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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.

Network1.112.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
1.112.0.0
Broadcast address
1.127.255.255
First usable
1.112.0.1
Last usable
1.127.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 01700000 · Integer 24117248 to 25165823
Reverse DNS zones
112.1.in-addr.arpa
113.1.in-addr.arpa
114.1.in-addr.arpa
115.1.in-addr.arpa
116.1.in-addr.arpa
117.1.in-addr.arpa
118.1.in-addr.arpa
119.1.in-addr.arpa
120.1.in-addr.arpa
121.1.in-addr.arpa
122.1.in-addr.arpa
123.1.in-addr.arpa
124.1.in-addr.arpa
125.1.in-addr.arpa
126.1.in-addr.arpa
127.1.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000001.01110000.00000000.000000001.112.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00000001.01110000.00000000.000000001.112.0.0
Broadcast00000001.01111111.11111111.111111111.127.255.255
Split into smaller subnets/20
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

1.112.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
11.112.0.0/201.112.0.1 to 1.112.15.2541.112.15.2554,094
21.112.16.0/201.112.16.1 to 1.112.31.2541.112.31.2554,094
31.112.32.0/201.112.32.1 to 1.112.47.2541.112.47.2554,094
41.112.48.0/201.112.48.1 to 1.112.63.2541.112.63.2554,094
51.112.64.0/201.112.64.1 to 1.112.79.2541.112.79.2554,094
61.112.80.0/201.112.80.1 to 1.112.95.2541.112.95.2554,094
71.112.96.0/201.112.96.1 to 1.112.111.2541.112.111.2554,094
81.112.112.0/201.112.112.1 to 1.112.127.2541.112.127.2554,094
91.112.128.0/201.112.128.1 to 1.112.143.2541.112.143.2554,094
101.112.144.0/201.112.144.1 to 1.112.159.2541.112.159.2554,094
111.112.160.0/201.112.160.1 to 1.112.175.2541.112.175.2554,094
121.112.176.0/201.112.176.1 to 1.112.191.2541.112.191.2554,094
131.112.192.0/201.112.192.1 to 1.112.207.2541.112.207.2554,094
141.112.208.0/201.112.208.1 to 1.112.223.2541.112.223.2554,094
151.112.224.0/201.112.224.1 to 1.112.239.2541.112.239.2554,094
161.112.240.0/201.112.240.1 to 1.112.255.2541.112.255.2554,094
171.113.0.0/201.113.0.1 to 1.113.15.2541.113.15.2554,094
181.113.16.0/201.113.16.1 to 1.113.31.2541.113.31.2554,094
191.113.32.0/201.113.32.1 to 1.113.47.2541.113.47.2554,094
201.113.48.0/201.113.48.1 to 1.113.63.2541.113.63.2554,094
211.113.64.0/201.113.64.1 to 1.113.79.2541.113.79.2554,094
221.113.80.0/201.113.80.1 to 1.113.95.2541.113.95.2554,094
231.113.96.0/201.113.96.1 to 1.113.111.2541.113.111.2554,094
241.113.112.0/201.113.112.1 to 1.113.127.2541.113.127.2554,094
251.113.128.0/201.113.128.1 to 1.113.143.2541.113.143.2554,094
261.113.144.0/201.113.144.1 to 1.113.159.2541.113.159.2554,094
271.113.160.0/201.113.160.1 to 1.113.175.2541.113.175.2554,094
281.113.176.0/201.113.176.1 to 1.113.191.2541.113.191.2554,094
291.113.192.0/201.113.192.1 to 1.113.207.2541.113.207.2554,094
301.113.208.0/201.113.208.1 to 1.113.223.2541.113.223.2554,094
311.113.224.0/201.113.224.1 to 1.113.239.2541.113.239.2554,094
321.113.240.0/201.113.240.1 to 1.113.255.2541.113.255.2554,094
331.114.0.0/201.114.0.1 to 1.114.15.2541.114.15.2554,094
341.114.16.0/201.114.16.1 to 1.114.31.2541.114.31.2554,094
351.114.32.0/201.114.32.1 to 1.114.47.2541.114.47.2554,094
361.114.48.0/201.114.48.1 to 1.114.63.2541.114.63.2554,094
371.114.64.0/201.114.64.1 to 1.114.79.2541.114.79.2554,094
381.114.80.0/201.114.80.1 to 1.114.95.2541.114.95.2554,094
391.114.96.0/201.114.96.1 to 1.114.111.2541.114.111.2554,094
401.114.112.0/201.114.112.1 to 1.114.127.2541.114.127.2554,094
411.114.128.0/201.114.128.1 to 1.114.143.2541.114.143.2554,094
421.114.144.0/201.114.144.1 to 1.114.159.2541.114.159.2554,094
431.114.160.0/201.114.160.1 to 1.114.175.2541.114.175.2554,094
441.114.176.0/201.114.176.1 to 1.114.191.2541.114.191.2554,094
451.114.192.0/201.114.192.1 to 1.114.207.2541.114.207.2554,094
461.114.208.0/201.114.208.1 to 1.114.223.2541.114.223.2554,094
471.114.224.0/201.114.224.1 to 1.114.239.2541.114.239.2554,094
481.114.240.0/201.114.240.1 to 1.114.255.2541.114.255.2554,094
491.115.0.0/201.115.0.1 to 1.115.15.2541.115.15.2554,094
501.115.16.0/201.115.16.1 to 1.115.31.2541.115.31.2554,094
511.115.32.0/201.115.32.1 to 1.115.47.2541.115.47.2554,094
521.115.48.0/201.115.48.1 to 1.115.63.2541.115.63.2554,094
531.115.64.0/201.115.64.1 to 1.115.79.2541.115.79.2554,094
541.115.80.0/201.115.80.1 to 1.115.95.2541.115.95.2554,094
551.115.96.0/201.115.96.1 to 1.115.111.2541.115.111.2554,094
561.115.112.0/201.115.112.1 to 1.115.127.2541.115.127.2554,094
571.115.128.0/201.115.128.1 to 1.115.143.2541.115.143.2554,094
581.115.144.0/201.115.144.1 to 1.115.159.2541.115.159.2554,094
591.115.160.0/201.115.160.1 to 1.115.175.2541.115.175.2554,094
601.115.176.0/201.115.176.1 to 1.115.191.2541.115.191.2554,094
611.115.192.0/201.115.192.1 to 1.115.207.2541.115.207.2554,094
621.115.208.0/201.115.208.1 to 1.115.223.2541.115.223.2554,094
631.115.224.0/201.115.224.1 to 1.115.239.2541.115.239.2554,094
641.115.240.0/201.115.240.1 to 1.115.255.2541.115.255.2554,094
651.116.0.0/201.116.0.1 to 1.116.15.2541.116.15.2554,094
661.116.16.0/201.116.16.1 to 1.116.31.2541.116.31.2554,094
671.116.32.0/201.116.32.1 to 1.116.47.2541.116.47.2554,094
681.116.48.0/201.116.48.1 to 1.116.63.2541.116.63.2554,094
691.116.64.0/201.116.64.1 to 1.116.79.2541.116.79.2554,094
701.116.80.0/201.116.80.1 to 1.116.95.2541.116.95.2554,094
711.116.96.0/201.116.96.1 to 1.116.111.2541.116.111.2554,094
721.116.112.0/201.116.112.1 to 1.116.127.2541.116.127.2554,094
731.116.128.0/201.116.128.1 to 1.116.143.2541.116.143.2554,094
741.116.144.0/201.116.144.1 to 1.116.159.2541.116.159.2554,094
751.116.160.0/201.116.160.1 to 1.116.175.2541.116.175.2554,094
761.116.176.0/201.116.176.1 to 1.116.191.2541.116.191.2554,094
771.116.192.0/201.116.192.1 to 1.116.207.2541.116.207.2554,094
781.116.208.0/201.116.208.1 to 1.116.223.2541.116.223.2554,094
791.116.224.0/201.116.224.1 to 1.116.239.2541.116.239.2554,094
801.116.240.0/201.116.240.1 to 1.116.255.2541.116.255.2554,094
811.117.0.0/201.117.0.1 to 1.117.15.2541.117.15.2554,094
821.117.16.0/201.117.16.1 to 1.117.31.2541.117.31.2554,094
831.117.32.0/201.117.32.1 to 1.117.47.2541.117.47.2554,094
841.117.48.0/201.117.48.1 to 1.117.63.2541.117.63.2554,094
851.117.64.0/201.117.64.1 to 1.117.79.2541.117.79.2554,094
861.117.80.0/201.117.80.1 to 1.117.95.2541.117.95.2554,094
871.117.96.0/201.117.96.1 to 1.117.111.2541.117.111.2554,094
881.117.112.0/201.117.112.1 to 1.117.127.2541.117.127.2554,094
891.117.128.0/201.117.128.1 to 1.117.143.2541.117.143.2554,094
901.117.144.0/201.117.144.1 to 1.117.159.2541.117.159.2554,094
911.117.160.0/201.117.160.1 to 1.117.175.2541.117.175.2554,094
921.117.176.0/201.117.176.1 to 1.117.191.2541.117.191.2554,094
931.117.192.0/201.117.192.1 to 1.117.207.2541.117.207.2554,094
941.117.208.0/201.117.208.1 to 1.117.223.2541.117.223.2554,094
951.117.224.0/201.117.224.1 to 1.117.239.2541.117.239.2554,094
961.117.240.0/201.117.240.1 to 1.117.255.2541.117.255.2554,094
971.118.0.0/201.118.0.1 to 1.118.15.2541.118.15.2554,094
981.118.16.0/201.118.16.1 to 1.118.31.2541.118.31.2554,094
991.118.32.0/201.118.32.1 to 1.118.47.2541.118.47.2554,094
1001.118.48.0/201.118.48.1 to 1.118.63.2541.118.63.2554,094
1011.118.64.0/201.118.64.1 to 1.118.79.2541.118.79.2554,094
1021.118.80.0/201.118.80.1 to 1.118.95.2541.118.95.2554,094
1031.118.96.0/201.118.96.1 to 1.118.111.2541.118.111.2554,094
1041.118.112.0/201.118.112.1 to 1.118.127.2541.118.127.2554,094
1051.118.128.0/201.118.128.1 to 1.118.143.2541.118.143.2554,094
1061.118.144.0/201.118.144.1 to 1.118.159.2541.118.159.2554,094
1071.118.160.0/201.118.160.1 to 1.118.175.2541.118.175.2554,094
1081.118.176.0/201.118.176.1 to 1.118.191.2541.118.191.2554,094
1091.118.192.0/201.118.192.1 to 1.118.207.2541.118.207.2554,094
1101.118.208.0/201.118.208.1 to 1.118.223.2541.118.223.2554,094
1111.118.224.0/201.118.224.1 to 1.118.239.2541.118.239.2554,094
1121.118.240.0/201.118.240.1 to 1.118.255.2541.118.255.2554,094
1131.119.0.0/201.119.0.1 to 1.119.15.2541.119.15.2554,094
1141.119.16.0/201.119.16.1 to 1.119.31.2541.119.31.2554,094
1151.119.32.0/201.119.32.1 to 1.119.47.2541.119.47.2554,094
1161.119.48.0/201.119.48.1 to 1.119.63.2541.119.63.2554,094
1171.119.64.0/201.119.64.1 to 1.119.79.2541.119.79.2554,094
1181.119.80.0/201.119.80.1 to 1.119.95.2541.119.95.2554,094
1191.119.96.0/201.119.96.1 to 1.119.111.2541.119.111.2554,094
1201.119.112.0/201.119.112.1 to 1.119.127.2541.119.127.2554,094
1211.119.128.0/201.119.128.1 to 1.119.143.2541.119.143.2554,094
1221.119.144.0/201.119.144.1 to 1.119.159.2541.119.159.2554,094
1231.119.160.0/201.119.160.1 to 1.119.175.2541.119.175.2554,094
1241.119.176.0/201.119.176.1 to 1.119.191.2541.119.191.2554,094
1251.119.192.0/201.119.192.1 to 1.119.207.2541.119.207.2554,094
1261.119.208.0/201.119.208.1 to 1.119.223.2541.119.223.2554,094
1271.119.224.0/201.119.224.1 to 1.119.239.2541.119.239.2554,094
1281.119.240.0/201.119.240.1 to 1.119.255.2541.119.255.2554,094
1291.120.0.0/201.120.0.1 to 1.120.15.2541.120.15.2554,094
1301.120.16.0/201.120.16.1 to 1.120.31.2541.120.31.2554,094
1311.120.32.0/201.120.32.1 to 1.120.47.2541.120.47.2554,094
1321.120.48.0/201.120.48.1 to 1.120.63.2541.120.63.2554,094
1331.120.64.0/201.120.64.1 to 1.120.79.2541.120.79.2554,094
1341.120.80.0/201.120.80.1 to 1.120.95.2541.120.95.2554,094
1351.120.96.0/201.120.96.1 to 1.120.111.2541.120.111.2554,094
1361.120.112.0/201.120.112.1 to 1.120.127.2541.120.127.2554,094
1371.120.128.0/201.120.128.1 to 1.120.143.2541.120.143.2554,094
1381.120.144.0/201.120.144.1 to 1.120.159.2541.120.159.2554,094
1391.120.160.0/201.120.160.1 to 1.120.175.2541.120.175.2554,094
1401.120.176.0/201.120.176.1 to 1.120.191.2541.120.191.2554,094
1411.120.192.0/201.120.192.1 to 1.120.207.2541.120.207.2554,094
1421.120.208.0/201.120.208.1 to 1.120.223.2541.120.223.2554,094
1431.120.224.0/201.120.224.1 to 1.120.239.2541.120.239.2554,094
1441.120.240.0/201.120.240.1 to 1.120.255.2541.120.255.2554,094
1451.121.0.0/201.121.0.1 to 1.121.15.2541.121.15.2554,094
1461.121.16.0/201.121.16.1 to 1.121.31.2541.121.31.2554,094
1471.121.32.0/201.121.32.1 to 1.121.47.2541.121.47.2554,094
1481.121.48.0/201.121.48.1 to 1.121.63.2541.121.63.2554,094
1491.121.64.0/201.121.64.1 to 1.121.79.2541.121.79.2554,094
1501.121.80.0/201.121.80.1 to 1.121.95.2541.121.95.2554,094
1511.121.96.0/201.121.96.1 to 1.121.111.2541.121.111.2554,094
1521.121.112.0/201.121.112.1 to 1.121.127.2541.121.127.2554,094
1531.121.128.0/201.121.128.1 to 1.121.143.2541.121.143.2554,094
1541.121.144.0/201.121.144.1 to 1.121.159.2541.121.159.2554,094
1551.121.160.0/201.121.160.1 to 1.121.175.2541.121.175.2554,094
1561.121.176.0/201.121.176.1 to 1.121.191.2541.121.191.2554,094
1571.121.192.0/201.121.192.1 to 1.121.207.2541.121.207.2554,094
1581.121.208.0/201.121.208.1 to 1.121.223.2541.121.223.2554,094
1591.121.224.0/201.121.224.1 to 1.121.239.2541.121.239.2554,094
1601.121.240.0/201.121.240.1 to 1.121.255.2541.121.255.2554,094
1611.122.0.0/201.122.0.1 to 1.122.15.2541.122.15.2554,094
1621.122.16.0/201.122.16.1 to 1.122.31.2541.122.31.2554,094
1631.122.32.0/201.122.32.1 to 1.122.47.2541.122.47.2554,094
1641.122.48.0/201.122.48.1 to 1.122.63.2541.122.63.2554,094
1651.122.64.0/201.122.64.1 to 1.122.79.2541.122.79.2554,094
1661.122.80.0/201.122.80.1 to 1.122.95.2541.122.95.2554,094
1671.122.96.0/201.122.96.1 to 1.122.111.2541.122.111.2554,094
1681.122.112.0/201.122.112.1 to 1.122.127.2541.122.127.2554,094
1691.122.128.0/201.122.128.1 to 1.122.143.2541.122.143.2554,094
1701.122.144.0/201.122.144.1 to 1.122.159.2541.122.159.2554,094
1711.122.160.0/201.122.160.1 to 1.122.175.2541.122.175.2554,094
1721.122.176.0/201.122.176.1 to 1.122.191.2541.122.191.2554,094
1731.122.192.0/201.122.192.1 to 1.122.207.2541.122.207.2554,094
1741.122.208.0/201.122.208.1 to 1.122.223.2541.122.223.2554,094
1751.122.224.0/201.122.224.1 to 1.122.239.2541.122.239.2554,094
1761.122.240.0/201.122.240.1 to 1.122.255.2541.122.255.2554,094
1771.123.0.0/201.123.0.1 to 1.123.15.2541.123.15.2554,094
1781.123.16.0/201.123.16.1 to 1.123.31.2541.123.31.2554,094
1791.123.32.0/201.123.32.1 to 1.123.47.2541.123.47.2554,094
1801.123.48.0/201.123.48.1 to 1.123.63.2541.123.63.2554,094
1811.123.64.0/201.123.64.1 to 1.123.79.2541.123.79.2554,094
1821.123.80.0/201.123.80.1 to 1.123.95.2541.123.95.2554,094
1831.123.96.0/201.123.96.1 to 1.123.111.2541.123.111.2554,094
1841.123.112.0/201.123.112.1 to 1.123.127.2541.123.127.2554,094
1851.123.128.0/201.123.128.1 to 1.123.143.2541.123.143.2554,094
1861.123.144.0/201.123.144.1 to 1.123.159.2541.123.159.2554,094
1871.123.160.0/201.123.160.1 to 1.123.175.2541.123.175.2554,094
1881.123.176.0/201.123.176.1 to 1.123.191.2541.123.191.2554,094
1891.123.192.0/201.123.192.1 to 1.123.207.2541.123.207.2554,094
1901.123.208.0/201.123.208.1 to 1.123.223.2541.123.223.2554,094
1911.123.224.0/201.123.224.1 to 1.123.239.2541.123.239.2554,094
1921.123.240.0/201.123.240.1 to 1.123.255.2541.123.255.2554,094
1931.124.0.0/201.124.0.1 to 1.124.15.2541.124.15.2554,094
1941.124.16.0/201.124.16.1 to 1.124.31.2541.124.31.2554,094
1951.124.32.0/201.124.32.1 to 1.124.47.2541.124.47.2554,094
1961.124.48.0/201.124.48.1 to 1.124.63.2541.124.63.2554,094
1971.124.64.0/201.124.64.1 to 1.124.79.2541.124.79.2554,094
1981.124.80.0/201.124.80.1 to 1.124.95.2541.124.95.2554,094
1991.124.96.0/201.124.96.1 to 1.124.111.2541.124.111.2554,094
2001.124.112.0/201.124.112.1 to 1.124.127.2541.124.127.2554,094
2011.124.128.0/201.124.128.1 to 1.124.143.2541.124.143.2554,094
2021.124.144.0/201.124.144.1 to 1.124.159.2541.124.159.2554,094
2031.124.160.0/201.124.160.1 to 1.124.175.2541.124.175.2554,094
2041.124.176.0/201.124.176.1 to 1.124.191.2541.124.191.2554,094
2051.124.192.0/201.124.192.1 to 1.124.207.2541.124.207.2554,094
2061.124.208.0/201.124.208.1 to 1.124.223.2541.124.223.2554,094
2071.124.224.0/201.124.224.1 to 1.124.239.2541.124.239.2554,094
2081.124.240.0/201.124.240.1 to 1.124.255.2541.124.255.2554,094
2091.125.0.0/201.125.0.1 to 1.125.15.2541.125.15.2554,094
2101.125.16.0/201.125.16.1 to 1.125.31.2541.125.31.2554,094
2111.125.32.0/201.125.32.1 to 1.125.47.2541.125.47.2554,094
2121.125.48.0/201.125.48.1 to 1.125.63.2541.125.63.2554,094
2131.125.64.0/201.125.64.1 to 1.125.79.2541.125.79.2554,094
2141.125.80.0/201.125.80.1 to 1.125.95.2541.125.95.2554,094
2151.125.96.0/201.125.96.1 to 1.125.111.2541.125.111.2554,094
2161.125.112.0/201.125.112.1 to 1.125.127.2541.125.127.2554,094
2171.125.128.0/201.125.128.1 to 1.125.143.2541.125.143.2554,094
2181.125.144.0/201.125.144.1 to 1.125.159.2541.125.159.2554,094
2191.125.160.0/201.125.160.1 to 1.125.175.2541.125.175.2554,094
2201.125.176.0/201.125.176.1 to 1.125.191.2541.125.191.2554,094
2211.125.192.0/201.125.192.1 to 1.125.207.2541.125.207.2554,094
2221.125.208.0/201.125.208.1 to 1.125.223.2541.125.223.2554,094
2231.125.224.0/201.125.224.1 to 1.125.239.2541.125.239.2554,094
2241.125.240.0/201.125.240.1 to 1.125.255.2541.125.255.2554,094
2251.126.0.0/201.126.0.1 to 1.126.15.2541.126.15.2554,094
2261.126.16.0/201.126.16.1 to 1.126.31.2541.126.31.2554,094
2271.126.32.0/201.126.32.1 to 1.126.47.2541.126.47.2554,094
2281.126.48.0/201.126.48.1 to 1.126.63.2541.126.63.2554,094
2291.126.64.0/201.126.64.1 to 1.126.79.2541.126.79.2554,094
2301.126.80.0/201.126.80.1 to 1.126.95.2541.126.95.2554,094
2311.126.96.0/201.126.96.1 to 1.126.111.2541.126.111.2554,094
2321.126.112.0/201.126.112.1 to 1.126.127.2541.126.127.2554,094
2331.126.128.0/201.126.128.1 to 1.126.143.2541.126.143.2554,094
2341.126.144.0/201.126.144.1 to 1.126.159.2541.126.159.2554,094
2351.126.160.0/201.126.160.1 to 1.126.175.2541.126.175.2554,094
2361.126.176.0/201.126.176.1 to 1.126.191.2541.126.191.2554,094
2371.126.192.0/201.126.192.1 to 1.126.207.2541.126.207.2554,094
2381.126.208.0/201.126.208.1 to 1.126.223.2541.126.223.2554,094
2391.126.224.0/201.126.224.1 to 1.126.239.2541.126.239.2554,094
2401.126.240.0/201.126.240.1 to 1.126.255.2541.126.255.2554,094
2411.127.0.0/201.127.0.1 to 1.127.15.2541.127.15.2554,094
2421.127.16.0/201.127.16.1 to 1.127.31.2541.127.31.2554,094
2431.127.32.0/201.127.32.1 to 1.127.47.2541.127.47.2554,094
2441.127.48.0/201.127.48.1 to 1.127.63.2541.127.63.2554,094
2451.127.64.0/201.127.64.1 to 1.127.79.2541.127.79.2554,094
2461.127.80.0/201.127.80.1 to 1.127.95.2541.127.95.2554,094
2471.127.96.0/201.127.96.1 to 1.127.111.2541.127.111.2554,094
2481.127.112.0/201.127.112.1 to 1.127.127.2541.127.127.2554,094
2491.127.128.0/201.127.128.1 to 1.127.143.2541.127.143.2554,094
2501.127.144.0/201.127.144.1 to 1.127.159.2541.127.159.2554,094
2511.127.160.0/201.127.160.1 to 1.127.175.2541.127.175.2554,094
2521.127.176.0/201.127.176.1 to 1.127.191.2541.127.191.2554,094
2531.127.192.0/201.127.192.1 to 1.127.207.2541.127.207.2554,094
2541.127.208.0/201.127.208.1 to 1.127.223.2541.127.223.2554,094
2551.127.224.0/201.127.224.1 to 1.127.239.2541.127.239.2554,094
2561.127.240.0/201.127.240.1 to 1.127.255.2541.127.255.2554,094

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.