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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.

Network216.80.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
216.80.0.0
Broadcast address
216.87.255.255
First usable
216.80.0.1
Last usable
216.87.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
C (default /24)
As numbers
Hex D8500000 · Integer 3629121536 to 3629645823
Reverse DNS zones
80.216.in-addr.arpa
81.216.in-addr.arpa
82.216.in-addr.arpa
83.216.in-addr.arpa
84.216.in-addr.arpa
85.216.in-addr.arpa
86.216.in-addr.arpa
87.216.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
Address11011000.01010000.00000000.00000000216.80.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11011000.01010000.00000000.00000000216.80.0.0
Broadcast11011000.01010111.11111111.11111111216.87.255.255
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)

216.80.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1216.80.0.0/21216.80.0.1 to 216.80.7.254216.80.7.2552,046
2216.80.8.0/21216.80.8.1 to 216.80.15.254216.80.15.2552,046
3216.80.16.0/21216.80.16.1 to 216.80.23.254216.80.23.2552,046
4216.80.24.0/21216.80.24.1 to 216.80.31.254216.80.31.2552,046
5216.80.32.0/21216.80.32.1 to 216.80.39.254216.80.39.2552,046
6216.80.40.0/21216.80.40.1 to 216.80.47.254216.80.47.2552,046
7216.80.48.0/21216.80.48.1 to 216.80.55.254216.80.55.2552,046
8216.80.56.0/21216.80.56.1 to 216.80.63.254216.80.63.2552,046
9216.80.64.0/21216.80.64.1 to 216.80.71.254216.80.71.2552,046
10216.80.72.0/21216.80.72.1 to 216.80.79.254216.80.79.2552,046
11216.80.80.0/21216.80.80.1 to 216.80.87.254216.80.87.2552,046
12216.80.88.0/21216.80.88.1 to 216.80.95.254216.80.95.2552,046
13216.80.96.0/21216.80.96.1 to 216.80.103.254216.80.103.2552,046
14216.80.104.0/21216.80.104.1 to 216.80.111.254216.80.111.2552,046
15216.80.112.0/21216.80.112.1 to 216.80.119.254216.80.119.2552,046
16216.80.120.0/21216.80.120.1 to 216.80.127.254216.80.127.2552,046
17216.80.128.0/21216.80.128.1 to 216.80.135.254216.80.135.2552,046
18216.80.136.0/21216.80.136.1 to 216.80.143.254216.80.143.2552,046
19216.80.144.0/21216.80.144.1 to 216.80.151.254216.80.151.2552,046
20216.80.152.0/21216.80.152.1 to 216.80.159.254216.80.159.2552,046
21216.80.160.0/21216.80.160.1 to 216.80.167.254216.80.167.2552,046
22216.80.168.0/21216.80.168.1 to 216.80.175.254216.80.175.2552,046
23216.80.176.0/21216.80.176.1 to 216.80.183.254216.80.183.2552,046
24216.80.184.0/21216.80.184.1 to 216.80.191.254216.80.191.2552,046
25216.80.192.0/21216.80.192.1 to 216.80.199.254216.80.199.2552,046
26216.80.200.0/21216.80.200.1 to 216.80.207.254216.80.207.2552,046
27216.80.208.0/21216.80.208.1 to 216.80.215.254216.80.215.2552,046
28216.80.216.0/21216.80.216.1 to 216.80.223.254216.80.223.2552,046
29216.80.224.0/21216.80.224.1 to 216.80.231.254216.80.231.2552,046
30216.80.232.0/21216.80.232.1 to 216.80.239.254216.80.239.2552,046
31216.80.240.0/21216.80.240.1 to 216.80.247.254216.80.247.2552,046
32216.80.248.0/21216.80.248.1 to 216.80.255.254216.80.255.2552,046
33216.81.0.0/21216.81.0.1 to 216.81.7.254216.81.7.2552,046
34216.81.8.0/21216.81.8.1 to 216.81.15.254216.81.15.2552,046
35216.81.16.0/21216.81.16.1 to 216.81.23.254216.81.23.2552,046
36216.81.24.0/21216.81.24.1 to 216.81.31.254216.81.31.2552,046
37216.81.32.0/21216.81.32.1 to 216.81.39.254216.81.39.2552,046
38216.81.40.0/21216.81.40.1 to 216.81.47.254216.81.47.2552,046
39216.81.48.0/21216.81.48.1 to 216.81.55.254216.81.55.2552,046
40216.81.56.0/21216.81.56.1 to 216.81.63.254216.81.63.2552,046
41216.81.64.0/21216.81.64.1 to 216.81.71.254216.81.71.2552,046
42216.81.72.0/21216.81.72.1 to 216.81.79.254216.81.79.2552,046
43216.81.80.0/21216.81.80.1 to 216.81.87.254216.81.87.2552,046
44216.81.88.0/21216.81.88.1 to 216.81.95.254216.81.95.2552,046
45216.81.96.0/21216.81.96.1 to 216.81.103.254216.81.103.2552,046
46216.81.104.0/21216.81.104.1 to 216.81.111.254216.81.111.2552,046
47216.81.112.0/21216.81.112.1 to 216.81.119.254216.81.119.2552,046
48216.81.120.0/21216.81.120.1 to 216.81.127.254216.81.127.2552,046
49216.81.128.0/21216.81.128.1 to 216.81.135.254216.81.135.2552,046
50216.81.136.0/21216.81.136.1 to 216.81.143.254216.81.143.2552,046
51216.81.144.0/21216.81.144.1 to 216.81.151.254216.81.151.2552,046
52216.81.152.0/21216.81.152.1 to 216.81.159.254216.81.159.2552,046
53216.81.160.0/21216.81.160.1 to 216.81.167.254216.81.167.2552,046
54216.81.168.0/21216.81.168.1 to 216.81.175.254216.81.175.2552,046
55216.81.176.0/21216.81.176.1 to 216.81.183.254216.81.183.2552,046
56216.81.184.0/21216.81.184.1 to 216.81.191.254216.81.191.2552,046
57216.81.192.0/21216.81.192.1 to 216.81.199.254216.81.199.2552,046
58216.81.200.0/21216.81.200.1 to 216.81.207.254216.81.207.2552,046
59216.81.208.0/21216.81.208.1 to 216.81.215.254216.81.215.2552,046
60216.81.216.0/21216.81.216.1 to 216.81.223.254216.81.223.2552,046
61216.81.224.0/21216.81.224.1 to 216.81.231.254216.81.231.2552,046
62216.81.232.0/21216.81.232.1 to 216.81.239.254216.81.239.2552,046
63216.81.240.0/21216.81.240.1 to 216.81.247.254216.81.247.2552,046
64216.81.248.0/21216.81.248.1 to 216.81.255.254216.81.255.2552,046
65216.82.0.0/21216.82.0.1 to 216.82.7.254216.82.7.2552,046
66216.82.8.0/21216.82.8.1 to 216.82.15.254216.82.15.2552,046
67216.82.16.0/21216.82.16.1 to 216.82.23.254216.82.23.2552,046
68216.82.24.0/21216.82.24.1 to 216.82.31.254216.82.31.2552,046
69216.82.32.0/21216.82.32.1 to 216.82.39.254216.82.39.2552,046
70216.82.40.0/21216.82.40.1 to 216.82.47.254216.82.47.2552,046
71216.82.48.0/21216.82.48.1 to 216.82.55.254216.82.55.2552,046
72216.82.56.0/21216.82.56.1 to 216.82.63.254216.82.63.2552,046
73216.82.64.0/21216.82.64.1 to 216.82.71.254216.82.71.2552,046
74216.82.72.0/21216.82.72.1 to 216.82.79.254216.82.79.2552,046
75216.82.80.0/21216.82.80.1 to 216.82.87.254216.82.87.2552,046
76216.82.88.0/21216.82.88.1 to 216.82.95.254216.82.95.2552,046
77216.82.96.0/21216.82.96.1 to 216.82.103.254216.82.103.2552,046
78216.82.104.0/21216.82.104.1 to 216.82.111.254216.82.111.2552,046
79216.82.112.0/21216.82.112.1 to 216.82.119.254216.82.119.2552,046
80216.82.120.0/21216.82.120.1 to 216.82.127.254216.82.127.2552,046
81216.82.128.0/21216.82.128.1 to 216.82.135.254216.82.135.2552,046
82216.82.136.0/21216.82.136.1 to 216.82.143.254216.82.143.2552,046
83216.82.144.0/21216.82.144.1 to 216.82.151.254216.82.151.2552,046
84216.82.152.0/21216.82.152.1 to 216.82.159.254216.82.159.2552,046
85216.82.160.0/21216.82.160.1 to 216.82.167.254216.82.167.2552,046
86216.82.168.0/21216.82.168.1 to 216.82.175.254216.82.175.2552,046
87216.82.176.0/21216.82.176.1 to 216.82.183.254216.82.183.2552,046
88216.82.184.0/21216.82.184.1 to 216.82.191.254216.82.191.2552,046
89216.82.192.0/21216.82.192.1 to 216.82.199.254216.82.199.2552,046
90216.82.200.0/21216.82.200.1 to 216.82.207.254216.82.207.2552,046
91216.82.208.0/21216.82.208.1 to 216.82.215.254216.82.215.2552,046
92216.82.216.0/21216.82.216.1 to 216.82.223.254216.82.223.2552,046
93216.82.224.0/21216.82.224.1 to 216.82.231.254216.82.231.2552,046
94216.82.232.0/21216.82.232.1 to 216.82.239.254216.82.239.2552,046
95216.82.240.0/21216.82.240.1 to 216.82.247.254216.82.247.2552,046
96216.82.248.0/21216.82.248.1 to 216.82.255.254216.82.255.2552,046
97216.83.0.0/21216.83.0.1 to 216.83.7.254216.83.7.2552,046
98216.83.8.0/21216.83.8.1 to 216.83.15.254216.83.15.2552,046
99216.83.16.0/21216.83.16.1 to 216.83.23.254216.83.23.2552,046
100216.83.24.0/21216.83.24.1 to 216.83.31.254216.83.31.2552,046
101216.83.32.0/21216.83.32.1 to 216.83.39.254216.83.39.2552,046
102216.83.40.0/21216.83.40.1 to 216.83.47.254216.83.47.2552,046
103216.83.48.0/21216.83.48.1 to 216.83.55.254216.83.55.2552,046
104216.83.56.0/21216.83.56.1 to 216.83.63.254216.83.63.2552,046
105216.83.64.0/21216.83.64.1 to 216.83.71.254216.83.71.2552,046
106216.83.72.0/21216.83.72.1 to 216.83.79.254216.83.79.2552,046
107216.83.80.0/21216.83.80.1 to 216.83.87.254216.83.87.2552,046
108216.83.88.0/21216.83.88.1 to 216.83.95.254216.83.95.2552,046
109216.83.96.0/21216.83.96.1 to 216.83.103.254216.83.103.2552,046
110216.83.104.0/21216.83.104.1 to 216.83.111.254216.83.111.2552,046
111216.83.112.0/21216.83.112.1 to 216.83.119.254216.83.119.2552,046
112216.83.120.0/21216.83.120.1 to 216.83.127.254216.83.127.2552,046
113216.83.128.0/21216.83.128.1 to 216.83.135.254216.83.135.2552,046
114216.83.136.0/21216.83.136.1 to 216.83.143.254216.83.143.2552,046
115216.83.144.0/21216.83.144.1 to 216.83.151.254216.83.151.2552,046
116216.83.152.0/21216.83.152.1 to 216.83.159.254216.83.159.2552,046
117216.83.160.0/21216.83.160.1 to 216.83.167.254216.83.167.2552,046
118216.83.168.0/21216.83.168.1 to 216.83.175.254216.83.175.2552,046
119216.83.176.0/21216.83.176.1 to 216.83.183.254216.83.183.2552,046
120216.83.184.0/21216.83.184.1 to 216.83.191.254216.83.191.2552,046
121216.83.192.0/21216.83.192.1 to 216.83.199.254216.83.199.2552,046
122216.83.200.0/21216.83.200.1 to 216.83.207.254216.83.207.2552,046
123216.83.208.0/21216.83.208.1 to 216.83.215.254216.83.215.2552,046
124216.83.216.0/21216.83.216.1 to 216.83.223.254216.83.223.2552,046
125216.83.224.0/21216.83.224.1 to 216.83.231.254216.83.231.2552,046
126216.83.232.0/21216.83.232.1 to 216.83.239.254216.83.239.2552,046
127216.83.240.0/21216.83.240.1 to 216.83.247.254216.83.247.2552,046
128216.83.248.0/21216.83.248.1 to 216.83.255.254216.83.255.2552,046
129216.84.0.0/21216.84.0.1 to 216.84.7.254216.84.7.2552,046
130216.84.8.0/21216.84.8.1 to 216.84.15.254216.84.15.2552,046
131216.84.16.0/21216.84.16.1 to 216.84.23.254216.84.23.2552,046
132216.84.24.0/21216.84.24.1 to 216.84.31.254216.84.31.2552,046
133216.84.32.0/21216.84.32.1 to 216.84.39.254216.84.39.2552,046
134216.84.40.0/21216.84.40.1 to 216.84.47.254216.84.47.2552,046
135216.84.48.0/21216.84.48.1 to 216.84.55.254216.84.55.2552,046
136216.84.56.0/21216.84.56.1 to 216.84.63.254216.84.63.2552,046
137216.84.64.0/21216.84.64.1 to 216.84.71.254216.84.71.2552,046
138216.84.72.0/21216.84.72.1 to 216.84.79.254216.84.79.2552,046
139216.84.80.0/21216.84.80.1 to 216.84.87.254216.84.87.2552,046
140216.84.88.0/21216.84.88.1 to 216.84.95.254216.84.95.2552,046
141216.84.96.0/21216.84.96.1 to 216.84.103.254216.84.103.2552,046
142216.84.104.0/21216.84.104.1 to 216.84.111.254216.84.111.2552,046
143216.84.112.0/21216.84.112.1 to 216.84.119.254216.84.119.2552,046
144216.84.120.0/21216.84.120.1 to 216.84.127.254216.84.127.2552,046
145216.84.128.0/21216.84.128.1 to 216.84.135.254216.84.135.2552,046
146216.84.136.0/21216.84.136.1 to 216.84.143.254216.84.143.2552,046
147216.84.144.0/21216.84.144.1 to 216.84.151.254216.84.151.2552,046
148216.84.152.0/21216.84.152.1 to 216.84.159.254216.84.159.2552,046
149216.84.160.0/21216.84.160.1 to 216.84.167.254216.84.167.2552,046
150216.84.168.0/21216.84.168.1 to 216.84.175.254216.84.175.2552,046
151216.84.176.0/21216.84.176.1 to 216.84.183.254216.84.183.2552,046
152216.84.184.0/21216.84.184.1 to 216.84.191.254216.84.191.2552,046
153216.84.192.0/21216.84.192.1 to 216.84.199.254216.84.199.2552,046
154216.84.200.0/21216.84.200.1 to 216.84.207.254216.84.207.2552,046
155216.84.208.0/21216.84.208.1 to 216.84.215.254216.84.215.2552,046
156216.84.216.0/21216.84.216.1 to 216.84.223.254216.84.223.2552,046
157216.84.224.0/21216.84.224.1 to 216.84.231.254216.84.231.2552,046
158216.84.232.0/21216.84.232.1 to 216.84.239.254216.84.239.2552,046
159216.84.240.0/21216.84.240.1 to 216.84.247.254216.84.247.2552,046
160216.84.248.0/21216.84.248.1 to 216.84.255.254216.84.255.2552,046
161216.85.0.0/21216.85.0.1 to 216.85.7.254216.85.7.2552,046
162216.85.8.0/21216.85.8.1 to 216.85.15.254216.85.15.2552,046
163216.85.16.0/21216.85.16.1 to 216.85.23.254216.85.23.2552,046
164216.85.24.0/21216.85.24.1 to 216.85.31.254216.85.31.2552,046
165216.85.32.0/21216.85.32.1 to 216.85.39.254216.85.39.2552,046
166216.85.40.0/21216.85.40.1 to 216.85.47.254216.85.47.2552,046
167216.85.48.0/21216.85.48.1 to 216.85.55.254216.85.55.2552,046
168216.85.56.0/21216.85.56.1 to 216.85.63.254216.85.63.2552,046
169216.85.64.0/21216.85.64.1 to 216.85.71.254216.85.71.2552,046
170216.85.72.0/21216.85.72.1 to 216.85.79.254216.85.79.2552,046
171216.85.80.0/21216.85.80.1 to 216.85.87.254216.85.87.2552,046
172216.85.88.0/21216.85.88.1 to 216.85.95.254216.85.95.2552,046
173216.85.96.0/21216.85.96.1 to 216.85.103.254216.85.103.2552,046
174216.85.104.0/21216.85.104.1 to 216.85.111.254216.85.111.2552,046
175216.85.112.0/21216.85.112.1 to 216.85.119.254216.85.119.2552,046
176216.85.120.0/21216.85.120.1 to 216.85.127.254216.85.127.2552,046
177216.85.128.0/21216.85.128.1 to 216.85.135.254216.85.135.2552,046
178216.85.136.0/21216.85.136.1 to 216.85.143.254216.85.143.2552,046
179216.85.144.0/21216.85.144.1 to 216.85.151.254216.85.151.2552,046
180216.85.152.0/21216.85.152.1 to 216.85.159.254216.85.159.2552,046
181216.85.160.0/21216.85.160.1 to 216.85.167.254216.85.167.2552,046
182216.85.168.0/21216.85.168.1 to 216.85.175.254216.85.175.2552,046
183216.85.176.0/21216.85.176.1 to 216.85.183.254216.85.183.2552,046
184216.85.184.0/21216.85.184.1 to 216.85.191.254216.85.191.2552,046
185216.85.192.0/21216.85.192.1 to 216.85.199.254216.85.199.2552,046
186216.85.200.0/21216.85.200.1 to 216.85.207.254216.85.207.2552,046
187216.85.208.0/21216.85.208.1 to 216.85.215.254216.85.215.2552,046
188216.85.216.0/21216.85.216.1 to 216.85.223.254216.85.223.2552,046
189216.85.224.0/21216.85.224.1 to 216.85.231.254216.85.231.2552,046
190216.85.232.0/21216.85.232.1 to 216.85.239.254216.85.239.2552,046
191216.85.240.0/21216.85.240.1 to 216.85.247.254216.85.247.2552,046
192216.85.248.0/21216.85.248.1 to 216.85.255.254216.85.255.2552,046
193216.86.0.0/21216.86.0.1 to 216.86.7.254216.86.7.2552,046
194216.86.8.0/21216.86.8.1 to 216.86.15.254216.86.15.2552,046
195216.86.16.0/21216.86.16.1 to 216.86.23.254216.86.23.2552,046
196216.86.24.0/21216.86.24.1 to 216.86.31.254216.86.31.2552,046
197216.86.32.0/21216.86.32.1 to 216.86.39.254216.86.39.2552,046
198216.86.40.0/21216.86.40.1 to 216.86.47.254216.86.47.2552,046
199216.86.48.0/21216.86.48.1 to 216.86.55.254216.86.55.2552,046
200216.86.56.0/21216.86.56.1 to 216.86.63.254216.86.63.2552,046
201216.86.64.0/21216.86.64.1 to 216.86.71.254216.86.71.2552,046
202216.86.72.0/21216.86.72.1 to 216.86.79.254216.86.79.2552,046
203216.86.80.0/21216.86.80.1 to 216.86.87.254216.86.87.2552,046
204216.86.88.0/21216.86.88.1 to 216.86.95.254216.86.95.2552,046
205216.86.96.0/21216.86.96.1 to 216.86.103.254216.86.103.2552,046
206216.86.104.0/21216.86.104.1 to 216.86.111.254216.86.111.2552,046
207216.86.112.0/21216.86.112.1 to 216.86.119.254216.86.119.2552,046
208216.86.120.0/21216.86.120.1 to 216.86.127.254216.86.127.2552,046
209216.86.128.0/21216.86.128.1 to 216.86.135.254216.86.135.2552,046
210216.86.136.0/21216.86.136.1 to 216.86.143.254216.86.143.2552,046
211216.86.144.0/21216.86.144.1 to 216.86.151.254216.86.151.2552,046
212216.86.152.0/21216.86.152.1 to 216.86.159.254216.86.159.2552,046
213216.86.160.0/21216.86.160.1 to 216.86.167.254216.86.167.2552,046
214216.86.168.0/21216.86.168.1 to 216.86.175.254216.86.175.2552,046
215216.86.176.0/21216.86.176.1 to 216.86.183.254216.86.183.2552,046
216216.86.184.0/21216.86.184.1 to 216.86.191.254216.86.191.2552,046
217216.86.192.0/21216.86.192.1 to 216.86.199.254216.86.199.2552,046
218216.86.200.0/21216.86.200.1 to 216.86.207.254216.86.207.2552,046
219216.86.208.0/21216.86.208.1 to 216.86.215.254216.86.215.2552,046
220216.86.216.0/21216.86.216.1 to 216.86.223.254216.86.223.2552,046
221216.86.224.0/21216.86.224.1 to 216.86.231.254216.86.231.2552,046
222216.86.232.0/21216.86.232.1 to 216.86.239.254216.86.239.2552,046
223216.86.240.0/21216.86.240.1 to 216.86.247.254216.86.247.2552,046
224216.86.248.0/21216.86.248.1 to 216.86.255.254216.86.255.2552,046
225216.87.0.0/21216.87.0.1 to 216.87.7.254216.87.7.2552,046
226216.87.8.0/21216.87.8.1 to 216.87.15.254216.87.15.2552,046
227216.87.16.0/21216.87.16.1 to 216.87.23.254216.87.23.2552,046
228216.87.24.0/21216.87.24.1 to 216.87.31.254216.87.31.2552,046
229216.87.32.0/21216.87.32.1 to 216.87.39.254216.87.39.2552,046
230216.87.40.0/21216.87.40.1 to 216.87.47.254216.87.47.2552,046
231216.87.48.0/21216.87.48.1 to 216.87.55.254216.87.55.2552,046
232216.87.56.0/21216.87.56.1 to 216.87.63.254216.87.63.2552,046
233216.87.64.0/21216.87.64.1 to 216.87.71.254216.87.71.2552,046
234216.87.72.0/21216.87.72.1 to 216.87.79.254216.87.79.2552,046
235216.87.80.0/21216.87.80.1 to 216.87.87.254216.87.87.2552,046
236216.87.88.0/21216.87.88.1 to 216.87.95.254216.87.95.2552,046
237216.87.96.0/21216.87.96.1 to 216.87.103.254216.87.103.2552,046
238216.87.104.0/21216.87.104.1 to 216.87.111.254216.87.111.2552,046
239216.87.112.0/21216.87.112.1 to 216.87.119.254216.87.119.2552,046
240216.87.120.0/21216.87.120.1 to 216.87.127.254216.87.127.2552,046
241216.87.128.0/21216.87.128.1 to 216.87.135.254216.87.135.2552,046
242216.87.136.0/21216.87.136.1 to 216.87.143.254216.87.143.2552,046
243216.87.144.0/21216.87.144.1 to 216.87.151.254216.87.151.2552,046
244216.87.152.0/21216.87.152.1 to 216.87.159.254216.87.159.2552,046
245216.87.160.0/21216.87.160.1 to 216.87.167.254216.87.167.2552,046
246216.87.168.0/21216.87.168.1 to 216.87.175.254216.87.175.2552,046
247216.87.176.0/21216.87.176.1 to 216.87.183.254216.87.183.2552,046
248216.87.184.0/21216.87.184.1 to 216.87.191.254216.87.191.2552,046
249216.87.192.0/21216.87.192.1 to 216.87.199.254216.87.199.2552,046
250216.87.200.0/21216.87.200.1 to 216.87.207.254216.87.207.2552,046
251216.87.208.0/21216.87.208.1 to 216.87.215.254216.87.215.2552,046
252216.87.216.0/21216.87.216.1 to 216.87.223.254216.87.223.2552,046
253216.87.224.0/21216.87.224.1 to 216.87.231.254216.87.231.2552,046
254216.87.232.0/21216.87.232.1 to 216.87.239.254216.87.239.2552,046
255216.87.240.0/21216.87.240.1 to 216.87.247.254216.87.247.2552,046
256216.87.248.0/21216.87.248.1 to 216.87.255.254216.87.255.2552,046

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.