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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.

Network239.32.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
239.32.0.0
Broadcast address
239.47.255.255
First usable
239.32.0.1
Last usable
239.47.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EF200000 · Integer 4011851776 to 4012900351
Reverse DNS zones
32.239.in-addr.arpa
33.239.in-addr.arpa
34.239.in-addr.arpa
35.239.in-addr.arpa
36.239.in-addr.arpa
37.239.in-addr.arpa
38.239.in-addr.arpa
39.239.in-addr.arpa
40.239.in-addr.arpa
41.239.in-addr.arpa
42.239.in-addr.arpa
43.239.in-addr.arpa
44.239.in-addr.arpa
45.239.in-addr.arpa
46.239.in-addr.arpa
47.239.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101111.00100000.00000000.00000000239.32.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11101111.00100000.00000000.00000000239.32.0.0
Broadcast11101111.00101111.11111111.11111111239.47.255.255
Split into smaller subnets/21
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

239.32.0.0/12 makes 512 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1239.32.0.0/21239.32.0.1 to 239.32.7.254239.32.7.2552,046
2239.32.8.0/21239.32.8.1 to 239.32.15.254239.32.15.2552,046
3239.32.16.0/21239.32.16.1 to 239.32.23.254239.32.23.2552,046
4239.32.24.0/21239.32.24.1 to 239.32.31.254239.32.31.2552,046
5239.32.32.0/21239.32.32.1 to 239.32.39.254239.32.39.2552,046
6239.32.40.0/21239.32.40.1 to 239.32.47.254239.32.47.2552,046
7239.32.48.0/21239.32.48.1 to 239.32.55.254239.32.55.2552,046
8239.32.56.0/21239.32.56.1 to 239.32.63.254239.32.63.2552,046
9239.32.64.0/21239.32.64.1 to 239.32.71.254239.32.71.2552,046
10239.32.72.0/21239.32.72.1 to 239.32.79.254239.32.79.2552,046
11239.32.80.0/21239.32.80.1 to 239.32.87.254239.32.87.2552,046
12239.32.88.0/21239.32.88.1 to 239.32.95.254239.32.95.2552,046
13239.32.96.0/21239.32.96.1 to 239.32.103.254239.32.103.2552,046
14239.32.104.0/21239.32.104.1 to 239.32.111.254239.32.111.2552,046
15239.32.112.0/21239.32.112.1 to 239.32.119.254239.32.119.2552,046
16239.32.120.0/21239.32.120.1 to 239.32.127.254239.32.127.2552,046
17239.32.128.0/21239.32.128.1 to 239.32.135.254239.32.135.2552,046
18239.32.136.0/21239.32.136.1 to 239.32.143.254239.32.143.2552,046
19239.32.144.0/21239.32.144.1 to 239.32.151.254239.32.151.2552,046
20239.32.152.0/21239.32.152.1 to 239.32.159.254239.32.159.2552,046
21239.32.160.0/21239.32.160.1 to 239.32.167.254239.32.167.2552,046
22239.32.168.0/21239.32.168.1 to 239.32.175.254239.32.175.2552,046
23239.32.176.0/21239.32.176.1 to 239.32.183.254239.32.183.2552,046
24239.32.184.0/21239.32.184.1 to 239.32.191.254239.32.191.2552,046
25239.32.192.0/21239.32.192.1 to 239.32.199.254239.32.199.2552,046
26239.32.200.0/21239.32.200.1 to 239.32.207.254239.32.207.2552,046
27239.32.208.0/21239.32.208.1 to 239.32.215.254239.32.215.2552,046
28239.32.216.0/21239.32.216.1 to 239.32.223.254239.32.223.2552,046
29239.32.224.0/21239.32.224.1 to 239.32.231.254239.32.231.2552,046
30239.32.232.0/21239.32.232.1 to 239.32.239.254239.32.239.2552,046
31239.32.240.0/21239.32.240.1 to 239.32.247.254239.32.247.2552,046
32239.32.248.0/21239.32.248.1 to 239.32.255.254239.32.255.2552,046
33239.33.0.0/21239.33.0.1 to 239.33.7.254239.33.7.2552,046
34239.33.8.0/21239.33.8.1 to 239.33.15.254239.33.15.2552,046
35239.33.16.0/21239.33.16.1 to 239.33.23.254239.33.23.2552,046
36239.33.24.0/21239.33.24.1 to 239.33.31.254239.33.31.2552,046
37239.33.32.0/21239.33.32.1 to 239.33.39.254239.33.39.2552,046
38239.33.40.0/21239.33.40.1 to 239.33.47.254239.33.47.2552,046
39239.33.48.0/21239.33.48.1 to 239.33.55.254239.33.55.2552,046
40239.33.56.0/21239.33.56.1 to 239.33.63.254239.33.63.2552,046
41239.33.64.0/21239.33.64.1 to 239.33.71.254239.33.71.2552,046
42239.33.72.0/21239.33.72.1 to 239.33.79.254239.33.79.2552,046
43239.33.80.0/21239.33.80.1 to 239.33.87.254239.33.87.2552,046
44239.33.88.0/21239.33.88.1 to 239.33.95.254239.33.95.2552,046
45239.33.96.0/21239.33.96.1 to 239.33.103.254239.33.103.2552,046
46239.33.104.0/21239.33.104.1 to 239.33.111.254239.33.111.2552,046
47239.33.112.0/21239.33.112.1 to 239.33.119.254239.33.119.2552,046
48239.33.120.0/21239.33.120.1 to 239.33.127.254239.33.127.2552,046
49239.33.128.0/21239.33.128.1 to 239.33.135.254239.33.135.2552,046
50239.33.136.0/21239.33.136.1 to 239.33.143.254239.33.143.2552,046
51239.33.144.0/21239.33.144.1 to 239.33.151.254239.33.151.2552,046
52239.33.152.0/21239.33.152.1 to 239.33.159.254239.33.159.2552,046
53239.33.160.0/21239.33.160.1 to 239.33.167.254239.33.167.2552,046
54239.33.168.0/21239.33.168.1 to 239.33.175.254239.33.175.2552,046
55239.33.176.0/21239.33.176.1 to 239.33.183.254239.33.183.2552,046
56239.33.184.0/21239.33.184.1 to 239.33.191.254239.33.191.2552,046
57239.33.192.0/21239.33.192.1 to 239.33.199.254239.33.199.2552,046
58239.33.200.0/21239.33.200.1 to 239.33.207.254239.33.207.2552,046
59239.33.208.0/21239.33.208.1 to 239.33.215.254239.33.215.2552,046
60239.33.216.0/21239.33.216.1 to 239.33.223.254239.33.223.2552,046
61239.33.224.0/21239.33.224.1 to 239.33.231.254239.33.231.2552,046
62239.33.232.0/21239.33.232.1 to 239.33.239.254239.33.239.2552,046
63239.33.240.0/21239.33.240.1 to 239.33.247.254239.33.247.2552,046
64239.33.248.0/21239.33.248.1 to 239.33.255.254239.33.255.2552,046
65239.34.0.0/21239.34.0.1 to 239.34.7.254239.34.7.2552,046
66239.34.8.0/21239.34.8.1 to 239.34.15.254239.34.15.2552,046
67239.34.16.0/21239.34.16.1 to 239.34.23.254239.34.23.2552,046
68239.34.24.0/21239.34.24.1 to 239.34.31.254239.34.31.2552,046
69239.34.32.0/21239.34.32.1 to 239.34.39.254239.34.39.2552,046
70239.34.40.0/21239.34.40.1 to 239.34.47.254239.34.47.2552,046
71239.34.48.0/21239.34.48.1 to 239.34.55.254239.34.55.2552,046
72239.34.56.0/21239.34.56.1 to 239.34.63.254239.34.63.2552,046
73239.34.64.0/21239.34.64.1 to 239.34.71.254239.34.71.2552,046
74239.34.72.0/21239.34.72.1 to 239.34.79.254239.34.79.2552,046
75239.34.80.0/21239.34.80.1 to 239.34.87.254239.34.87.2552,046
76239.34.88.0/21239.34.88.1 to 239.34.95.254239.34.95.2552,046
77239.34.96.0/21239.34.96.1 to 239.34.103.254239.34.103.2552,046
78239.34.104.0/21239.34.104.1 to 239.34.111.254239.34.111.2552,046
79239.34.112.0/21239.34.112.1 to 239.34.119.254239.34.119.2552,046
80239.34.120.0/21239.34.120.1 to 239.34.127.254239.34.127.2552,046
81239.34.128.0/21239.34.128.1 to 239.34.135.254239.34.135.2552,046
82239.34.136.0/21239.34.136.1 to 239.34.143.254239.34.143.2552,046
83239.34.144.0/21239.34.144.1 to 239.34.151.254239.34.151.2552,046
84239.34.152.0/21239.34.152.1 to 239.34.159.254239.34.159.2552,046
85239.34.160.0/21239.34.160.1 to 239.34.167.254239.34.167.2552,046
86239.34.168.0/21239.34.168.1 to 239.34.175.254239.34.175.2552,046
87239.34.176.0/21239.34.176.1 to 239.34.183.254239.34.183.2552,046
88239.34.184.0/21239.34.184.1 to 239.34.191.254239.34.191.2552,046
89239.34.192.0/21239.34.192.1 to 239.34.199.254239.34.199.2552,046
90239.34.200.0/21239.34.200.1 to 239.34.207.254239.34.207.2552,046
91239.34.208.0/21239.34.208.1 to 239.34.215.254239.34.215.2552,046
92239.34.216.0/21239.34.216.1 to 239.34.223.254239.34.223.2552,046
93239.34.224.0/21239.34.224.1 to 239.34.231.254239.34.231.2552,046
94239.34.232.0/21239.34.232.1 to 239.34.239.254239.34.239.2552,046
95239.34.240.0/21239.34.240.1 to 239.34.247.254239.34.247.2552,046
96239.34.248.0/21239.34.248.1 to 239.34.255.254239.34.255.2552,046
97239.35.0.0/21239.35.0.1 to 239.35.7.254239.35.7.2552,046
98239.35.8.0/21239.35.8.1 to 239.35.15.254239.35.15.2552,046
99239.35.16.0/21239.35.16.1 to 239.35.23.254239.35.23.2552,046
100239.35.24.0/21239.35.24.1 to 239.35.31.254239.35.31.2552,046
101239.35.32.0/21239.35.32.1 to 239.35.39.254239.35.39.2552,046
102239.35.40.0/21239.35.40.1 to 239.35.47.254239.35.47.2552,046
103239.35.48.0/21239.35.48.1 to 239.35.55.254239.35.55.2552,046
104239.35.56.0/21239.35.56.1 to 239.35.63.254239.35.63.2552,046
105239.35.64.0/21239.35.64.1 to 239.35.71.254239.35.71.2552,046
106239.35.72.0/21239.35.72.1 to 239.35.79.254239.35.79.2552,046
107239.35.80.0/21239.35.80.1 to 239.35.87.254239.35.87.2552,046
108239.35.88.0/21239.35.88.1 to 239.35.95.254239.35.95.2552,046
109239.35.96.0/21239.35.96.1 to 239.35.103.254239.35.103.2552,046
110239.35.104.0/21239.35.104.1 to 239.35.111.254239.35.111.2552,046
111239.35.112.0/21239.35.112.1 to 239.35.119.254239.35.119.2552,046
112239.35.120.0/21239.35.120.1 to 239.35.127.254239.35.127.2552,046
113239.35.128.0/21239.35.128.1 to 239.35.135.254239.35.135.2552,046
114239.35.136.0/21239.35.136.1 to 239.35.143.254239.35.143.2552,046
115239.35.144.0/21239.35.144.1 to 239.35.151.254239.35.151.2552,046
116239.35.152.0/21239.35.152.1 to 239.35.159.254239.35.159.2552,046
117239.35.160.0/21239.35.160.1 to 239.35.167.254239.35.167.2552,046
118239.35.168.0/21239.35.168.1 to 239.35.175.254239.35.175.2552,046
119239.35.176.0/21239.35.176.1 to 239.35.183.254239.35.183.2552,046
120239.35.184.0/21239.35.184.1 to 239.35.191.254239.35.191.2552,046
121239.35.192.0/21239.35.192.1 to 239.35.199.254239.35.199.2552,046
122239.35.200.0/21239.35.200.1 to 239.35.207.254239.35.207.2552,046
123239.35.208.0/21239.35.208.1 to 239.35.215.254239.35.215.2552,046
124239.35.216.0/21239.35.216.1 to 239.35.223.254239.35.223.2552,046
125239.35.224.0/21239.35.224.1 to 239.35.231.254239.35.231.2552,046
126239.35.232.0/21239.35.232.1 to 239.35.239.254239.35.239.2552,046
127239.35.240.0/21239.35.240.1 to 239.35.247.254239.35.247.2552,046
128239.35.248.0/21239.35.248.1 to 239.35.255.254239.35.255.2552,046
129239.36.0.0/21239.36.0.1 to 239.36.7.254239.36.7.2552,046
130239.36.8.0/21239.36.8.1 to 239.36.15.254239.36.15.2552,046
131239.36.16.0/21239.36.16.1 to 239.36.23.254239.36.23.2552,046
132239.36.24.0/21239.36.24.1 to 239.36.31.254239.36.31.2552,046
133239.36.32.0/21239.36.32.1 to 239.36.39.254239.36.39.2552,046
134239.36.40.0/21239.36.40.1 to 239.36.47.254239.36.47.2552,046
135239.36.48.0/21239.36.48.1 to 239.36.55.254239.36.55.2552,046
136239.36.56.0/21239.36.56.1 to 239.36.63.254239.36.63.2552,046
137239.36.64.0/21239.36.64.1 to 239.36.71.254239.36.71.2552,046
138239.36.72.0/21239.36.72.1 to 239.36.79.254239.36.79.2552,046
139239.36.80.0/21239.36.80.1 to 239.36.87.254239.36.87.2552,046
140239.36.88.0/21239.36.88.1 to 239.36.95.254239.36.95.2552,046
141239.36.96.0/21239.36.96.1 to 239.36.103.254239.36.103.2552,046
142239.36.104.0/21239.36.104.1 to 239.36.111.254239.36.111.2552,046
143239.36.112.0/21239.36.112.1 to 239.36.119.254239.36.119.2552,046
144239.36.120.0/21239.36.120.1 to 239.36.127.254239.36.127.2552,046
145239.36.128.0/21239.36.128.1 to 239.36.135.254239.36.135.2552,046
146239.36.136.0/21239.36.136.1 to 239.36.143.254239.36.143.2552,046
147239.36.144.0/21239.36.144.1 to 239.36.151.254239.36.151.2552,046
148239.36.152.0/21239.36.152.1 to 239.36.159.254239.36.159.2552,046
149239.36.160.0/21239.36.160.1 to 239.36.167.254239.36.167.2552,046
150239.36.168.0/21239.36.168.1 to 239.36.175.254239.36.175.2552,046
151239.36.176.0/21239.36.176.1 to 239.36.183.254239.36.183.2552,046
152239.36.184.0/21239.36.184.1 to 239.36.191.254239.36.191.2552,046
153239.36.192.0/21239.36.192.1 to 239.36.199.254239.36.199.2552,046
154239.36.200.0/21239.36.200.1 to 239.36.207.254239.36.207.2552,046
155239.36.208.0/21239.36.208.1 to 239.36.215.254239.36.215.2552,046
156239.36.216.0/21239.36.216.1 to 239.36.223.254239.36.223.2552,046
157239.36.224.0/21239.36.224.1 to 239.36.231.254239.36.231.2552,046
158239.36.232.0/21239.36.232.1 to 239.36.239.254239.36.239.2552,046
159239.36.240.0/21239.36.240.1 to 239.36.247.254239.36.247.2552,046
160239.36.248.0/21239.36.248.1 to 239.36.255.254239.36.255.2552,046
161239.37.0.0/21239.37.0.1 to 239.37.7.254239.37.7.2552,046
162239.37.8.0/21239.37.8.1 to 239.37.15.254239.37.15.2552,046
163239.37.16.0/21239.37.16.1 to 239.37.23.254239.37.23.2552,046
164239.37.24.0/21239.37.24.1 to 239.37.31.254239.37.31.2552,046
165239.37.32.0/21239.37.32.1 to 239.37.39.254239.37.39.2552,046
166239.37.40.0/21239.37.40.1 to 239.37.47.254239.37.47.2552,046
167239.37.48.0/21239.37.48.1 to 239.37.55.254239.37.55.2552,046
168239.37.56.0/21239.37.56.1 to 239.37.63.254239.37.63.2552,046
169239.37.64.0/21239.37.64.1 to 239.37.71.254239.37.71.2552,046
170239.37.72.0/21239.37.72.1 to 239.37.79.254239.37.79.2552,046
171239.37.80.0/21239.37.80.1 to 239.37.87.254239.37.87.2552,046
172239.37.88.0/21239.37.88.1 to 239.37.95.254239.37.95.2552,046
173239.37.96.0/21239.37.96.1 to 239.37.103.254239.37.103.2552,046
174239.37.104.0/21239.37.104.1 to 239.37.111.254239.37.111.2552,046
175239.37.112.0/21239.37.112.1 to 239.37.119.254239.37.119.2552,046
176239.37.120.0/21239.37.120.1 to 239.37.127.254239.37.127.2552,046
177239.37.128.0/21239.37.128.1 to 239.37.135.254239.37.135.2552,046
178239.37.136.0/21239.37.136.1 to 239.37.143.254239.37.143.2552,046
179239.37.144.0/21239.37.144.1 to 239.37.151.254239.37.151.2552,046
180239.37.152.0/21239.37.152.1 to 239.37.159.254239.37.159.2552,046
181239.37.160.0/21239.37.160.1 to 239.37.167.254239.37.167.2552,046
182239.37.168.0/21239.37.168.1 to 239.37.175.254239.37.175.2552,046
183239.37.176.0/21239.37.176.1 to 239.37.183.254239.37.183.2552,046
184239.37.184.0/21239.37.184.1 to 239.37.191.254239.37.191.2552,046
185239.37.192.0/21239.37.192.1 to 239.37.199.254239.37.199.2552,046
186239.37.200.0/21239.37.200.1 to 239.37.207.254239.37.207.2552,046
187239.37.208.0/21239.37.208.1 to 239.37.215.254239.37.215.2552,046
188239.37.216.0/21239.37.216.1 to 239.37.223.254239.37.223.2552,046
189239.37.224.0/21239.37.224.1 to 239.37.231.254239.37.231.2552,046
190239.37.232.0/21239.37.232.1 to 239.37.239.254239.37.239.2552,046
191239.37.240.0/21239.37.240.1 to 239.37.247.254239.37.247.2552,046
192239.37.248.0/21239.37.248.1 to 239.37.255.254239.37.255.2552,046
193239.38.0.0/21239.38.0.1 to 239.38.7.254239.38.7.2552,046
194239.38.8.0/21239.38.8.1 to 239.38.15.254239.38.15.2552,046
195239.38.16.0/21239.38.16.1 to 239.38.23.254239.38.23.2552,046
196239.38.24.0/21239.38.24.1 to 239.38.31.254239.38.31.2552,046
197239.38.32.0/21239.38.32.1 to 239.38.39.254239.38.39.2552,046
198239.38.40.0/21239.38.40.1 to 239.38.47.254239.38.47.2552,046
199239.38.48.0/21239.38.48.1 to 239.38.55.254239.38.55.2552,046
200239.38.56.0/21239.38.56.1 to 239.38.63.254239.38.63.2552,046
201239.38.64.0/21239.38.64.1 to 239.38.71.254239.38.71.2552,046
202239.38.72.0/21239.38.72.1 to 239.38.79.254239.38.79.2552,046
203239.38.80.0/21239.38.80.1 to 239.38.87.254239.38.87.2552,046
204239.38.88.0/21239.38.88.1 to 239.38.95.254239.38.95.2552,046
205239.38.96.0/21239.38.96.1 to 239.38.103.254239.38.103.2552,046
206239.38.104.0/21239.38.104.1 to 239.38.111.254239.38.111.2552,046
207239.38.112.0/21239.38.112.1 to 239.38.119.254239.38.119.2552,046
208239.38.120.0/21239.38.120.1 to 239.38.127.254239.38.127.2552,046
209239.38.128.0/21239.38.128.1 to 239.38.135.254239.38.135.2552,046
210239.38.136.0/21239.38.136.1 to 239.38.143.254239.38.143.2552,046
211239.38.144.0/21239.38.144.1 to 239.38.151.254239.38.151.2552,046
212239.38.152.0/21239.38.152.1 to 239.38.159.254239.38.159.2552,046
213239.38.160.0/21239.38.160.1 to 239.38.167.254239.38.167.2552,046
214239.38.168.0/21239.38.168.1 to 239.38.175.254239.38.175.2552,046
215239.38.176.0/21239.38.176.1 to 239.38.183.254239.38.183.2552,046
216239.38.184.0/21239.38.184.1 to 239.38.191.254239.38.191.2552,046
217239.38.192.0/21239.38.192.1 to 239.38.199.254239.38.199.2552,046
218239.38.200.0/21239.38.200.1 to 239.38.207.254239.38.207.2552,046
219239.38.208.0/21239.38.208.1 to 239.38.215.254239.38.215.2552,046
220239.38.216.0/21239.38.216.1 to 239.38.223.254239.38.223.2552,046
221239.38.224.0/21239.38.224.1 to 239.38.231.254239.38.231.2552,046
222239.38.232.0/21239.38.232.1 to 239.38.239.254239.38.239.2552,046
223239.38.240.0/21239.38.240.1 to 239.38.247.254239.38.247.2552,046
224239.38.248.0/21239.38.248.1 to 239.38.255.254239.38.255.2552,046
225239.39.0.0/21239.39.0.1 to 239.39.7.254239.39.7.2552,046
226239.39.8.0/21239.39.8.1 to 239.39.15.254239.39.15.2552,046
227239.39.16.0/21239.39.16.1 to 239.39.23.254239.39.23.2552,046
228239.39.24.0/21239.39.24.1 to 239.39.31.254239.39.31.2552,046
229239.39.32.0/21239.39.32.1 to 239.39.39.254239.39.39.2552,046
230239.39.40.0/21239.39.40.1 to 239.39.47.254239.39.47.2552,046
231239.39.48.0/21239.39.48.1 to 239.39.55.254239.39.55.2552,046
232239.39.56.0/21239.39.56.1 to 239.39.63.254239.39.63.2552,046
233239.39.64.0/21239.39.64.1 to 239.39.71.254239.39.71.2552,046
234239.39.72.0/21239.39.72.1 to 239.39.79.254239.39.79.2552,046
235239.39.80.0/21239.39.80.1 to 239.39.87.254239.39.87.2552,046
236239.39.88.0/21239.39.88.1 to 239.39.95.254239.39.95.2552,046
237239.39.96.0/21239.39.96.1 to 239.39.103.254239.39.103.2552,046
238239.39.104.0/21239.39.104.1 to 239.39.111.254239.39.111.2552,046
239239.39.112.0/21239.39.112.1 to 239.39.119.254239.39.119.2552,046
240239.39.120.0/21239.39.120.1 to 239.39.127.254239.39.127.2552,046
241239.39.128.0/21239.39.128.1 to 239.39.135.254239.39.135.2552,046
242239.39.136.0/21239.39.136.1 to 239.39.143.254239.39.143.2552,046
243239.39.144.0/21239.39.144.1 to 239.39.151.254239.39.151.2552,046
244239.39.152.0/21239.39.152.1 to 239.39.159.254239.39.159.2552,046
245239.39.160.0/21239.39.160.1 to 239.39.167.254239.39.167.2552,046
246239.39.168.0/21239.39.168.1 to 239.39.175.254239.39.175.2552,046
247239.39.176.0/21239.39.176.1 to 239.39.183.254239.39.183.2552,046
248239.39.184.0/21239.39.184.1 to 239.39.191.254239.39.191.2552,046
249239.39.192.0/21239.39.192.1 to 239.39.199.254239.39.199.2552,046
250239.39.200.0/21239.39.200.1 to 239.39.207.254239.39.207.2552,046
251239.39.208.0/21239.39.208.1 to 239.39.215.254239.39.215.2552,046
252239.39.216.0/21239.39.216.1 to 239.39.223.254239.39.223.2552,046
253239.39.224.0/21239.39.224.1 to 239.39.231.254239.39.231.2552,046
254239.39.232.0/21239.39.232.1 to 239.39.239.254239.39.239.2552,046
255239.39.240.0/21239.39.240.1 to 239.39.247.254239.39.247.2552,046
256239.39.248.0/21239.39.248.1 to 239.39.255.254239.39.255.2552,046

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.