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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.

Network246.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
246.0.0.0
Broadcast address
246.7.255.255
First usable
246.0.0.1
Last usable
246.7.255.254
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 F6000000 · Integer 4127195136 to 4127719423
Reverse DNS zones
0.246.in-addr.arpa
1.246.in-addr.arpa
2.246.in-addr.arpa
3.246.in-addr.arpa
4.246.in-addr.arpa
5.246.in-addr.arpa
6.246.in-addr.arpa
7.246.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
Address11110110.00000000.00000000.00000000246.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11110110.00000000.00000000.00000000246.0.0.0
Broadcast11110110.00000111.11111111.11111111246.7.255.255
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)

246.0.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1246.0.0.0/21246.0.0.1 to 246.0.7.254246.0.7.2552,046
2246.0.8.0/21246.0.8.1 to 246.0.15.254246.0.15.2552,046
3246.0.16.0/21246.0.16.1 to 246.0.23.254246.0.23.2552,046
4246.0.24.0/21246.0.24.1 to 246.0.31.254246.0.31.2552,046
5246.0.32.0/21246.0.32.1 to 246.0.39.254246.0.39.2552,046
6246.0.40.0/21246.0.40.1 to 246.0.47.254246.0.47.2552,046
7246.0.48.0/21246.0.48.1 to 246.0.55.254246.0.55.2552,046
8246.0.56.0/21246.0.56.1 to 246.0.63.254246.0.63.2552,046
9246.0.64.0/21246.0.64.1 to 246.0.71.254246.0.71.2552,046
10246.0.72.0/21246.0.72.1 to 246.0.79.254246.0.79.2552,046
11246.0.80.0/21246.0.80.1 to 246.0.87.254246.0.87.2552,046
12246.0.88.0/21246.0.88.1 to 246.0.95.254246.0.95.2552,046
13246.0.96.0/21246.0.96.1 to 246.0.103.254246.0.103.2552,046
14246.0.104.0/21246.0.104.1 to 246.0.111.254246.0.111.2552,046
15246.0.112.0/21246.0.112.1 to 246.0.119.254246.0.119.2552,046
16246.0.120.0/21246.0.120.1 to 246.0.127.254246.0.127.2552,046
17246.0.128.0/21246.0.128.1 to 246.0.135.254246.0.135.2552,046
18246.0.136.0/21246.0.136.1 to 246.0.143.254246.0.143.2552,046
19246.0.144.0/21246.0.144.1 to 246.0.151.254246.0.151.2552,046
20246.0.152.0/21246.0.152.1 to 246.0.159.254246.0.159.2552,046
21246.0.160.0/21246.0.160.1 to 246.0.167.254246.0.167.2552,046
22246.0.168.0/21246.0.168.1 to 246.0.175.254246.0.175.2552,046
23246.0.176.0/21246.0.176.1 to 246.0.183.254246.0.183.2552,046
24246.0.184.0/21246.0.184.1 to 246.0.191.254246.0.191.2552,046
25246.0.192.0/21246.0.192.1 to 246.0.199.254246.0.199.2552,046
26246.0.200.0/21246.0.200.1 to 246.0.207.254246.0.207.2552,046
27246.0.208.0/21246.0.208.1 to 246.0.215.254246.0.215.2552,046
28246.0.216.0/21246.0.216.1 to 246.0.223.254246.0.223.2552,046
29246.0.224.0/21246.0.224.1 to 246.0.231.254246.0.231.2552,046
30246.0.232.0/21246.0.232.1 to 246.0.239.254246.0.239.2552,046
31246.0.240.0/21246.0.240.1 to 246.0.247.254246.0.247.2552,046
32246.0.248.0/21246.0.248.1 to 246.0.255.254246.0.255.2552,046
33246.1.0.0/21246.1.0.1 to 246.1.7.254246.1.7.2552,046
34246.1.8.0/21246.1.8.1 to 246.1.15.254246.1.15.2552,046
35246.1.16.0/21246.1.16.1 to 246.1.23.254246.1.23.2552,046
36246.1.24.0/21246.1.24.1 to 246.1.31.254246.1.31.2552,046
37246.1.32.0/21246.1.32.1 to 246.1.39.254246.1.39.2552,046
38246.1.40.0/21246.1.40.1 to 246.1.47.254246.1.47.2552,046
39246.1.48.0/21246.1.48.1 to 246.1.55.254246.1.55.2552,046
40246.1.56.0/21246.1.56.1 to 246.1.63.254246.1.63.2552,046
41246.1.64.0/21246.1.64.1 to 246.1.71.254246.1.71.2552,046
42246.1.72.0/21246.1.72.1 to 246.1.79.254246.1.79.2552,046
43246.1.80.0/21246.1.80.1 to 246.1.87.254246.1.87.2552,046
44246.1.88.0/21246.1.88.1 to 246.1.95.254246.1.95.2552,046
45246.1.96.0/21246.1.96.1 to 246.1.103.254246.1.103.2552,046
46246.1.104.0/21246.1.104.1 to 246.1.111.254246.1.111.2552,046
47246.1.112.0/21246.1.112.1 to 246.1.119.254246.1.119.2552,046
48246.1.120.0/21246.1.120.1 to 246.1.127.254246.1.127.2552,046
49246.1.128.0/21246.1.128.1 to 246.1.135.254246.1.135.2552,046
50246.1.136.0/21246.1.136.1 to 246.1.143.254246.1.143.2552,046
51246.1.144.0/21246.1.144.1 to 246.1.151.254246.1.151.2552,046
52246.1.152.0/21246.1.152.1 to 246.1.159.254246.1.159.2552,046
53246.1.160.0/21246.1.160.1 to 246.1.167.254246.1.167.2552,046
54246.1.168.0/21246.1.168.1 to 246.1.175.254246.1.175.2552,046
55246.1.176.0/21246.1.176.1 to 246.1.183.254246.1.183.2552,046
56246.1.184.0/21246.1.184.1 to 246.1.191.254246.1.191.2552,046
57246.1.192.0/21246.1.192.1 to 246.1.199.254246.1.199.2552,046
58246.1.200.0/21246.1.200.1 to 246.1.207.254246.1.207.2552,046
59246.1.208.0/21246.1.208.1 to 246.1.215.254246.1.215.2552,046
60246.1.216.0/21246.1.216.1 to 246.1.223.254246.1.223.2552,046
61246.1.224.0/21246.1.224.1 to 246.1.231.254246.1.231.2552,046
62246.1.232.0/21246.1.232.1 to 246.1.239.254246.1.239.2552,046
63246.1.240.0/21246.1.240.1 to 246.1.247.254246.1.247.2552,046
64246.1.248.0/21246.1.248.1 to 246.1.255.254246.1.255.2552,046
65246.2.0.0/21246.2.0.1 to 246.2.7.254246.2.7.2552,046
66246.2.8.0/21246.2.8.1 to 246.2.15.254246.2.15.2552,046
67246.2.16.0/21246.2.16.1 to 246.2.23.254246.2.23.2552,046
68246.2.24.0/21246.2.24.1 to 246.2.31.254246.2.31.2552,046
69246.2.32.0/21246.2.32.1 to 246.2.39.254246.2.39.2552,046
70246.2.40.0/21246.2.40.1 to 246.2.47.254246.2.47.2552,046
71246.2.48.0/21246.2.48.1 to 246.2.55.254246.2.55.2552,046
72246.2.56.0/21246.2.56.1 to 246.2.63.254246.2.63.2552,046
73246.2.64.0/21246.2.64.1 to 246.2.71.254246.2.71.2552,046
74246.2.72.0/21246.2.72.1 to 246.2.79.254246.2.79.2552,046
75246.2.80.0/21246.2.80.1 to 246.2.87.254246.2.87.2552,046
76246.2.88.0/21246.2.88.1 to 246.2.95.254246.2.95.2552,046
77246.2.96.0/21246.2.96.1 to 246.2.103.254246.2.103.2552,046
78246.2.104.0/21246.2.104.1 to 246.2.111.254246.2.111.2552,046
79246.2.112.0/21246.2.112.1 to 246.2.119.254246.2.119.2552,046
80246.2.120.0/21246.2.120.1 to 246.2.127.254246.2.127.2552,046
81246.2.128.0/21246.2.128.1 to 246.2.135.254246.2.135.2552,046
82246.2.136.0/21246.2.136.1 to 246.2.143.254246.2.143.2552,046
83246.2.144.0/21246.2.144.1 to 246.2.151.254246.2.151.2552,046
84246.2.152.0/21246.2.152.1 to 246.2.159.254246.2.159.2552,046
85246.2.160.0/21246.2.160.1 to 246.2.167.254246.2.167.2552,046
86246.2.168.0/21246.2.168.1 to 246.2.175.254246.2.175.2552,046
87246.2.176.0/21246.2.176.1 to 246.2.183.254246.2.183.2552,046
88246.2.184.0/21246.2.184.1 to 246.2.191.254246.2.191.2552,046
89246.2.192.0/21246.2.192.1 to 246.2.199.254246.2.199.2552,046
90246.2.200.0/21246.2.200.1 to 246.2.207.254246.2.207.2552,046
91246.2.208.0/21246.2.208.1 to 246.2.215.254246.2.215.2552,046
92246.2.216.0/21246.2.216.1 to 246.2.223.254246.2.223.2552,046
93246.2.224.0/21246.2.224.1 to 246.2.231.254246.2.231.2552,046
94246.2.232.0/21246.2.232.1 to 246.2.239.254246.2.239.2552,046
95246.2.240.0/21246.2.240.1 to 246.2.247.254246.2.247.2552,046
96246.2.248.0/21246.2.248.1 to 246.2.255.254246.2.255.2552,046
97246.3.0.0/21246.3.0.1 to 246.3.7.254246.3.7.2552,046
98246.3.8.0/21246.3.8.1 to 246.3.15.254246.3.15.2552,046
99246.3.16.0/21246.3.16.1 to 246.3.23.254246.3.23.2552,046
100246.3.24.0/21246.3.24.1 to 246.3.31.254246.3.31.2552,046
101246.3.32.0/21246.3.32.1 to 246.3.39.254246.3.39.2552,046
102246.3.40.0/21246.3.40.1 to 246.3.47.254246.3.47.2552,046
103246.3.48.0/21246.3.48.1 to 246.3.55.254246.3.55.2552,046
104246.3.56.0/21246.3.56.1 to 246.3.63.254246.3.63.2552,046
105246.3.64.0/21246.3.64.1 to 246.3.71.254246.3.71.2552,046
106246.3.72.0/21246.3.72.1 to 246.3.79.254246.3.79.2552,046
107246.3.80.0/21246.3.80.1 to 246.3.87.254246.3.87.2552,046
108246.3.88.0/21246.3.88.1 to 246.3.95.254246.3.95.2552,046
109246.3.96.0/21246.3.96.1 to 246.3.103.254246.3.103.2552,046
110246.3.104.0/21246.3.104.1 to 246.3.111.254246.3.111.2552,046
111246.3.112.0/21246.3.112.1 to 246.3.119.254246.3.119.2552,046
112246.3.120.0/21246.3.120.1 to 246.3.127.254246.3.127.2552,046
113246.3.128.0/21246.3.128.1 to 246.3.135.254246.3.135.2552,046
114246.3.136.0/21246.3.136.1 to 246.3.143.254246.3.143.2552,046
115246.3.144.0/21246.3.144.1 to 246.3.151.254246.3.151.2552,046
116246.3.152.0/21246.3.152.1 to 246.3.159.254246.3.159.2552,046
117246.3.160.0/21246.3.160.1 to 246.3.167.254246.3.167.2552,046
118246.3.168.0/21246.3.168.1 to 246.3.175.254246.3.175.2552,046
119246.3.176.0/21246.3.176.1 to 246.3.183.254246.3.183.2552,046
120246.3.184.0/21246.3.184.1 to 246.3.191.254246.3.191.2552,046
121246.3.192.0/21246.3.192.1 to 246.3.199.254246.3.199.2552,046
122246.3.200.0/21246.3.200.1 to 246.3.207.254246.3.207.2552,046
123246.3.208.0/21246.3.208.1 to 246.3.215.254246.3.215.2552,046
124246.3.216.0/21246.3.216.1 to 246.3.223.254246.3.223.2552,046
125246.3.224.0/21246.3.224.1 to 246.3.231.254246.3.231.2552,046
126246.3.232.0/21246.3.232.1 to 246.3.239.254246.3.239.2552,046
127246.3.240.0/21246.3.240.1 to 246.3.247.254246.3.247.2552,046
128246.3.248.0/21246.3.248.1 to 246.3.255.254246.3.255.2552,046
129246.4.0.0/21246.4.0.1 to 246.4.7.254246.4.7.2552,046
130246.4.8.0/21246.4.8.1 to 246.4.15.254246.4.15.2552,046
131246.4.16.0/21246.4.16.1 to 246.4.23.254246.4.23.2552,046
132246.4.24.0/21246.4.24.1 to 246.4.31.254246.4.31.2552,046
133246.4.32.0/21246.4.32.1 to 246.4.39.254246.4.39.2552,046
134246.4.40.0/21246.4.40.1 to 246.4.47.254246.4.47.2552,046
135246.4.48.0/21246.4.48.1 to 246.4.55.254246.4.55.2552,046
136246.4.56.0/21246.4.56.1 to 246.4.63.254246.4.63.2552,046
137246.4.64.0/21246.4.64.1 to 246.4.71.254246.4.71.2552,046
138246.4.72.0/21246.4.72.1 to 246.4.79.254246.4.79.2552,046
139246.4.80.0/21246.4.80.1 to 246.4.87.254246.4.87.2552,046
140246.4.88.0/21246.4.88.1 to 246.4.95.254246.4.95.2552,046
141246.4.96.0/21246.4.96.1 to 246.4.103.254246.4.103.2552,046
142246.4.104.0/21246.4.104.1 to 246.4.111.254246.4.111.2552,046
143246.4.112.0/21246.4.112.1 to 246.4.119.254246.4.119.2552,046
144246.4.120.0/21246.4.120.1 to 246.4.127.254246.4.127.2552,046
145246.4.128.0/21246.4.128.1 to 246.4.135.254246.4.135.2552,046
146246.4.136.0/21246.4.136.1 to 246.4.143.254246.4.143.2552,046
147246.4.144.0/21246.4.144.1 to 246.4.151.254246.4.151.2552,046
148246.4.152.0/21246.4.152.1 to 246.4.159.254246.4.159.2552,046
149246.4.160.0/21246.4.160.1 to 246.4.167.254246.4.167.2552,046
150246.4.168.0/21246.4.168.1 to 246.4.175.254246.4.175.2552,046
151246.4.176.0/21246.4.176.1 to 246.4.183.254246.4.183.2552,046
152246.4.184.0/21246.4.184.1 to 246.4.191.254246.4.191.2552,046
153246.4.192.0/21246.4.192.1 to 246.4.199.254246.4.199.2552,046
154246.4.200.0/21246.4.200.1 to 246.4.207.254246.4.207.2552,046
155246.4.208.0/21246.4.208.1 to 246.4.215.254246.4.215.2552,046
156246.4.216.0/21246.4.216.1 to 246.4.223.254246.4.223.2552,046
157246.4.224.0/21246.4.224.1 to 246.4.231.254246.4.231.2552,046
158246.4.232.0/21246.4.232.1 to 246.4.239.254246.4.239.2552,046
159246.4.240.0/21246.4.240.1 to 246.4.247.254246.4.247.2552,046
160246.4.248.0/21246.4.248.1 to 246.4.255.254246.4.255.2552,046
161246.5.0.0/21246.5.0.1 to 246.5.7.254246.5.7.2552,046
162246.5.8.0/21246.5.8.1 to 246.5.15.254246.5.15.2552,046
163246.5.16.0/21246.5.16.1 to 246.5.23.254246.5.23.2552,046
164246.5.24.0/21246.5.24.1 to 246.5.31.254246.5.31.2552,046
165246.5.32.0/21246.5.32.1 to 246.5.39.254246.5.39.2552,046
166246.5.40.0/21246.5.40.1 to 246.5.47.254246.5.47.2552,046
167246.5.48.0/21246.5.48.1 to 246.5.55.254246.5.55.2552,046
168246.5.56.0/21246.5.56.1 to 246.5.63.254246.5.63.2552,046
169246.5.64.0/21246.5.64.1 to 246.5.71.254246.5.71.2552,046
170246.5.72.0/21246.5.72.1 to 246.5.79.254246.5.79.2552,046
171246.5.80.0/21246.5.80.1 to 246.5.87.254246.5.87.2552,046
172246.5.88.0/21246.5.88.1 to 246.5.95.254246.5.95.2552,046
173246.5.96.0/21246.5.96.1 to 246.5.103.254246.5.103.2552,046
174246.5.104.0/21246.5.104.1 to 246.5.111.254246.5.111.2552,046
175246.5.112.0/21246.5.112.1 to 246.5.119.254246.5.119.2552,046
176246.5.120.0/21246.5.120.1 to 246.5.127.254246.5.127.2552,046
177246.5.128.0/21246.5.128.1 to 246.5.135.254246.5.135.2552,046
178246.5.136.0/21246.5.136.1 to 246.5.143.254246.5.143.2552,046
179246.5.144.0/21246.5.144.1 to 246.5.151.254246.5.151.2552,046
180246.5.152.0/21246.5.152.1 to 246.5.159.254246.5.159.2552,046
181246.5.160.0/21246.5.160.1 to 246.5.167.254246.5.167.2552,046
182246.5.168.0/21246.5.168.1 to 246.5.175.254246.5.175.2552,046
183246.5.176.0/21246.5.176.1 to 246.5.183.254246.5.183.2552,046
184246.5.184.0/21246.5.184.1 to 246.5.191.254246.5.191.2552,046
185246.5.192.0/21246.5.192.1 to 246.5.199.254246.5.199.2552,046
186246.5.200.0/21246.5.200.1 to 246.5.207.254246.5.207.2552,046
187246.5.208.0/21246.5.208.1 to 246.5.215.254246.5.215.2552,046
188246.5.216.0/21246.5.216.1 to 246.5.223.254246.5.223.2552,046
189246.5.224.0/21246.5.224.1 to 246.5.231.254246.5.231.2552,046
190246.5.232.0/21246.5.232.1 to 246.5.239.254246.5.239.2552,046
191246.5.240.0/21246.5.240.1 to 246.5.247.254246.5.247.2552,046
192246.5.248.0/21246.5.248.1 to 246.5.255.254246.5.255.2552,046
193246.6.0.0/21246.6.0.1 to 246.6.7.254246.6.7.2552,046
194246.6.8.0/21246.6.8.1 to 246.6.15.254246.6.15.2552,046
195246.6.16.0/21246.6.16.1 to 246.6.23.254246.6.23.2552,046
196246.6.24.0/21246.6.24.1 to 246.6.31.254246.6.31.2552,046
197246.6.32.0/21246.6.32.1 to 246.6.39.254246.6.39.2552,046
198246.6.40.0/21246.6.40.1 to 246.6.47.254246.6.47.2552,046
199246.6.48.0/21246.6.48.1 to 246.6.55.254246.6.55.2552,046
200246.6.56.0/21246.6.56.1 to 246.6.63.254246.6.63.2552,046
201246.6.64.0/21246.6.64.1 to 246.6.71.254246.6.71.2552,046
202246.6.72.0/21246.6.72.1 to 246.6.79.254246.6.79.2552,046
203246.6.80.0/21246.6.80.1 to 246.6.87.254246.6.87.2552,046
204246.6.88.0/21246.6.88.1 to 246.6.95.254246.6.95.2552,046
205246.6.96.0/21246.6.96.1 to 246.6.103.254246.6.103.2552,046
206246.6.104.0/21246.6.104.1 to 246.6.111.254246.6.111.2552,046
207246.6.112.0/21246.6.112.1 to 246.6.119.254246.6.119.2552,046
208246.6.120.0/21246.6.120.1 to 246.6.127.254246.6.127.2552,046
209246.6.128.0/21246.6.128.1 to 246.6.135.254246.6.135.2552,046
210246.6.136.0/21246.6.136.1 to 246.6.143.254246.6.143.2552,046
211246.6.144.0/21246.6.144.1 to 246.6.151.254246.6.151.2552,046
212246.6.152.0/21246.6.152.1 to 246.6.159.254246.6.159.2552,046
213246.6.160.0/21246.6.160.1 to 246.6.167.254246.6.167.2552,046
214246.6.168.0/21246.6.168.1 to 246.6.175.254246.6.175.2552,046
215246.6.176.0/21246.6.176.1 to 246.6.183.254246.6.183.2552,046
216246.6.184.0/21246.6.184.1 to 246.6.191.254246.6.191.2552,046
217246.6.192.0/21246.6.192.1 to 246.6.199.254246.6.199.2552,046
218246.6.200.0/21246.6.200.1 to 246.6.207.254246.6.207.2552,046
219246.6.208.0/21246.6.208.1 to 246.6.215.254246.6.215.2552,046
220246.6.216.0/21246.6.216.1 to 246.6.223.254246.6.223.2552,046
221246.6.224.0/21246.6.224.1 to 246.6.231.254246.6.231.2552,046
222246.6.232.0/21246.6.232.1 to 246.6.239.254246.6.239.2552,046
223246.6.240.0/21246.6.240.1 to 246.6.247.254246.6.247.2552,046
224246.6.248.0/21246.6.248.1 to 246.6.255.254246.6.255.2552,046
225246.7.0.0/21246.7.0.1 to 246.7.7.254246.7.7.2552,046
226246.7.8.0/21246.7.8.1 to 246.7.15.254246.7.15.2552,046
227246.7.16.0/21246.7.16.1 to 246.7.23.254246.7.23.2552,046
228246.7.24.0/21246.7.24.1 to 246.7.31.254246.7.31.2552,046
229246.7.32.0/21246.7.32.1 to 246.7.39.254246.7.39.2552,046
230246.7.40.0/21246.7.40.1 to 246.7.47.254246.7.47.2552,046
231246.7.48.0/21246.7.48.1 to 246.7.55.254246.7.55.2552,046
232246.7.56.0/21246.7.56.1 to 246.7.63.254246.7.63.2552,046
233246.7.64.0/21246.7.64.1 to 246.7.71.254246.7.71.2552,046
234246.7.72.0/21246.7.72.1 to 246.7.79.254246.7.79.2552,046
235246.7.80.0/21246.7.80.1 to 246.7.87.254246.7.87.2552,046
236246.7.88.0/21246.7.88.1 to 246.7.95.254246.7.95.2552,046
237246.7.96.0/21246.7.96.1 to 246.7.103.254246.7.103.2552,046
238246.7.104.0/21246.7.104.1 to 246.7.111.254246.7.111.2552,046
239246.7.112.0/21246.7.112.1 to 246.7.119.254246.7.119.2552,046
240246.7.120.0/21246.7.120.1 to 246.7.127.254246.7.127.2552,046
241246.7.128.0/21246.7.128.1 to 246.7.135.254246.7.135.2552,046
242246.7.136.0/21246.7.136.1 to 246.7.143.254246.7.143.2552,046
243246.7.144.0/21246.7.144.1 to 246.7.151.254246.7.151.2552,046
244246.7.152.0/21246.7.152.1 to 246.7.159.254246.7.159.2552,046
245246.7.160.0/21246.7.160.1 to 246.7.167.254246.7.167.2552,046
246246.7.168.0/21246.7.168.1 to 246.7.175.254246.7.175.2552,046
247246.7.176.0/21246.7.176.1 to 246.7.183.254246.7.183.2552,046
248246.7.184.0/21246.7.184.1 to 246.7.191.254246.7.191.2552,046
249246.7.192.0/21246.7.192.1 to 246.7.199.254246.7.199.2552,046
250246.7.200.0/21246.7.200.1 to 246.7.207.254246.7.207.2552,046
251246.7.208.0/21246.7.208.1 to 246.7.215.254246.7.215.2552,046
252246.7.216.0/21246.7.216.1 to 246.7.223.254246.7.223.2552,046
253246.7.224.0/21246.7.224.1 to 246.7.231.254246.7.231.2552,046
254246.7.232.0/21246.7.232.1 to 246.7.239.254246.7.239.2552,046
255246.7.240.0/21246.7.240.1 to 246.7.247.254246.7.247.2552,046
256246.7.248.0/21246.7.248.1 to 246.7.255.254246.7.255.2552,046

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.