237.128.0/21240.237.128.1 to 240.237.135.254240.237.135.2552,046
178240.237.136.0/21240.237.136.1 to 240.237.143.254240.237.143.2552,046
179240.237.144.0/21240.237.144.1 to 240.237.151.254240.237.151.2552,046
180240.237.152.0/21240.237.152.1 to 240.237.159.254240.237.159.2552,046
181240.237.160.0/21240.237.160.1 to 240.237.167.254240.237.167.2552,046
182240.237.168.0/21240.237.168.1 to 240.237.175.254240.237.175.2552,046
183240.237.176.0/21240.237.176.1 to 240.237.183.254240.237.183.2552,046
184240.237.184.0/21240.237.184.1 to 240.237.191.254240.237.191.2552,046
185240.237.192.0/21240.237.192.1 to 240.237.199.254240.237.199.2552,046
186240.237.200.0/21240.237.200.1 to 240.237.207.254240.237.207.2552,046
187240.237.208.0/21240.237.208.1 to 240.237.215.254240.237.215.2552,046
188240.237.216.0/21240.237.216.1 to 240.237.223.254240.237.223.2552,046
189240.237.224.0/21240.237.224.1 to 240.237.231.254240.237.231.2552,046
190240.237.232.0/21240.237.232.1 to 240.237.239.254240.237.239.2552,046
191240.237.240.0/21240.237.240.1 to 240.237.247.254240.237.247.2552,046
192240.237.248.0/21240.237.248.1 to 240.237.255.254240.237.255.2552,046
193240.238.0.0/21240.238.0.1 to 240.238.7.254240.238.7.2552,046
194240.238.8.0/21240.238.8.1 to 240.238.15.254240.238.15.2552,046
195240.238.16.0/21240.238.16.1 to 240.238.23.254240.238.23.2552,046
196240.238.24.0/21240.238.24.1 to 240.238.31.254240.238.31.2552,046
197240.238.32.0/21240.238.32.1 to 240.238.39.254240.238.39.2552,046
198240.238.40.0/21240.238.40.1 to 240.238.47.254240.238.47.2552,046
199240.238.48.0/21240.238.48.1 to 240.238.55.254240.238.55.2552,046
200240.238.56.0/21240.238.56.1 to 240.238.63.254240.238.63.2552,046
201240.238.64.0/21240.238.64.1 to 240.238.71.254240.238.71.2552,046
202240.238.72.0/21240.238.72.1 to 240.238.79.254240.238.79.2552,046
203240.238.80.0/21240.238.80.1 to 240.238.87.254240.238.87.2552,046
204240.238.88.0/21240.238.88.1 to 240.238.95.254240.238.95.2552,046
205240.238.96.0/21240.238.96.1 to 240.238.103.254240.238.103.2552,046
206240.238.104.0/21240.238.104.1 to 240.238.111.254240.238.111.2552,046
207240.238.112.0/21240.238.112.1 to 240.238.119.254240.238.119.2552,046
208240.238.120.0/21240.238.120.1 to 240.238.127.254240.238.127.2552,046
209240.238.128.0/21240.238.128.1 to 240.238.135.254240.238.135.2552,046
210240.238.136.0/21240.238.136.1 to 240.238.143.254240.238.143.2552,046
211240.238.144.0/21240.238.144.1 to 240.238.151.254240.238.151.2552,046
212240.238.152.0/21240.238.152.1 to 240.238.159.254240.238.159.2552,046
213240.238.160.0/21240.238.160.1 to 240.238.167.254240.238.167.2552,046
214240.238.168.0/21240.238.168.1 to 240.238.175.254240.238.175.2552,046
215240.238.176.0/21240.238.176.1 to 240.238.183.254240.238.183.2552,046
216240.238.184.0/21240.238.184.1 to 240.238.191.254240.238.191.2552,046
217240.238.192.0/21240.238.192.1 to 240.238.199.254240.238.199.2552,046
218240.238.200.0/21240.238.200.1 to 240.238.207.254240.238.207.2552,046
219240.238.208.0/21240.238.208.1 to 240.238.215.254240.238.215.2552,046
220240.238.216.0/21240.238.216.1 to 240.238.223.254240.238.223.2552,046
221240.238.224.0/21240.238.224.1 to 240.238.231.254240.238.231.2552,046
222240.238.232.0/21240.238.232.1 to 240.238.239.254240.238.239.2552,046
223240.238.240.0/21240.238.240.1 to 240.238.247.254240.238.247.2552,046
224240.238.248.0/21240.238.248.1 to 240.238.255.254240.238.255.2552,046
225240.239.0.0/21240.239.0.1 to 240.239.7.254240.239.7.2552,046
226240.239.8.0/21240.239.8.1 to 240.239.15.254240.239.15.2552,046
227240.239.16.0/21240.239.16.1 to 240.239.23.254240.239.23.2552,046
228240.239.24.0/21240.239.24.1 to 240.239.31.254240.239.31.2552,046
229240.239.32.0/21240.239.32.1 to 240.239.39.254240.239.39.2552,046
230240.239.40.0/21240.239.40.1 to 240.239.47.254240.239.47.2552,046
231240.239.48.0/21240.239.48.1 to 240.239.55.254240.239.55.2552,046
232240.239.56.0/21240.239.56.1 to 240.239.63.254240.239.63.2552,046
233240.239.64.0/21240.239.64.1 to 240.239.71.254240.239.71.2552,046
234240.239.72.0/21240.239.72.1 to 240.239.79.254240.239.79.2552,046
235240.239.80.0/21240.239.80.1 to 240.239.87.254240.239.87.2552,046
236240.239.88.0/21240.239.88.1 to 240.239.95.254240.239.95.2552,046
237240.239.96.0/21240.239.96.1 to 240.239.103.254240.239.103.2552,046
238240.239.104.0/21240.239.104.1 to 240.239.111.254240.239.111.2552,046
239240.239.112.0/21240.239.112.1 to 240.239.119.254240.239.119.2552,046
240240.239.120.0/21240.239.120.1 to 240.239.127.254240.239.127.2552,046
241240.239.128.0/21240.239.128.1 to 240.239.135.254240.239.135.2552,046
242240.239.136.0/21240.239.136.1 to 240.239.143.254240.239.143.2552,046
243240.239.144.0/21240.239.144.1 to 240.239.151.254240.239.151.2552,046
244240.239.152.0/21240.239.152.1 to 240.239.159.254240.239.159.2552,046
245240.239.160.0/21240.239.160.1 to 240.239.167.254240.239.167.2552,046
246240.239.168.0/21240.239.168.1 to 240.239.175.254240.239.175.2552,046
247240.239.176.0/21240.239.176.1 to 240.239.183.254240.239.183.2552,046
248240.239.184.0/21240.239.184.1 to 240.239.191.254240.239.191.2552,046
249240.239.192.0/21240.239.192.1 to 240.239.199.254240.239.199.2552,046
250240.239.200.0/21240.239.200.1 to 240.239.207.254240.239.207.2552,046
251240.239.208.0/21240.239.208.1 to 240.239.215.254240.239.215.2552,046
252240.239.216.0/21240.239.216.1 to 240.239.223.254240.239.223.2552,046
253240.239.224.0/21240.239.224.1 to 240.239.231.254240.239.231.2552,046
254240.239.232.0/21240.239.232.1 to 240.239.239.254240.239.239.2552,046
255240.239.240.0/21240.239.240.1 to 240.239.247.254240.239.247.2552,046
256240.239.248.0/21240.239.248.1 to 240.239.255.254240.239.255.2552,046

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.