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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.

Network7.167.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
7.167.0.0
Broadcast address
7.167.63.255
First usable
7.167.0.1
Last usable
7.167.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 07A70000 · Integer 128385024 to 128401407
Reverse DNS zones
0.167.7.in-addr.arpa
1.167.7.in-addr.arpa
2.167.7.in-addr.arpa
3.167.7.in-addr.arpa
4.167.7.in-addr.arpa
5.167.7.in-addr.arpa
6.167.7.in-addr.arpa
7.167.7.in-addr.arpa
8.167.7.in-addr.arpa
9.167.7.in-addr.arpa
10.167.7.in-addr.arpa
11.167.7.in-addr.arpa
12.167.7.in-addr.arpa
13.167.7.in-addr.arpa
14.167.7.in-addr.arpa
15.167.7.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000111.10100111.00000000.000000007.167.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00000111.10100111.00000000.000000007.167.0.0
Broadcast00000111.10100111.00111111.111111117.167.63.255
Split into smaller subnets/27
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

7.167.0.0/18 makes 512 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
17.167.0.0/277.167.0.1 to 7.167.0.307.167.0.3130
27.167.0.32/277.167.0.33 to 7.167.0.627.167.0.6330
37.167.0.64/277.167.0.65 to 7.167.0.947.167.0.9530
47.167.0.96/277.167.0.97 to 7.167.0.1267.167.0.12730
57.167.0.128/277.167.0.129 to 7.167.0.1587.167.0.15930
67.167.0.160/277.167.0.161 to 7.167.0.1907.167.0.19130
77.167.0.192/277.167.0.193 to 7.167.0.2227.167.0.22330
87.167.0.224/277.167.0.225 to 7.167.0.2547.167.0.25530
97.167.1.0/277.167.1.1 to 7.167.1.307.167.1.3130
107.167.1.32/277.167.1.33 to 7.167.1.627.167.1.6330
117.167.1.64/277.167.1.65 to 7.167.1.947.167.1.9530
127.167.1.96/277.167.1.97 to 7.167.1.1267.167.1.12730
137.167.1.128/277.167.1.129 to 7.167.1.1587.167.1.15930
147.167.1.160/277.167.1.161 to 7.167.1.1907.167.1.19130
157.167.1.192/277.167.1.193 to 7.167.1.2227.167.1.22330
167.167.1.224/277.167.1.225 to 7.167.1.2547.167.1.25530
177.167.2.0/277.167.2.1 to 7.167.2.307.167.2.3130
187.167.2.32/277.167.2.33 to 7.167.2.627.167.2.6330
197.167.2.64/277.167.2.65 to 7.167.2.947.167.2.9530
207.167.2.96/277.167.2.97 to 7.167.2.1267.167.2.12730
217.167.2.128/277.167.2.129 to 7.167.2.1587.167.2.15930
227.167.2.160/277.167.2.161 to 7.167.2.1907.167.2.19130
237.167.2.192/277.167.2.193 to 7.167.2.2227.167.2.22330
247.167.2.224/277.167.2.225 to 7.167.2.2547.167.2.25530
257.167.3.0/277.167.3.1 to 7.167.3.307.167.3.3130
267.167.3.32/277.167.3.33 to 7.167.3.627.167.3.6330
277.167.3.64/277.167.3.65 to 7.167.3.947.167.3.9530
287.167.3.96/277.167.3.97 to 7.167.3.1267.167.3.12730
297.167.3.128/277.167.3.129 to 7.167.3.1587.167.3.15930
307.167.3.160/277.167.3.161 to 7.167.3.1907.167.3.19130
317.167.3.192/277.167.3.193 to 7.167.3.2227.167.3.22330
327.167.3.224/277.167.3.225 to 7.167.3.2547.167.3.25530
337.167.4.0/277.167.4.1 to 7.167.4.307.167.4.3130
347.167.4.32/277.167.4.33 to 7.167.4.627.167.4.6330
357.167.4.64/277.167.4.65 to 7.167.4.947.167.4.9530
367.167.4.96/277.167.4.97 to 7.167.4.1267.167.4.12730
377.167.4.128/277.167.4.129 to 7.167.4.1587.167.4.15930
387.167.4.160/277.167.4.161 to 7.167.4.1907.167.4.19130
397.167.4.192/277.167.4.193 to 7.167.4.2227.167.4.22330
407.167.4.224/277.167.4.225 to 7.167.4.2547.167.4.25530
417.167.5.0/277.167.5.1 to 7.167.5.307.167.5.3130
427.167.5.32/277.167.5.33 to 7.167.5.627.167.5.6330
437.167.5.64/277.167.5.65 to 7.167.5.947.167.5.9530
447.167.5.96/277.167.5.97 to 7.167.5.1267.167.5.12730
457.167.5.128/277.167.5.129 to 7.167.5.1587.167.5.15930
467.167.5.160/277.167.5.161 to 7.167.5.1907.167.5.19130
477.167.5.192/277.167.5.193 to 7.167.5.2227.167.5.22330
487.167.5.224/277.167.5.225 to 7.167.5.2547.167.5.25530
497.167.6.0/277.167.6.1 to 7.167.6.307.167.6.3130
507.167.6.32/277.167.6.33 to 7.167.6.627.167.6.6330
517.167.6.64/277.167.6.65 to 7.167.6.947.167.6.9530
527.167.6.96/277.167.6.97 to 7.167.6.1267.167.6.12730
537.167.6.128/277.167.6.129 to 7.167.6.1587.167.6.15930
547.167.6.160/277.167.6.161 to 7.167.6.1907.167.6.19130
557.167.6.192/277.167.6.193 to 7.167.6.2227.167.6.22330
567.167.6.224/277.167.6.225 to 7.167.6.2547.167.6.25530
577.167.7.0/277.167.7.1 to 7.167.7.307.167.7.3130
587.167.7.32/277.167.7.33 to 7.167.7.627.167.7.6330
597.167.7.64/277.167.7.65 to 7.167.7.947.167.7.9530
607.167.7.96/277.167.7.97 to 7.167.7.1267.167.7.12730
617.167.7.128/277.167.7.129 to 7.167.7.1587.167.7.15930
627.167.7.160/277.167.7.161 to 7.167.7.1907.167.7.19130
637.167.7.192/277.167.7.193 to 7.167.7.2227.167.7.22330
647.167.7.224/277.167.7.225 to 7.167.7.2547.167.7.25530
657.167.8.0/277.167.8.1 to 7.167.8.307.167.8.3130
667.167.8.32/277.167.8.33 to 7.167.8.627.167.8.6330
677.167.8.64/277.167.8.65 to 7.167.8.947.167.8.9530
687.167.8.96/277.167.8.97 to 7.167.8.1267.167.8.12730
697.167.8.128/277.167.8.129 to 7.167.8.1587.167.8.15930
707.167.8.160/277.167.8.161 to 7.167.8.1907.167.8.19130
717.167.8.192/277.167.8.193 to 7.167.8.2227.167.8.22330
727.167.8.224/277.167.8.225 to 7.167.8.2547.167.8.25530
737.167.9.0/277.167.9.1 to 7.167.9.307.167.9.3130
747.167.9.32/277.167.9.33 to 7.167.9.627.167.9.6330
757.167.9.64/277.167.9.65 to 7.167.9.947.167.9.9530
767.167.9.96/277.167.9.97 to 7.167.9.1267.167.9.12730
777.167.9.128/277.167.9.129 to 7.167.9.1587.167.9.15930
787.167.9.160/277.167.9.161 to 7.167.9.1907.167.9.19130
797.167.9.192/277.167.9.193 to 7.167.9.2227.167.9.22330
807.167.9.224/277.167.9.225 to 7.167.9.2547.167.9.25530
817.167.10.0/277.167.10.1 to 7.167.10.307.167.10.3130
827.167.10.32/277.167.10.33 to 7.167.10.627.167.10.6330
837.167.10.64/277.167.10.65 to 7.167.10.947.167.10.9530
847.167.10.96/277.167.10.97 to 7.167.10.1267.167.10.12730
857.167.10.128/277.167.10.129 to 7.167.10.1587.167.10.15930
867.167.10.160/277.167.10.161 to 7.167.10.1907.167.10.19130
877.167.10.192/277.167.10.193 to 7.167.10.2227.167.10.22330
887.167.10.224/277.167.10.225 to 7.167.10.2547.167.10.25530
897.167.11.0/277.167.11.1 to 7.167.11.307.167.11.3130
907.167.11.32/277.167.11.33 to 7.167.11.627.167.11.6330
917.167.11.64/277.167.11.65 to 7.167.11.947.167.11.9530
927.167.11.96/277.167.11.97 to 7.167.11.1267.167.11.12730
937.167.11.128/277.167.11.129 to 7.167.11.1587.167.11.15930
947.167.11.160/277.167.11.161 to 7.167.11.1907.167.11.19130
957.167.11.192/277.167.11.193 to 7.167.11.2227.167.11.22330
967.167.11.224/277.167.11.225 to 7.167.11.2547.167.11.25530
977.167.12.0/277.167.12.1 to 7.167.12.307.167.12.3130
987.167.12.32/277.167.12.33 to 7.167.12.627.167.12.6330
997.167.12.64/277.167.12.65 to 7.167.12.947.167.12.9530
1007.167.12.96/277.167.12.97 to 7.167.12.1267.167.12.12730
1017.167.12.128/277.167.12.129 to 7.167.12.1587.167.12.15930
1027.167.12.160/277.167.12.161 to 7.167.12.1907.167.12.19130
1037.167.12.192/277.167.12.193 to 7.167.12.2227.167.12.22330
1047.167.12.224/277.167.12.225 to 7.167.12.2547.167.12.25530
1057.167.13.0/277.167.13.1 to 7.167.13.307.167.13.3130
1067.167.13.32/277.167.13.33 to 7.167.13.627.167.13.6330
1077.167.13.64/277.167.13.65 to 7.167.13.947.167.13.9530
1087.167.13.96/277.167.13.97 to 7.167.13.1267.167.13.12730
1097.167.13.128/277.167.13.129 to 7.167.13.1587.167.13.15930
1107.167.13.160/277.167.13.161 to 7.167.13.1907.167.13.19130
1117.167.13.192/277.167.13.193 to 7.167.13.2227.167.13.22330
1127.167.13.224/277.167.13.225 to 7.167.13.2547.167.13.25530
1137.167.14.0/277.167.14.1 to 7.167.14.307.167.14.3130
1147.167.14.32/277.167.14.33 to 7.167.14.627.167.14.6330
1157.167.14.64/277.167.14.65 to 7.167.14.947.167.14.9530
1167.167.14.96/277.167.14.97 to 7.167.14.1267.167.14.12730
1177.167.14.128/277.167.14.129 to 7.167.14.1587.167.14.15930
1187.167.14.160/277.167.14.161 to 7.167.14.1907.167.14.19130
1197.167.14.192/277.167.14.193 to 7.167.14.2227.167.14.22330
1207.167.14.224/277.167.14.225 to 7.167.14.2547.167.14.25530
1217.167.15.0/277.167.15.1 to 7.167.15.307.167.15.3130
1227.167.15.32/277.167.15.33 to 7.167.15.627.167.15.6330
1237.167.15.64/277.167.15.65 to 7.167.15.947.167.15.9530
1247.167.15.96/277.167.15.97 to 7.167.15.1267.167.15.12730
1257.167.15.128/277.167.15.129 to 7.167.15.1587.167.15.15930
1267.167.15.160/277.167.15.161 to 7.167.15.1907.167.15.19130
1277.167.15.192/277.167.15.193 to 7.167.15.2227.167.15.22330
1287.167.15.224/277.167.15.225 to 7.167.15.2547.167.15.25530
1297.167.16.0/277.167.16.1 to 7.167.16.307.167.16.3130
1307.167.16.32/277.167.16.33 to 7.167.16.627.167.16.6330
1317.167.16.64/277.167.16.65 to 7.167.16.947.167.16.9530
1327.167.16.96/277.167.16.97 to 7.167.16.1267.167.16.12730
1337.167.16.128/277.167.16.129 to 7.167.16.1587.167.16.15930
1347.167.16.160/277.167.16.161 to 7.167.16.1907.167.16.19130
1357.167.16.192/277.167.16.193 to 7.167.16.2227.167.16.22330
1367.167.16.224/277.167.16.225 to 7.167.16.2547.167.16.25530
1377.167.17.0/277.167.17.1 to 7.167.17.307.167.17.3130
1387.167.17.32/277.167.17.33 to 7.167.17.627.167.17.6330
1397.167.17.64/277.167.17.65 to 7.167.17.947.167.17.9530
1407.167.17.96/277.167.17.97 to 7.167.17.1267.167.17.12730
1417.167.17.128/277.167.17.129 to 7.167.17.1587.167.17.15930
1427.167.17.160/277.167.17.161 to 7.167.17.1907.167.17.19130
1437.167.17.192/277.167.17.193 to 7.167.17.2227.167.17.22330
1447.167.17.224/277.167.17.225 to 7.167.17.2547.167.17.25530
1457.167.18.0/277.167.18.1 to 7.167.18.307.167.18.3130
1467.167.18.32/277.167.18.33 to 7.167.18.627.167.18.6330
1477.167.18.64/277.167.18.65 to 7.167.18.947.167.18.9530
1487.167.18.96/277.167.18.97 to 7.167.18.1267.167.18.12730
1497.167.18.128/277.167.18.129 to 7.167.18.1587.167.18.15930
1507.167.18.160/277.167.18.161 to 7.167.18.1907.167.18.19130
1517.167.18.192/277.167.18.193 to 7.167.18.2227.167.18.22330
1527.167.18.224/277.167.18.225 to 7.167.18.2547.167.18.25530
1537.167.19.0/277.167.19.1 to 7.167.19.307.167.19.3130
1547.167.19.32/277.167.19.33 to 7.167.19.627.167.19.6330
1557.167.19.64/277.167.19.65 to 7.167.19.947.167.19.9530
1567.167.19.96/277.167.19.97 to 7.167.19.1267.167.19.12730
1577.167.19.128/277.167.19.129 to 7.167.19.1587.167.19.15930
1587.167.19.160/277.167.19.161 to 7.167.19.1907.167.19.19130
1597.167.19.192/277.167.19.193 to 7.167.19.2227.167.19.22330
1607.167.19.224/277.167.19.225 to 7.167.19.2547.167.19.25530
1617.167.20.0/277.167.20.1 to 7.167.20.307.167.20.3130
1627.167.20.32/277.167.20.33 to 7.167.20.627.167.20.6330
1637.167.20.64/277.167.20.65 to 7.167.20.947.167.20.9530
1647.167.20.96/277.167.20.97 to 7.167.20.1267.167.20.12730
1657.167.20.128/277.167.20.129 to 7.167.20.1587.167.20.15930
1667.167.20.160/277.167.20.161 to 7.167.20.1907.167.20.19130
1677.167.20.192/277.167.20.193 to 7.167.20.2227.167.20.22330
1687.167.20.224/277.167.20.225 to 7.167.20.2547.167.20.25530
1697.167.21.0/277.167.21.1 to 7.167.21.307.167.21.3130
1707.167.21.32/277.167.21.33 to 7.167.21.627.167.21.6330
1717.167.21.64/277.167.21.65 to 7.167.21.947.167.21.9530
1727.167.21.96/277.167.21.97 to 7.167.21.1267.167.21.12730
1737.167.21.128/277.167.21.129 to 7.167.21.1587.167.21.15930
1747.167.21.160/277.167.21.161 to 7.167.21.1907.167.21.19130
1757.167.21.192/277.167.21.193 to 7.167.21.2227.167.21.22330
1767.167.21.224/277.167.21.225 to 7.167.21.2547.167.21.25530
1777.167.22.0/277.167.22.1 to 7.167.22.307.167.22.3130
1787.167.22.32/277.167.22.33 to 7.167.22.627.167.22.6330
1797.167.22.64/277.167.22.65 to 7.167.22.947.167.22.9530
1807.167.22.96/277.167.22.97 to 7.167.22.1267.167.22.12730
1817.167.22.128/277.167.22.129 to 7.167.22.1587.167.22.15930
1827.167.22.160/277.167.22.161 to 7.167.22.1907.167.22.19130
1837.167.22.192/277.167.22.193 to 7.167.22.2227.167.22.22330
1847.167.22.224/277.167.22.225 to 7.167.22.2547.167.22.25530
1857.167.23.0/277.167.23.1 to 7.167.23.307.167.23.3130
1867.167.23.32/277.167.23.33 to 7.167.23.627.167.23.6330
1877.167.23.64/277.167.23.65 to 7.167.23.947.167.23.9530
1887.167.23.96/277.167.23.97 to 7.167.23.1267.167.23.12730
1897.167.23.128/277.167.23.129 to 7.167.23.1587.167.23.15930
1907.167.23.160/277.167.23.161 to 7.167.23.1907.167.23.19130
1917.167.23.192/277.167.23.193 to 7.167.23.2227.167.23.22330
1927.167.23.224/277.167.23.225 to 7.167.23.2547.167.23.25530
1937.167.24.0/277.167.24.1 to 7.167.24.307.167.24.3130
1947.167.24.32/277.167.24.33 to 7.167.24.627.167.24.6330
1957.167.24.64/277.167.24.65 to 7.167.24.947.167.24.9530
1967.167.24.96/277.167.24.97 to 7.167.24.1267.167.24.12730
1977.167.24.128/277.167.24.129 to 7.167.24.1587.167.24.15930
1987.167.24.160/277.167.24.161 to 7.167.24.1907.167.24.19130
1997.167.24.192/277.167.24.193 to 7.167.24.2227.167.24.22330
2007.167.24.224/277.167.24.225 to 7.167.24.2547.167.24.25530
2017.167.25.0/277.167.25.1 to 7.167.25.307.167.25.3130
2027.167.25.32/277.167.25.33 to 7.167.25.627.167.25.6330
2037.167.25.64/277.167.25.65 to 7.167.25.947.167.25.9530
2047.167.25.96/277.167.25.97 to 7.167.25.1267.167.25.12730
2057.167.25.128/277.167.25.129 to 7.167.25.1587.167.25.15930
2067.167.25.160/277.167.25.161 to 7.167.25.1907.167.25.19130
2077.167.25.192/277.167.25.193 to 7.167.25.2227.167.25.22330
2087.167.25.224/277.167.25.225 to 7.167.25.2547.167.25.25530
2097.167.26.0/277.167.26.1 to 7.167.26.307.167.26.3130
2107.167.26.32/277.167.26.33 to 7.167.26.627.167.26.6330
2117.167.26.64/277.167.26.65 to 7.167.26.947.167.26.9530
2127.167.26.96/277.167.26.97 to 7.167.26.1267.167.26.12730
2137.167.26.128/277.167.26.129 to 7.167.26.1587.167.26.15930
2147.167.26.160/277.167.26.161 to 7.167.26.1907.167.26.19130
2157.167.26.192/277.167.26.193 to 7.167.26.2227.167.26.22330
2167.167.26.224/277.167.26.225 to 7.167.26.2547.167.26.25530
2177.167.27.0/277.167.27.1 to 7.167.27.307.167.27.3130
2187.167.27.32/277.167.27.33 to 7.167.27.627.167.27.6330
2197.167.27.64/277.167.27.65 to 7.167.27.947.167.27.9530
2207.167.27.96/277.167.27.97 to 7.167.27.1267.167.27.12730
2217.167.27.128/277.167.27.129 to 7.167.27.1587.167.27.15930
2227.167.27.160/277.167.27.161 to 7.167.27.1907.167.27.19130
2237.167.27.192/277.167.27.193 to 7.167.27.2227.167.27.22330
2247.167.27.224/277.167.27.225 to 7.167.27.2547.167.27.25530
2257.167.28.0/277.167.28.1 to 7.167.28.307.167.28.3130
2267.167.28.32/277.167.28.33 to 7.167.28.627.167.28.6330
2277.167.28.64/277.167.28.65 to 7.167.28.947.167.28.9530
2287.167.28.96/277.167.28.97 to 7.167.28.1267.167.28.12730
2297.167.28.128/277.167.28.129 to 7.167.28.1587.167.28.15930
2307.167.28.160/277.167.28.161 to 7.167.28.1907.167.28.19130
2317.167.28.192/277.167.28.193 to 7.167.28.2227.167.28.22330
2327.167.28.224/277.167.28.225 to 7.167.28.2547.167.28.25530
2337.167.29.0/277.167.29.1 to 7.167.29.307.167.29.3130
2347.167.29.32/277.167.29.33 to 7.167.29.627.167.29.6330
2357.167.29.64/277.167.29.65 to 7.167.29.947.167.29.9530
2367.167.29.96/277.167.29.97 to 7.167.29.1267.167.29.12730
2377.167.29.128/277.167.29.129 to 7.167.29.1587.167.29.15930
2387.167.29.160/277.167.29.161 to 7.167.29.1907.167.29.19130
2397.167.29.192/277.167.29.193 to 7.167.29.2227.167.29.22330
2407.167.29.224/277.167.29.225 to 7.167.29.2547.167.29.25530
2417.167.30.0/277.167.30.1 to 7.167.30.307.167.30.3130
2427.167.30.32/277.167.30.33 to 7.167.30.627.167.30.6330
2437.167.30.64/277.167.30.65 to 7.167.30.947.167.30.9530
2447.167.30.96/277.167.30.97 to 7.167.30.1267.167.30.12730
2457.167.30.128/277.167.30.129 to 7.167.30.1587.167.30.15930
2467.167.30.160/277.167.30.161 to 7.167.30.1907.167.30.19130
2477.167.30.192/277.167.30.193 to 7.167.30.2227.167.30.22330
2487.167.30.224/277.167.30.225 to 7.167.30.2547.167.30.25530
2497.167.31.0/277.167.31.1 to 7.167.31.307.167.31.3130
2507.167.31.32/277.167.31.33 to 7.167.31.627.167.31.6330
2517.167.31.64/277.167.31.65 to 7.167.31.947.167.31.9530
2527.167.31.96/277.167.31.97 to 7.167.31.1267.167.31.12730
2537.167.31.128/277.167.31.129 to 7.167.31.1587.167.31.15930
2547.167.31.160/277.167.31.161 to 7.167.31.1907.167.31.19130
2557.167.31.192/277.167.31.193 to 7.167.31.2227.167.31.22330
2567.167.31.224/277.167.31.225 to 7.167.31.2547.167.31.25530

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.