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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.

Network4.16.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
4.16.0.0
Broadcast address
4.23.255.255
First usable
4.16.0.1
Last usable
4.23.255.254
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 04100000 · Integer 68157440 to 68681727
Reverse DNS zones
16.4.in-addr.arpa
17.4.in-addr.arpa
18.4.in-addr.arpa
19.4.in-addr.arpa
20.4.in-addr.arpa
21.4.in-addr.arpa
22.4.in-addr.arpa
23.4.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
Address00000100.00010000.00000000.000000004.16.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00000100.00010000.00000000.000000004.16.0.0
Broadcast00000100.00010111.11111111.111111114.23.255.255
Split into smaller subnets/23
/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)

4.16.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.16.0.0/234.16.0.1 to 4.16.1.2544.16.1.255510
24.16.2.0/234.16.2.1 to 4.16.3.2544.16.3.255510
34.16.4.0/234.16.4.1 to 4.16.5.2544.16.5.255510
44.16.6.0/234.16.6.1 to 4.16.7.2544.16.7.255510
54.16.8.0/234.16.8.1 to 4.16.9.2544.16.9.255510
64.16.10.0/234.16.10.1 to 4.16.11.2544.16.11.255510
74.16.12.0/234.16.12.1 to 4.16.13.2544.16.13.255510
84.16.14.0/234.16.14.1 to 4.16.15.2544.16.15.255510
94.16.16.0/234.16.16.1 to 4.16.17.2544.16.17.255510
104.16.18.0/234.16.18.1 to 4.16.19.2544.16.19.255510
114.16.20.0/234.16.20.1 to 4.16.21.2544.16.21.255510
124.16.22.0/234.16.22.1 to 4.16.23.2544.16.23.255510
134.16.24.0/234.16.24.1 to 4.16.25.2544.16.25.255510
144.16.26.0/234.16.26.1 to 4.16.27.2544.16.27.255510
154.16.28.0/234.16.28.1 to 4.16.29.2544.16.29.255510
164.16.30.0/234.16.30.1 to 4.16.31.2544.16.31.255510
174.16.32.0/234.16.32.1 to 4.16.33.2544.16.33.255510
184.16.34.0/234.16.34.1 to 4.16.35.2544.16.35.255510
194.16.36.0/234.16.36.1 to 4.16.37.2544.16.37.255510
204.16.38.0/234.16.38.1 to 4.16.39.2544.16.39.255510
214.16.40.0/234.16.40.1 to 4.16.41.2544.16.41.255510
224.16.42.0/234.16.42.1 to 4.16.43.2544.16.43.255510
234.16.44.0/234.16.44.1 to 4.16.45.2544.16.45.255510
244.16.46.0/234.16.46.1 to 4.16.47.2544.16.47.255510
254.16.48.0/234.16.48.1 to 4.16.49.2544.16.49.255510
264.16.50.0/234.16.50.1 to 4.16.51.2544.16.51.255510
274.16.52.0/234.16.52.1 to 4.16.53.2544.16.53.255510
284.16.54.0/234.16.54.1 to 4.16.55.2544.16.55.255510
294.16.56.0/234.16.56.1 to 4.16.57.2544.16.57.255510
304.16.58.0/234.16.58.1 to 4.16.59.2544.16.59.255510
314.16.60.0/234.16.60.1 to 4.16.61.2544.16.61.255510
324.16.62.0/234.16.62.1 to 4.16.63.2544.16.63.255510
334.16.64.0/234.16.64.1 to 4.16.65.2544.16.65.255510
344.16.66.0/234.16.66.1 to 4.16.67.2544.16.67.255510
354.16.68.0/234.16.68.1 to 4.16.69.2544.16.69.255510
364.16.70.0/234.16.70.1 to 4.16.71.2544.16.71.255510
374.16.72.0/234.16.72.1 to 4.16.73.2544.16.73.255510
384.16.74.0/234.16.74.1 to 4.16.75.2544.16.75.255510
394.16.76.0/234.16.76.1 to 4.16.77.2544.16.77.255510
404.16.78.0/234.16.78.1 to 4.16.79.2544.16.79.255510
414.16.80.0/234.16.80.1 to 4.16.81.2544.16.81.255510
424.16.82.0/234.16.82.1 to 4.16.83.2544.16.83.255510
434.16.84.0/234.16.84.1 to 4.16.85.2544.16.85.255510
444.16.86.0/234.16.86.1 to 4.16.87.2544.16.87.255510
454.16.88.0/234.16.88.1 to 4.16.89.2544.16.89.255510
464.16.90.0/234.16.90.1 to 4.16.91.2544.16.91.255510
474.16.92.0/234.16.92.1 to 4.16.93.2544.16.93.255510
484.16.94.0/234.16.94.1 to 4.16.95.2544.16.95.255510
494.16.96.0/234.16.96.1 to 4.16.97.2544.16.97.255510
504.16.98.0/234.16.98.1 to 4.16.99.2544.16.99.255510
514.16.100.0/234.16.100.1 to 4.16.101.2544.16.101.255510
524.16.102.0/234.16.102.1 to 4.16.103.2544.16.103.255510
534.16.104.0/234.16.104.1 to 4.16.105.2544.16.105.255510
544.16.106.0/234.16.106.1 to 4.16.107.2544.16.107.255510
554.16.108.0/234.16.108.1 to 4.16.109.2544.16.109.255510
564.16.110.0/234.16.110.1 to 4.16.111.2544.16.111.255510
574.16.112.0/234.16.112.1 to 4.16.113.2544.16.113.255510
584.16.114.0/234.16.114.1 to 4.16.115.2544.16.115.255510
594.16.116.0/234.16.116.1 to 4.16.117.2544.16.117.255510
604.16.118.0/234.16.118.1 to 4.16.119.2544.16.119.255510
614.16.120.0/234.16.120.1 to 4.16.121.2544.16.121.255510
624.16.122.0/234.16.122.1 to 4.16.123.2544.16.123.255510
634.16.124.0/234.16.124.1 to 4.16.125.2544.16.125.255510
644.16.126.0/234.16.126.1 to 4.16.127.2544.16.127.255510
654.16.128.0/234.16.128.1 to 4.16.129.2544.16.129.255510
664.16.130.0/234.16.130.1 to 4.16.131.2544.16.131.255510
674.16.132.0/234.16.132.1 to 4.16.133.2544.16.133.255510
684.16.134.0/234.16.134.1 to 4.16.135.2544.16.135.255510
694.16.136.0/234.16.136.1 to 4.16.137.2544.16.137.255510
704.16.138.0/234.16.138.1 to 4.16.139.2544.16.139.255510
714.16.140.0/234.16.140.1 to 4.16.141.2544.16.141.255510
724.16.142.0/234.16.142.1 to 4.16.143.2544.16.143.255510
734.16.144.0/234.16.144.1 to 4.16.145.2544.16.145.255510
744.16.146.0/234.16.146.1 to 4.16.147.2544.16.147.255510
754.16.148.0/234.16.148.1 to 4.16.149.2544.16.149.255510
764.16.150.0/234.16.150.1 to 4.16.151.2544.16.151.255510
774.16.152.0/234.16.152.1 to 4.16.153.2544.16.153.255510
784.16.154.0/234.16.154.1 to 4.16.155.2544.16.155.255510
794.16.156.0/234.16.156.1 to 4.16.157.2544.16.157.255510
804.16.158.0/234.16.158.1 to 4.16.159.2544.16.159.255510
814.16.160.0/234.16.160.1 to 4.16.161.2544.16.161.255510
824.16.162.0/234.16.162.1 to 4.16.163.2544.16.163.255510
834.16.164.0/234.16.164.1 to 4.16.165.2544.16.165.255510
844.16.166.0/234.16.166.1 to 4.16.167.2544.16.167.255510
854.16.168.0/234.16.168.1 to 4.16.169.2544.16.169.255510
864.16.170.0/234.16.170.1 to 4.16.171.2544.16.171.255510
874.16.172.0/234.16.172.1 to 4.16.173.2544.16.173.255510
884.16.174.0/234.16.174.1 to 4.16.175.2544.16.175.255510
894.16.176.0/234.16.176.1 to 4.16.177.2544.16.177.255510
904.16.178.0/234.16.178.1 to 4.16.179.2544.16.179.255510
914.16.180.0/234.16.180.1 to 4.16.181.2544.16.181.255510
924.16.182.0/234.16.182.1 to 4.16.183.2544.16.183.255510
934.16.184.0/234.16.184.1 to 4.16.185.2544.16.185.255510
944.16.186.0/234.16.186.1 to 4.16.187.2544.16.187.255510
954.16.188.0/234.16.188.1 to 4.16.189.2544.16.189.255510
964.16.190.0/234.16.190.1 to 4.16.191.2544.16.191.255510
974.16.192.0/234.16.192.1 to 4.16.193.2544.16.193.255510
984.16.194.0/234.16.194.1 to 4.16.195.2544.16.195.255510
994.16.196.0/234.16.196.1 to 4.16.197.2544.16.197.255510
1004.16.198.0/234.16.198.1 to 4.16.199.2544.16.199.255510
1014.16.200.0/234.16.200.1 to 4.16.201.2544.16.201.255510
1024.16.202.0/234.16.202.1 to 4.16.203.2544.16.203.255510
1034.16.204.0/234.16.204.1 to 4.16.205.2544.16.205.255510
1044.16.206.0/234.16.206.1 to 4.16.207.2544.16.207.255510
1054.16.208.0/234.16.208.1 to 4.16.209.2544.16.209.255510
1064.16.210.0/234.16.210.1 to 4.16.211.2544.16.211.255510
1074.16.212.0/234.16.212.1 to 4.16.213.2544.16.213.255510
1084.16.214.0/234.16.214.1 to 4.16.215.2544.16.215.255510
1094.16.216.0/234.16.216.1 to 4.16.217.2544.16.217.255510
1104.16.218.0/234.16.218.1 to 4.16.219.2544.16.219.255510
1114.16.220.0/234.16.220.1 to 4.16.221.2544.16.221.255510
1124.16.222.0/234.16.222.1 to 4.16.223.2544.16.223.255510
1134.16.224.0/234.16.224.1 to 4.16.225.2544.16.225.255510
1144.16.226.0/234.16.226.1 to 4.16.227.2544.16.227.255510
1154.16.228.0/234.16.228.1 to 4.16.229.2544.16.229.255510
1164.16.230.0/234.16.230.1 to 4.16.231.2544.16.231.255510
1174.16.232.0/234.16.232.1 to 4.16.233.2544.16.233.255510
1184.16.234.0/234.16.234.1 to 4.16.235.2544.16.235.255510
1194.16.236.0/234.16.236.1 to 4.16.237.2544.16.237.255510
1204.16.238.0/234.16.238.1 to 4.16.239.2544.16.239.255510
1214.16.240.0/234.16.240.1 to 4.16.241.2544.16.241.255510
1224.16.242.0/234.16.242.1 to 4.16.243.2544.16.243.255510
1234.16.244.0/234.16.244.1 to 4.16.245.2544.16.245.255510
1244.16.246.0/234.16.246.1 to 4.16.247.2544.16.247.255510
1254.16.248.0/234.16.248.1 to 4.16.249.2544.16.249.255510
1264.16.250.0/234.16.250.1 to 4.16.251.2544.16.251.255510
1274.16.252.0/234.16.252.1 to 4.16.253.2544.16.253.255510
1284.16.254.0/234.16.254.1 to 4.16.255.2544.16.255.255510
1294.17.0.0/234.17.0.1 to 4.17.1.2544.17.1.255510
1304.17.2.0/234.17.2.1 to 4.17.3.2544.17.3.255510
1314.17.4.0/234.17.4.1 to 4.17.5.2544.17.5.255510
1324.17.6.0/234.17.6.1 to 4.17.7.2544.17.7.255510
1334.17.8.0/234.17.8.1 to 4.17.9.2544.17.9.255510
1344.17.10.0/234.17.10.1 to 4.17.11.2544.17.11.255510
1354.17.12.0/234.17.12.1 to 4.17.13.2544.17.13.255510
1364.17.14.0/234.17.14.1 to 4.17.15.2544.17.15.255510
1374.17.16.0/234.17.16.1 to 4.17.17.2544.17.17.255510
1384.17.18.0/234.17.18.1 to 4.17.19.2544.17.19.255510
1394.17.20.0/234.17.20.1 to 4.17.21.2544.17.21.255510
1404.17.22.0/234.17.22.1 to 4.17.23.2544.17.23.255510
1414.17.24.0/234.17.24.1 to 4.17.25.2544.17.25.255510
1424.17.26.0/234.17.26.1 to 4.17.27.2544.17.27.255510
1434.17.28.0/234.17.28.1 to 4.17.29.2544.17.29.255510
1444.17.30.0/234.17.30.1 to 4.17.31.2544.17.31.255510
1454.17.32.0/234.17.32.1 to 4.17.33.2544.17.33.255510
1464.17.34.0/234.17.34.1 to 4.17.35.2544.17.35.255510
1474.17.36.0/234.17.36.1 to 4.17.37.2544.17.37.255510
1484.17.38.0/234.17.38.1 to 4.17.39.2544.17.39.255510
1494.17.40.0/234.17.40.1 to 4.17.41.2544.17.41.255510
1504.17.42.0/234.17.42.1 to 4.17.43.2544.17.43.255510
1514.17.44.0/234.17.44.1 to 4.17.45.2544.17.45.255510
1524.17.46.0/234.17.46.1 to 4.17.47.2544.17.47.255510
1534.17.48.0/234.17.48.1 to 4.17.49.2544.17.49.255510
1544.17.50.0/234.17.50.1 to 4.17.51.2544.17.51.255510
1554.17.52.0/234.17.52.1 to 4.17.53.2544.17.53.255510
1564.17.54.0/234.17.54.1 to 4.17.55.2544.17.55.255510
1574.17.56.0/234.17.56.1 to 4.17.57.2544.17.57.255510
1584.17.58.0/234.17.58.1 to 4.17.59.2544.17.59.255510
1594.17.60.0/234.17.60.1 to 4.17.61.2544.17.61.255510
1604.17.62.0/234.17.62.1 to 4.17.63.2544.17.63.255510
1614.17.64.0/234.17.64.1 to 4.17.65.2544.17.65.255510
1624.17.66.0/234.17.66.1 to 4.17.67.2544.17.67.255510
1634.17.68.0/234.17.68.1 to 4.17.69.2544.17.69.255510
1644.17.70.0/234.17.70.1 to 4.17.71.2544.17.71.255510
1654.17.72.0/234.17.72.1 to 4.17.73.2544.17.73.255510
1664.17.74.0/234.17.74.1 to 4.17.75.2544.17.75.255510
1674.17.76.0/234.17.76.1 to 4.17.77.2544.17.77.255510
1684.17.78.0/234.17.78.1 to 4.17.79.2544.17.79.255510
1694.17.80.0/234.17.80.1 to 4.17.81.2544.17.81.255510
1704.17.82.0/234.17.82.1 to 4.17.83.2544.17.83.255510
1714.17.84.0/234.17.84.1 to 4.17.85.2544.17.85.255510
1724.17.86.0/234.17.86.1 to 4.17.87.2544.17.87.255510
1734.17.88.0/234.17.88.1 to 4.17.89.2544.17.89.255510
1744.17.90.0/234.17.90.1 to 4.17.91.2544.17.91.255510
1754.17.92.0/234.17.92.1 to 4.17.93.2544.17.93.255510
1764.17.94.0/234.17.94.1 to 4.17.95.2544.17.95.255510
1774.17.96.0/234.17.96.1 to 4.17.97.2544.17.97.255510
1784.17.98.0/234.17.98.1 to 4.17.99.2544.17.99.255510
1794.17.100.0/234.17.100.1 to 4.17.101.2544.17.101.255510
1804.17.102.0/234.17.102.1 to 4.17.103.2544.17.103.255510
1814.17.104.0/234.17.104.1 to 4.17.105.2544.17.105.255510
1824.17.106.0/234.17.106.1 to 4.17.107.2544.17.107.255510
1834.17.108.0/234.17.108.1 to 4.17.109.2544.17.109.255510
1844.17.110.0/234.17.110.1 to 4.17.111.2544.17.111.255510
1854.17.112.0/234.17.112.1 to 4.17.113.2544.17.113.255510
1864.17.114.0/234.17.114.1 to 4.17.115.2544.17.115.255510
1874.17.116.0/234.17.116.1 to 4.17.117.2544.17.117.255510
1884.17.118.0/234.17.118.1 to 4.17.119.2544.17.119.255510
1894.17.120.0/234.17.120.1 to 4.17.121.2544.17.121.255510
1904.17.122.0/234.17.122.1 to 4.17.123.2544.17.123.255510
1914.17.124.0/234.17.124.1 to 4.17.125.2544.17.125.255510
1924.17.126.0/234.17.126.1 to 4.17.127.2544.17.127.255510
1934.17.128.0/234.17.128.1 to 4.17.129.2544.17.129.255510
1944.17.130.0/234.17.130.1 to 4.17.131.2544.17.131.255510
1954.17.132.0/234.17.132.1 to 4.17.133.2544.17.133.255510
1964.17.134.0/234.17.134.1 to 4.17.135.2544.17.135.255510
1974.17.136.0/234.17.136.1 to 4.17.137.2544.17.137.255510
1984.17.138.0/234.17.138.1 to 4.17.139.2544.17.139.255510
1994.17.140.0/234.17.140.1 to 4.17.141.2544.17.141.255510
2004.17.142.0/234.17.142.1 to 4.17.143.2544.17.143.255510
2014.17.144.0/234.17.144.1 to 4.17.145.2544.17.145.255510
2024.17.146.0/234.17.146.1 to 4.17.147.2544.17.147.255510
2034.17.148.0/234.17.148.1 to 4.17.149.2544.17.149.255510
2044.17.150.0/234.17.150.1 to 4.17.151.2544.17.151.255510
2054.17.152.0/234.17.152.1 to 4.17.153.2544.17.153.255510
2064.17.154.0/234.17.154.1 to 4.17.155.2544.17.155.255510
2074.17.156.0/234.17.156.1 to 4.17.157.2544.17.157.255510
2084.17.158.0/234.17.158.1 to 4.17.159.2544.17.159.255510
2094.17.160.0/234.17.160.1 to 4.17.161.2544.17.161.255510
2104.17.162.0/234.17.162.1 to 4.17.163.2544.17.163.255510
2114.17.164.0/234.17.164.1 to 4.17.165.2544.17.165.255510
2124.17.166.0/234.17.166.1 to 4.17.167.2544.17.167.255510
2134.17.168.0/234.17.168.1 to 4.17.169.2544.17.169.255510
2144.17.170.0/234.17.170.1 to 4.17.171.2544.17.171.255510
2154.17.172.0/234.17.172.1 to 4.17.173.2544.17.173.255510
2164.17.174.0/234.17.174.1 to 4.17.175.2544.17.175.255510
2174.17.176.0/234.17.176.1 to 4.17.177.2544.17.177.255510
2184.17.178.0/234.17.178.1 to 4.17.179.2544.17.179.255510
2194.17.180.0/234.17.180.1 to 4.17.181.2544.17.181.255510
2204.17.182.0/234.17.182.1 to 4.17.183.2544.17.183.255510
2214.17.184.0/234.17.184.1 to 4.17.185.2544.17.185.255510
2224.17.186.0/234.17.186.1 to 4.17.187.2544.17.187.255510
2234.17.188.0/234.17.188.1 to 4.17.189.2544.17.189.255510
2244.17.190.0/234.17.190.1 to 4.17.191.2544.17.191.255510
2254.17.192.0/234.17.192.1 to 4.17.193.2544.17.193.255510
2264.17.194.0/234.17.194.1 to 4.17.195.2544.17.195.255510
2274.17.196.0/234.17.196.1 to 4.17.197.2544.17.197.255510
2284.17.198.0/234.17.198.1 to 4.17.199.2544.17.199.255510
2294.17.200.0/234.17.200.1 to 4.17.201.2544.17.201.255510
2304.17.202.0/234.17.202.1 to 4.17.203.2544.17.203.255510
2314.17.204.0/234.17.204.1 to 4.17.205.2544.17.205.255510
2324.17.206.0/234.17.206.1 to 4.17.207.2544.17.207.255510
2334.17.208.0/234.17.208.1 to 4.17.209.2544.17.209.255510
2344.17.210.0/234.17.210.1 to 4.17.211.2544.17.211.255510
2354.17.212.0/234.17.212.1 to 4.17.213.2544.17.213.255510
2364.17.214.0/234.17.214.1 to 4.17.215.2544.17.215.255510
2374.17.216.0/234.17.216.1 to 4.17.217.2544.17.217.255510
2384.17.218.0/234.17.218.1 to 4.17.219.2544.17.219.255510
2394.17.220.0/234.17.220.1 to 4.17.221.2544.17.221.255510
2404.17.222.0/234.17.222.1 to 4.17.223.2544.17.223.255510
2414.17.224.0/234.17.224.1 to 4.17.225.2544.17.225.255510
2424.17.226.0/234.17.226.1 to 4.17.227.2544.17.227.255510
2434.17.228.0/234.17.228.1 to 4.17.229.2544.17.229.255510
2444.17.230.0/234.17.230.1 to 4.17.231.2544.17.231.255510
2454.17.232.0/234.17.232.1 to 4.17.233.2544.17.233.255510
2464.17.234.0/234.17.234.1 to 4.17.235.2544.17.235.255510
2474.17.236.0/234.17.236.1 to 4.17.237.2544.17.237.255510
2484.17.238.0/234.17.238.1 to 4.17.239.2544.17.239.255510
2494.17.240.0/234.17.240.1 to 4.17.241.2544.17.241.255510
2504.17.242.0/234.17.242.1 to 4.17.243.2544.17.243.255510
2514.17.244.0/234.17.244.1 to 4.17.245.2544.17.245.255510
2524.17.246.0/234.17.246.1 to 4.17.247.2544.17.247.255510
2534.17.248.0/234.17.248.1 to 4.17.249.2544.17.249.255510
2544.17.250.0/234.17.250.1 to 4.17.251.2544.17.251.255510
2554.17.252.0/234.17.252.1 to 4.17.253.2544.17.253.255510
2564.17.254.0/234.17.254.1 to 4.17.255.2544.17.255.255510

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.