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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.

Network0.0.0.0/4
Usable hosts268,435,454
Subnet mask240.0.0.0
Addresses268,435,456
Network address
0.0.0.0
Broadcast address
15.255.255.255
First usable
0.0.0.1
Last usable
15.255.255.254
Usable hosts
268,435,454 (268,435,456 less the network and broadcast addresses)
Subnet mask
240.0.0.0
Wildcard mask
15.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/4
Type
Public public
Old class
A (default /8)
As numbers
Hex 00000000 · Integer 0 to 268435455
Reverse DNS zones
0.in-addr.arpa
1.in-addr.arpa
2.in-addr.arpa
3.in-addr.arpa
4.in-addr.arpa
5.in-addr.arpa
6.in-addr.arpa
7.in-addr.arpa
8.in-addr.arpa
9.in-addr.arpa
10.in-addr.arpa
11.in-addr.arpa
12.in-addr.arpa
13.in-addr.arpa
14.in-addr.arpa
15.in-addr.arpa
/4 is not on a 8-bit boundary, so it takes 16 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000000.00000000.00000000.000000000.0.0.0
Subnet mask11110000.00000000.00000000.00000000240.0.0.0
Network00000000.00000000.00000000.000000000.0.0.0
Broadcast00001111.11111111.11111111.1111111115.255.255.255
Split into smaller subnets/14
/5 (2)/6 (4)/7 (8)/8 (16)/9 (32)/10 (64)/11 (128)/12 (256)/13 (512)/14 (1,024)/15 (2,048)/16 (4,096)

0.0.0.0/4 makes 1,024 subnets of /14; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.0.0.0/140.0.0.1 to 0.3.255.2540.3.255.255262,142
20.4.0.0/140.4.0.1 to 0.7.255.2540.7.255.255262,142
30.8.0.0/140.8.0.1 to 0.11.255.2540.11.255.255262,142
40.12.0.0/140.12.0.1 to 0.15.255.2540.15.255.255262,142
50.16.0.0/140.16.0.1 to 0.19.255.2540.19.255.255262,142
60.20.0.0/140.20.0.1 to 0.23.255.2540.23.255.255262,142
70.24.0.0/140.24.0.1 to 0.27.255.2540.27.255.255262,142
80.28.0.0/140.28.0.1 to 0.31.255.2540.31.255.255262,142
90.32.0.0/140.32.0.1 to 0.35.255.2540.35.255.255262,142
100.36.0.0/140.36.0.1 to 0.39.255.2540.39.255.255262,142
110.40.0.0/140.40.0.1 to 0.43.255.2540.43.255.255262,142
120.44.0.0/140.44.0.1 to 0.47.255.2540.47.255.255262,142
130.48.0.0/140.48.0.1 to 0.51.255.2540.51.255.255262,142
140.52.0.0/140.52.0.1 to 0.55.255.2540.55.255.255262,142
150.56.0.0/140.56.0.1 to 0.59.255.2540.59.255.255262,142
160.60.0.0/140.60.0.1 to 0.63.255.2540.63.255.255262,142
170.64.0.0/140.64.0.1 to 0.67.255.2540.67.255.255262,142
180.68.0.0/140.68.0.1 to 0.71.255.2540.71.255.255262,142
190.72.0.0/140.72.0.1 to 0.75.255.2540.75.255.255262,142
200.76.0.0/140.76.0.1 to 0.79.255.2540.79.255.255262,142
210.80.0.0/140.80.0.1 to 0.83.255.2540.83.255.255262,142
220.84.0.0/140.84.0.1 to 0.87.255.2540.87.255.255262,142
230.88.0.0/140.88.0.1 to 0.91.255.2540.91.255.255262,142
240.92.0.0/140.92.0.1 to 0.95.255.2540.95.255.255262,142
250.96.0.0/140.96.0.1 to 0.99.255.2540.99.255.255262,142
260.100.0.0/140.100.0.1 to 0.103.255.2540.103.255.255262,142
270.104.0.0/140.104.0.1 to 0.107.255.2540.107.255.255262,142
280.108.0.0/140.108.0.1 to 0.111.255.2540.111.255.255262,142
290.112.0.0/140.112.0.1 to 0.115.255.2540.115.255.255262,142
300.116.0.0/140.116.0.1 to 0.119.255.2540.119.255.255262,142
310.120.0.0/140.120.0.1 to 0.123.255.2540.123.255.255262,142
320.124.0.0/140.124.0.1 to 0.127.255.2540.127.255.255262,142
330.128.0.0/140.128.0.1 to 0.131.255.2540.131.255.255262,142
340.132.0.0/140.132.0.1 to 0.135.255.2540.135.255.255262,142
350.136.0.0/140.136.0.1 to 0.139.255.2540.139.255.255262,142
360.140.0.0/140.140.0.1 to 0.143.255.2540.143.255.255262,142
370.144.0.0/140.144.0.1 to 0.147.255.2540.147.255.255262,142
380.148.0.0/140.148.0.1 to 0.151.255.2540.151.255.255262,142
390.152.0.0/140.152.0.1 to 0.155.255.2540.155.255.255262,142
400.156.0.0/140.156.0.1 to 0.159.255.2540.159.255.255262,142
410.160.0.0/140.160.0.1 to 0.163.255.2540.163.255.255262,142
420.164.0.0/140.164.0.1 to 0.167.255.2540.167.255.255262,142
430.168.0.0/140.168.0.1 to 0.171.255.2540.171.255.255262,142
440.172.0.0/140.172.0.1 to 0.175.255.2540.175.255.255262,142
450.176.0.0/140.176.0.1 to 0.179.255.2540.179.255.255262,142
460.180.0.0/140.180.0.1 to 0.183.255.2540.183.255.255262,142
470.184.0.0/140.184.0.1 to 0.187.255.2540.187.255.255262,142
480.188.0.0/140.188.0.1 to 0.191.255.2540.191.255.255262,142
490.192.0.0/140.192.0.1 to 0.195.255.2540.195.255.255262,142
500.196.0.0/140.196.0.1 to 0.199.255.2540.199.255.255262,142
510.200.0.0/140.200.0.1 to 0.203.255.2540.203.255.255262,142
520.204.0.0/140.204.0.1 to 0.207.255.2540.207.255.255262,142
530.208.0.0/140.208.0.1 to 0.211.255.2540.211.255.255262,142
540.212.0.0/140.212.0.1 to 0.215.255.2540.215.255.255262,142
550.216.0.0/140.216.0.1 to 0.219.255.2540.219.255.255262,142
560.220.0.0/140.220.0.1 to 0.223.255.2540.223.255.255262,142
570.224.0.0/140.224.0.1 to 0.227.255.2540.227.255.255262,142
580.228.0.0/140.228.0.1 to 0.231.255.2540.231.255.255262,142
590.232.0.0/140.232.0.1 to 0.235.255.2540.235.255.255262,142
600.236.0.0/140.236.0.1 to 0.239.255.2540.239.255.255262,142
610.240.0.0/140.240.0.1 to 0.243.255.2540.243.255.255262,142
620.244.0.0/140.244.0.1 to 0.247.255.2540.247.255.255262,142
630.248.0.0/140.248.0.1 to 0.251.255.2540.251.255.255262,142
640.252.0.0/140.252.0.1 to 0.255.255.2540.255.255.255262,142
651.0.0.0/141.0.0.1 to 1.3.255.2541.3.255.255262,142
661.4.0.0/141.4.0.1 to 1.7.255.2541.7.255.255262,142
671.8.0.0/141.8.0.1 to 1.11.255.2541.11.255.255262,142
681.12.0.0/141.12.0.1 to 1.15.255.2541.15.255.255262,142
691.16.0.0/141.16.0.1 to 1.19.255.2541.19.255.255262,142
701.20.0.0/141.20.0.1 to 1.23.255.2541.23.255.255262,142
711.24.0.0/141.24.0.1 to 1.27.255.2541.27.255.255262,142
721.28.0.0/141.28.0.1 to 1.31.255.2541.31.255.255262,142
731.32.0.0/141.32.0.1 to 1.35.255.2541.35.255.255262,142
741.36.0.0/141.36.0.1 to 1.39.255.2541.39.255.255262,142
751.40.0.0/141.40.0.1 to 1.43.255.2541.43.255.255262,142
761.44.0.0/141.44.0.1 to 1.47.255.2541.47.255.255262,142
771.48.0.0/141.48.0.1 to 1.51.255.2541.51.255.255262,142
781.52.0.0/141.52.0.1 to 1.55.255.2541.55.255.255262,142
791.56.0.0/141.56.0.1 to 1.59.255.2541.59.255.255262,142
801.60.0.0/141.60.0.1 to 1.63.255.2541.63.255.255262,142
811.64.0.0/141.64.0.1 to 1.67.255.2541.67.255.255262,142
821.68.0.0/141.68.0.1 to 1.71.255.2541.71.255.255262,142
831.72.0.0/141.72.0.1 to 1.75.255.2541.75.255.255262,142
841.76.0.0/141.76.0.1 to 1.79.255.2541.79.255.255262,142
851.80.0.0/141.80.0.1 to 1.83.255.2541.83.255.255262,142
861.84.0.0/141.84.0.1 to 1.87.255.2541.87.255.255262,142
871.88.0.0/141.88.0.1 to 1.91.255.2541.91.255.255262,142
881.92.0.0/141.92.0.1 to 1.95.255.2541.95.255.255262,142
891.96.0.0/141.96.0.1 to 1.99.255.2541.99.255.255262,142
901.100.0.0/141.100.0.1 to 1.103.255.2541.103.255.255262,142
911.104.0.0/141.104.0.1 to 1.107.255.2541.107.255.255262,142
921.108.0.0/141.108.0.1 to 1.111.255.2541.111.255.255262,142
931.112.0.0/141.112.0.1 to 1.115.255.2541.115.255.255262,142
941.116.0.0/141.116.0.1 to 1.119.255.2541.119.255.255262,142
951.120.0.0/141.120.0.1 to 1.123.255.2541.123.255.255262,142
961.124.0.0/141.124.0.1 to 1.127.255.2541.127.255.255262,142
971.128.0.0/141.128.0.1 to 1.131.255.2541.131.255.255262,142
981.132.0.0/141.132.0.1 to 1.135.255.2541.135.255.255262,142
991.136.0.0/141.136.0.1 to 1.139.255.2541.139.255.255262,142
1001.140.0.0/141.140.0.1 to 1.143.255.2541.143.255.255262,142
1011.144.0.0/141.144.0.1 to 1.147.255.2541.147.255.255262,142
1021.148.0.0/141.148.0.1 to 1.151.255.2541.151.255.255262,142
1031.152.0.0/141.152.0.1 to 1.155.255.2541.155.255.255262,142
1041.156.0.0/141.156.0.1 to 1.159.255.2541.159.255.255262,142
1051.160.0.0/141.160.0.1 to 1.163.255.2541.163.255.255262,142
1061.164.0.0/141.164.0.1 to 1.167.255.2541.167.255.255262,142
1071.168.0.0/141.168.0.1 to 1.171.255.2541.171.255.255262,142
1081.172.0.0/141.172.0.1 to 1.175.255.2541.175.255.255262,142
1091.176.0.0/141.176.0.1 to 1.179.255.2541.179.255.255262,142
1101.180.0.0/141.180.0.1 to 1.183.255.2541.183.255.255262,142
1111.184.0.0/141.184.0.1 to 1.187.255.2541.187.255.255262,142
1121.188.0.0/141.188.0.1 to 1.191.255.2541.191.255.255262,142
1131.192.0.0/141.192.0.1 to 1.195.255.2541.195.255.255262,142
1141.196.0.0/141.196.0.1 to 1.199.255.2541.199.255.255262,142
1151.200.0.0/141.200.0.1 to 1.203.255.2541.203.255.255262,142
1161.204.0.0/141.204.0.1 to 1.207.255.2541.207.255.255262,142
1171.208.0.0/141.208.0.1 to 1.211.255.2541.211.255.255262,142
1181.212.0.0/141.212.0.1 to 1.215.255.2541.215.255.255262,142
1191.216.0.0/141.216.0.1 to 1.219.255.2541.219.255.255262,142
1201.220.0.0/141.220.0.1 to 1.223.255.2541.223.255.255262,142
1211.224.0.0/141.224.0.1 to 1.227.255.2541.227.255.255262,142
1221.228.0.0/141.228.0.1 to 1.231.255.2541.231.255.255262,142
1231.232.0.0/141.232.0.1 to 1.235.255.2541.235.255.255262,142
1241.236.0.0/141.236.0.1 to 1.239.255.2541.239.255.255262,142
1251.240.0.0/141.240.0.1 to 1.243.255.2541.243.255.255262,142
1261.244.0.0/141.244.0.1 to 1.247.255.2541.247.255.255262,142
1271.248.0.0/141.248.0.1 to 1.251.255.2541.251.255.255262,142
1281.252.0.0/141.252.0.1 to 1.255.255.2541.255.255.255262,142
1292.0.0.0/142.0.0.1 to 2.3.255.2542.3.255.255262,142
1302.4.0.0/142.4.0.1 to 2.7.255.2542.7.255.255262,142
1312.8.0.0/142.8.0.1 to 2.11.255.2542.11.255.255262,142
1322.12.0.0/142.12.0.1 to 2.15.255.2542.15.255.255262,142
1332.16.0.0/142.16.0.1 to 2.19.255.2542.19.255.255262,142
1342.20.0.0/142.20.0.1 to 2.23.255.2542.23.255.255262,142
1352.24.0.0/142.24.0.1 to 2.27.255.2542.27.255.255262,142
1362.28.0.0/142.28.0.1 to 2.31.255.2542.31.255.255262,142
1372.32.0.0/142.32.0.1 to 2.35.255.2542.35.255.255262,142
1382.36.0.0/142.36.0.1 to 2.39.255.2542.39.255.255262,142
1392.40.0.0/142.40.0.1 to 2.43.255.2542.43.255.255262,142
1402.44.0.0/142.44.0.1 to 2.47.255.2542.47.255.255262,142
1412.48.0.0/142.48.0.1 to 2.51.255.2542.51.255.255262,142
1422.52.0.0/142.52.0.1 to 2.55.255.2542.55.255.255262,142
1432.56.0.0/142.56.0.1 to 2.59.255.2542.59.255.255262,142
1442.60.0.0/142.60.0.1 to 2.63.255.2542.63.255.255262,142
1452.64.0.0/142.64.0.1 to 2.67.255.2542.67.255.255262,142
1462.68.0.0/142.68.0.1 to 2.71.255.2542.71.255.255262,142
1472.72.0.0/142.72.0.1 to 2.75.255.2542.75.255.255262,142
1482.76.0.0/142.76.0.1 to 2.79.255.2542.79.255.255262,142
1492.80.0.0/142.80.0.1 to 2.83.255.2542.83.255.255262,142
1502.84.0.0/142.84.0.1 to 2.87.255.2542.87.255.255262,142
1512.88.0.0/142.88.0.1 to 2.91.255.2542.91.255.255262,142
1522.92.0.0/142.92.0.1 to 2.95.255.2542.95.255.255262,142
1532.96.0.0/142.96.0.1 to 2.99.255.2542.99.255.255262,142
1542.100.0.0/142.100.0.1 to 2.103.255.2542.103.255.255262,142
1552.104.0.0/142.104.0.1 to 2.107.255.2542.107.255.255262,142
1562.108.0.0/142.108.0.1 to 2.111.255.2542.111.255.255262,142
1572.112.0.0/142.112.0.1 to 2.115.255.2542.115.255.255262,142
1582.116.0.0/142.116.0.1 to 2.119.255.2542.119.255.255262,142
1592.120.0.0/142.120.0.1 to 2.123.255.2542.123.255.255262,142
1602.124.0.0/142.124.0.1 to 2.127.255.2542.127.255.255262,142
1612.128.0.0/142.128.0.1 to 2.131.255.2542.131.255.255262,142
1622.132.0.0/142.132.0.1 to 2.135.255.2542.135.255.255262,142
1632.136.0.0/142.136.0.1 to 2.139.255.2542.139.255.255262,142
1642.140.0.0/142.140.0.1 to 2.143.255.2542.143.255.255262,142
1652.144.0.0/142.144.0.1 to 2.147.255.2542.147.255.255262,142
1662.148.0.0/142.148.0.1 to 2.151.255.2542.151.255.255262,142
1672.152.0.0/142.152.0.1 to 2.155.255.2542.155.255.255262,142
1682.156.0.0/142.156.0.1 to 2.159.255.2542.159.255.255262,142
1692.160.0.0/142.160.0.1 to 2.163.255.2542.163.255.255262,142
1702.164.0.0/142.164.0.1 to 2.167.255.2542.167.255.255262,142
1712.168.0.0/142.168.0.1 to 2.171.255.2542.171.255.255262,142
1722.172.0.0/142.172.0.1 to 2.175.255.2542.175.255.255262,142
1732.176.0.0/142.176.0.1 to 2.179.255.2542.179.255.255262,142
1742.180.0.0/142.180.0.1 to 2.183.255.2542.183.255.255262,142
1752.184.0.0/142.184.0.1 to 2.187.255.2542.187.255.255262,142
1762.188.0.0/142.188.0.1 to 2.191.255.2542.191.255.255262,142
1772.192.0.0/142.192.0.1 to 2.195.255.2542.195.255.255262,142
1782.196.0.0/142.196.0.1 to 2.199.255.2542.199.255.255262,142
1792.200.0.0/142.200.0.1 to 2.203.255.2542.203.255.255262,142
1802.204.0.0/142.204.0.1 to 2.207.255.2542.207.255.255262,142
1812.208.0.0/142.208.0.1 to 2.211.255.2542.211.255.255262,142
1822.212.0.0/142.212.0.1 to 2.215.255.2542.215.255.255262,142
1832.216.0.0/142.216.0.1 to 2.219.255.2542.219.255.255262,142
1842.220.0.0/142.220.0.1 to 2.223.255.2542.223.255.255262,142
1852.224.0.0/142.224.0.1 to 2.227.255.2542.227.255.255262,142
1862.228.0.0/142.228.0.1 to 2.231.255.2542.231.255.255262,142
1872.232.0.0/142.232.0.1 to 2.235.255.2542.235.255.255262,142
1882.236.0.0/142.236.0.1 to 2.239.255.2542.239.255.255262,142
1892.240.0.0/142.240.0.1 to 2.243.255.2542.243.255.255262,142
1902.244.0.0/142.244.0.1 to 2.247.255.2542.247.255.255262,142
1912.248.0.0/142.248.0.1 to 2.251.255.2542.251.255.255262,142
1922.252.0.0/142.252.0.1 to 2.255.255.2542.255.255.255262,142
1933.0.0.0/143.0.0.1 to 3.3.255.2543.3.255.255262,142
1943.4.0.0/143.4.0.1 to 3.7.255.2543.7.255.255262,142
1953.8.0.0/143.8.0.1 to 3.11.255.2543.11.255.255262,142
1963.12.0.0/143.12.0.1 to 3.15.255.2543.15.255.255262,142
1973.16.0.0/143.16.0.1 to 3.19.255.2543.19.255.255262,142
1983.20.0.0/143.20.0.1 to 3.23.255.2543.23.255.255262,142
1993.24.0.0/143.24.0.1 to 3.27.255.2543.27.255.255262,142
2003.28.0.0/143.28.0.1 to 3.31.255.2543.31.255.255262,142
2013.32.0.0/143.32.0.1 to 3.35.255.2543.35.255.255262,142
2023.36.0.0/143.36.0.1 to 3.39.255.2543.39.255.255262,142
2033.40.0.0/143.40.0.1 to 3.43.255.2543.43.255.255262,142
2043.44.0.0/143.44.0.1 to 3.47.255.2543.47.255.255262,142
2053.48.0.0/143.48.0.1 to 3.51.255.2543.51.255.255262,142
2063.52.0.0/143.52.0.1 to 3.55.255.2543.55.255.255262,142
2073.56.0.0/143.56.0.1 to 3.59.255.2543.59.255.255262,142
2083.60.0.0/143.60.0.1 to 3.63.255.2543.63.255.255262,142
2093.64.0.0/143.64.0.1 to 3.67.255.2543.67.255.255262,142
2103.68.0.0/143.68.0.1 to 3.71.255.2543.71.255.255262,142
2113.72.0.0/143.72.0.1 to 3.75.255.2543.75.255.255262,142
2123.76.0.0/143.76.0.1 to 3.79.255.2543.79.255.255262,142
2133.80.0.0/143.80.0.1 to 3.83.255.2543.83.255.255262,142
2143.84.0.0/143.84.0.1 to 3.87.255.2543.87.255.255262,142
2153.88.0.0/143.88.0.1 to 3.91.255.2543.91.255.255262,142
2163.92.0.0/143.92.0.1 to 3.95.255.2543.95.255.255262,142
2173.96.0.0/143.96.0.1 to 3.99.255.2543.99.255.255262,142
2183.100.0.0/143.100.0.1 to 3.103.255.2543.103.255.255262,142
2193.104.0.0/143.104.0.1 to 3.107.255.2543.107.255.255262,142
2203.108.0.0/143.108.0.1 to 3.111.255.2543.111.255.255262,142
2213.112.0.0/143.112.0.1 to 3.115.255.2543.115.255.255262,142
2223.116.0.0/143.116.0.1 to 3.119.255.2543.119.255.255262,142
2233.120.0.0/143.120.0.1 to 3.123.255.2543.123.255.255262,142
2243.124.0.0/143.124.0.1 to 3.127.255.2543.127.255.255262,142
2253.128.0.0/143.128.0.1 to 3.131.255.2543.131.255.255262,142
2263.132.0.0/143.132.0.1 to 3.135.255.2543.135.255.255262,142
2273.136.0.0/143.136.0.1 to 3.139.255.2543.139.255.255262,142
2283.140.0.0/143.140.0.1 to 3.143.255.2543.143.255.255262,142
2293.144.0.0/143.144.0.1 to 3.147.255.2543.147.255.255262,142
2303.148.0.0/143.148.0.1 to 3.151.255.2543.151.255.255262,142
2313.152.0.0/143.152.0.1 to 3.155.255.2543.155.255.255262,142
2323.156.0.0/143.156.0.1 to 3.159.255.2543.159.255.255262,142
2333.160.0.0/143.160.0.1 to 3.163.255.2543.163.255.255262,142
2343.164.0.0/143.164.0.1 to 3.167.255.2543.167.255.255262,142
2353.168.0.0/143.168.0.1 to 3.171.255.2543.171.255.255262,142
2363.172.0.0/143.172.0.1 to 3.175.255.2543.175.255.255262,142
2373.176.0.0/143.176.0.1 to 3.179.255.2543.179.255.255262,142
2383.180.0.0/143.180.0.1 to 3.183.255.2543.183.255.255262,142
2393.184.0.0/143.184.0.1 to 3.187.255.2543.187.255.255262,142
2403.188.0.0/143.188.0.1 to 3.191.255.2543.191.255.255262,142
2413.192.0.0/143.192.0.1 to 3.195.255.2543.195.255.255262,142
2423.196.0.0/143.196.0.1 to 3.199.255.2543.199.255.255262,142
2433.200.0.0/143.200.0.1 to 3.203.255.2543.203.255.255262,142
2443.204.0.0/143.204.0.1 to 3.207.255.2543.207.255.255262,142
2453.208.0.0/143.208.0.1 to 3.211.255.2543.211.255.255262,142
2463.212.0.0/143.212.0.1 to 3.215.255.2543.215.255.255262,142
2473.216.0.0/143.216.0.1 to 3.219.255.2543.219.255.255262,142
2483.220.0.0/143.220.0.1 to 3.223.255.2543.223.255.255262,142
2493.224.0.0/143.224.0.1 to 3.227.255.2543.227.255.255262,142
2503.228.0.0/143.228.0.1 to 3.231.255.2543.231.255.255262,142
2513.232.0.0/143.232.0.1 to 3.235.255.2543.235.255.255262,142
2523.236.0.0/143.236.0.1 to 3.239.255.2543.239.255.255262,142
2533.240.0.0/143.240.0.1 to 3.243.255.2543.243.255.255262,142
2543.244.0.0/143.244.0.1 to 3.247.255.2543.247.255.255262,142
2553.248.0.0/143.248.0.1 to 3.251.255.2543.251.255.255262,142
2563.252.0.0/143.252.0.1 to 3.255.255.2543.255.255.255262,142

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.