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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.

Network1.180.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
1.180.0.0
Broadcast address
1.181.255.255
First usable
1.180.0.1
Last usable
1.181.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 01B40000 · Integer 28573696 to 28704767
Reverse DNS zones
180.1.in-addr.arpa
181.1.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000001.10110100.00000000.000000001.180.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network00000001.10110100.00000000.000000001.180.0.0
Broadcast00000001.10110101.11111111.111111111.181.255.255
Split into smaller subnets/27
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

1.180.0.0/15 makes 4,096 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
11.180.0.0/271.180.0.1 to 1.180.0.301.180.0.3130
21.180.0.32/271.180.0.33 to 1.180.0.621.180.0.6330
31.180.0.64/271.180.0.65 to 1.180.0.941.180.0.9530
41.180.0.96/271.180.0.97 to 1.180.0.1261.180.0.12730
51.180.0.128/271.180.0.129 to 1.180.0.1581.180.0.15930
61.180.0.160/271.180.0.161 to 1.180.0.1901.180.0.19130
71.180.0.192/271.180.0.193 to 1.180.0.2221.180.0.22330
81.180.0.224/271.180.0.225 to 1.180.0.2541.180.0.25530
91.180.1.0/271.180.1.1 to 1.180.1.301.180.1.3130
101.180.1.32/271.180.1.33 to 1.180.1.621.180.1.6330
111.180.1.64/271.180.1.65 to 1.180.1.941.180.1.9530
121.180.1.96/271.180.1.97 to 1.180.1.1261.180.1.12730
131.180.1.128/271.180.1.129 to 1.180.1.1581.180.1.15930
141.180.1.160/271.180.1.161 to 1.180.1.1901.180.1.19130
151.180.1.192/271.180.1.193 to 1.180.1.2221.180.1.22330
161.180.1.224/271.180.1.225 to 1.180.1.2541.180.1.25530
171.180.2.0/271.180.2.1 to 1.180.2.301.180.2.3130
181.180.2.32/271.180.2.33 to 1.180.2.621.180.2.6330
191.180.2.64/271.180.2.65 to 1.180.2.941.180.2.9530
201.180.2.96/271.180.2.97 to 1.180.2.1261.180.2.12730
211.180.2.128/271.180.2.129 to 1.180.2.1581.180.2.15930
221.180.2.160/271.180.2.161 to 1.180.2.1901.180.2.19130
231.180.2.192/271.180.2.193 to 1.180.2.2221.180.2.22330
241.180.2.224/271.180.2.225 to 1.180.2.2541.180.2.25530
251.180.3.0/271.180.3.1 to 1.180.3.301.180.3.3130
261.180.3.32/271.180.3.33 to 1.180.3.621.180.3.6330
271.180.3.64/271.180.3.65 to 1.180.3.941.180.3.9530
281.180.3.96/271.180.3.97 to 1.180.3.1261.180.3.12730
291.180.3.128/271.180.3.129 to 1.180.3.1581.180.3.15930
301.180.3.160/271.180.3.161 to 1.180.3.1901.180.3.19130
311.180.3.192/271.180.3.193 to 1.180.3.2221.180.3.22330
321.180.3.224/271.180.3.225 to 1.180.3.2541.180.3.25530
331.180.4.0/271.180.4.1 to 1.180.4.301.180.4.3130
341.180.4.32/271.180.4.33 to 1.180.4.621.180.4.6330
351.180.4.64/271.180.4.65 to 1.180.4.941.180.4.9530
361.180.4.96/271.180.4.97 to 1.180.4.1261.180.4.12730
371.180.4.128/271.180.4.129 to 1.180.4.1581.180.4.15930
381.180.4.160/271.180.4.161 to 1.180.4.1901.180.4.19130
391.180.4.192/271.180.4.193 to 1.180.4.2221.180.4.22330
401.180.4.224/271.180.4.225 to 1.180.4.2541.180.4.25530
411.180.5.0/271.180.5.1 to 1.180.5.301.180.5.3130
421.180.5.32/271.180.5.33 to 1.180.5.621.180.5.6330
431.180.5.64/271.180.5.65 to 1.180.5.941.180.5.9530
441.180.5.96/271.180.5.97 to 1.180.5.1261.180.5.12730
451.180.5.128/271.180.5.129 to 1.180.5.1581.180.5.15930
461.180.5.160/271.180.5.161 to 1.180.5.1901.180.5.19130
471.180.5.192/271.180.5.193 to 1.180.5.2221.180.5.22330
481.180.5.224/271.180.5.225 to 1.180.5.2541.180.5.25530
491.180.6.0/271.180.6.1 to 1.180.6.301.180.6.3130
501.180.6.32/271.180.6.33 to 1.180.6.621.180.6.6330
511.180.6.64/271.180.6.65 to 1.180.6.941.180.6.9530
521.180.6.96/271.180.6.97 to 1.180.6.1261.180.6.12730
531.180.6.128/271.180.6.129 to 1.180.6.1581.180.6.15930
541.180.6.160/271.180.6.161 to 1.180.6.1901.180.6.19130
551.180.6.192/271.180.6.193 to 1.180.6.2221.180.6.22330
561.180.6.224/271.180.6.225 to 1.180.6.2541.180.6.25530
571.180.7.0/271.180.7.1 to 1.180.7.301.180.7.3130
581.180.7.32/271.180.7.33 to 1.180.7.621.180.7.6330
591.180.7.64/271.180.7.65 to 1.180.7.941.180.7.9530
601.180.7.96/271.180.7.97 to 1.180.7.1261.180.7.12730
611.180.7.128/271.180.7.129 to 1.180.7.1581.180.7.15930
621.180.7.160/271.180.7.161 to 1.180.7.1901.180.7.19130
631.180.7.192/271.180.7.193 to 1.180.7.2221.180.7.22330
641.180.7.224/271.180.7.225 to 1.180.7.2541.180.7.25530
651.180.8.0/271.180.8.1 to 1.180.8.301.180.8.3130
661.180.8.32/271.180.8.33 to 1.180.8.621.180.8.6330
671.180.8.64/271.180.8.65 to 1.180.8.941.180.8.9530
681.180.8.96/271.180.8.97 to 1.180.8.1261.180.8.12730
691.180.8.128/271.180.8.129 to 1.180.8.1581.180.8.15930
701.180.8.160/271.180.8.161 to 1.180.8.1901.180.8.19130
711.180.8.192/271.180.8.193 to 1.180.8.2221.180.8.22330
721.180.8.224/271.180.8.225 to 1.180.8.2541.180.8.25530
731.180.9.0/271.180.9.1 to 1.180.9.301.180.9.3130
741.180.9.32/271.180.9.33 to 1.180.9.621.180.9.6330
751.180.9.64/271.180.9.65 to 1.180.9.941.180.9.9530
761.180.9.96/271.180.9.97 to 1.180.9.1261.180.9.12730
771.180.9.128/271.180.9.129 to 1.180.9.1581.180.9.15930
781.180.9.160/271.180.9.161 to 1.180.9.1901.180.9.19130
791.180.9.192/271.180.9.193 to 1.180.9.2221.180.9.22330
801.180.9.224/271.180.9.225 to 1.180.9.2541.180.9.25530
811.180.10.0/271.180.10.1 to 1.180.10.301.180.10.3130
821.180.10.32/271.180.10.33 to 1.180.10.621.180.10.6330
831.180.10.64/271.180.10.65 to 1.180.10.941.180.10.9530
841.180.10.96/271.180.10.97 to 1.180.10.1261.180.10.12730
851.180.10.128/271.180.10.129 to 1.180.10.1581.180.10.15930
861.180.10.160/271.180.10.161 to 1.180.10.1901.180.10.19130
871.180.10.192/271.180.10.193 to 1.180.10.2221.180.10.22330
881.180.10.224/271.180.10.225 to 1.180.10.2541.180.10.25530
891.180.11.0/271.180.11.1 to 1.180.11.301.180.11.3130
901.180.11.32/271.180.11.33 to 1.180.11.621.180.11.6330
911.180.11.64/271.180.11.65 to 1.180.11.941.180.11.9530
921.180.11.96/271.180.11.97 to 1.180.11.1261.180.11.12730
931.180.11.128/271.180.11.129 to 1.180.11.1581.180.11.15930
941.180.11.160/271.180.11.161 to 1.180.11.1901.180.11.19130
951.180.11.192/271.180.11.193 to 1.180.11.2221.180.11.22330
961.180.11.224/271.180.11.225 to 1.180.11.2541.180.11.25530
971.180.12.0/271.180.12.1 to 1.180.12.301.180.12.3130
981.180.12.32/271.180.12.33 to 1.180.12.621.180.12.6330
991.180.12.64/271.180.12.65 to 1.180.12.941.180.12.9530
1001.180.12.96/271.180.12.97 to 1.180.12.1261.180.12.12730
1011.180.12.128/271.180.12.129 to 1.180.12.1581.180.12.15930
1021.180.12.160/271.180.12.161 to 1.180.12.1901.180.12.19130
1031.180.12.192/271.180.12.193 to 1.180.12.2221.180.12.22330
1041.180.12.224/271.180.12.225 to 1.180.12.2541.180.12.25530
1051.180.13.0/271.180.13.1 to 1.180.13.301.180.13.3130
1061.180.13.32/271.180.13.33 to 1.180.13.621.180.13.6330
1071.180.13.64/271.180.13.65 to 1.180.13.941.180.13.9530
1081.180.13.96/271.180.13.97 to 1.180.13.1261.180.13.12730
1091.180.13.128/271.180.13.129 to 1.180.13.1581.180.13.15930
1101.180.13.160/271.180.13.161 to 1.180.13.1901.180.13.19130
1111.180.13.192/271.180.13.193 to 1.180.13.2221.180.13.22330
1121.180.13.224/271.180.13.225 to 1.180.13.2541.180.13.25530
1131.180.14.0/271.180.14.1 to 1.180.14.301.180.14.3130
1141.180.14.32/271.180.14.33 to 1.180.14.621.180.14.6330
1151.180.14.64/271.180.14.65 to 1.180.14.941.180.14.9530
1161.180.14.96/271.180.14.97 to 1.180.14.1261.180.14.12730
1171.180.14.128/271.180.14.129 to 1.180.14.1581.180.14.15930
1181.180.14.160/271.180.14.161 to 1.180.14.1901.180.14.19130
1191.180.14.192/271.180.14.193 to 1.180.14.2221.180.14.22330
1201.180.14.224/271.180.14.225 to 1.180.14.2541.180.14.25530
1211.180.15.0/271.180.15.1 to 1.180.15.301.180.15.3130
1221.180.15.32/271.180.15.33 to 1.180.15.621.180.15.6330
1231.180.15.64/271.180.15.65 to 1.180.15.941.180.15.9530
1241.180.15.96/271.180.15.97 to 1.180.15.1261.180.15.12730
1251.180.15.128/271.180.15.129 to 1.180.15.1581.180.15.15930
1261.180.15.160/271.180.15.161 to 1.180.15.1901.180.15.19130
1271.180.15.192/271.180.15.193 to 1.180.15.2221.180.15.22330
1281.180.15.224/271.180.15.225 to 1.180.15.2541.180.15.25530
1291.180.16.0/271.180.16.1 to 1.180.16.301.180.16.3130
1301.180.16.32/271.180.16.33 to 1.180.16.621.180.16.6330
1311.180.16.64/271.180.16.65 to 1.180.16.941.180.16.9530
1321.180.16.96/271.180.16.97 to 1.180.16.1261.180.16.12730
1331.180.16.128/271.180.16.129 to 1.180.16.1581.180.16.15930
1341.180.16.160/271.180.16.161 to 1.180.16.1901.180.16.19130
1351.180.16.192/271.180.16.193 to 1.180.16.2221.180.16.22330
1361.180.16.224/271.180.16.225 to 1.180.16.2541.180.16.25530
1371.180.17.0/271.180.17.1 to 1.180.17.301.180.17.3130
1381.180.17.32/271.180.17.33 to 1.180.17.621.180.17.6330
1391.180.17.64/271.180.17.65 to 1.180.17.941.180.17.9530
1401.180.17.96/271.180.17.97 to 1.180.17.1261.180.17.12730
1411.180.17.128/271.180.17.129 to 1.180.17.1581.180.17.15930
1421.180.17.160/271.180.17.161 to 1.180.17.1901.180.17.19130
1431.180.17.192/271.180.17.193 to 1.180.17.2221.180.17.22330
1441.180.17.224/271.180.17.225 to 1.180.17.2541.180.17.25530
1451.180.18.0/271.180.18.1 to 1.180.18.301.180.18.3130
1461.180.18.32/271.180.18.33 to 1.180.18.621.180.18.6330
1471.180.18.64/271.180.18.65 to 1.180.18.941.180.18.9530
1481.180.18.96/271.180.18.97 to 1.180.18.1261.180.18.12730
1491.180.18.128/271.180.18.129 to 1.180.18.1581.180.18.15930
1501.180.18.160/271.180.18.161 to 1.180.18.1901.180.18.19130
1511.180.18.192/271.180.18.193 to 1.180.18.2221.180.18.22330
1521.180.18.224/271.180.18.225 to 1.180.18.2541.180.18.25530
1531.180.19.0/271.180.19.1 to 1.180.19.301.180.19.3130
1541.180.19.32/271.180.19.33 to 1.180.19.621.180.19.6330
1551.180.19.64/271.180.19.65 to 1.180.19.941.180.19.9530
1561.180.19.96/271.180.19.97 to 1.180.19.1261.180.19.12730
1571.180.19.128/271.180.19.129 to 1.180.19.1581.180.19.15930
1581.180.19.160/271.180.19.161 to 1.180.19.1901.180.19.19130
1591.180.19.192/271.180.19.193 to 1.180.19.2221.180.19.22330
1601.180.19.224/271.180.19.225 to 1.180.19.2541.180.19.25530
1611.180.20.0/271.180.20.1 to 1.180.20.301.180.20.3130
1621.180.20.32/271.180.20.33 to 1.180.20.621.180.20.6330
1631.180.20.64/271.180.20.65 to 1.180.20.941.180.20.9530
1641.180.20.96/271.180.20.97 to 1.180.20.1261.180.20.12730
1651.180.20.128/271.180.20.129 to 1.180.20.1581.180.20.15930
1661.180.20.160/271.180.20.161 to 1.180.20.1901.180.20.19130
1671.180.20.192/271.180.20.193 to 1.180.20.2221.180.20.22330
1681.180.20.224/271.180.20.225 to 1.180.20.2541.180.20.25530
1691.180.21.0/271.180.21.1 to 1.180.21.301.180.21.3130
1701.180.21.32/271.180.21.33 to 1.180.21.621.180.21.6330
1711.180.21.64/271.180.21.65 to 1.180.21.941.180.21.9530
1721.180.21.96/271.180.21.97 to 1.180.21.1261.180.21.12730
1731.180.21.128/271.180.21.129 to 1.180.21.1581.180.21.15930
1741.180.21.160/271.180.21.161 to 1.180.21.1901.180.21.19130
1751.180.21.192/271.180.21.193 to 1.180.21.2221.180.21.22330
1761.180.21.224/271.180.21.225 to 1.180.21.2541.180.21.25530
1771.180.22.0/271.180.22.1 to 1.180.22.301.180.22.3130
1781.180.22.32/271.180.22.33 to 1.180.22.621.180.22.6330
1791.180.22.64/271.180.22.65 to 1.180.22.941.180.22.9530
1801.180.22.96/271.180.22.97 to 1.180.22.1261.180.22.12730
1811.180.22.128/271.180.22.129 to 1.180.22.1581.180.22.15930
1821.180.22.160/271.180.22.161 to 1.180.22.1901.180.22.19130
1831.180.22.192/271.180.22.193 to 1.180.22.2221.180.22.22330
1841.180.22.224/271.180.22.225 to 1.180.22.2541.180.22.25530
1851.180.23.0/271.180.23.1 to 1.180.23.301.180.23.3130
1861.180.23.32/271.180.23.33 to 1.180.23.621.180.23.6330
1871.180.23.64/271.180.23.65 to 1.180.23.941.180.23.9530
1881.180.23.96/271.180.23.97 to 1.180.23.1261.180.23.12730
1891.180.23.128/271.180.23.129 to 1.180.23.1581.180.23.15930
1901.180.23.160/271.180.23.161 to 1.180.23.1901.180.23.19130
1911.180.23.192/271.180.23.193 to 1.180.23.2221.180.23.22330
1921.180.23.224/271.180.23.225 to 1.180.23.2541.180.23.25530
1931.180.24.0/271.180.24.1 to 1.180.24.301.180.24.3130
1941.180.24.32/271.180.24.33 to 1.180.24.621.180.24.6330
1951.180.24.64/271.180.24.65 to 1.180.24.941.180.24.9530
1961.180.24.96/271.180.24.97 to 1.180.24.1261.180.24.12730
1971.180.24.128/271.180.24.129 to 1.180.24.1581.180.24.15930
1981.180.24.160/271.180.24.161 to 1.180.24.1901.180.24.19130
1991.180.24.192/271.180.24.193 to 1.180.24.2221.180.24.22330
2001.180.24.224/271.180.24.225 to 1.180.24.2541.180.24.25530
2011.180.25.0/271.180.25.1 to 1.180.25.301.180.25.3130
2021.180.25.32/271.180.25.33 to 1.180.25.621.180.25.6330
2031.180.25.64/271.180.25.65 to 1.180.25.941.180.25.9530
2041.180.25.96/271.180.25.97 to 1.180.25.1261.180.25.12730
2051.180.25.128/271.180.25.129 to 1.180.25.1581.180.25.15930
2061.180.25.160/271.180.25.161 to 1.180.25.1901.180.25.19130
2071.180.25.192/271.180.25.193 to 1.180.25.2221.180.25.22330
2081.180.25.224/271.180.25.225 to 1.180.25.2541.180.25.25530
2091.180.26.0/271.180.26.1 to 1.180.26.301.180.26.3130
2101.180.26.32/271.180.26.33 to 1.180.26.621.180.26.6330
2111.180.26.64/271.180.26.65 to 1.180.26.941.180.26.9530
2121.180.26.96/271.180.26.97 to 1.180.26.1261.180.26.12730
2131.180.26.128/271.180.26.129 to 1.180.26.1581.180.26.15930
2141.180.26.160/271.180.26.161 to 1.180.26.1901.180.26.19130
2151.180.26.192/271.180.26.193 to 1.180.26.2221.180.26.22330
2161.180.26.224/271.180.26.225 to 1.180.26.2541.180.26.25530
2171.180.27.0/271.180.27.1 to 1.180.27.301.180.27.3130
2181.180.27.32/271.180.27.33 to 1.180.27.621.180.27.6330
2191.180.27.64/271.180.27.65 to 1.180.27.941.180.27.9530
2201.180.27.96/271.180.27.97 to 1.180.27.1261.180.27.12730
2211.180.27.128/271.180.27.129 to 1.180.27.1581.180.27.15930
2221.180.27.160/271.180.27.161 to 1.180.27.1901.180.27.19130
2231.180.27.192/271.180.27.193 to 1.180.27.2221.180.27.22330
2241.180.27.224/271.180.27.225 to 1.180.27.2541.180.27.25530
2251.180.28.0/271.180.28.1 to 1.180.28.301.180.28.3130
2261.180.28.32/271.180.28.33 to 1.180.28.621.180.28.6330
2271.180.28.64/271.180.28.65 to 1.180.28.941.180.28.9530
2281.180.28.96/271.180.28.97 to 1.180.28.1261.180.28.12730
2291.180.28.128/271.180.28.129 to 1.180.28.1581.180.28.15930
2301.180.28.160/271.180.28.161 to 1.180.28.1901.180.28.19130
2311.180.28.192/271.180.28.193 to 1.180.28.2221.180.28.22330
2321.180.28.224/271.180.28.225 to 1.180.28.2541.180.28.25530
2331.180.29.0/271.180.29.1 to 1.180.29.301.180.29.3130
2341.180.29.32/271.180.29.33 to 1.180.29.621.180.29.6330
2351.180.29.64/271.180.29.65 to 1.180.29.941.180.29.9530
2361.180.29.96/271.180.29.97 to 1.180.29.1261.180.29.12730
2371.180.29.128/271.180.29.129 to 1.180.29.1581.180.29.15930
2381.180.29.160/271.180.29.161 to 1.180.29.1901.180.29.19130
2391.180.29.192/271.180.29.193 to 1.180.29.2221.180.29.22330
2401.180.29.224/271.180.29.225 to 1.180.29.2541.180.29.25530
2411.180.30.0/271.180.30.1 to 1.180.30.301.180.30.3130
2421.180.30.32/271.180.30.33 to 1.180.30.621.180.30.6330
2431.180.30.64/271.180.30.65 to 1.180.30.941.180.30.9530
2441.180.30.96/271.180.30.97 to 1.180.30.1261.180.30.12730
2451.180.30.128/271.180.30.129 to 1.180.30.1581.180.30.15930
2461.180.30.160/271.180.30.161 to 1.180.30.1901.180.30.19130
2471.180.30.192/271.180.30.193 to 1.180.30.2221.180.30.22330
2481.180.30.224/271.180.30.225 to 1.180.30.2541.180.30.25530
2491.180.31.0/271.180.31.1 to 1.180.31.301.180.31.3130
2501.180.31.32/271.180.31.33 to 1.180.31.621.180.31.6330
2511.180.31.64/271.180.31.65 to 1.180.31.941.180.31.9530
2521.180.31.96/271.180.31.97 to 1.180.31.1261.180.31.12730
2531.180.31.128/271.180.31.129 to 1.180.31.1581.180.31.15930
2541.180.31.160/271.180.31.161 to 1.180.31.1901.180.31.19130
2551.180.31.192/271.180.31.193 to 1.180.31.2221.180.31.22330
2561.180.31.224/271.180.31.225 to 1.180.31.2541.180.31.25530

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.