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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.

Network4.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
4.0.0.0
Broadcast address
5.255.255.255
First usable
4.0.0.1
Last usable
5.255.255.254
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 04000000 · Integer 67108864 to 100663295
Reverse DNS zones
4.in-addr.arpa
5.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
Address00000100.00000000.00000000.000000004.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000100.00000000.00000000.000000004.0.0.0
Broadcast00000101.11111111.11111111.111111115.255.255.255
Split into smaller subnets/16
/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)

4.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.0.0.0/164.0.0.1 to 4.0.255.2544.0.255.25565,534
24.1.0.0/164.1.0.1 to 4.1.255.2544.1.255.25565,534
34.2.0.0/164.2.0.1 to 4.2.255.2544.2.255.25565,534
44.3.0.0/164.3.0.1 to 4.3.255.2544.3.255.25565,534
54.4.0.0/164.4.0.1 to 4.4.255.2544.4.255.25565,534
64.5.0.0/164.5.0.1 to 4.5.255.2544.5.255.25565,534
74.6.0.0/164.6.0.1 to 4.6.255.2544.6.255.25565,534
84.7.0.0/164.7.0.1 to 4.7.255.2544.7.255.25565,534
94.8.0.0/164.8.0.1 to 4.8.255.2544.8.255.25565,534
104.9.0.0/164.9.0.1 to 4.9.255.2544.9.255.25565,534
114.10.0.0/164.10.0.1 to 4.10.255.2544.10.255.25565,534
124.11.0.0/164.11.0.1 to 4.11.255.2544.11.255.25565,534
134.12.0.0/164.12.0.1 to 4.12.255.2544.12.255.25565,534
144.13.0.0/164.13.0.1 to 4.13.255.2544.13.255.25565,534
154.14.0.0/164.14.0.1 to 4.14.255.2544.14.255.25565,534
164.15.0.0/164.15.0.1 to 4.15.255.2544.15.255.25565,534
174.16.0.0/164.16.0.1 to 4.16.255.2544.16.255.25565,534
184.17.0.0/164.17.0.1 to 4.17.255.2544.17.255.25565,534
194.18.0.0/164.18.0.1 to 4.18.255.2544.18.255.25565,534
204.19.0.0/164.19.0.1 to 4.19.255.2544.19.255.25565,534
214.20.0.0/164.20.0.1 to 4.20.255.2544.20.255.25565,534
224.21.0.0/164.21.0.1 to 4.21.255.2544.21.255.25565,534
234.22.0.0/164.22.0.1 to 4.22.255.2544.22.255.25565,534
244.23.0.0/164.23.0.1 to 4.23.255.2544.23.255.25565,534
254.24.0.0/164.24.0.1 to 4.24.255.2544.24.255.25565,534
264.25.0.0/164.25.0.1 to 4.25.255.2544.25.255.25565,534
274.26.0.0/164.26.0.1 to 4.26.255.2544.26.255.25565,534
284.27.0.0/164.27.0.1 to 4.27.255.2544.27.255.25565,534
294.28.0.0/164.28.0.1 to 4.28.255.2544.28.255.25565,534
304.29.0.0/164.29.0.1 to 4.29.255.2544.29.255.25565,534
314.30.0.0/164.30.0.1 to 4.30.255.2544.30.255.25565,534
324.31.0.0/164.31.0.1 to 4.31.255.2544.31.255.25565,534
334.32.0.0/164.32.0.1 to 4.32.255.2544.32.255.25565,534
344.33.0.0/164.33.0.1 to 4.33.255.2544.33.255.25565,534
354.34.0.0/164.34.0.1 to 4.34.255.2544.34.255.25565,534
364.35.0.0/164.35.0.1 to 4.35.255.2544.35.255.25565,534
374.36.0.0/164.36.0.1 to 4.36.255.2544.36.255.25565,534
384.37.0.0/164.37.0.1 to 4.37.255.2544.37.255.25565,534
394.38.0.0/164.38.0.1 to 4.38.255.2544.38.255.25565,534
404.39.0.0/164.39.0.1 to 4.39.255.2544.39.255.25565,534
414.40.0.0/164.40.0.1 to 4.40.255.2544.40.255.25565,534
424.41.0.0/164.41.0.1 to 4.41.255.2544.41.255.25565,534
434.42.0.0/164.42.0.1 to 4.42.255.2544.42.255.25565,534
444.43.0.0/164.43.0.1 to 4.43.255.2544.43.255.25565,534
454.44.0.0/164.44.0.1 to 4.44.255.2544.44.255.25565,534
464.45.0.0/164.45.0.1 to 4.45.255.2544.45.255.25565,534
474.46.0.0/164.46.0.1 to 4.46.255.2544.46.255.25565,534
484.47.0.0/164.47.0.1 to 4.47.255.2544.47.255.25565,534
494.48.0.0/164.48.0.1 to 4.48.255.2544.48.255.25565,534
504.49.0.0/164.49.0.1 to 4.49.255.2544.49.255.25565,534
514.50.0.0/164.50.0.1 to 4.50.255.2544.50.255.25565,534
524.51.0.0/164.51.0.1 to 4.51.255.2544.51.255.25565,534
534.52.0.0/164.52.0.1 to 4.52.255.2544.52.255.25565,534
544.53.0.0/164.53.0.1 to 4.53.255.2544.53.255.25565,534
554.54.0.0/164.54.0.1 to 4.54.255.2544.54.255.25565,534
564.55.0.0/164.55.0.1 to 4.55.255.2544.55.255.25565,534
574.56.0.0/164.56.0.1 to 4.56.255.2544.56.255.25565,534
584.57.0.0/164.57.0.1 to 4.57.255.2544.57.255.25565,534
594.58.0.0/164.58.0.1 to 4.58.255.2544.58.255.25565,534
604.59.0.0/164.59.0.1 to 4.59.255.2544.59.255.25565,534
614.60.0.0/164.60.0.1 to 4.60.255.2544.60.255.25565,534
624.61.0.0/164.61.0.1 to 4.61.255.2544.61.255.25565,534
634.62.0.0/164.62.0.1 to 4.62.255.2544.62.255.25565,534
644.63.0.0/164.63.0.1 to 4.63.255.2544.63.255.25565,534
654.64.0.0/164.64.0.1 to 4.64.255.2544.64.255.25565,534
664.65.0.0/164.65.0.1 to 4.65.255.2544.65.255.25565,534
674.66.0.0/164.66.0.1 to 4.66.255.2544.66.255.25565,534
684.67.0.0/164.67.0.1 to 4.67.255.2544.67.255.25565,534
694.68.0.0/164.68.0.1 to 4.68.255.2544.68.255.25565,534
704.69.0.0/164.69.0.1 to 4.69.255.2544.69.255.25565,534
714.70.0.0/164.70.0.1 to 4.70.255.2544.70.255.25565,534
724.71.0.0/164.71.0.1 to 4.71.255.2544.71.255.25565,534
734.72.0.0/164.72.0.1 to 4.72.255.2544.72.255.25565,534
744.73.0.0/164.73.0.1 to 4.73.255.2544.73.255.25565,534
754.74.0.0/164.74.0.1 to 4.74.255.2544.74.255.25565,534
764.75.0.0/164.75.0.1 to 4.75.255.2544.75.255.25565,534
774.76.0.0/164.76.0.1 to 4.76.255.2544.76.255.25565,534
784.77.0.0/164.77.0.1 to 4.77.255.2544.77.255.25565,534
794.78.0.0/164.78.0.1 to 4.78.255.2544.78.255.25565,534
804.79.0.0/164.79.0.1 to 4.79.255.2544.79.255.25565,534
814.80.0.0/164.80.0.1 to 4.80.255.2544.80.255.25565,534
824.81.0.0/164.81.0.1 to 4.81.255.2544.81.255.25565,534
834.82.0.0/164.82.0.1 to 4.82.255.2544.82.255.25565,534
844.83.0.0/164.83.0.1 to 4.83.255.2544.83.255.25565,534
854.84.0.0/164.84.0.1 to 4.84.255.2544.84.255.25565,534
864.85.0.0/164.85.0.1 to 4.85.255.2544.85.255.25565,534
874.86.0.0/164.86.0.1 to 4.86.255.2544.86.255.25565,534
884.87.0.0/164.87.0.1 to 4.87.255.2544.87.255.25565,534
894.88.0.0/164.88.0.1 to 4.88.255.2544.88.255.25565,534
904.89.0.0/164.89.0.1 to 4.89.255.2544.89.255.25565,534
914.90.0.0/164.90.0.1 to 4.90.255.2544.90.255.25565,534
924.91.0.0/164.91.0.1 to 4.91.255.2544.91.255.25565,534
934.92.0.0/164.92.0.1 to 4.92.255.2544.92.255.25565,534
944.93.0.0/164.93.0.1 to 4.93.255.2544.93.255.25565,534
954.94.0.0/164.94.0.1 to 4.94.255.2544.94.255.25565,534
964.95.0.0/164.95.0.1 to 4.95.255.2544.95.255.25565,534
974.96.0.0/164.96.0.1 to 4.96.255.2544.96.255.25565,534
984.97.0.0/164.97.0.1 to 4.97.255.2544.97.255.25565,534
994.98.0.0/164.98.0.1 to 4.98.255.2544.98.255.25565,534
1004.99.0.0/164.99.0.1 to 4.99.255.2544.99.255.25565,534
1014.100.0.0/164.100.0.1 to 4.100.255.2544.100.255.25565,534
1024.101.0.0/164.101.0.1 to 4.101.255.2544.101.255.25565,534
1034.102.0.0/164.102.0.1 to 4.102.255.2544.102.255.25565,534
1044.103.0.0/164.103.0.1 to 4.103.255.2544.103.255.25565,534
1054.104.0.0/164.104.0.1 to 4.104.255.2544.104.255.25565,534
1064.105.0.0/164.105.0.1 to 4.105.255.2544.105.255.25565,534
1074.106.0.0/164.106.0.1 to 4.106.255.2544.106.255.25565,534
1084.107.0.0/164.107.0.1 to 4.107.255.2544.107.255.25565,534
1094.108.0.0/164.108.0.1 to 4.108.255.2544.108.255.25565,534
1104.109.0.0/164.109.0.1 to 4.109.255.2544.109.255.25565,534
1114.110.0.0/164.110.0.1 to 4.110.255.2544.110.255.25565,534
1124.111.0.0/164.111.0.1 to 4.111.255.2544.111.255.25565,534
1134.112.0.0/164.112.0.1 to 4.112.255.2544.112.255.25565,534
1144.113.0.0/164.113.0.1 to 4.113.255.2544.113.255.25565,534
1154.114.0.0/164.114.0.1 to 4.114.255.2544.114.255.25565,534
1164.115.0.0/164.115.0.1 to 4.115.255.2544.115.255.25565,534
1174.116.0.0/164.116.0.1 to 4.116.255.2544.116.255.25565,534
1184.117.0.0/164.117.0.1 to 4.117.255.2544.117.255.25565,534
1194.118.0.0/164.118.0.1 to 4.118.255.2544.118.255.25565,534
1204.119.0.0/164.119.0.1 to 4.119.255.2544.119.255.25565,534
1214.120.0.0/164.120.0.1 to 4.120.255.2544.120.255.25565,534
1224.121.0.0/164.121.0.1 to 4.121.255.2544.121.255.25565,534
1234.122.0.0/164.122.0.1 to 4.122.255.2544.122.255.25565,534
1244.123.0.0/164.123.0.1 to 4.123.255.2544.123.255.25565,534
1254.124.0.0/164.124.0.1 to 4.124.255.2544.124.255.25565,534
1264.125.0.0/164.125.0.1 to 4.125.255.2544.125.255.25565,534
1274.126.0.0/164.126.0.1 to 4.126.255.2544.126.255.25565,534
1284.127.0.0/164.127.0.1 to 4.127.255.2544.127.255.25565,534
1294.128.0.0/164.128.0.1 to 4.128.255.2544.128.255.25565,534
1304.129.0.0/164.129.0.1 to 4.129.255.2544.129.255.25565,534
1314.130.0.0/164.130.0.1 to 4.130.255.2544.130.255.25565,534
1324.131.0.0/164.131.0.1 to 4.131.255.2544.131.255.25565,534
1334.132.0.0/164.132.0.1 to 4.132.255.2544.132.255.25565,534
1344.133.0.0/164.133.0.1 to 4.133.255.2544.133.255.25565,534
1354.134.0.0/164.134.0.1 to 4.134.255.2544.134.255.25565,534
1364.135.0.0/164.135.0.1 to 4.135.255.2544.135.255.25565,534
1374.136.0.0/164.136.0.1 to 4.136.255.2544.136.255.25565,534
1384.137.0.0/164.137.0.1 to 4.137.255.2544.137.255.25565,534
1394.138.0.0/164.138.0.1 to 4.138.255.2544.138.255.25565,534
1404.139.0.0/164.139.0.1 to 4.139.255.2544.139.255.25565,534
1414.140.0.0/164.140.0.1 to 4.140.255.2544.140.255.25565,534
1424.141.0.0/164.141.0.1 to 4.141.255.2544.141.255.25565,534
1434.142.0.0/164.142.0.1 to 4.142.255.2544.142.255.25565,534
1444.143.0.0/164.143.0.1 to 4.143.255.2544.143.255.25565,534
1454.144.0.0/164.144.0.1 to 4.144.255.2544.144.255.25565,534
1464.145.0.0/164.145.0.1 to 4.145.255.2544.145.255.25565,534
1474.146.0.0/164.146.0.1 to 4.146.255.2544.146.255.25565,534
1484.147.0.0/164.147.0.1 to 4.147.255.2544.147.255.25565,534
1494.148.0.0/164.148.0.1 to 4.148.255.2544.148.255.25565,534
1504.149.0.0/164.149.0.1 to 4.149.255.2544.149.255.25565,534
1514.150.0.0/164.150.0.1 to 4.150.255.2544.150.255.25565,534
1524.151.0.0/164.151.0.1 to 4.151.255.2544.151.255.25565,534
1534.152.0.0/164.152.0.1 to 4.152.255.2544.152.255.25565,534
1544.153.0.0/164.153.0.1 to 4.153.255.2544.153.255.25565,534
1554.154.0.0/164.154.0.1 to 4.154.255.2544.154.255.25565,534
1564.155.0.0/164.155.0.1 to 4.155.255.2544.155.255.25565,534
1574.156.0.0/164.156.0.1 to 4.156.255.2544.156.255.25565,534
1584.157.0.0/164.157.0.1 to 4.157.255.2544.157.255.25565,534
1594.158.0.0/164.158.0.1 to 4.158.255.2544.158.255.25565,534
1604.159.0.0/164.159.0.1 to 4.159.255.2544.159.255.25565,534
1614.160.0.0/164.160.0.1 to 4.160.255.2544.160.255.25565,534
1624.161.0.0/164.161.0.1 to 4.161.255.2544.161.255.25565,534
1634.162.0.0/164.162.0.1 to 4.162.255.2544.162.255.25565,534
1644.163.0.0/164.163.0.1 to 4.163.255.2544.163.255.25565,534
1654.164.0.0/164.164.0.1 to 4.164.255.2544.164.255.25565,534
1664.165.0.0/164.165.0.1 to 4.165.255.2544.165.255.25565,534
1674.166.0.0/164.166.0.1 to 4.166.255.2544.166.255.25565,534
1684.167.0.0/164.167.0.1 to 4.167.255.2544.167.255.25565,534
1694.168.0.0/164.168.0.1 to 4.168.255.2544.168.255.25565,534
1704.169.0.0/164.169.0.1 to 4.169.255.2544.169.255.25565,534
1714.170.0.0/164.170.0.1 to 4.170.255.2544.170.255.25565,534
1724.171.0.0/164.171.0.1 to 4.171.255.2544.171.255.25565,534
1734.172.0.0/164.172.0.1 to 4.172.255.2544.172.255.25565,534
1744.173.0.0/164.173.0.1 to 4.173.255.2544.173.255.25565,534
1754.174.0.0/164.174.0.1 to 4.174.255.2544.174.255.25565,534
1764.175.0.0/164.175.0.1 to 4.175.255.2544.175.255.25565,534
1774.176.0.0/164.176.0.1 to 4.176.255.2544.176.255.25565,534
1784.177.0.0/164.177.0.1 to 4.177.255.2544.177.255.25565,534
1794.178.0.0/164.178.0.1 to 4.178.255.2544.178.255.25565,534
1804.179.0.0/164.179.0.1 to 4.179.255.2544.179.255.25565,534
1814.180.0.0/164.180.0.1 to 4.180.255.2544.180.255.25565,534
1824.181.0.0/164.181.0.1 to 4.181.255.2544.181.255.25565,534
1834.182.0.0/164.182.0.1 to 4.182.255.2544.182.255.25565,534
1844.183.0.0/164.183.0.1 to 4.183.255.2544.183.255.25565,534
1854.184.0.0/164.184.0.1 to 4.184.255.2544.184.255.25565,534
1864.185.0.0/164.185.0.1 to 4.185.255.2544.185.255.25565,534
1874.186.0.0/164.186.0.1 to 4.186.255.2544.186.255.25565,534
1884.187.0.0/164.187.0.1 to 4.187.255.2544.187.255.25565,534
1894.188.0.0/164.188.0.1 to 4.188.255.2544.188.255.25565,534
1904.189.0.0/164.189.0.1 to 4.189.255.2544.189.255.25565,534
1914.190.0.0/164.190.0.1 to 4.190.255.2544.190.255.25565,534
1924.191.0.0/164.191.0.1 to 4.191.255.2544.191.255.25565,534
1934.192.0.0/164.192.0.1 to 4.192.255.2544.192.255.25565,534
1944.193.0.0/164.193.0.1 to 4.193.255.2544.193.255.25565,534
1954.194.0.0/164.194.0.1 to 4.194.255.2544.194.255.25565,534
1964.195.0.0/164.195.0.1 to 4.195.255.2544.195.255.25565,534
1974.196.0.0/164.196.0.1 to 4.196.255.2544.196.255.25565,534
1984.197.0.0/164.197.0.1 to 4.197.255.2544.197.255.25565,534
1994.198.0.0/164.198.0.1 to 4.198.255.2544.198.255.25565,534
2004.199.0.0/164.199.0.1 to 4.199.255.2544.199.255.25565,534
2014.200.0.0/164.200.0.1 to 4.200.255.2544.200.255.25565,534
2024.201.0.0/164.201.0.1 to 4.201.255.2544.201.255.25565,534
2034.202.0.0/164.202.0.1 to 4.202.255.2544.202.255.25565,534
2044.203.0.0/164.203.0.1 to 4.203.255.2544.203.255.25565,534
2054.204.0.0/164.204.0.1 to 4.204.255.2544.204.255.25565,534
2064.205.0.0/164.205.0.1 to 4.205.255.2544.205.255.25565,534
2074.206.0.0/164.206.0.1 to 4.206.255.2544.206.255.25565,534
2084.207.0.0/164.207.0.1 to 4.207.255.2544.207.255.25565,534
2094.208.0.0/164.208.0.1 to 4.208.255.2544.208.255.25565,534
2104.209.0.0/164.209.0.1 to 4.209.255.2544.209.255.25565,534
2114.210.0.0/164.210.0.1 to 4.210.255.2544.210.255.25565,534
2124.211.0.0/164.211.0.1 to 4.211.255.2544.211.255.25565,534
2134.212.0.0/164.212.0.1 to 4.212.255.2544.212.255.25565,534
2144.213.0.0/164.213.0.1 to 4.213.255.2544.213.255.25565,534
2154.214.0.0/164.214.0.1 to 4.214.255.2544.214.255.25565,534
2164.215.0.0/164.215.0.1 to 4.215.255.2544.215.255.25565,534
2174.216.0.0/164.216.0.1 to 4.216.255.2544.216.255.25565,534
2184.217.0.0/164.217.0.1 to 4.217.255.2544.217.255.25565,534
2194.218.0.0/164.218.0.1 to 4.218.255.2544.218.255.25565,534
2204.219.0.0/164.219.0.1 to 4.219.255.2544.219.255.25565,534
2214.220.0.0/164.220.0.1 to 4.220.255.2544.220.255.25565,534
2224.221.0.0/164.221.0.1 to 4.221.255.2544.221.255.25565,534
2234.222.0.0/164.222.0.1 to 4.222.255.2544.222.255.25565,534
2244.223.0.0/164.223.0.1 to 4.223.255.2544.223.255.25565,534
2254.224.0.0/164.224.0.1 to 4.224.255.2544.224.255.25565,534
2264.225.0.0/164.225.0.1 to 4.225.255.2544.225.255.25565,534
2274.226.0.0/164.226.0.1 to 4.226.255.2544.226.255.25565,534
2284.227.0.0/164.227.0.1 to 4.227.255.2544.227.255.25565,534
2294.228.0.0/164.228.0.1 to 4.228.255.2544.228.255.25565,534
2304.229.0.0/164.229.0.1 to 4.229.255.2544.229.255.25565,534
2314.230.0.0/164.230.0.1 to 4.230.255.2544.230.255.25565,534
2324.231.0.0/164.231.0.1 to 4.231.255.2544.231.255.25565,534
2334.232.0.0/164.232.0.1 to 4.232.255.2544.232.255.25565,534
2344.233.0.0/164.233.0.1 to 4.233.255.2544.233.255.25565,534
2354.234.0.0/164.234.0.1 to 4.234.255.2544.234.255.25565,534
2364.235.0.0/164.235.0.1 to 4.235.255.2544.235.255.25565,534
2374.236.0.0/164.236.0.1 to 4.236.255.2544.236.255.25565,534
2384.237.0.0/164.237.0.1 to 4.237.255.2544.237.255.25565,534
2394.238.0.0/164.238.0.1 to 4.238.255.2544.238.255.25565,534
2404.239.0.0/164.239.0.1 to 4.239.255.2544.239.255.25565,534
2414.240.0.0/164.240.0.1 to 4.240.255.2544.240.255.25565,534
2424.241.0.0/164.241.0.1 to 4.241.255.2544.241.255.25565,534
2434.242.0.0/164.242.0.1 to 4.242.255.2544.242.255.25565,534
2444.243.0.0/164.243.0.1 to 4.243.255.2544.243.255.25565,534
2454.244.0.0/164.244.0.1 to 4.244.255.2544.244.255.25565,534
2464.245.0.0/164.245.0.1 to 4.245.255.2544.245.255.25565,534
2474.246.0.0/164.246.0.1 to 4.246.255.2544.246.255.25565,534
2484.247.0.0/164.247.0.1 to 4.247.255.2544.247.255.25565,534
2494.248.0.0/164.248.0.1 to 4.248.255.2544.248.255.25565,534
2504.249.0.0/164.249.0.1 to 4.249.255.2544.249.255.25565,534
2514.250.0.0/164.250.0.1 to 4.250.255.2544.250.255.25565,534
2524.251.0.0/164.251.0.1 to 4.251.255.2544.251.255.25565,534
2534.252.0.0/164.252.0.1 to 4.252.255.2544.252.255.25565,534
2544.253.0.0/164.253.0.1 to 4.253.255.2544.253.255.25565,534
2554.254.0.0/164.254.0.1 to 4.254.255.2544.254.255.25565,534
2564.255.0.0/164.255.0.1 to 4.255.255.2544.255.255.25565,534

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.