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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.

Network6.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
6.0.0.0
Broadcast address
7.255.255.255
First usable
6.0.0.1
Last usable
7.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 06000000 · Integer 100663296 to 134217727
Reverse DNS zones
6.in-addr.arpa
7.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000110.00000000.00000000.000000006.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000110.00000000.00000000.000000006.0.0.0
Broadcast00000111.11111111.11111111.111111117.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

6.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.0.0.0/156.0.0.1 to 6.1.255.2546.1.255.255131,070
26.2.0.0/156.2.0.1 to 6.3.255.2546.3.255.255131,070
36.4.0.0/156.4.0.1 to 6.5.255.2546.5.255.255131,070
46.6.0.0/156.6.0.1 to 6.7.255.2546.7.255.255131,070
56.8.0.0/156.8.0.1 to 6.9.255.2546.9.255.255131,070
66.10.0.0/156.10.0.1 to 6.11.255.2546.11.255.255131,070
76.12.0.0/156.12.0.1 to 6.13.255.2546.13.255.255131,070
86.14.0.0/156.14.0.1 to 6.15.255.2546.15.255.255131,070
96.16.0.0/156.16.0.1 to 6.17.255.2546.17.255.255131,070
106.18.0.0/156.18.0.1 to 6.19.255.2546.19.255.255131,070
116.20.0.0/156.20.0.1 to 6.21.255.2546.21.255.255131,070
126.22.0.0/156.22.0.1 to 6.23.255.2546.23.255.255131,070
136.24.0.0/156.24.0.1 to 6.25.255.2546.25.255.255131,070
146.26.0.0/156.26.0.1 to 6.27.255.2546.27.255.255131,070
156.28.0.0/156.28.0.1 to 6.29.255.2546.29.255.255131,070
166.30.0.0/156.30.0.1 to 6.31.255.2546.31.255.255131,070
176.32.0.0/156.32.0.1 to 6.33.255.2546.33.255.255131,070
186.34.0.0/156.34.0.1 to 6.35.255.2546.35.255.255131,070
196.36.0.0/156.36.0.1 to 6.37.255.2546.37.255.255131,070
206.38.0.0/156.38.0.1 to 6.39.255.2546.39.255.255131,070
216.40.0.0/156.40.0.1 to 6.41.255.2546.41.255.255131,070
226.42.0.0/156.42.0.1 to 6.43.255.2546.43.255.255131,070
236.44.0.0/156.44.0.1 to 6.45.255.2546.45.255.255131,070
246.46.0.0/156.46.0.1 to 6.47.255.2546.47.255.255131,070
256.48.0.0/156.48.0.1 to 6.49.255.2546.49.255.255131,070
266.50.0.0/156.50.0.1 to 6.51.255.2546.51.255.255131,070
276.52.0.0/156.52.0.1 to 6.53.255.2546.53.255.255131,070
286.54.0.0/156.54.0.1 to 6.55.255.2546.55.255.255131,070
296.56.0.0/156.56.0.1 to 6.57.255.2546.57.255.255131,070
306.58.0.0/156.58.0.1 to 6.59.255.2546.59.255.255131,070
316.60.0.0/156.60.0.1 to 6.61.255.2546.61.255.255131,070
326.62.0.0/156.62.0.1 to 6.63.255.2546.63.255.255131,070
336.64.0.0/156.64.0.1 to 6.65.255.2546.65.255.255131,070
346.66.0.0/156.66.0.1 to 6.67.255.2546.67.255.255131,070
356.68.0.0/156.68.0.1 to 6.69.255.2546.69.255.255131,070
366.70.0.0/156.70.0.1 to 6.71.255.2546.71.255.255131,070
376.72.0.0/156.72.0.1 to 6.73.255.2546.73.255.255131,070
386.74.0.0/156.74.0.1 to 6.75.255.2546.75.255.255131,070
396.76.0.0/156.76.0.1 to 6.77.255.2546.77.255.255131,070
406.78.0.0/156.78.0.1 to 6.79.255.2546.79.255.255131,070
416.80.0.0/156.80.0.1 to 6.81.255.2546.81.255.255131,070
426.82.0.0/156.82.0.1 to 6.83.255.2546.83.255.255131,070
436.84.0.0/156.84.0.1 to 6.85.255.2546.85.255.255131,070
446.86.0.0/156.86.0.1 to 6.87.255.2546.87.255.255131,070
456.88.0.0/156.88.0.1 to 6.89.255.2546.89.255.255131,070
466.90.0.0/156.90.0.1 to 6.91.255.2546.91.255.255131,070
476.92.0.0/156.92.0.1 to 6.93.255.2546.93.255.255131,070
486.94.0.0/156.94.0.1 to 6.95.255.2546.95.255.255131,070
496.96.0.0/156.96.0.1 to 6.97.255.2546.97.255.255131,070
506.98.0.0/156.98.0.1 to 6.99.255.2546.99.255.255131,070
516.100.0.0/156.100.0.1 to 6.101.255.2546.101.255.255131,070
526.102.0.0/156.102.0.1 to 6.103.255.2546.103.255.255131,070
536.104.0.0/156.104.0.1 to 6.105.255.2546.105.255.255131,070
546.106.0.0/156.106.0.1 to 6.107.255.2546.107.255.255131,070
556.108.0.0/156.108.0.1 to 6.109.255.2546.109.255.255131,070
566.110.0.0/156.110.0.1 to 6.111.255.2546.111.255.255131,070
576.112.0.0/156.112.0.1 to 6.113.255.2546.113.255.255131,070
586.114.0.0/156.114.0.1 to 6.115.255.2546.115.255.255131,070
596.116.0.0/156.116.0.1 to 6.117.255.2546.117.255.255131,070
606.118.0.0/156.118.0.1 to 6.119.255.2546.119.255.255131,070
616.120.0.0/156.120.0.1 to 6.121.255.2546.121.255.255131,070
626.122.0.0/156.122.0.1 to 6.123.255.2546.123.255.255131,070
636.124.0.0/156.124.0.1 to 6.125.255.2546.125.255.255131,070
646.126.0.0/156.126.0.1 to 6.127.255.2546.127.255.255131,070
656.128.0.0/156.128.0.1 to 6.129.255.2546.129.255.255131,070
666.130.0.0/156.130.0.1 to 6.131.255.2546.131.255.255131,070
676.132.0.0/156.132.0.1 to 6.133.255.2546.133.255.255131,070
686.134.0.0/156.134.0.1 to 6.135.255.2546.135.255.255131,070
696.136.0.0/156.136.0.1 to 6.137.255.2546.137.255.255131,070
706.138.0.0/156.138.0.1 to 6.139.255.2546.139.255.255131,070
716.140.0.0/156.140.0.1 to 6.141.255.2546.141.255.255131,070
726.142.0.0/156.142.0.1 to 6.143.255.2546.143.255.255131,070
736.144.0.0/156.144.0.1 to 6.145.255.2546.145.255.255131,070
746.146.0.0/156.146.0.1 to 6.147.255.2546.147.255.255131,070
756.148.0.0/156.148.0.1 to 6.149.255.2546.149.255.255131,070
766.150.0.0/156.150.0.1 to 6.151.255.2546.151.255.255131,070
776.152.0.0/156.152.0.1 to 6.153.255.2546.153.255.255131,070
786.154.0.0/156.154.0.1 to 6.155.255.2546.155.255.255131,070
796.156.0.0/156.156.0.1 to 6.157.255.2546.157.255.255131,070
806.158.0.0/156.158.0.1 to 6.159.255.2546.159.255.255131,070
816.160.0.0/156.160.0.1 to 6.161.255.2546.161.255.255131,070
826.162.0.0/156.162.0.1 to 6.163.255.2546.163.255.255131,070
836.164.0.0/156.164.0.1 to 6.165.255.2546.165.255.255131,070
846.166.0.0/156.166.0.1 to 6.167.255.2546.167.255.255131,070
856.168.0.0/156.168.0.1 to 6.169.255.2546.169.255.255131,070
866.170.0.0/156.170.0.1 to 6.171.255.2546.171.255.255131,070
876.172.0.0/156.172.0.1 to 6.173.255.2546.173.255.255131,070
886.174.0.0/156.174.0.1 to 6.175.255.2546.175.255.255131,070
896.176.0.0/156.176.0.1 to 6.177.255.2546.177.255.255131,070
906.178.0.0/156.178.0.1 to 6.179.255.2546.179.255.255131,070
916.180.0.0/156.180.0.1 to 6.181.255.2546.181.255.255131,070
926.182.0.0/156.182.0.1 to 6.183.255.2546.183.255.255131,070
936.184.0.0/156.184.0.1 to 6.185.255.2546.185.255.255131,070
946.186.0.0/156.186.0.1 to 6.187.255.2546.187.255.255131,070
956.188.0.0/156.188.0.1 to 6.189.255.2546.189.255.255131,070
966.190.0.0/156.190.0.1 to 6.191.255.2546.191.255.255131,070
976.192.0.0/156.192.0.1 to 6.193.255.2546.193.255.255131,070
986.194.0.0/156.194.0.1 to 6.195.255.2546.195.255.255131,070
996.196.0.0/156.196.0.1 to 6.197.255.2546.197.255.255131,070
1006.198.0.0/156.198.0.1 to 6.199.255.2546.199.255.255131,070
1016.200.0.0/156.200.0.1 to 6.201.255.2546.201.255.255131,070
1026.202.0.0/156.202.0.1 to 6.203.255.2546.203.255.255131,070
1036.204.0.0/156.204.0.1 to 6.205.255.2546.205.255.255131,070
1046.206.0.0/156.206.0.1 to 6.207.255.2546.207.255.255131,070
1056.208.0.0/156.208.0.1 to 6.209.255.2546.209.255.255131,070
1066.210.0.0/156.210.0.1 to 6.211.255.2546.211.255.255131,070
1076.212.0.0/156.212.0.1 to 6.213.255.2546.213.255.255131,070
1086.214.0.0/156.214.0.1 to 6.215.255.2546.215.255.255131,070
1096.216.0.0/156.216.0.1 to 6.217.255.2546.217.255.255131,070
1106.218.0.0/156.218.0.1 to 6.219.255.2546.219.255.255131,070
1116.220.0.0/156.220.0.1 to 6.221.255.2546.221.255.255131,070
1126.222.0.0/156.222.0.1 to 6.223.255.2546.223.255.255131,070
1136.224.0.0/156.224.0.1 to 6.225.255.2546.225.255.255131,070
1146.226.0.0/156.226.0.1 to 6.227.255.2546.227.255.255131,070
1156.228.0.0/156.228.0.1 to 6.229.255.2546.229.255.255131,070
1166.230.0.0/156.230.0.1 to 6.231.255.2546.231.255.255131,070
1176.232.0.0/156.232.0.1 to 6.233.255.2546.233.255.255131,070
1186.234.0.0/156.234.0.1 to 6.235.255.2546.235.255.255131,070
1196.236.0.0/156.236.0.1 to 6.237.255.2546.237.255.255131,070
1206.238.0.0/156.238.0.1 to 6.239.255.2546.239.255.255131,070
1216.240.0.0/156.240.0.1 to 6.241.255.2546.241.255.255131,070
1226.242.0.0/156.242.0.1 to 6.243.255.2546.243.255.255131,070
1236.244.0.0/156.244.0.1 to 6.245.255.2546.245.255.255131,070
1246.246.0.0/156.246.0.1 to 6.247.255.2546.247.255.255131,070
1256.248.0.0/156.248.0.1 to 6.249.255.2546.249.255.255131,070
1266.250.0.0/156.250.0.1 to 6.251.255.2546.251.255.255131,070
1276.252.0.0/156.252.0.1 to 6.253.255.2546.253.255.255131,070
1286.254.0.0/156.254.0.1 to 6.255.255.2546.255.255.255131,070
1297.0.0.0/157.0.0.1 to 7.1.255.2547.1.255.255131,070
1307.2.0.0/157.2.0.1 to 7.3.255.2547.3.255.255131,070
1317.4.0.0/157.4.0.1 to 7.5.255.2547.5.255.255131,070
1327.6.0.0/157.6.0.1 to 7.7.255.2547.7.255.255131,070
1337.8.0.0/157.8.0.1 to 7.9.255.2547.9.255.255131,070
1347.10.0.0/157.10.0.1 to 7.11.255.2547.11.255.255131,070
1357.12.0.0/157.12.0.1 to 7.13.255.2547.13.255.255131,070
1367.14.0.0/157.14.0.1 to 7.15.255.2547.15.255.255131,070
1377.16.0.0/157.16.0.1 to 7.17.255.2547.17.255.255131,070
1387.18.0.0/157.18.0.1 to 7.19.255.2547.19.255.255131,070
1397.20.0.0/157.20.0.1 to 7.21.255.2547.21.255.255131,070
1407.22.0.0/157.22.0.1 to 7.23.255.2547.23.255.255131,070
1417.24.0.0/157.24.0.1 to 7.25.255.2547.25.255.255131,070
1427.26.0.0/157.26.0.1 to 7.27.255.2547.27.255.255131,070
1437.28.0.0/157.28.0.1 to 7.29.255.2547.29.255.255131,070
1447.30.0.0/157.30.0.1 to 7.31.255.2547.31.255.255131,070
1457.32.0.0/157.32.0.1 to 7.33.255.2547.33.255.255131,070
1467.34.0.0/157.34.0.1 to 7.35.255.2547.35.255.255131,070
1477.36.0.0/157.36.0.1 to 7.37.255.2547.37.255.255131,070
1487.38.0.0/157.38.0.1 to 7.39.255.2547.39.255.255131,070
1497.40.0.0/157.40.0.1 to 7.41.255.2547.41.255.255131,070
1507.42.0.0/157.42.0.1 to 7.43.255.2547.43.255.255131,070
1517.44.0.0/157.44.0.1 to 7.45.255.2547.45.255.255131,070
1527.46.0.0/157.46.0.1 to 7.47.255.2547.47.255.255131,070
1537.48.0.0/157.48.0.1 to 7.49.255.2547.49.255.255131,070
1547.50.0.0/157.50.0.1 to 7.51.255.2547.51.255.255131,070
1557.52.0.0/157.52.0.1 to 7.53.255.2547.53.255.255131,070
1567.54.0.0/157.54.0.1 to 7.55.255.2547.55.255.255131,070
1577.56.0.0/157.56.0.1 to 7.57.255.2547.57.255.255131,070
1587.58.0.0/157.58.0.1 to 7.59.255.2547.59.255.255131,070
1597.60.0.0/157.60.0.1 to 7.61.255.2547.61.255.255131,070
1607.62.0.0/157.62.0.1 to 7.63.255.2547.63.255.255131,070
1617.64.0.0/157.64.0.1 to 7.65.255.2547.65.255.255131,070
1627.66.0.0/157.66.0.1 to 7.67.255.2547.67.255.255131,070
1637.68.0.0/157.68.0.1 to 7.69.255.2547.69.255.255131,070
1647.70.0.0/157.70.0.1 to 7.71.255.2547.71.255.255131,070
1657.72.0.0/157.72.0.1 to 7.73.255.2547.73.255.255131,070
1667.74.0.0/157.74.0.1 to 7.75.255.2547.75.255.255131,070
1677.76.0.0/157.76.0.1 to 7.77.255.2547.77.255.255131,070
1687.78.0.0/157.78.0.1 to 7.79.255.2547.79.255.255131,070
1697.80.0.0/157.80.0.1 to 7.81.255.2547.81.255.255131,070
1707.82.0.0/157.82.0.1 to 7.83.255.2547.83.255.255131,070
1717.84.0.0/157.84.0.1 to 7.85.255.2547.85.255.255131,070
1727.86.0.0/157.86.0.1 to 7.87.255.2547.87.255.255131,070
1737.88.0.0/157.88.0.1 to 7.89.255.2547.89.255.255131,070
1747.90.0.0/157.90.0.1 to 7.91.255.2547.91.255.255131,070
1757.92.0.0/157.92.0.1 to 7.93.255.2547.93.255.255131,070
1767.94.0.0/157.94.0.1 to 7.95.255.2547.95.255.255131,070
1777.96.0.0/157.96.0.1 to 7.97.255.2547.97.255.255131,070
1787.98.0.0/157.98.0.1 to 7.99.255.2547.99.255.255131,070
1797.100.0.0/157.100.0.1 to 7.101.255.2547.101.255.255131,070
1807.102.0.0/157.102.0.1 to 7.103.255.2547.103.255.255131,070
1817.104.0.0/157.104.0.1 to 7.105.255.2547.105.255.255131,070
1827.106.0.0/157.106.0.1 to 7.107.255.2547.107.255.255131,070
1837.108.0.0/157.108.0.1 to 7.109.255.2547.109.255.255131,070
1847.110.0.0/157.110.0.1 to 7.111.255.2547.111.255.255131,070
1857.112.0.0/157.112.0.1 to 7.113.255.2547.113.255.255131,070
1867.114.0.0/157.114.0.1 to 7.115.255.2547.115.255.255131,070
1877.116.0.0/157.116.0.1 to 7.117.255.2547.117.255.255131,070
1887.118.0.0/157.118.0.1 to 7.119.255.2547.119.255.255131,070
1897.120.0.0/157.120.0.1 to 7.121.255.2547.121.255.255131,070
1907.122.0.0/157.122.0.1 to 7.123.255.2547.123.255.255131,070
1917.124.0.0/157.124.0.1 to 7.125.255.2547.125.255.255131,070
1927.126.0.0/157.126.0.1 to 7.127.255.2547.127.255.255131,070
1937.128.0.0/157.128.0.1 to 7.129.255.2547.129.255.255131,070
1947.130.0.0/157.130.0.1 to 7.131.255.2547.131.255.255131,070
1957.132.0.0/157.132.0.1 to 7.133.255.2547.133.255.255131,070
1967.134.0.0/157.134.0.1 to 7.135.255.2547.135.255.255131,070
1977.136.0.0/157.136.0.1 to 7.137.255.2547.137.255.255131,070
1987.138.0.0/157.138.0.1 to 7.139.255.2547.139.255.255131,070
1997.140.0.0/157.140.0.1 to 7.141.255.2547.141.255.255131,070
2007.142.0.0/157.142.0.1 to 7.143.255.2547.143.255.255131,070
2017.144.0.0/157.144.0.1 to 7.145.255.2547.145.255.255131,070
2027.146.0.0/157.146.0.1 to 7.147.255.2547.147.255.255131,070
2037.148.0.0/157.148.0.1 to 7.149.255.2547.149.255.255131,070
2047.150.0.0/157.150.0.1 to 7.151.255.2547.151.255.255131,070
2057.152.0.0/157.152.0.1 to 7.153.255.2547.153.255.255131,070
2067.154.0.0/157.154.0.1 to 7.155.255.2547.155.255.255131,070
2077.156.0.0/157.156.0.1 to 7.157.255.2547.157.255.255131,070
2087.158.0.0/157.158.0.1 to 7.159.255.2547.159.255.255131,070
2097.160.0.0/157.160.0.1 to 7.161.255.2547.161.255.255131,070
2107.162.0.0/157.162.0.1 to 7.163.255.2547.163.255.255131,070
2117.164.0.0/157.164.0.1 to 7.165.255.2547.165.255.255131,070
2127.166.0.0/157.166.0.1 to 7.167.255.2547.167.255.255131,070
2137.168.0.0/157.168.0.1 to 7.169.255.2547.169.255.255131,070
2147.170.0.0/157.170.0.1 to 7.171.255.2547.171.255.255131,070
2157.172.0.0/157.172.0.1 to 7.173.255.2547.173.255.255131,070
2167.174.0.0/157.174.0.1 to 7.175.255.2547.175.255.255131,070
2177.176.0.0/157.176.0.1 to 7.177.255.2547.177.255.255131,070
2187.178.0.0/157.178.0.1 to 7.179.255.2547.179.255.255131,070
2197.180.0.0/157.180.0.1 to 7.181.255.2547.181.255.255131,070
2207.182.0.0/157.182.0.1 to 7.183.255.2547.183.255.255131,070
2217.184.0.0/157.184.0.1 to 7.185.255.2547.185.255.255131,070
2227.186.0.0/157.186.0.1 to 7.187.255.2547.187.255.255131,070
2237.188.0.0/157.188.0.1 to 7.189.255.2547.189.255.255131,070
2247.190.0.0/157.190.0.1 to 7.191.255.2547.191.255.255131,070
2257.192.0.0/157.192.0.1 to 7.193.255.2547.193.255.255131,070
2267.194.0.0/157.194.0.1 to 7.195.255.2547.195.255.255131,070
2277.196.0.0/157.196.0.1 to 7.197.255.2547.197.255.255131,070
2287.198.0.0/157.198.0.1 to 7.199.255.2547.199.255.255131,070
2297.200.0.0/157.200.0.1 to 7.201.255.2547.201.255.255131,070
2307.202.0.0/157.202.0.1 to 7.203.255.2547.203.255.255131,070
2317.204.0.0/157.204.0.1 to 7.205.255.2547.205.255.255131,070
2327.206.0.0/157.206.0.1 to 7.207.255.2547.207.255.255131,070
2337.208.0.0/157.208.0.1 to 7.209.255.2547.209.255.255131,070
2347.210.0.0/157.210.0.1 to 7.211.255.2547.211.255.255131,070
2357.212.0.0/157.212.0.1 to 7.213.255.2547.213.255.255131,070
2367.214.0.0/157.214.0.1 to 7.215.255.2547.215.255.255131,070
2377.216.0.0/157.216.0.1 to 7.217.255.2547.217.255.255131,070
2387.218.0.0/157.218.0.1 to 7.219.255.2547.219.255.255131,070
2397.220.0.0/157.220.0.1 to 7.221.255.2547.221.255.255131,070
2407.222.0.0/157.222.0.1 to 7.223.255.2547.223.255.255131,070
2417.224.0.0/157.224.0.1 to 7.225.255.2547.225.255.255131,070
2427.226.0.0/157.226.0.1 to 7.227.255.2547.227.255.255131,070
2437.228.0.0/157.228.0.1 to 7.229.255.2547.229.255.255131,070
2447.230.0.0/157.230.0.1 to 7.231.255.2547.231.255.255131,070
2457.232.0.0/157.232.0.1 to 7.233.255.2547.233.255.255131,070
2467.234.0.0/157.234.0.1 to 7.235.255.2547.235.255.255131,070
2477.236.0.0/157.236.0.1 to 7.237.255.2547.237.255.255131,070
2487.238.0.0/157.238.0.1 to 7.239.255.2547.239.255.255131,070
2497.240.0.0/157.240.0.1 to 7.241.255.2547.241.255.255131,070
2507.242.0.0/157.242.0.1 to 7.243.255.2547.243.255.255131,070
2517.244.0.0/157.244.0.1 to 7.245.255.2547.245.255.255131,070
2527.246.0.0/157.246.0.1 to 7.247.255.2547.247.255.255131,070
2537.248.0.0/157.248.0.1 to 7.249.255.2547.249.255.255131,070
2547.250.0.0/157.250.0.1 to 7.251.255.2547.251.255.255131,070
2557.252.0.0/157.252.0.1 to 7.253.255.2547.253.255.255131,070
2567.254.0.0/157.254.0.1 to 7.255.255.2547.255.255.255131,070

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.