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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.

Network8.120.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
8.120.0.0
Broadcast address
8.127.255.255
First usable
8.120.0.1
Last usable
8.127.255.254
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
A (default /8)
As numbers
Hex 08780000 · Integer 142082048 to 142606335
Reverse DNS zones
120.8.in-addr.arpa
121.8.in-addr.arpa
122.8.in-addr.arpa
123.8.in-addr.arpa
124.8.in-addr.arpa
125.8.in-addr.arpa
126.8.in-addr.arpa
127.8.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
Address00001000.01111000.00000000.000000008.120.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00001000.01111000.00000000.000000008.120.0.0
Broadcast00001000.01111111.11111111.111111118.127.255.255
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)

8.120.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
18.120.0.0/218.120.0.1 to 8.120.7.2548.120.7.2552,046
28.120.8.0/218.120.8.1 to 8.120.15.2548.120.15.2552,046
38.120.16.0/218.120.16.1 to 8.120.23.2548.120.23.2552,046
48.120.24.0/218.120.24.1 to 8.120.31.2548.120.31.2552,046
58.120.32.0/218.120.32.1 to 8.120.39.2548.120.39.2552,046
68.120.40.0/218.120.40.1 to 8.120.47.2548.120.47.2552,046
78.120.48.0/218.120.48.1 to 8.120.55.2548.120.55.2552,046
88.120.56.0/218.120.56.1 to 8.120.63.2548.120.63.2552,046
98.120.64.0/218.120.64.1 to 8.120.71.2548.120.71.2552,046
108.120.72.0/218.120.72.1 to 8.120.79.2548.120.79.2552,046
118.120.80.0/218.120.80.1 to 8.120.87.2548.120.87.2552,046
128.120.88.0/218.120.88.1 to 8.120.95.2548.120.95.2552,046
138.120.96.0/218.120.96.1 to 8.120.103.2548.120.103.2552,046
148.120.104.0/218.120.104.1 to 8.120.111.2548.120.111.2552,046
158.120.112.0/218.120.112.1 to 8.120.119.2548.120.119.2552,046
168.120.120.0/218.120.120.1 to 8.120.127.2548.120.127.2552,046
178.120.128.0/218.120.128.1 to 8.120.135.2548.120.135.2552,046
188.120.136.0/218.120.136.1 to 8.120.143.2548.120.143.2552,046
198.120.144.0/218.120.144.1 to 8.120.151.2548.120.151.2552,046
208.120.152.0/218.120.152.1 to 8.120.159.2548.120.159.2552,046
218.120.160.0/218.120.160.1 to 8.120.167.2548.120.167.2552,046
228.120.168.0/218.120.168.1 to 8.120.175.2548.120.175.2552,046
238.120.176.0/218.120.176.1 to 8.120.183.2548.120.183.2552,046
248.120.184.0/218.120.184.1 to 8.120.191.2548.120.191.2552,046
258.120.192.0/218.120.192.1 to 8.120.199.2548.120.199.2552,046
268.120.200.0/218.120.200.1 to 8.120.207.2548.120.207.2552,046
278.120.208.0/218.120.208.1 to 8.120.215.2548.120.215.2552,046
288.120.216.0/218.120.216.1 to 8.120.223.2548.120.223.2552,046
298.120.224.0/218.120.224.1 to 8.120.231.2548.120.231.2552,046
308.120.232.0/218.120.232.1 to 8.120.239.2548.120.239.2552,046
318.120.240.0/218.120.240.1 to 8.120.247.2548.120.247.2552,046
328.120.248.0/218.120.248.1 to 8.120.255.2548.120.255.2552,046
338.121.0.0/218.121.0.1 to 8.121.7.2548.121.7.2552,046
348.121.8.0/218.121.8.1 to 8.121.15.2548.121.15.2552,046
358.121.16.0/218.121.16.1 to 8.121.23.2548.121.23.2552,046
368.121.24.0/218.121.24.1 to 8.121.31.2548.121.31.2552,046
378.121.32.0/218.121.32.1 to 8.121.39.2548.121.39.2552,046
388.121.40.0/218.121.40.1 to 8.121.47.2548.121.47.2552,046
398.121.48.0/218.121.48.1 to 8.121.55.2548.121.55.2552,046
408.121.56.0/218.121.56.1 to 8.121.63.2548.121.63.2552,046
418.121.64.0/218.121.64.1 to 8.121.71.2548.121.71.2552,046
428.121.72.0/218.121.72.1 to 8.121.79.2548.121.79.2552,046
438.121.80.0/218.121.80.1 to 8.121.87.2548.121.87.2552,046
448.121.88.0/218.121.88.1 to 8.121.95.2548.121.95.2552,046
458.121.96.0/218.121.96.1 to 8.121.103.2548.121.103.2552,046
468.121.104.0/218.121.104.1 to 8.121.111.2548.121.111.2552,046
478.121.112.0/218.121.112.1 to 8.121.119.2548.121.119.2552,046
488.121.120.0/218.121.120.1 to 8.121.127.2548.121.127.2552,046
498.121.128.0/218.121.128.1 to 8.121.135.2548.121.135.2552,046
508.121.136.0/218.121.136.1 to 8.121.143.2548.121.143.2552,046
518.121.144.0/218.121.144.1 to 8.121.151.2548.121.151.2552,046
528.121.152.0/218.121.152.1 to 8.121.159.2548.121.159.2552,046
538.121.160.0/218.121.160.1 to 8.121.167.2548.121.167.2552,046
548.121.168.0/218.121.168.1 to 8.121.175.2548.121.175.2552,046
558.121.176.0/218.121.176.1 to 8.121.183.2548.121.183.2552,046
568.121.184.0/218.121.184.1 to 8.121.191.2548.121.191.2552,046
578.121.192.0/218.121.192.1 to 8.121.199.2548.121.199.2552,046
588.121.200.0/218.121.200.1 to 8.121.207.2548.121.207.2552,046
598.121.208.0/218.121.208.1 to 8.121.215.2548.121.215.2552,046
608.121.216.0/218.121.216.1 to 8.121.223.2548.121.223.2552,046
618.121.224.0/218.121.224.1 to 8.121.231.2548.121.231.2552,046
628.121.232.0/218.121.232.1 to 8.121.239.2548.121.239.2552,046
638.121.240.0/218.121.240.1 to 8.121.247.2548.121.247.2552,046
648.121.248.0/218.121.248.1 to 8.121.255.2548.121.255.2552,046
658.122.0.0/218.122.0.1 to 8.122.7.2548.122.7.2552,046
668.122.8.0/218.122.8.1 to 8.122.15.2548.122.15.2552,046
678.122.16.0/218.122.16.1 to 8.122.23.2548.122.23.2552,046
688.122.24.0/218.122.24.1 to 8.122.31.2548.122.31.2552,046
698.122.32.0/218.122.32.1 to 8.122.39.2548.122.39.2552,046
708.122.40.0/218.122.40.1 to 8.122.47.2548.122.47.2552,046
718.122.48.0/218.122.48.1 to 8.122.55.2548.122.55.2552,046
728.122.56.0/218.122.56.1 to 8.122.63.2548.122.63.2552,046
738.122.64.0/218.122.64.1 to 8.122.71.2548.122.71.2552,046
748.122.72.0/218.122.72.1 to 8.122.79.2548.122.79.2552,046
758.122.80.0/218.122.80.1 to 8.122.87.2548.122.87.2552,046
768.122.88.0/218.122.88.1 to 8.122.95.2548.122.95.2552,046
778.122.96.0/218.122.96.1 to 8.122.103.2548.122.103.2552,046
788.122.104.0/218.122.104.1 to 8.122.111.2548.122.111.2552,046
798.122.112.0/218.122.112.1 to 8.122.119.2548.122.119.2552,046
808.122.120.0/218.122.120.1 to 8.122.127.2548.122.127.2552,046
818.122.128.0/218.122.128.1 to 8.122.135.2548.122.135.2552,046
828.122.136.0/218.122.136.1 to 8.122.143.2548.122.143.2552,046
838.122.144.0/218.122.144.1 to 8.122.151.2548.122.151.2552,046
848.122.152.0/218.122.152.1 to 8.122.159.2548.122.159.2552,046
858.122.160.0/218.122.160.1 to 8.122.167.2548.122.167.2552,046
868.122.168.0/218.122.168.1 to 8.122.175.2548.122.175.2552,046
878.122.176.0/218.122.176.1 to 8.122.183.2548.122.183.2552,046
888.122.184.0/218.122.184.1 to 8.122.191.2548.122.191.2552,046
898.122.192.0/218.122.192.1 to 8.122.199.2548.122.199.2552,046
908.122.200.0/218.122.200.1 to 8.122.207.2548.122.207.2552,046
918.122.208.0/218.122.208.1 to 8.122.215.2548.122.215.2552,046
928.122.216.0/218.122.216.1 to 8.122.223.2548.122.223.2552,046
938.122.224.0/218.122.224.1 to 8.122.231.2548.122.231.2552,046
948.122.232.0/218.122.232.1 to 8.122.239.2548.122.239.2552,046
958.122.240.0/218.122.240.1 to 8.122.247.2548.122.247.2552,046
968.122.248.0/218.122.248.1 to 8.122.255.2548.122.255.2552,046
978.123.0.0/218.123.0.1 to 8.123.7.2548.123.7.2552,046
988.123.8.0/218.123.8.1 to 8.123.15.2548.123.15.2552,046
998.123.16.0/218.123.16.1 to 8.123.23.2548.123.23.2552,046
1008.123.24.0/218.123.24.1 to 8.123.31.2548.123.31.2552,046
1018.123.32.0/218.123.32.1 to 8.123.39.2548.123.39.2552,046
1028.123.40.0/218.123.40.1 to 8.123.47.2548.123.47.2552,046
1038.123.48.0/218.123.48.1 to 8.123.55.2548.123.55.2552,046
1048.123.56.0/218.123.56.1 to 8.123.63.2548.123.63.2552,046
1058.123.64.0/218.123.64.1 to 8.123.71.2548.123.71.2552,046
1068.123.72.0/218.123.72.1 to 8.123.79.2548.123.79.2552,046
1078.123.80.0/218.123.80.1 to 8.123.87.2548.123.87.2552,046
1088.123.88.0/218.123.88.1 to 8.123.95.2548.123.95.2552,046
1098.123.96.0/218.123.96.1 to 8.123.103.2548.123.103.2552,046
1108.123.104.0/218.123.104.1 to 8.123.111.2548.123.111.2552,046
1118.123.112.0/218.123.112.1 to 8.123.119.2548.123.119.2552,046
1128.123.120.0/218.123.120.1 to 8.123.127.2548.123.127.2552,046
1138.123.128.0/218.123.128.1 to 8.123.135.2548.123.135.2552,046
1148.123.136.0/218.123.136.1 to 8.123.143.2548.123.143.2552,046
1158.123.144.0/218.123.144.1 to 8.123.151.2548.123.151.2552,046
1168.123.152.0/218.123.152.1 to 8.123.159.2548.123.159.2552,046
1178.123.160.0/218.123.160.1 to 8.123.167.2548.123.167.2552,046
1188.123.168.0/218.123.168.1 to 8.123.175.2548.123.175.2552,046
1198.123.176.0/218.123.176.1 to 8.123.183.2548.123.183.2552,046
1208.123.184.0/218.123.184.1 to 8.123.191.2548.123.191.2552,046
1218.123.192.0/218.123.192.1 to 8.123.199.2548.123.199.2552,046
1228.123.200.0/218.123.200.1 to 8.123.207.2548.123.207.2552,046
1238.123.208.0/218.123.208.1 to 8.123.215.2548.123.215.2552,046
1248.123.216.0/218.123.216.1 to 8.123.223.2548.123.223.2552,046
1258.123.224.0/218.123.224.1 to 8.123.231.2548.123.231.2552,046
1268.123.232.0/218.123.232.1 to 8.123.239.2548.123.239.2552,046
1278.123.240.0/218.123.240.1 to 8.123.247.2548.123.247.2552,046
1288.123.248.0/218.123.248.1 to 8.123.255.2548.123.255.2552,046
1298.124.0.0/218.124.0.1 to 8.124.7.2548.124.7.2552,046
1308.124.8.0/218.124.8.1 to 8.124.15.2548.124.15.2552,046
1318.124.16.0/218.124.16.1 to 8.124.23.2548.124.23.2552,046
1328.124.24.0/218.124.24.1 to 8.124.31.2548.124.31.2552,046
1338.124.32.0/218.124.32.1 to 8.124.39.2548.124.39.2552,046
1348.124.40.0/218.124.40.1 to 8.124.47.2548.124.47.2552,046
1358.124.48.0/218.124.48.1 to 8.124.55.2548.124.55.2552,046
1368.124.56.0/218.124.56.1 to 8.124.63.2548.124.63.2552,046
1378.124.64.0/218.124.64.1 to 8.124.71.2548.124.71.2552,046
1388.124.72.0/218.124.72.1 to 8.124.79.2548.124.79.2552,046
1398.124.80.0/218.124.80.1 to 8.124.87.2548.124.87.2552,046
1408.124.88.0/218.124.88.1 to 8.124.95.2548.124.95.2552,046
1418.124.96.0/218.124.96.1 to 8.124.103.2548.124.103.2552,046
1428.124.104.0/218.124.104.1 to 8.124.111.2548.124.111.2552,046
1438.124.112.0/218.124.112.1 to 8.124.119.2548.124.119.2552,046
1448.124.120.0/218.124.120.1 to 8.124.127.2548.124.127.2552,046
1458.124.128.0/218.124.128.1 to 8.124.135.2548.124.135.2552,046
1468.124.136.0/218.124.136.1 to 8.124.143.2548.124.143.2552,046
1478.124.144.0/218.124.144.1 to 8.124.151.2548.124.151.2552,046
1488.124.152.0/218.124.152.1 to 8.124.159.2548.124.159.2552,046
1498.124.160.0/218.124.160.1 to 8.124.167.2548.124.167.2552,046
1508.124.168.0/218.124.168.1 to 8.124.175.2548.124.175.2552,046
1518.124.176.0/218.124.176.1 to 8.124.183.2548.124.183.2552,046
1528.124.184.0/218.124.184.1 to 8.124.191.2548.124.191.2552,046
1538.124.192.0/218.124.192.1 to 8.124.199.2548.124.199.2552,046
1548.124.200.0/218.124.200.1 to 8.124.207.2548.124.207.2552,046
1558.124.208.0/218.124.208.1 to 8.124.215.2548.124.215.2552,046
1568.124.216.0/218.124.216.1 to 8.124.223.2548.124.223.2552,046
1578.124.224.0/218.124.224.1 to 8.124.231.2548.124.231.2552,046
1588.124.232.0/218.124.232.1 to 8.124.239.2548.124.239.2552,046
1598.124.240.0/218.124.240.1 to 8.124.247.2548.124.247.2552,046
1608.124.248.0/218.124.248.1 to 8.124.255.2548.124.255.2552,046
1618.125.0.0/218.125.0.1 to 8.125.7.2548.125.7.2552,046
1628.125.8.0/218.125.8.1 to 8.125.15.2548.125.15.2552,046
1638.125.16.0/218.125.16.1 to 8.125.23.2548.125.23.2552,046
1648.125.24.0/218.125.24.1 to 8.125.31.2548.125.31.2552,046
1658.125.32.0/218.125.32.1 to 8.125.39.2548.125.39.2552,046
1668.125.40.0/218.125.40.1 to 8.125.47.2548.125.47.2552,046
1678.125.48.0/218.125.48.1 to 8.125.55.2548.125.55.2552,046
1688.125.56.0/218.125.56.1 to 8.125.63.2548.125.63.2552,046
1698.125.64.0/218.125.64.1 to 8.125.71.2548.125.71.2552,046
1708.125.72.0/218.125.72.1 to 8.125.79.2548.125.79.2552,046
1718.125.80.0/218.125.80.1 to 8.125.87.2548.125.87.2552,046
1728.125.88.0/218.125.88.1 to 8.125.95.2548.125.95.2552,046
1738.125.96.0/218.125.96.1 to 8.125.103.2548.125.103.2552,046
1748.125.104.0/218.125.104.1 to 8.125.111.2548.125.111.2552,046
1758.125.112.0/218.125.112.1 to 8.125.119.2548.125.119.2552,046
1768.125.120.0/218.125.120.1 to 8.125.127.2548.125.127.2552,046
1778.125.128.0/218.125.128.1 to 8.125.135.2548.125.135.2552,046
1788.125.136.0/218.125.136.1 to 8.125.143.2548.125.143.2552,046
1798.125.144.0/218.125.144.1 to 8.125.151.2548.125.151.2552,046
1808.125.152.0/218.125.152.1 to 8.125.159.2548.125.159.2552,046
1818.125.160.0/218.125.160.1 to 8.125.167.2548.125.167.2552,046
1828.125.168.0/218.125.168.1 to 8.125.175.2548.125.175.2552,046
1838.125.176.0/218.125.176.1 to 8.125.183.2548.125.183.2552,046
1848.125.184.0/218.125.184.1 to 8.125.191.2548.125.191.2552,046
1858.125.192.0/218.125.192.1 to 8.125.199.2548.125.199.2552,046
1868.125.200.0/218.125.200.1 to 8.125.207.2548.125.207.2552,046
1878.125.208.0/218.125.208.1 to 8.125.215.2548.125.215.2552,046
1888.125.216.0/218.125.216.1 to 8.125.223.2548.125.223.2552,046
1898.125.224.0/218.125.224.1 to 8.125.231.2548.125.231.2552,046
1908.125.232.0/218.125.232.1 to 8.125.239.2548.125.239.2552,046
1918.125.240.0/218.125.240.1 to 8.125.247.2548.125.247.2552,046
1928.125.248.0/218.125.248.1 to 8.125.255.2548.125.255.2552,046
1938.126.0.0/218.126.0.1 to 8.126.7.2548.126.7.2552,046
1948.126.8.0/218.126.8.1 to 8.126.15.2548.126.15.2552,046
1958.126.16.0/218.126.16.1 to 8.126.23.2548.126.23.2552,046
1968.126.24.0/218.126.24.1 to 8.126.31.2548.126.31.2552,046
1978.126.32.0/218.126.32.1 to 8.126.39.2548.126.39.2552,046
1988.126.40.0/218.126.40.1 to 8.126.47.2548.126.47.2552,046
1998.126.48.0/218.126.48.1 to 8.126.55.2548.126.55.2552,046
2008.126.56.0/218.126.56.1 to 8.126.63.2548.126.63.2552,046
2018.126.64.0/218.126.64.1 to 8.126.71.2548.126.71.2552,046
2028.126.72.0/218.126.72.1 to 8.126.79.2548.126.79.2552,046
2038.126.80.0/218.126.80.1 to 8.126.87.2548.126.87.2552,046
2048.126.88.0/218.126.88.1 to 8.126.95.2548.126.95.2552,046
2058.126.96.0/218.126.96.1 to 8.126.103.2548.126.103.2552,046
2068.126.104.0/218.126.104.1 to 8.126.111.2548.126.111.2552,046
2078.126.112.0/218.126.112.1 to 8.126.119.2548.126.119.2552,046
2088.126.120.0/218.126.120.1 to 8.126.127.2548.126.127.2552,046
2098.126.128.0/218.126.128.1 to 8.126.135.2548.126.135.2552,046
2108.126.136.0/218.126.136.1 to 8.126.143.2548.126.143.2552,046
2118.126.144.0/218.126.144.1 to 8.126.151.2548.126.151.2552,046
2128.126.152.0/218.126.152.1 to 8.126.159.2548.126.159.2552,046
2138.126.160.0/218.126.160.1 to 8.126.167.2548.126.167.2552,046
2148.126.168.0/218.126.168.1 to 8.126.175.2548.126.175.2552,046
2158.126.176.0/218.126.176.1 to 8.126.183.2548.126.183.2552,046
2168.126.184.0/218.126.184.1 to 8.126.191.2548.126.191.2552,046
2178.126.192.0/218.126.192.1 to 8.126.199.2548.126.199.2552,046
2188.126.200.0/218.126.200.1 to 8.126.207.2548.126.207.2552,046
2198.126.208.0/218.126.208.1 to 8.126.215.2548.126.215.2552,046
2208.126.216.0/218.126.216.1 to 8.126.223.2548.126.223.2552,046
2218.126.224.0/218.126.224.1 to 8.126.231.2548.126.231.2552,046
2228.126.232.0/218.126.232.1 to 8.126.239.2548.126.239.2552,046
2238.126.240.0/218.126.240.1 to 8.126.247.2548.126.247.2552,046
2248.126.248.0/218.126.248.1 to 8.126.255.2548.126.255.2552,046
2258.127.0.0/218.127.0.1 to 8.127.7.2548.127.7.2552,046
2268.127.8.0/218.127.8.1 to 8.127.15.2548.127.15.2552,046
2278.127.16.0/218.127.16.1 to 8.127.23.2548.127.23.2552,046
2288.127.24.0/218.127.24.1 to 8.127.31.2548.127.31.2552,046
2298.127.32.0/218.127.32.1 to 8.127.39.2548.127.39.2552,046
2308.127.40.0/218.127.40.1 to 8.127.47.2548.127.47.2552,046
2318.127.48.0/218.127.48.1 to 8.127.55.2548.127.55.2552,046
2328.127.56.0/218.127.56.1 to 8.127.63.2548.127.63.2552,046
2338.127.64.0/218.127.64.1 to 8.127.71.2548.127.71.2552,046
2348.127.72.0/218.127.72.1 to 8.127.79.2548.127.79.2552,046
2358.127.80.0/218.127.80.1 to 8.127.87.2548.127.87.2552,046
2368.127.88.0/218.127.88.1 to 8.127.95.2548.127.95.2552,046
2378.127.96.0/218.127.96.1 to 8.127.103.2548.127.103.2552,046
2388.127.104.0/218.127.104.1 to 8.127.111.2548.127.111.2552,046
2398.127.112.0/218.127.112.1 to 8.127.119.2548.127.119.2552,046
2408.127.120.0/218.127.120.1 to 8.127.127.2548.127.127.2552,046
2418.127.128.0/218.127.128.1 to 8.127.135.2548.127.135.2552,046
2428.127.136.0/218.127.136.1 to 8.127.143.2548.127.143.2552,046
2438.127.144.0/218.127.144.1 to 8.127.151.2548.127.151.2552,046
2448.127.152.0/218.127.152.1 to 8.127.159.2548.127.159.2552,046
2458.127.160.0/218.127.160.1 to 8.127.167.2548.127.167.2552,046
2468.127.168.0/218.127.168.1 to 8.127.175.2548.127.175.2552,046
2478.127.176.0/218.127.176.1 to 8.127.183.2548.127.183.2552,046
2488.127.184.0/218.127.184.1 to 8.127.191.2548.127.191.2552,046
2498.127.192.0/218.127.192.1 to 8.127.199.2548.127.199.2552,046
2508.127.200.0/218.127.200.1 to 8.127.207.2548.127.207.2552,046
2518.127.208.0/218.127.208.1 to 8.127.215.2548.127.215.2552,046
2528.127.216.0/218.127.216.1 to 8.127.223.2548.127.223.2552,046
2538.127.224.0/218.127.224.1 to 8.127.231.2548.127.231.2552,046
2548.127.232.0/218.127.232.1 to 8.127.239.2548.127.239.2552,046
2558.127.240.0/218.127.240.1 to 8.127.247.2548.127.247.2552,046
2568.127.248.0/218.127.248.1 to 8.127.255.2548.127.255.2552,046

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.