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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.

Network2.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
2.0.0.0
Broadcast address
3.255.255.255
First usable
2.0.0.1
Last usable
3.255.255.254
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 02000000 · Integer 33554432 to 67108863
Reverse DNS zones
2.in-addr.arpa
3.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
Address00000010.00000000.00000000.000000002.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000010.00000000.00000000.000000002.0.0.0
Broadcast00000011.11111111.11111111.111111113.255.255.255
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)

2.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.0.0.0/162.0.0.1 to 2.0.255.2542.0.255.25565,534
22.1.0.0/162.1.0.1 to 2.1.255.2542.1.255.25565,534
32.2.0.0/162.2.0.1 to 2.2.255.2542.2.255.25565,534
42.3.0.0/162.3.0.1 to 2.3.255.2542.3.255.25565,534
52.4.0.0/162.4.0.1 to 2.4.255.2542.4.255.25565,534
62.5.0.0/162.5.0.1 to 2.5.255.2542.5.255.25565,534
72.6.0.0/162.6.0.1 to 2.6.255.2542.6.255.25565,534
82.7.0.0/162.7.0.1 to 2.7.255.2542.7.255.25565,534
92.8.0.0/162.8.0.1 to 2.8.255.2542.8.255.25565,534
102.9.0.0/162.9.0.1 to 2.9.255.2542.9.255.25565,534
112.10.0.0/162.10.0.1 to 2.10.255.2542.10.255.25565,534
122.11.0.0/162.11.0.1 to 2.11.255.2542.11.255.25565,534
132.12.0.0/162.12.0.1 to 2.12.255.2542.12.255.25565,534
142.13.0.0/162.13.0.1 to 2.13.255.2542.13.255.25565,534
152.14.0.0/162.14.0.1 to 2.14.255.2542.14.255.25565,534
162.15.0.0/162.15.0.1 to 2.15.255.2542.15.255.25565,534
172.16.0.0/162.16.0.1 to 2.16.255.2542.16.255.25565,534
182.17.0.0/162.17.0.1 to 2.17.255.2542.17.255.25565,534
192.18.0.0/162.18.0.1 to 2.18.255.2542.18.255.25565,534
202.19.0.0/162.19.0.1 to 2.19.255.2542.19.255.25565,534
212.20.0.0/162.20.0.1 to 2.20.255.2542.20.255.25565,534
222.21.0.0/162.21.0.1 to 2.21.255.2542.21.255.25565,534
232.22.0.0/162.22.0.1 to 2.22.255.2542.22.255.25565,534
242.23.0.0/162.23.0.1 to 2.23.255.2542.23.255.25565,534
252.24.0.0/162.24.0.1 to 2.24.255.2542.24.255.25565,534
262.25.0.0/162.25.0.1 to 2.25.255.2542.25.255.25565,534
272.26.0.0/162.26.0.1 to 2.26.255.2542.26.255.25565,534
282.27.0.0/162.27.0.1 to 2.27.255.2542.27.255.25565,534
292.28.0.0/162.28.0.1 to 2.28.255.2542.28.255.25565,534
302.29.0.0/162.29.0.1 to 2.29.255.2542.29.255.25565,534
312.30.0.0/162.30.0.1 to 2.30.255.2542.30.255.25565,534
322.31.0.0/162.31.0.1 to 2.31.255.2542.31.255.25565,534
332.32.0.0/162.32.0.1 to 2.32.255.2542.32.255.25565,534
342.33.0.0/162.33.0.1 to 2.33.255.2542.33.255.25565,534
352.34.0.0/162.34.0.1 to 2.34.255.2542.34.255.25565,534
362.35.0.0/162.35.0.1 to 2.35.255.2542.35.255.25565,534
372.36.0.0/162.36.0.1 to 2.36.255.2542.36.255.25565,534
382.37.0.0/162.37.0.1 to 2.37.255.2542.37.255.25565,534
392.38.0.0/162.38.0.1 to 2.38.255.2542.38.255.25565,534
402.39.0.0/162.39.0.1 to 2.39.255.2542.39.255.25565,534
412.40.0.0/162.40.0.1 to 2.40.255.2542.40.255.25565,534
422.41.0.0/162.41.0.1 to 2.41.255.2542.41.255.25565,534
432.42.0.0/162.42.0.1 to 2.42.255.2542.42.255.25565,534
442.43.0.0/162.43.0.1 to 2.43.255.2542.43.255.25565,534
452.44.0.0/162.44.0.1 to 2.44.255.2542.44.255.25565,534
462.45.0.0/162.45.0.1 to 2.45.255.2542.45.255.25565,534
472.46.0.0/162.46.0.1 to 2.46.255.2542.46.255.25565,534
482.47.0.0/162.47.0.1 to 2.47.255.2542.47.255.25565,534
492.48.0.0/162.48.0.1 to 2.48.255.2542.48.255.25565,534
502.49.0.0/162.49.0.1 to 2.49.255.2542.49.255.25565,534
512.50.0.0/162.50.0.1 to 2.50.255.2542.50.255.25565,534
522.51.0.0/162.51.0.1 to 2.51.255.2542.51.255.25565,534
532.52.0.0/162.52.0.1 to 2.52.255.2542.52.255.25565,534
542.53.0.0/162.53.0.1 to 2.53.255.2542.53.255.25565,534
552.54.0.0/162.54.0.1 to 2.54.255.2542.54.255.25565,534
562.55.0.0/162.55.0.1 to 2.55.255.2542.55.255.25565,534
572.56.0.0/162.56.0.1 to 2.56.255.2542.56.255.25565,534
582.57.0.0/162.57.0.1 to 2.57.255.2542.57.255.25565,534
592.58.0.0/162.58.0.1 to 2.58.255.2542.58.255.25565,534
602.59.0.0/162.59.0.1 to 2.59.255.2542.59.255.25565,534
612.60.0.0/162.60.0.1 to 2.60.255.2542.60.255.25565,534
622.61.0.0/162.61.0.1 to 2.61.255.2542.61.255.25565,534
632.62.0.0/162.62.0.1 to 2.62.255.2542.62.255.25565,534
642.63.0.0/162.63.0.1 to 2.63.255.2542.63.255.25565,534
652.64.0.0/162.64.0.1 to 2.64.255.2542.64.255.25565,534
662.65.0.0/162.65.0.1 to 2.65.255.2542.65.255.25565,534
672.66.0.0/162.66.0.1 to 2.66.255.2542.66.255.25565,534
682.67.0.0/162.67.0.1 to 2.67.255.2542.67.255.25565,534
692.68.0.0/162.68.0.1 to 2.68.255.2542.68.255.25565,534
702.69.0.0/162.69.0.1 to 2.69.255.2542.69.255.25565,534
712.70.0.0/162.70.0.1 to 2.70.255.2542.70.255.25565,534
722.71.0.0/162.71.0.1 to 2.71.255.2542.71.255.25565,534
732.72.0.0/162.72.0.1 to 2.72.255.2542.72.255.25565,534
742.73.0.0/162.73.0.1 to 2.73.255.2542.73.255.25565,534
752.74.0.0/162.74.0.1 to 2.74.255.2542.74.255.25565,534
762.75.0.0/162.75.0.1 to 2.75.255.2542.75.255.25565,534
772.76.0.0/162.76.0.1 to 2.76.255.2542.76.255.25565,534
782.77.0.0/162.77.0.1 to 2.77.255.2542.77.255.25565,534
792.78.0.0/162.78.0.1 to 2.78.255.2542.78.255.25565,534
802.79.0.0/162.79.0.1 to 2.79.255.2542.79.255.25565,534
812.80.0.0/162.80.0.1 to 2.80.255.2542.80.255.25565,534
822.81.0.0/162.81.0.1 to 2.81.255.2542.81.255.25565,534
832.82.0.0/162.82.0.1 to 2.82.255.2542.82.255.25565,534
842.83.0.0/162.83.0.1 to 2.83.255.2542.83.255.25565,534
852.84.0.0/162.84.0.1 to 2.84.255.2542.84.255.25565,534
862.85.0.0/162.85.0.1 to 2.85.255.2542.85.255.25565,534
872.86.0.0/162.86.0.1 to 2.86.255.2542.86.255.25565,534
882.87.0.0/162.87.0.1 to 2.87.255.2542.87.255.25565,534
892.88.0.0/162.88.0.1 to 2.88.255.2542.88.255.25565,534
902.89.0.0/162.89.0.1 to 2.89.255.2542.89.255.25565,534
912.90.0.0/162.90.0.1 to 2.90.255.2542.90.255.25565,534
922.91.0.0/162.91.0.1 to 2.91.255.2542.91.255.25565,534
932.92.0.0/162.92.0.1 to 2.92.255.2542.92.255.25565,534
942.93.0.0/162.93.0.1 to 2.93.255.2542.93.255.25565,534
952.94.0.0/162.94.0.1 to 2.94.255.2542.94.255.25565,534
962.95.0.0/162.95.0.1 to 2.95.255.2542.95.255.25565,534
972.96.0.0/162.96.0.1 to 2.96.255.2542.96.255.25565,534
982.97.0.0/162.97.0.1 to 2.97.255.2542.97.255.25565,534
992.98.0.0/162.98.0.1 to 2.98.255.2542.98.255.25565,534
1002.99.0.0/162.99.0.1 to 2.99.255.2542.99.255.25565,534
1012.100.0.0/162.100.0.1 to 2.100.255.2542.100.255.25565,534
1022.101.0.0/162.101.0.1 to 2.101.255.2542.101.255.25565,534
1032.102.0.0/162.102.0.1 to 2.102.255.2542.102.255.25565,534
1042.103.0.0/162.103.0.1 to 2.103.255.2542.103.255.25565,534
1052.104.0.0/162.104.0.1 to 2.104.255.2542.104.255.25565,534
1062.105.0.0/162.105.0.1 to 2.105.255.2542.105.255.25565,534
1072.106.0.0/162.106.0.1 to 2.106.255.2542.106.255.25565,534
1082.107.0.0/162.107.0.1 to 2.107.255.2542.107.255.25565,534
1092.108.0.0/162.108.0.1 to 2.108.255.2542.108.255.25565,534
1102.109.0.0/162.109.0.1 to 2.109.255.2542.109.255.25565,534
1112.110.0.0/162.110.0.1 to 2.110.255.2542.110.255.25565,534
1122.111.0.0/162.111.0.1 to 2.111.255.2542.111.255.25565,534
1132.112.0.0/162.112.0.1 to 2.112.255.2542.112.255.25565,534
1142.113.0.0/162.113.0.1 to 2.113.255.2542.113.255.25565,534
1152.114.0.0/162.114.0.1 to 2.114.255.2542.114.255.25565,534
1162.115.0.0/162.115.0.1 to 2.115.255.2542.115.255.25565,534
1172.116.0.0/162.116.0.1 to 2.116.255.2542.116.255.25565,534
1182.117.0.0/162.117.0.1 to 2.117.255.2542.117.255.25565,534
1192.118.0.0/162.118.0.1 to 2.118.255.2542.118.255.25565,534
1202.119.0.0/162.119.0.1 to 2.119.255.2542.119.255.25565,534
1212.120.0.0/162.120.0.1 to 2.120.255.2542.120.255.25565,534
1222.121.0.0/162.121.0.1 to 2.121.255.2542.121.255.25565,534
1232.122.0.0/162.122.0.1 to 2.122.255.2542.122.255.25565,534
1242.123.0.0/162.123.0.1 to 2.123.255.2542.123.255.25565,534
1252.124.0.0/162.124.0.1 to 2.124.255.2542.124.255.25565,534
1262.125.0.0/162.125.0.1 to 2.125.255.2542.125.255.25565,534
1272.126.0.0/162.126.0.1 to 2.126.255.2542.126.255.25565,534
1282.127.0.0/162.127.0.1 to 2.127.255.2542.127.255.25565,534
1292.128.0.0/162.128.0.1 to 2.128.255.2542.128.255.25565,534
1302.129.0.0/162.129.0.1 to 2.129.255.2542.129.255.25565,534
1312.130.0.0/162.130.0.1 to 2.130.255.2542.130.255.25565,534
1322.131.0.0/162.131.0.1 to 2.131.255.2542.131.255.25565,534
1332.132.0.0/162.132.0.1 to 2.132.255.2542.132.255.25565,534
1342.133.0.0/162.133.0.1 to 2.133.255.2542.133.255.25565,534
1352.134.0.0/162.134.0.1 to 2.134.255.2542.134.255.25565,534
1362.135.0.0/162.135.0.1 to 2.135.255.2542.135.255.25565,534
1372.136.0.0/162.136.0.1 to 2.136.255.2542.136.255.25565,534
1382.137.0.0/162.137.0.1 to 2.137.255.2542.137.255.25565,534
1392.138.0.0/162.138.0.1 to 2.138.255.2542.138.255.25565,534
1402.139.0.0/162.139.0.1 to 2.139.255.2542.139.255.25565,534
1412.140.0.0/162.140.0.1 to 2.140.255.2542.140.255.25565,534
1422.141.0.0/162.141.0.1 to 2.141.255.2542.141.255.25565,534
1432.142.0.0/162.142.0.1 to 2.142.255.2542.142.255.25565,534
1442.143.0.0/162.143.0.1 to 2.143.255.2542.143.255.25565,534
1452.144.0.0/162.144.0.1 to 2.144.255.2542.144.255.25565,534
1462.145.0.0/162.145.0.1 to 2.145.255.2542.145.255.25565,534
1472.146.0.0/162.146.0.1 to 2.146.255.2542.146.255.25565,534
1482.147.0.0/162.147.0.1 to 2.147.255.2542.147.255.25565,534
1492.148.0.0/162.148.0.1 to 2.148.255.2542.148.255.25565,534
1502.149.0.0/162.149.0.1 to 2.149.255.2542.149.255.25565,534
1512.150.0.0/162.150.0.1 to 2.150.255.2542.150.255.25565,534
1522.151.0.0/162.151.0.1 to 2.151.255.2542.151.255.25565,534
1532.152.0.0/162.152.0.1 to 2.152.255.2542.152.255.25565,534
1542.153.0.0/162.153.0.1 to 2.153.255.2542.153.255.25565,534
1552.154.0.0/162.154.0.1 to 2.154.255.2542.154.255.25565,534
1562.155.0.0/162.155.0.1 to 2.155.255.2542.155.255.25565,534
1572.156.0.0/162.156.0.1 to 2.156.255.2542.156.255.25565,534
1582.157.0.0/162.157.0.1 to 2.157.255.2542.157.255.25565,534
1592.158.0.0/162.158.0.1 to 2.158.255.2542.158.255.25565,534
1602.159.0.0/162.159.0.1 to 2.159.255.2542.159.255.25565,534
1612.160.0.0/162.160.0.1 to 2.160.255.2542.160.255.25565,534
1622.161.0.0/162.161.0.1 to 2.161.255.2542.161.255.25565,534
1632.162.0.0/162.162.0.1 to 2.162.255.2542.162.255.25565,534
1642.163.0.0/162.163.0.1 to 2.163.255.2542.163.255.25565,534
1652.164.0.0/162.164.0.1 to 2.164.255.2542.164.255.25565,534
1662.165.0.0/162.165.0.1 to 2.165.255.2542.165.255.25565,534
1672.166.0.0/162.166.0.1 to 2.166.255.2542.166.255.25565,534
1682.167.0.0/162.167.0.1 to 2.167.255.2542.167.255.25565,534
1692.168.0.0/162.168.0.1 to 2.168.255.2542.168.255.25565,534
1702.169.0.0/162.169.0.1 to 2.169.255.2542.169.255.25565,534
1712.170.0.0/162.170.0.1 to 2.170.255.2542.170.255.25565,534
1722.171.0.0/162.171.0.1 to 2.171.255.2542.171.255.25565,534
1732.172.0.0/162.172.0.1 to 2.172.255.2542.172.255.25565,534
1742.173.0.0/162.173.0.1 to 2.173.255.2542.173.255.25565,534
1752.174.0.0/162.174.0.1 to 2.174.255.2542.174.255.25565,534
1762.175.0.0/162.175.0.1 to 2.175.255.2542.175.255.25565,534
1772.176.0.0/162.176.0.1 to 2.176.255.2542.176.255.25565,534
1782.177.0.0/162.177.0.1 to 2.177.255.2542.177.255.25565,534
1792.178.0.0/162.178.0.1 to 2.178.255.2542.178.255.25565,534
1802.179.0.0/162.179.0.1 to 2.179.255.2542.179.255.25565,534
1812.180.0.0/162.180.0.1 to 2.180.255.2542.180.255.25565,534
1822.181.0.0/162.181.0.1 to 2.181.255.2542.181.255.25565,534
1832.182.0.0/162.182.0.1 to 2.182.255.2542.182.255.25565,534
1842.183.0.0/162.183.0.1 to 2.183.255.2542.183.255.25565,534
1852.184.0.0/162.184.0.1 to 2.184.255.2542.184.255.25565,534
1862.185.0.0/162.185.0.1 to 2.185.255.2542.185.255.25565,534
1872.186.0.0/162.186.0.1 to 2.186.255.2542.186.255.25565,534
1882.187.0.0/162.187.0.1 to 2.187.255.2542.187.255.25565,534
1892.188.0.0/162.188.0.1 to 2.188.255.2542.188.255.25565,534
1902.189.0.0/162.189.0.1 to 2.189.255.2542.189.255.25565,534
1912.190.0.0/162.190.0.1 to 2.190.255.2542.190.255.25565,534
1922.191.0.0/162.191.0.1 to 2.191.255.2542.191.255.25565,534
1932.192.0.0/162.192.0.1 to 2.192.255.2542.192.255.25565,534
1942.193.0.0/162.193.0.1 to 2.193.255.2542.193.255.25565,534
1952.194.0.0/162.194.0.1 to 2.194.255.2542.194.255.25565,534
1962.195.0.0/162.195.0.1 to 2.195.255.2542.195.255.25565,534
1972.196.0.0/162.196.0.1 to 2.196.255.2542.196.255.25565,534
1982.197.0.0/162.197.0.1 to 2.197.255.2542.197.255.25565,534
1992.198.0.0/162.198.0.1 to 2.198.255.2542.198.255.25565,534
2002.199.0.0/162.199.0.1 to 2.199.255.2542.199.255.25565,534
2012.200.0.0/162.200.0.1 to 2.200.255.2542.200.255.25565,534
2022.201.0.0/162.201.0.1 to 2.201.255.2542.201.255.25565,534
2032.202.0.0/162.202.0.1 to 2.202.255.2542.202.255.25565,534
2042.203.0.0/162.203.0.1 to 2.203.255.2542.203.255.25565,534
2052.204.0.0/162.204.0.1 to 2.204.255.2542.204.255.25565,534
2062.205.0.0/162.205.0.1 to 2.205.255.2542.205.255.25565,534
2072.206.0.0/162.206.0.1 to 2.206.255.2542.206.255.25565,534
2082.207.0.0/162.207.0.1 to 2.207.255.2542.207.255.25565,534
2092.208.0.0/162.208.0.1 to 2.208.255.2542.208.255.25565,534
2102.209.0.0/162.209.0.1 to 2.209.255.2542.209.255.25565,534
2112.210.0.0/162.210.0.1 to 2.210.255.2542.210.255.25565,534
2122.211.0.0/162.211.0.1 to 2.211.255.2542.211.255.25565,534
2132.212.0.0/162.212.0.1 to 2.212.255.2542.212.255.25565,534
2142.213.0.0/162.213.0.1 to 2.213.255.2542.213.255.25565,534
2152.214.0.0/162.214.0.1 to 2.214.255.2542.214.255.25565,534
2162.215.0.0/162.215.0.1 to 2.215.255.2542.215.255.25565,534
2172.216.0.0/162.216.0.1 to 2.216.255.2542.216.255.25565,534
2182.217.0.0/162.217.0.1 to 2.217.255.2542.217.255.25565,534
2192.218.0.0/162.218.0.1 to 2.218.255.2542.218.255.25565,534
2202.219.0.0/162.219.0.1 to 2.219.255.2542.219.255.25565,534
2212.220.0.0/162.220.0.1 to 2.220.255.2542.220.255.25565,534
2222.221.0.0/162.221.0.1 to 2.221.255.2542.221.255.25565,534
2232.222.0.0/162.222.0.1 to 2.222.255.2542.222.255.25565,534
2242.223.0.0/162.223.0.1 to 2.223.255.2542.223.255.25565,534
2252.224.0.0/162.224.0.1 to 2.224.255.2542.224.255.25565,534
2262.225.0.0/162.225.0.1 to 2.225.255.2542.225.255.25565,534
2272.226.0.0/162.226.0.1 to 2.226.255.2542.226.255.25565,534
2282.227.0.0/162.227.0.1 to 2.227.255.2542.227.255.25565,534
2292.228.0.0/162.228.0.1 to 2.228.255.2542.228.255.25565,534
2302.229.0.0/162.229.0.1 to 2.229.255.2542.229.255.25565,534
2312.230.0.0/162.230.0.1 to 2.230.255.2542.230.255.25565,534
2322.231.0.0/162.231.0.1 to 2.231.255.2542.231.255.25565,534
2332.232.0.0/162.232.0.1 to 2.232.255.2542.232.255.25565,534
2342.233.0.0/162.233.0.1 to 2.233.255.2542.233.255.25565,534
2352.234.0.0/162.234.0.1 to 2.234.255.2542.234.255.25565,534
2362.235.0.0/162.235.0.1 to 2.235.255.2542.235.255.25565,534
2372.236.0.0/162.236.0.1 to 2.236.255.2542.236.255.25565,534
2382.237.0.0/162.237.0.1 to 2.237.255.2542.237.255.25565,534
2392.238.0.0/162.238.0.1 to 2.238.255.2542.238.255.25565,534
2402.239.0.0/162.239.0.1 to 2.239.255.2542.239.255.25565,534
2412.240.0.0/162.240.0.1 to 2.240.255.2542.240.255.25565,534
2422.241.0.0/162.241.0.1 to 2.241.255.2542.241.255.25565,534
2432.242.0.0/162.242.0.1 to 2.242.255.2542.242.255.25565,534
2442.243.0.0/162.243.0.1 to 2.243.255.2542.243.255.25565,534
2452.244.0.0/162.244.0.1 to 2.244.255.2542.244.255.25565,534
2462.245.0.0/162.245.0.1 to 2.245.255.2542.245.255.25565,534
2472.246.0.0/162.246.0.1 to 2.246.255.2542.246.255.25565,534
2482.247.0.0/162.247.0.1 to 2.247.255.2542.247.255.25565,534
2492.248.0.0/162.248.0.1 to 2.248.255.2542.248.255.25565,534
2502.249.0.0/162.249.0.1 to 2.249.255.2542.249.255.25565,534
2512.250.0.0/162.250.0.1 to 2.250.255.2542.250.255.25565,534
2522.251.0.0/162.251.0.1 to 2.251.255.2542.251.255.25565,534
2532.252.0.0/162.252.0.1 to 2.252.255.2542.252.255.25565,534
2542.253.0.0/162.253.0.1 to 2.253.255.2542.253.255.25565,534
2552.254.0.0/162.254.0.1 to 2.254.255.2542.254.255.25565,534
2562.255.0.0/162.255.0.1 to 2.255.255.2542.255.255.25565,534

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.