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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.

Network87.82.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
87.82.0.0
Broadcast address
87.83.255.255
First usable
87.82.0.1
Last usable
87.83.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 57520000 · Integer 1464991744 to 1465122815
Reverse DNS zones
82.87.in-addr.arpa
83.87.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010111.01010010.00000000.0000000087.82.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01010111.01010010.00000000.0000000087.82.0.0
Broadcast01010111.01010011.11111111.1111111187.83.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

87.82.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.82.0.0/2587.82.0.1 to 87.82.0.12687.82.0.127126
287.82.0.128/2587.82.0.129 to 87.82.0.25487.82.0.255126
387.82.1.0/2587.82.1.1 to 87.82.1.12687.82.1.127126
487.82.1.128/2587.82.1.129 to 87.82.1.25487.82.1.255126
587.82.2.0/2587.82.2.1 to 87.82.2.12687.82.2.127126
687.82.2.128/2587.82.2.129 to 87.82.2.25487.82.2.255126
787.82.3.0/2587.82.3.1 to 87.82.3.12687.82.3.127126
887.82.3.128/2587.82.3.129 to 87.82.3.25487.82.3.255126
987.82.4.0/2587.82.4.1 to 87.82.4.12687.82.4.127126
1087.82.4.128/2587.82.4.129 to 87.82.4.25487.82.4.255126
1187.82.5.0/2587.82.5.1 to 87.82.5.12687.82.5.127126
1287.82.5.128/2587.82.5.129 to 87.82.5.25487.82.5.255126
1387.82.6.0/2587.82.6.1 to 87.82.6.12687.82.6.127126
1487.82.6.128/2587.82.6.129 to 87.82.6.25487.82.6.255126
1587.82.7.0/2587.82.7.1 to 87.82.7.12687.82.7.127126
1687.82.7.128/2587.82.7.129 to 87.82.7.25487.82.7.255126
1787.82.8.0/2587.82.8.1 to 87.82.8.12687.82.8.127126
1887.82.8.128/2587.82.8.129 to 87.82.8.25487.82.8.255126
1987.82.9.0/2587.82.9.1 to 87.82.9.12687.82.9.127126
2087.82.9.128/2587.82.9.129 to 87.82.9.25487.82.9.255126
2187.82.10.0/2587.82.10.1 to 87.82.10.12687.82.10.127126
2287.82.10.128/2587.82.10.129 to 87.82.10.25487.82.10.255126
2387.82.11.0/2587.82.11.1 to 87.82.11.12687.82.11.127126
2487.82.11.128/2587.82.11.129 to 87.82.11.25487.82.11.255126
2587.82.12.0/2587.82.12.1 to 87.82.12.12687.82.12.127126
2687.82.12.128/2587.82.12.129 to 87.82.12.25487.82.12.255126
2787.82.13.0/2587.82.13.1 to 87.82.13.12687.82.13.127126
2887.82.13.128/2587.82.13.129 to 87.82.13.25487.82.13.255126
2987.82.14.0/2587.82.14.1 to 87.82.14.12687.82.14.127126
3087.82.14.128/2587.82.14.129 to 87.82.14.25487.82.14.255126
3187.82.15.0/2587.82.15.1 to 87.82.15.12687.82.15.127126
3287.82.15.128/2587.82.15.129 to 87.82.15.25487.82.15.255126
3387.82.16.0/2587.82.16.1 to 87.82.16.12687.82.16.127126
3487.82.16.128/2587.82.16.129 to 87.82.16.25487.82.16.255126
3587.82.17.0/2587.82.17.1 to 87.82.17.12687.82.17.127126
3687.82.17.128/2587.82.17.129 to 87.82.17.25487.82.17.255126
3787.82.18.0/2587.82.18.1 to 87.82.18.12687.82.18.127126
3887.82.18.128/2587.82.18.129 to 87.82.18.25487.82.18.255126
3987.82.19.0/2587.82.19.1 to 87.82.19.12687.82.19.127126
4087.82.19.128/2587.82.19.129 to 87.82.19.25487.82.19.255126
4187.82.20.0/2587.82.20.1 to 87.82.20.12687.82.20.127126
4287.82.20.128/2587.82.20.129 to 87.82.20.25487.82.20.255126
4387.82.21.0/2587.82.21.1 to 87.82.21.12687.82.21.127126
4487.82.21.128/2587.82.21.129 to 87.82.21.25487.82.21.255126
4587.82.22.0/2587.82.22.1 to 87.82.22.12687.82.22.127126
4687.82.22.128/2587.82.22.129 to 87.82.22.25487.82.22.255126
4787.82.23.0/2587.82.23.1 to 87.82.23.12687.82.23.127126
4887.82.23.128/2587.82.23.129 to 87.82.23.25487.82.23.255126
4987.82.24.0/2587.82.24.1 to 87.82.24.12687.82.24.127126
5087.82.24.128/2587.82.24.129 to 87.82.24.25487.82.24.255126
5187.82.25.0/2587.82.25.1 to 87.82.25.12687.82.25.127126
5287.82.25.128/2587.82.25.129 to 87.82.25.25487.82.25.255126
5387.82.26.0/2587.82.26.1 to 87.82.26.12687.82.26.127126
5487.82.26.128/2587.82.26.129 to 87.82.26.25487.82.26.255126
5587.82.27.0/2587.82.27.1 to 87.82.27.12687.82.27.127126
5687.82.27.128/2587.82.27.129 to 87.82.27.25487.82.27.255126
5787.82.28.0/2587.82.28.1 to 87.82.28.12687.82.28.127126
5887.82.28.128/2587.82.28.129 to 87.82.28.25487.82.28.255126
5987.82.29.0/2587.82.29.1 to 87.82.29.12687.82.29.127126
6087.82.29.128/2587.82.29.129 to 87.82.29.25487.82.29.255126
6187.82.30.0/2587.82.30.1 to 87.82.30.12687.82.30.127126
6287.82.30.128/2587.82.30.129 to 87.82.30.25487.82.30.255126
6387.82.31.0/2587.82.31.1 to 87.82.31.12687.82.31.127126
6487.82.31.128/2587.82.31.129 to 87.82.31.25487.82.31.255126
6587.82.32.0/2587.82.32.1 to 87.82.32.12687.82.32.127126
6687.82.32.128/2587.82.32.129 to 87.82.32.25487.82.32.255126
6787.82.33.0/2587.82.33.1 to 87.82.33.12687.82.33.127126
6887.82.33.128/2587.82.33.129 to 87.82.33.25487.82.33.255126
6987.82.34.0/2587.82.34.1 to 87.82.34.12687.82.34.127126
7087.82.34.128/2587.82.34.129 to 87.82.34.25487.82.34.255126
7187.82.35.0/2587.82.35.1 to 87.82.35.12687.82.35.127126
7287.82.35.128/2587.82.35.129 to 87.82.35.25487.82.35.255126
7387.82.36.0/2587.82.36.1 to 87.82.36.12687.82.36.127126
7487.82.36.128/2587.82.36.129 to 87.82.36.25487.82.36.255126
7587.82.37.0/2587.82.37.1 to 87.82.37.12687.82.37.127126
7687.82.37.128/2587.82.37.129 to 87.82.37.25487.82.37.255126
7787.82.38.0/2587.82.38.1 to 87.82.38.12687.82.38.127126
7887.82.38.128/2587.82.38.129 to 87.82.38.25487.82.38.255126
7987.82.39.0/2587.82.39.1 to 87.82.39.12687.82.39.127126
8087.82.39.128/2587.82.39.129 to 87.82.39.25487.82.39.255126
8187.82.40.0/2587.82.40.1 to 87.82.40.12687.82.40.127126
8287.82.40.128/2587.82.40.129 to 87.82.40.25487.82.40.255126
8387.82.41.0/2587.82.41.1 to 87.82.41.12687.82.41.127126
8487.82.41.128/2587.82.41.129 to 87.82.41.25487.82.41.255126
8587.82.42.0/2587.82.42.1 to 87.82.42.12687.82.42.127126
8687.82.42.128/2587.82.42.129 to 87.82.42.25487.82.42.255126
8787.82.43.0/2587.82.43.1 to 87.82.43.12687.82.43.127126
8887.82.43.128/2587.82.43.129 to 87.82.43.25487.82.43.255126
8987.82.44.0/2587.82.44.1 to 87.82.44.12687.82.44.127126
9087.82.44.128/2587.82.44.129 to 87.82.44.25487.82.44.255126
9187.82.45.0/2587.82.45.1 to 87.82.45.12687.82.45.127126
9287.82.45.128/2587.82.45.129 to 87.82.45.25487.82.45.255126
9387.82.46.0/2587.82.46.1 to 87.82.46.12687.82.46.127126
9487.82.46.128/2587.82.46.129 to 87.82.46.25487.82.46.255126
9587.82.47.0/2587.82.47.1 to 87.82.47.12687.82.47.127126
9687.82.47.128/2587.82.47.129 to 87.82.47.25487.82.47.255126
9787.82.48.0/2587.82.48.1 to 87.82.48.12687.82.48.127126
9887.82.48.128/2587.82.48.129 to 87.82.48.25487.82.48.255126
9987.82.49.0/2587.82.49.1 to 87.82.49.12687.82.49.127126
10087.82.49.128/2587.82.49.129 to 87.82.49.25487.82.49.255126
10187.82.50.0/2587.82.50.1 to 87.82.50.12687.82.50.127126
10287.82.50.128/2587.82.50.129 to 87.82.50.25487.82.50.255126
10387.82.51.0/2587.82.51.1 to 87.82.51.12687.82.51.127126
10487.82.51.128/2587.82.51.129 to 87.82.51.25487.82.51.255126
10587.82.52.0/2587.82.52.1 to 87.82.52.12687.82.52.127126
10687.82.52.128/2587.82.52.129 to 87.82.52.25487.82.52.255126
10787.82.53.0/2587.82.53.1 to 87.82.53.12687.82.53.127126
10887.82.53.128/2587.82.53.129 to 87.82.53.25487.82.53.255126
10987.82.54.0/2587.82.54.1 to 87.82.54.12687.82.54.127126
11087.82.54.128/2587.82.54.129 to 87.82.54.25487.82.54.255126
11187.82.55.0/2587.82.55.1 to 87.82.55.12687.82.55.127126
11287.82.55.128/2587.82.55.129 to 87.82.55.25487.82.55.255126
11387.82.56.0/2587.82.56.1 to 87.82.56.12687.82.56.127126
11487.82.56.128/2587.82.56.129 to 87.82.56.25487.82.56.255126
11587.82.57.0/2587.82.57.1 to 87.82.57.12687.82.57.127126
11687.82.57.128/2587.82.57.129 to 87.82.57.25487.82.57.255126
11787.82.58.0/2587.82.58.1 to 87.82.58.12687.82.58.127126
11887.82.58.128/2587.82.58.129 to 87.82.58.25487.82.58.255126
11987.82.59.0/2587.82.59.1 to 87.82.59.12687.82.59.127126
12087.82.59.128/2587.82.59.129 to 87.82.59.25487.82.59.255126
12187.82.60.0/2587.82.60.1 to 87.82.60.12687.82.60.127126
12287.82.60.128/2587.82.60.129 to 87.82.60.25487.82.60.255126
12387.82.61.0/2587.82.61.1 to 87.82.61.12687.82.61.127126
12487.82.61.128/2587.82.61.129 to 87.82.61.25487.82.61.255126
12587.82.62.0/2587.82.62.1 to 87.82.62.12687.82.62.127126
12687.82.62.128/2587.82.62.129 to 87.82.62.25487.82.62.255126
12787.82.63.0/2587.82.63.1 to 87.82.63.12687.82.63.127126
12887.82.63.128/2587.82.63.129 to 87.82.63.25487.82.63.255126
12987.82.64.0/2587.82.64.1 to 87.82.64.12687.82.64.127126
13087.82.64.128/2587.82.64.129 to 87.82.64.25487.82.64.255126
13187.82.65.0/2587.82.65.1 to 87.82.65.12687.82.65.127126
13287.82.65.128/2587.82.65.129 to 87.82.65.25487.82.65.255126
13387.82.66.0/2587.82.66.1 to 87.82.66.12687.82.66.127126
13487.82.66.128/2587.82.66.129 to 87.82.66.25487.82.66.255126
13587.82.67.0/2587.82.67.1 to 87.82.67.12687.82.67.127126
13687.82.67.128/2587.82.67.129 to 87.82.67.25487.82.67.255126
13787.82.68.0/2587.82.68.1 to 87.82.68.12687.82.68.127126
13887.82.68.128/2587.82.68.129 to 87.82.68.25487.82.68.255126
13987.82.69.0/2587.82.69.1 to 87.82.69.12687.82.69.127126
14087.82.69.128/2587.82.69.129 to 87.82.69.25487.82.69.255126
14187.82.70.0/2587.82.70.1 to 87.82.70.12687.82.70.127126
14287.82.70.128/2587.82.70.129 to 87.82.70.25487.82.70.255126
14387.82.71.0/2587.82.71.1 to 87.82.71.12687.82.71.127126
14487.82.71.128/2587.82.71.129 to 87.82.71.25487.82.71.255126
14587.82.72.0/2587.82.72.1 to 87.82.72.12687.82.72.127126
14687.82.72.128/2587.82.72.129 to 87.82.72.25487.82.72.255126
14787.82.73.0/2587.82.73.1 to 87.82.73.12687.82.73.127126
14887.82.73.128/2587.82.73.129 to 87.82.73.25487.82.73.255126
14987.82.74.0/2587.82.74.1 to 87.82.74.12687.82.74.127126
15087.82.74.128/2587.82.74.129 to 87.82.74.25487.82.74.255126
15187.82.75.0/2587.82.75.1 to 87.82.75.12687.82.75.127126
15287.82.75.128/2587.82.75.129 to 87.82.75.25487.82.75.255126
15387.82.76.0/2587.82.76.1 to 87.82.76.12687.82.76.127126
15487.82.76.128/2587.82.76.129 to 87.82.76.25487.82.76.255126
15587.82.77.0/2587.82.77.1 to 87.82.77.12687.82.77.127126
15687.82.77.128/2587.82.77.129 to 87.82.77.25487.82.77.255126
15787.82.78.0/2587.82.78.1 to 87.82.78.12687.82.78.127126
15887.82.78.128/2587.82.78.129 to 87.82.78.25487.82.78.255126
15987.82.79.0/2587.82.79.1 to 87.82.79.12687.82.79.127126
16087.82.79.128/2587.82.79.129 to 87.82.79.25487.82.79.255126
16187.82.80.0/2587.82.80.1 to 87.82.80.12687.82.80.127126
16287.82.80.128/2587.82.80.129 to 87.82.80.25487.82.80.255126
16387.82.81.0/2587.82.81.1 to 87.82.81.12687.82.81.127126
16487.82.81.128/2587.82.81.129 to 87.82.81.25487.82.81.255126
16587.82.82.0/2587.82.82.1 to 87.82.82.12687.82.82.127126
16687.82.82.128/2587.82.82.129 to 87.82.82.25487.82.82.255126
16787.82.83.0/2587.82.83.1 to 87.82.83.12687.82.83.127126
16887.82.83.128/2587.82.83.129 to 87.82.83.25487.82.83.255126
16987.82.84.0/2587.82.84.1 to 87.82.84.12687.82.84.127126
17087.82.84.128/2587.82.84.129 to 87.82.84.25487.82.84.255126
17187.82.85.0/2587.82.85.1 to 87.82.85.12687.82.85.127126
17287.82.85.128/2587.82.85.129 to 87.82.85.25487.82.85.255126
17387.82.86.0/2587.82.86.1 to 87.82.86.12687.82.86.127126
17487.82.86.128/2587.82.86.129 to 87.82.86.25487.82.86.255126
17587.82.87.0/2587.82.87.1 to 87.82.87.12687.82.87.127126
17687.82.87.128/2587.82.87.129 to 87.82.87.25487.82.87.255126
17787.82.88.0/2587.82.88.1 to 87.82.88.12687.82.88.127126
17887.82.88.128/2587.82.88.129 to 87.82.88.25487.82.88.255126
17987.82.89.0/2587.82.89.1 to 87.82.89.12687.82.89.127126
18087.82.89.128/2587.82.89.129 to 87.82.89.25487.82.89.255126
18187.82.90.0/2587.82.90.1 to 87.82.90.12687.82.90.127126
18287.82.90.128/2587.82.90.129 to 87.82.90.25487.82.90.255126
18387.82.91.0/2587.82.91.1 to 87.82.91.12687.82.91.127126
18487.82.91.128/2587.82.91.129 to 87.82.91.25487.82.91.255126
18587.82.92.0/2587.82.92.1 to 87.82.92.12687.82.92.127126
18687.82.92.128/2587.82.92.129 to 87.82.92.25487.82.92.255126
18787.82.93.0/2587.82.93.1 to 87.82.93.12687.82.93.127126
18887.82.93.128/2587.82.93.129 to 87.82.93.25487.82.93.255126
18987.82.94.0/2587.82.94.1 to 87.82.94.12687.82.94.127126
19087.82.94.128/2587.82.94.129 to 87.82.94.25487.82.94.255126
19187.82.95.0/2587.82.95.1 to 87.82.95.12687.82.95.127126
19287.82.95.128/2587.82.95.129 to 87.82.95.25487.82.95.255126
19387.82.96.0/2587.82.96.1 to 87.82.96.12687.82.96.127126
19487.82.96.128/2587.82.96.129 to 87.82.96.25487.82.96.255126
19587.82.97.0/2587.82.97.1 to 87.82.97.12687.82.97.127126
19687.82.97.128/2587.82.97.129 to 87.82.97.25487.82.97.255126
19787.82.98.0/2587.82.98.1 to 87.82.98.12687.82.98.127126
19887.82.98.128/2587.82.98.129 to 87.82.98.25487.82.98.255126
19987.82.99.0/2587.82.99.1 to 87.82.99.12687.82.99.127126
20087.82.99.128/2587.82.99.129 to 87.82.99.25487.82.99.255126
20187.82.100.0/2587.82.100.1 to 87.82.100.12687.82.100.127126
20287.82.100.128/2587.82.100.129 to 87.82.100.25487.82.100.255126
20387.82.101.0/2587.82.101.1 to 87.82.101.12687.82.101.127126
20487.82.101.128/2587.82.101.129 to 87.82.101.25487.82.101.255126
20587.82.102.0/2587.82.102.1 to 87.82.102.12687.82.102.127126
20687.82.102.128/2587.82.102.129 to 87.82.102.25487.82.102.255126
20787.82.103.0/2587.82.103.1 to 87.82.103.12687.82.103.127126
20887.82.103.128/2587.82.103.129 to 87.82.103.25487.82.103.255126
20987.82.104.0/2587.82.104.1 to 87.82.104.12687.82.104.127126
21087.82.104.128/2587.82.104.129 to 87.82.104.25487.82.104.255126
21187.82.105.0/2587.82.105.1 to 87.82.105.12687.82.105.127126
21287.82.105.128/2587.82.105.129 to 87.82.105.25487.82.105.255126
21387.82.106.0/2587.82.106.1 to 87.82.106.12687.82.106.127126
21487.82.106.128/2587.82.106.129 to 87.82.106.25487.82.106.255126
21587.82.107.0/2587.82.107.1 to 87.82.107.12687.82.107.127126
21687.82.107.128/2587.82.107.129 to 87.82.107.25487.82.107.255126
21787.82.108.0/2587.82.108.1 to 87.82.108.12687.82.108.127126
21887.82.108.128/2587.82.108.129 to 87.82.108.25487.82.108.255126
21987.82.109.0/2587.82.109.1 to 87.82.109.12687.82.109.127126
22087.82.109.128/2587.82.109.129 to 87.82.109.25487.82.109.255126
22187.82.110.0/2587.82.110.1 to 87.82.110.12687.82.110.127126
22287.82.110.128/2587.82.110.129 to 87.82.110.25487.82.110.255126
22387.82.111.0/2587.82.111.1 to 87.82.111.12687.82.111.127126
22487.82.111.128/2587.82.111.129 to 87.82.111.25487.82.111.255126
22587.82.112.0/2587.82.112.1 to 87.82.112.12687.82.112.127126
22687.82.112.128/2587.82.112.129 to 87.82.112.25487.82.112.255126
22787.82.113.0/2587.82.113.1 to 87.82.113.12687.82.113.127126
22887.82.113.128/2587.82.113.129 to 87.82.113.25487.82.113.255126
22987.82.114.0/2587.82.114.1 to 87.82.114.12687.82.114.127126
23087.82.114.128/2587.82.114.129 to 87.82.114.25487.82.114.255126
23187.82.115.0/2587.82.115.1 to 87.82.115.12687.82.115.127126
23287.82.115.128/2587.82.115.129 to 87.82.115.25487.82.115.255126
23387.82.116.0/2587.82.116.1 to 87.82.116.12687.82.116.127126
23487.82.116.128/2587.82.116.129 to 87.82.116.25487.82.116.255126
23587.82.117.0/2587.82.117.1 to 87.82.117.12687.82.117.127126
23687.82.117.128/2587.82.117.129 to 87.82.117.25487.82.117.255126
23787.82.118.0/2587.82.118.1 to 87.82.118.12687.82.118.127126
23887.82.118.128/2587.82.118.129 to 87.82.118.25487.82.118.255126
23987.82.119.0/2587.82.119.1 to 87.82.119.12687.82.119.127126
24087.82.119.128/2587.82.119.129 to 87.82.119.25487.82.119.255126
24187.82.120.0/2587.82.120.1 to 87.82.120.12687.82.120.127126
24287.82.120.128/2587.82.120.129 to 87.82.120.25487.82.120.255126
24387.82.121.0/2587.82.121.1 to 87.82.121.12687.82.121.127126
24487.82.121.128/2587.82.121.129 to 87.82.121.25487.82.121.255126
24587.82.122.0/2587.82.122.1 to 87.82.122.12687.82.122.127126
24687.82.122.128/2587.82.122.129 to 87.82.122.25487.82.122.255126
24787.82.123.0/2587.82.123.1 to 87.82.123.12687.82.123.127126
24887.82.123.128/2587.82.123.129 to 87.82.123.25487.82.123.255126
24987.82.124.0/2587.82.124.1 to 87.82.124.12687.82.124.127126
25087.82.124.128/2587.82.124.129 to 87.82.124.25487.82.124.255126
25187.82.125.0/2587.82.125.1 to 87.82.125.12687.82.125.127126
25287.82.125.128/2587.82.125.129 to 87.82.125.25487.82.125.255126
25387.82.126.0/2587.82.126.1 to 87.82.126.12687.82.126.127126
25487.82.126.128/2587.82.126.129 to 87.82.126.25487.82.126.255126
25587.82.127.0/2587.82.127.1 to 87.82.127.12687.82.127.127126
25687.82.127.128/2587.82.127.129 to 87.82.127.25487.82.127.255126

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.