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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.

Network8.30.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
8.30.0.0
Broadcast address
8.31.255.255
First usable
8.30.0.1
Last usable
8.31.255.254
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 081E0000 · Integer 136183808 to 136314879
Reverse DNS zones
30.8.in-addr.arpa
31.8.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
Address00001000.00011110.00000000.000000008.30.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00001000.00011110.00000000.000000008.30.0.0
Broadcast00001000.00011111.11111111.111111118.31.255.255
Split into smaller subnets/23
/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)

8.30.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
18.30.0.0/238.30.0.1 to 8.30.1.2548.30.1.255510
28.30.2.0/238.30.2.1 to 8.30.3.2548.30.3.255510
38.30.4.0/238.30.4.1 to 8.30.5.2548.30.5.255510
48.30.6.0/238.30.6.1 to 8.30.7.2548.30.7.255510
58.30.8.0/238.30.8.1 to 8.30.9.2548.30.9.255510
68.30.10.0/238.30.10.1 to 8.30.11.2548.30.11.255510
78.30.12.0/238.30.12.1 to 8.30.13.2548.30.13.255510
88.30.14.0/238.30.14.1 to 8.30.15.2548.30.15.255510
98.30.16.0/238.30.16.1 to 8.30.17.2548.30.17.255510
108.30.18.0/238.30.18.1 to 8.30.19.2548.30.19.255510
118.30.20.0/238.30.20.1 to 8.30.21.2548.30.21.255510
128.30.22.0/238.30.22.1 to 8.30.23.2548.30.23.255510
138.30.24.0/238.30.24.1 to 8.30.25.2548.30.25.255510
148.30.26.0/238.30.26.1 to 8.30.27.2548.30.27.255510
158.30.28.0/238.30.28.1 to 8.30.29.2548.30.29.255510
168.30.30.0/238.30.30.1 to 8.30.31.2548.30.31.255510
178.30.32.0/238.30.32.1 to 8.30.33.2548.30.33.255510
188.30.34.0/238.30.34.1 to 8.30.35.2548.30.35.255510
198.30.36.0/238.30.36.1 to 8.30.37.2548.30.37.255510
208.30.38.0/238.30.38.1 to 8.30.39.2548.30.39.255510
218.30.40.0/238.30.40.1 to 8.30.41.2548.30.41.255510
228.30.42.0/238.30.42.1 to 8.30.43.2548.30.43.255510
238.30.44.0/238.30.44.1 to 8.30.45.2548.30.45.255510
248.30.46.0/238.30.46.1 to 8.30.47.2548.30.47.255510
258.30.48.0/238.30.48.1 to 8.30.49.2548.30.49.255510
268.30.50.0/238.30.50.1 to 8.30.51.2548.30.51.255510
278.30.52.0/238.30.52.1 to 8.30.53.2548.30.53.255510
288.30.54.0/238.30.54.1 to 8.30.55.2548.30.55.255510
298.30.56.0/238.30.56.1 to 8.30.57.2548.30.57.255510
308.30.58.0/238.30.58.1 to 8.30.59.2548.30.59.255510
318.30.60.0/238.30.60.1 to 8.30.61.2548.30.61.255510
328.30.62.0/238.30.62.1 to 8.30.63.2548.30.63.255510
338.30.64.0/238.30.64.1 to 8.30.65.2548.30.65.255510
348.30.66.0/238.30.66.1 to 8.30.67.2548.30.67.255510
358.30.68.0/238.30.68.1 to 8.30.69.2548.30.69.255510
368.30.70.0/238.30.70.1 to 8.30.71.2548.30.71.255510
378.30.72.0/238.30.72.1 to 8.30.73.2548.30.73.255510
388.30.74.0/238.30.74.1 to 8.30.75.2548.30.75.255510
398.30.76.0/238.30.76.1 to 8.30.77.2548.30.77.255510
408.30.78.0/238.30.78.1 to 8.30.79.2548.30.79.255510
418.30.80.0/238.30.80.1 to 8.30.81.2548.30.81.255510
428.30.82.0/238.30.82.1 to 8.30.83.2548.30.83.255510
438.30.84.0/238.30.84.1 to 8.30.85.2548.30.85.255510
448.30.86.0/238.30.86.1 to 8.30.87.2548.30.87.255510
458.30.88.0/238.30.88.1 to 8.30.89.2548.30.89.255510
468.30.90.0/238.30.90.1 to 8.30.91.2548.30.91.255510
478.30.92.0/238.30.92.1 to 8.30.93.2548.30.93.255510
488.30.94.0/238.30.94.1 to 8.30.95.2548.30.95.255510
498.30.96.0/238.30.96.1 to 8.30.97.2548.30.97.255510
508.30.98.0/238.30.98.1 to 8.30.99.2548.30.99.255510
518.30.100.0/238.30.100.1 to 8.30.101.2548.30.101.255510
528.30.102.0/238.30.102.1 to 8.30.103.2548.30.103.255510
538.30.104.0/238.30.104.1 to 8.30.105.2548.30.105.255510
548.30.106.0/238.30.106.1 to 8.30.107.2548.30.107.255510
558.30.108.0/238.30.108.1 to 8.30.109.2548.30.109.255510
568.30.110.0/238.30.110.1 to 8.30.111.2548.30.111.255510
578.30.112.0/238.30.112.1 to 8.30.113.2548.30.113.255510
588.30.114.0/238.30.114.1 to 8.30.115.2548.30.115.255510
598.30.116.0/238.30.116.1 to 8.30.117.2548.30.117.255510
608.30.118.0/238.30.118.1 to 8.30.119.2548.30.119.255510
618.30.120.0/238.30.120.1 to 8.30.121.2548.30.121.255510
628.30.122.0/238.30.122.1 to 8.30.123.2548.30.123.255510
638.30.124.0/238.30.124.1 to 8.30.125.2548.30.125.255510
648.30.126.0/238.30.126.1 to 8.30.127.2548.30.127.255510
658.30.128.0/238.30.128.1 to 8.30.129.2548.30.129.255510
668.30.130.0/238.30.130.1 to 8.30.131.2548.30.131.255510
678.30.132.0/238.30.132.1 to 8.30.133.2548.30.133.255510
688.30.134.0/238.30.134.1 to 8.30.135.2548.30.135.255510
698.30.136.0/238.30.136.1 to 8.30.137.2548.30.137.255510
708.30.138.0/238.30.138.1 to 8.30.139.2548.30.139.255510
718.30.140.0/238.30.140.1 to 8.30.141.2548.30.141.255510
728.30.142.0/238.30.142.1 to 8.30.143.2548.30.143.255510
738.30.144.0/238.30.144.1 to 8.30.145.2548.30.145.255510
748.30.146.0/238.30.146.1 to 8.30.147.2548.30.147.255510
758.30.148.0/238.30.148.1 to 8.30.149.2548.30.149.255510
768.30.150.0/238.30.150.1 to 8.30.151.2548.30.151.255510
778.30.152.0/238.30.152.1 to 8.30.153.2548.30.153.255510
788.30.154.0/238.30.154.1 to 8.30.155.2548.30.155.255510
798.30.156.0/238.30.156.1 to 8.30.157.2548.30.157.255510
808.30.158.0/238.30.158.1 to 8.30.159.2548.30.159.255510
818.30.160.0/238.30.160.1 to 8.30.161.2548.30.161.255510
828.30.162.0/238.30.162.1 to 8.30.163.2548.30.163.255510
838.30.164.0/238.30.164.1 to 8.30.165.2548.30.165.255510
848.30.166.0/238.30.166.1 to 8.30.167.2548.30.167.255510
858.30.168.0/238.30.168.1 to 8.30.169.2548.30.169.255510
868.30.170.0/238.30.170.1 to 8.30.171.2548.30.171.255510
878.30.172.0/238.30.172.1 to 8.30.173.2548.30.173.255510
888.30.174.0/238.30.174.1 to 8.30.175.2548.30.175.255510
898.30.176.0/238.30.176.1 to 8.30.177.2548.30.177.255510
908.30.178.0/238.30.178.1 to 8.30.179.2548.30.179.255510
918.30.180.0/238.30.180.1 to 8.30.181.2548.30.181.255510
928.30.182.0/238.30.182.1 to 8.30.183.2548.30.183.255510
938.30.184.0/238.30.184.1 to 8.30.185.2548.30.185.255510
948.30.186.0/238.30.186.1 to 8.30.187.2548.30.187.255510
958.30.188.0/238.30.188.1 to 8.30.189.2548.30.189.255510
968.30.190.0/238.30.190.1 to 8.30.191.2548.30.191.255510
978.30.192.0/238.30.192.1 to 8.30.193.2548.30.193.255510
988.30.194.0/238.30.194.1 to 8.30.195.2548.30.195.255510
998.30.196.0/238.30.196.1 to 8.30.197.2548.30.197.255510
1008.30.198.0/238.30.198.1 to 8.30.199.2548.30.199.255510
1018.30.200.0/238.30.200.1 to 8.30.201.2548.30.201.255510
1028.30.202.0/238.30.202.1 to 8.30.203.2548.30.203.255510
1038.30.204.0/238.30.204.1 to 8.30.205.2548.30.205.255510
1048.30.206.0/238.30.206.1 to 8.30.207.2548.30.207.255510
1058.30.208.0/238.30.208.1 to 8.30.209.2548.30.209.255510
1068.30.210.0/238.30.210.1 to 8.30.211.2548.30.211.255510
1078.30.212.0/238.30.212.1 to 8.30.213.2548.30.213.255510
1088.30.214.0/238.30.214.1 to 8.30.215.2548.30.215.255510
1098.30.216.0/238.30.216.1 to 8.30.217.2548.30.217.255510
1108.30.218.0/238.30.218.1 to 8.30.219.2548.30.219.255510
1118.30.220.0/238.30.220.1 to 8.30.221.2548.30.221.255510
1128.30.222.0/238.30.222.1 to 8.30.223.2548.30.223.255510
1138.30.224.0/238.30.224.1 to 8.30.225.2548.30.225.255510
1148.30.226.0/238.30.226.1 to 8.30.227.2548.30.227.255510
1158.30.228.0/238.30.228.1 to 8.30.229.2548.30.229.255510
1168.30.230.0/238.30.230.1 to 8.30.231.2548.30.231.255510
1178.30.232.0/238.30.232.1 to 8.30.233.2548.30.233.255510
1188.30.234.0/238.30.234.1 to 8.30.235.2548.30.235.255510
1198.30.236.0/238.30.236.1 to 8.30.237.2548.30.237.255510
1208.30.238.0/238.30.238.1 to 8.30.239.2548.30.239.255510
1218.30.240.0/238.30.240.1 to 8.30.241.2548.30.241.255510
1228.30.242.0/238.30.242.1 to 8.30.243.2548.30.243.255510
1238.30.244.0/238.30.244.1 to 8.30.245.2548.30.245.255510
1248.30.246.0/238.30.246.1 to 8.30.247.2548.30.247.255510
1258.30.248.0/238.30.248.1 to 8.30.249.2548.30.249.255510
1268.30.250.0/238.30.250.1 to 8.30.251.2548.30.251.255510
1278.30.252.0/238.30.252.1 to 8.30.253.2548.30.253.255510
1288.30.254.0/238.30.254.1 to 8.30.255.2548.30.255.255510
1298.31.0.0/238.31.0.1 to 8.31.1.2548.31.1.255510
1308.31.2.0/238.31.2.1 to 8.31.3.2548.31.3.255510
1318.31.4.0/238.31.4.1 to 8.31.5.2548.31.5.255510
1328.31.6.0/238.31.6.1 to 8.31.7.2548.31.7.255510
1338.31.8.0/238.31.8.1 to 8.31.9.2548.31.9.255510
1348.31.10.0/238.31.10.1 to 8.31.11.2548.31.11.255510
1358.31.12.0/238.31.12.1 to 8.31.13.2548.31.13.255510
1368.31.14.0/238.31.14.1 to 8.31.15.2548.31.15.255510
1378.31.16.0/238.31.16.1 to 8.31.17.2548.31.17.255510
1388.31.18.0/238.31.18.1 to 8.31.19.2548.31.19.255510
1398.31.20.0/238.31.20.1 to 8.31.21.2548.31.21.255510
1408.31.22.0/238.31.22.1 to 8.31.23.2548.31.23.255510
1418.31.24.0/238.31.24.1 to 8.31.25.2548.31.25.255510
1428.31.26.0/238.31.26.1 to 8.31.27.2548.31.27.255510
1438.31.28.0/238.31.28.1 to 8.31.29.2548.31.29.255510
1448.31.30.0/238.31.30.1 to 8.31.31.2548.31.31.255510
1458.31.32.0/238.31.32.1 to 8.31.33.2548.31.33.255510
1468.31.34.0/238.31.34.1 to 8.31.35.2548.31.35.255510
1478.31.36.0/238.31.36.1 to 8.31.37.2548.31.37.255510
1488.31.38.0/238.31.38.1 to 8.31.39.2548.31.39.255510
1498.31.40.0/238.31.40.1 to 8.31.41.2548.31.41.255510
1508.31.42.0/238.31.42.1 to 8.31.43.2548.31.43.255510
1518.31.44.0/238.31.44.1 to 8.31.45.2548.31.45.255510
1528.31.46.0/238.31.46.1 to 8.31.47.2548.31.47.255510
1538.31.48.0/238.31.48.1 to 8.31.49.2548.31.49.255510
1548.31.50.0/238.31.50.1 to 8.31.51.2548.31.51.255510
1558.31.52.0/238.31.52.1 to 8.31.53.2548.31.53.255510
1568.31.54.0/238.31.54.1 to 8.31.55.2548.31.55.255510
1578.31.56.0/238.31.56.1 to 8.31.57.2548.31.57.255510
1588.31.58.0/238.31.58.1 to 8.31.59.2548.31.59.255510
1598.31.60.0/238.31.60.1 to 8.31.61.2548.31.61.255510
1608.31.62.0/238.31.62.1 to 8.31.63.2548.31.63.255510
1618.31.64.0/238.31.64.1 to 8.31.65.2548.31.65.255510
1628.31.66.0/238.31.66.1 to 8.31.67.2548.31.67.255510
1638.31.68.0/238.31.68.1 to 8.31.69.2548.31.69.255510
1648.31.70.0/238.31.70.1 to 8.31.71.2548.31.71.255510
1658.31.72.0/238.31.72.1 to 8.31.73.2548.31.73.255510
1668.31.74.0/238.31.74.1 to 8.31.75.2548.31.75.255510
1678.31.76.0/238.31.76.1 to 8.31.77.2548.31.77.255510
1688.31.78.0/238.31.78.1 to 8.31.79.2548.31.79.255510
1698.31.80.0/238.31.80.1 to 8.31.81.2548.31.81.255510
1708.31.82.0/238.31.82.1 to 8.31.83.2548.31.83.255510
1718.31.84.0/238.31.84.1 to 8.31.85.2548.31.85.255510
1728.31.86.0/238.31.86.1 to 8.31.87.2548.31.87.255510
1738.31.88.0/238.31.88.1 to 8.31.89.2548.31.89.255510
1748.31.90.0/238.31.90.1 to 8.31.91.2548.31.91.255510
1758.31.92.0/238.31.92.1 to 8.31.93.2548.31.93.255510
1768.31.94.0/238.31.94.1 to 8.31.95.2548.31.95.255510
1778.31.96.0/238.31.96.1 to 8.31.97.2548.31.97.255510
1788.31.98.0/238.31.98.1 to 8.31.99.2548.31.99.255510
1798.31.100.0/238.31.100.1 to 8.31.101.2548.31.101.255510
1808.31.102.0/238.31.102.1 to 8.31.103.2548.31.103.255510
1818.31.104.0/238.31.104.1 to 8.31.105.2548.31.105.255510
1828.31.106.0/238.31.106.1 to 8.31.107.2548.31.107.255510
1838.31.108.0/238.31.108.1 to 8.31.109.2548.31.109.255510
1848.31.110.0/238.31.110.1 to 8.31.111.2548.31.111.255510
1858.31.112.0/238.31.112.1 to 8.31.113.2548.31.113.255510
1868.31.114.0/238.31.114.1 to 8.31.115.2548.31.115.255510
1878.31.116.0/238.31.116.1 to 8.31.117.2548.31.117.255510
1888.31.118.0/238.31.118.1 to 8.31.119.2548.31.119.255510
1898.31.120.0/238.31.120.1 to 8.31.121.2548.31.121.255510
1908.31.122.0/238.31.122.1 to 8.31.123.2548.31.123.255510
1918.31.124.0/238.31.124.1 to 8.31.125.2548.31.125.255510
1928.31.126.0/238.31.126.1 to 8.31.127.2548.31.127.255510
1938.31.128.0/238.31.128.1 to 8.31.129.2548.31.129.255510
1948.31.130.0/238.31.130.1 to 8.31.131.2548.31.131.255510
1958.31.132.0/238.31.132.1 to 8.31.133.2548.31.133.255510
1968.31.134.0/238.31.134.1 to 8.31.135.2548.31.135.255510
1978.31.136.0/238.31.136.1 to 8.31.137.2548.31.137.255510
1988.31.138.0/238.31.138.1 to 8.31.139.2548.31.139.255510
1998.31.140.0/238.31.140.1 to 8.31.141.2548.31.141.255510
2008.31.142.0/238.31.142.1 to 8.31.143.2548.31.143.255510
2018.31.144.0/238.31.144.1 to 8.31.145.2548.31.145.255510
2028.31.146.0/238.31.146.1 to 8.31.147.2548.31.147.255510
2038.31.148.0/238.31.148.1 to 8.31.149.2548.31.149.255510
2048.31.150.0/238.31.150.1 to 8.31.151.2548.31.151.255510
2058.31.152.0/238.31.152.1 to 8.31.153.2548.31.153.255510
2068.31.154.0/238.31.154.1 to 8.31.155.2548.31.155.255510
2078.31.156.0/238.31.156.1 to 8.31.157.2548.31.157.255510
2088.31.158.0/238.31.158.1 to 8.31.159.2548.31.159.255510
2098.31.160.0/238.31.160.1 to 8.31.161.2548.31.161.255510
2108.31.162.0/238.31.162.1 to 8.31.163.2548.31.163.255510
2118.31.164.0/238.31.164.1 to 8.31.165.2548.31.165.255510
2128.31.166.0/238.31.166.1 to 8.31.167.2548.31.167.255510
2138.31.168.0/238.31.168.1 to 8.31.169.2548.31.169.255510
2148.31.170.0/238.31.170.1 to 8.31.171.2548.31.171.255510
2158.31.172.0/238.31.172.1 to 8.31.173.2548.31.173.255510
2168.31.174.0/238.31.174.1 to 8.31.175.2548.31.175.255510
2178.31.176.0/238.31.176.1 to 8.31.177.2548.31.177.255510
2188.31.178.0/238.31.178.1 to 8.31.179.2548.31.179.255510
2198.31.180.0/238.31.180.1 to 8.31.181.2548.31.181.255510
2208.31.182.0/238.31.182.1 to 8.31.183.2548.31.183.255510
2218.31.184.0/238.31.184.1 to 8.31.185.2548.31.185.255510
2228.31.186.0/238.31.186.1 to 8.31.187.2548.31.187.255510
2238.31.188.0/238.31.188.1 to 8.31.189.2548.31.189.255510
2248.31.190.0/238.31.190.1 to 8.31.191.2548.31.191.255510
2258.31.192.0/238.31.192.1 to 8.31.193.2548.31.193.255510
2268.31.194.0/238.31.194.1 to 8.31.195.2548.31.195.255510
2278.31.196.0/238.31.196.1 to 8.31.197.2548.31.197.255510
2288.31.198.0/238.31.198.1 to 8.31.199.2548.31.199.255510
2298.31.200.0/238.31.200.1 to 8.31.201.2548.31.201.255510
2308.31.202.0/238.31.202.1 to 8.31.203.2548.31.203.255510
2318.31.204.0/238.31.204.1 to 8.31.205.2548.31.205.255510
2328.31.206.0/238.31.206.1 to 8.31.207.2548.31.207.255510
2338.31.208.0/238.31.208.1 to 8.31.209.2548.31.209.255510
2348.31.210.0/238.31.210.1 to 8.31.211.2548.31.211.255510
2358.31.212.0/238.31.212.1 to 8.31.213.2548.31.213.255510
2368.31.214.0/238.31.214.1 to 8.31.215.2548.31.215.255510
2378.31.216.0/238.31.216.1 to 8.31.217.2548.31.217.255510
2388.31.218.0/238.31.218.1 to 8.31.219.2548.31.219.255510
2398.31.220.0/238.31.220.1 to 8.31.221.2548.31.221.255510
2408.31.222.0/238.31.222.1 to 8.31.223.2548.31.223.255510
2418.31.224.0/238.31.224.1 to 8.31.225.2548.31.225.255510
2428.31.226.0/238.31.226.1 to 8.31.227.2548.31.227.255510
2438.31.228.0/238.31.228.1 to 8.31.229.2548.31.229.255510
2448.31.230.0/238.31.230.1 to 8.31.231.2548.31.231.255510
2458.31.232.0/238.31.232.1 to 8.31.233.2548.31.233.255510
2468.31.234.0/238.31.234.1 to 8.31.235.2548.31.235.255510
2478.31.236.0/238.31.236.1 to 8.31.237.2548.31.237.255510
2488.31.238.0/238.31.238.1 to 8.31.239.2548.31.239.255510
2498.31.240.0/238.31.240.1 to 8.31.241.2548.31.241.255510
2508.31.242.0/238.31.242.1 to 8.31.243.2548.31.243.255510
2518.31.244.0/238.31.244.1 to 8.31.245.2548.31.245.255510
2528.31.246.0/238.31.246.1 to 8.31.247.2548.31.247.255510
2538.31.248.0/238.31.248.1 to 8.31.249.2548.31.249.255510
2548.31.250.0/238.31.250.1 to 8.31.251.2548.31.251.255510
2558.31.252.0/238.31.252.1 to 8.31.253.2548.31.253.255510
2568.31.254.0/238.31.254.1 to 8.31.255.2548.31.255.255510

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.