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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.

Network7.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
7.64.0.0
Broadcast address
7.127.255.255
First usable
7.64.0.1
Last usable
7.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 07400000 · Integer 121634816 to 125829119
Reverse DNS zones
64.7.in-addr.arpa
65.7.in-addr.arpa
66.7.in-addr.arpa
67.7.in-addr.arpa
68.7.in-addr.arpa
69.7.in-addr.arpa
70.7.in-addr.arpa
71.7.in-addr.arpa
72.7.in-addr.arpa
73.7.in-addr.arpa
74.7.in-addr.arpa
75.7.in-addr.arpa
76.7.in-addr.arpa
77.7.in-addr.arpa
78.7.in-addr.arpa
79.7.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000111.01000000.00000000.000000007.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00000111.01000000.00000000.000000007.64.0.0
Broadcast00000111.01111111.11111111.111111117.127.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

7.64.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
17.64.0.0/187.64.0.1 to 7.64.63.2547.64.63.25516,382
27.64.64.0/187.64.64.1 to 7.64.127.2547.64.127.25516,382
37.64.128.0/187.64.128.1 to 7.64.191.2547.64.191.25516,382
47.64.192.0/187.64.192.1 to 7.64.255.2547.64.255.25516,382
57.65.0.0/187.65.0.1 to 7.65.63.2547.65.63.25516,382
67.65.64.0/187.65.64.1 to 7.65.127.2547.65.127.25516,382
77.65.128.0/187.65.128.1 to 7.65.191.2547.65.191.25516,382
87.65.192.0/187.65.192.1 to 7.65.255.2547.65.255.25516,382
97.66.0.0/187.66.0.1 to 7.66.63.2547.66.63.25516,382
107.66.64.0/187.66.64.1 to 7.66.127.2547.66.127.25516,382
117.66.128.0/187.66.128.1 to 7.66.191.2547.66.191.25516,382
127.66.192.0/187.66.192.1 to 7.66.255.2547.66.255.25516,382
137.67.0.0/187.67.0.1 to 7.67.63.2547.67.63.25516,382
147.67.64.0/187.67.64.1 to 7.67.127.2547.67.127.25516,382
157.67.128.0/187.67.128.1 to 7.67.191.2547.67.191.25516,382
167.67.192.0/187.67.192.1 to 7.67.255.2547.67.255.25516,382
177.68.0.0/187.68.0.1 to 7.68.63.2547.68.63.25516,382
187.68.64.0/187.68.64.1 to 7.68.127.2547.68.127.25516,382
197.68.128.0/187.68.128.1 to 7.68.191.2547.68.191.25516,382
207.68.192.0/187.68.192.1 to 7.68.255.2547.68.255.25516,382
217.69.0.0/187.69.0.1 to 7.69.63.2547.69.63.25516,382
227.69.64.0/187.69.64.1 to 7.69.127.2547.69.127.25516,382
237.69.128.0/187.69.128.1 to 7.69.191.2547.69.191.25516,382
247.69.192.0/187.69.192.1 to 7.69.255.2547.69.255.25516,382
257.70.0.0/187.70.0.1 to 7.70.63.2547.70.63.25516,382
267.70.64.0/187.70.64.1 to 7.70.127.2547.70.127.25516,382
277.70.128.0/187.70.128.1 to 7.70.191.2547.70.191.25516,382
287.70.192.0/187.70.192.1 to 7.70.255.2547.70.255.25516,382
297.71.0.0/187.71.0.1 to 7.71.63.2547.71.63.25516,382
307.71.64.0/187.71.64.1 to 7.71.127.2547.71.127.25516,382
317.71.128.0/187.71.128.1 to 7.71.191.2547.71.191.25516,382
327.71.192.0/187.71.192.1 to 7.71.255.2547.71.255.25516,382
337.72.0.0/187.72.0.1 to 7.72.63.2547.72.63.25516,382
347.72.64.0/187.72.64.1 to 7.72.127.2547.72.127.25516,382
357.72.128.0/187.72.128.1 to 7.72.191.2547.72.191.25516,382
367.72.192.0/187.72.192.1 to 7.72.255.2547.72.255.25516,382
377.73.0.0/187.73.0.1 to 7.73.63.2547.73.63.25516,382
387.73.64.0/187.73.64.1 to 7.73.127.2547.73.127.25516,382
397.73.128.0/187.73.128.1 to 7.73.191.2547.73.191.25516,382
407.73.192.0/187.73.192.1 to 7.73.255.2547.73.255.25516,382
417.74.0.0/187.74.0.1 to 7.74.63.2547.74.63.25516,382
427.74.64.0/187.74.64.1 to 7.74.127.2547.74.127.25516,382
437.74.128.0/187.74.128.1 to 7.74.191.2547.74.191.25516,382
447.74.192.0/187.74.192.1 to 7.74.255.2547.74.255.25516,382
457.75.0.0/187.75.0.1 to 7.75.63.2547.75.63.25516,382
467.75.64.0/187.75.64.1 to 7.75.127.2547.75.127.25516,382
477.75.128.0/187.75.128.1 to 7.75.191.2547.75.191.25516,382
487.75.192.0/187.75.192.1 to 7.75.255.2547.75.255.25516,382
497.76.0.0/187.76.0.1 to 7.76.63.2547.76.63.25516,382
507.76.64.0/187.76.64.1 to 7.76.127.2547.76.127.25516,382
517.76.128.0/187.76.128.1 to 7.76.191.2547.76.191.25516,382
527.76.192.0/187.76.192.1 to 7.76.255.2547.76.255.25516,382
537.77.0.0/187.77.0.1 to 7.77.63.2547.77.63.25516,382
547.77.64.0/187.77.64.1 to 7.77.127.2547.77.127.25516,382
557.77.128.0/187.77.128.1 to 7.77.191.2547.77.191.25516,382
567.77.192.0/187.77.192.1 to 7.77.255.2547.77.255.25516,382
577.78.0.0/187.78.0.1 to 7.78.63.2547.78.63.25516,382
587.78.64.0/187.78.64.1 to 7.78.127.2547.78.127.25516,382
597.78.128.0/187.78.128.1 to 7.78.191.2547.78.191.25516,382
607.78.192.0/187.78.192.1 to 7.78.255.2547.78.255.25516,382
617.79.0.0/187.79.0.1 to 7.79.63.2547.79.63.25516,382
627.79.64.0/187.79.64.1 to 7.79.127.2547.79.127.25516,382
637.79.128.0/187.79.128.1 to 7.79.191.2547.79.191.25516,382
647.79.192.0/187.79.192.1 to 7.79.255.2547.79.255.25516,382
657.80.0.0/187.80.0.1 to 7.80.63.2547.80.63.25516,382
667.80.64.0/187.80.64.1 to 7.80.127.2547.80.127.25516,382
677.80.128.0/187.80.128.1 to 7.80.191.2547.80.191.25516,382
687.80.192.0/187.80.192.1 to 7.80.255.2547.80.255.25516,382
697.81.0.0/187.81.0.1 to 7.81.63.2547.81.63.25516,382
707.81.64.0/187.81.64.1 to 7.81.127.2547.81.127.25516,382
717.81.128.0/187.81.128.1 to 7.81.191.2547.81.191.25516,382
727.81.192.0/187.81.192.1 to 7.81.255.2547.81.255.25516,382
737.82.0.0/187.82.0.1 to 7.82.63.2547.82.63.25516,382
747.82.64.0/187.82.64.1 to 7.82.127.2547.82.127.25516,382
757.82.128.0/187.82.128.1 to 7.82.191.2547.82.191.25516,382
767.82.192.0/187.82.192.1 to 7.82.255.2547.82.255.25516,382
777.83.0.0/187.83.0.1 to 7.83.63.2547.83.63.25516,382
787.83.64.0/187.83.64.1 to 7.83.127.2547.83.127.25516,382
797.83.128.0/187.83.128.1 to 7.83.191.2547.83.191.25516,382
807.83.192.0/187.83.192.1 to 7.83.255.2547.83.255.25516,382
817.84.0.0/187.84.0.1 to 7.84.63.2547.84.63.25516,382
827.84.64.0/187.84.64.1 to 7.84.127.2547.84.127.25516,382
837.84.128.0/187.84.128.1 to 7.84.191.2547.84.191.25516,382
847.84.192.0/187.84.192.1 to 7.84.255.2547.84.255.25516,382
857.85.0.0/187.85.0.1 to 7.85.63.2547.85.63.25516,382
867.85.64.0/187.85.64.1 to 7.85.127.2547.85.127.25516,382
877.85.128.0/187.85.128.1 to 7.85.191.2547.85.191.25516,382
887.85.192.0/187.85.192.1 to 7.85.255.2547.85.255.25516,382
897.86.0.0/187.86.0.1 to 7.86.63.2547.86.63.25516,382
907.86.64.0/187.86.64.1 to 7.86.127.2547.86.127.25516,382
917.86.128.0/187.86.128.1 to 7.86.191.2547.86.191.25516,382
927.86.192.0/187.86.192.1 to 7.86.255.2547.86.255.25516,382
937.87.0.0/187.87.0.1 to 7.87.63.2547.87.63.25516,382
947.87.64.0/187.87.64.1 to 7.87.127.2547.87.127.25516,382
957.87.128.0/187.87.128.1 to 7.87.191.2547.87.191.25516,382
967.87.192.0/187.87.192.1 to 7.87.255.2547.87.255.25516,382
977.88.0.0/187.88.0.1 to 7.88.63.2547.88.63.25516,382
987.88.64.0/187.88.64.1 to 7.88.127.2547.88.127.25516,382
997.88.128.0/187.88.128.1 to 7.88.191.2547.88.191.25516,382
1007.88.192.0/187.88.192.1 to 7.88.255.2547.88.255.25516,382
1017.89.0.0/187.89.0.1 to 7.89.63.2547.89.63.25516,382
1027.89.64.0/187.89.64.1 to 7.89.127.2547.89.127.25516,382
1037.89.128.0/187.89.128.1 to 7.89.191.2547.89.191.25516,382
1047.89.192.0/187.89.192.1 to 7.89.255.2547.89.255.25516,382
1057.90.0.0/187.90.0.1 to 7.90.63.2547.90.63.25516,382
1067.90.64.0/187.90.64.1 to 7.90.127.2547.90.127.25516,382
1077.90.128.0/187.90.128.1 to 7.90.191.2547.90.191.25516,382
1087.90.192.0/187.90.192.1 to 7.90.255.2547.90.255.25516,382
1097.91.0.0/187.91.0.1 to 7.91.63.2547.91.63.25516,382
1107.91.64.0/187.91.64.1 to 7.91.127.2547.91.127.25516,382
1117.91.128.0/187.91.128.1 to 7.91.191.2547.91.191.25516,382
1127.91.192.0/187.91.192.1 to 7.91.255.2547.91.255.25516,382
1137.92.0.0/187.92.0.1 to 7.92.63.2547.92.63.25516,382
1147.92.64.0/187.92.64.1 to 7.92.127.2547.92.127.25516,382
1157.92.128.0/187.92.128.1 to 7.92.191.2547.92.191.25516,382
1167.92.192.0/187.92.192.1 to 7.92.255.2547.92.255.25516,382
1177.93.0.0/187.93.0.1 to 7.93.63.2547.93.63.25516,382
1187.93.64.0/187.93.64.1 to 7.93.127.2547.93.127.25516,382
1197.93.128.0/187.93.128.1 to 7.93.191.2547.93.191.25516,382
1207.93.192.0/187.93.192.1 to 7.93.255.2547.93.255.25516,382
1217.94.0.0/187.94.0.1 to 7.94.63.2547.94.63.25516,382
1227.94.64.0/187.94.64.1 to 7.94.127.2547.94.127.25516,382
1237.94.128.0/187.94.128.1 to 7.94.191.2547.94.191.25516,382
1247.94.192.0/187.94.192.1 to 7.94.255.2547.94.255.25516,382
1257.95.0.0/187.95.0.1 to 7.95.63.2547.95.63.25516,382
1267.95.64.0/187.95.64.1 to 7.95.127.2547.95.127.25516,382
1277.95.128.0/187.95.128.1 to 7.95.191.2547.95.191.25516,382
1287.95.192.0/187.95.192.1 to 7.95.255.2547.95.255.25516,382
1297.96.0.0/187.96.0.1 to 7.96.63.2547.96.63.25516,382
1307.96.64.0/187.96.64.1 to 7.96.127.2547.96.127.25516,382
1317.96.128.0/187.96.128.1 to 7.96.191.2547.96.191.25516,382
1327.96.192.0/187.96.192.1 to 7.96.255.2547.96.255.25516,382
1337.97.0.0/187.97.0.1 to 7.97.63.2547.97.63.25516,382
1347.97.64.0/187.97.64.1 to 7.97.127.2547.97.127.25516,382
1357.97.128.0/187.97.128.1 to 7.97.191.2547.97.191.25516,382
1367.97.192.0/187.97.192.1 to 7.97.255.2547.97.255.25516,382
1377.98.0.0/187.98.0.1 to 7.98.63.2547.98.63.25516,382
1387.98.64.0/187.98.64.1 to 7.98.127.2547.98.127.25516,382
1397.98.128.0/187.98.128.1 to 7.98.191.2547.98.191.25516,382
1407.98.192.0/187.98.192.1 to 7.98.255.2547.98.255.25516,382
1417.99.0.0/187.99.0.1 to 7.99.63.2547.99.63.25516,382
1427.99.64.0/187.99.64.1 to 7.99.127.2547.99.127.25516,382
1437.99.128.0/187.99.128.1 to 7.99.191.2547.99.191.25516,382
1447.99.192.0/187.99.192.1 to 7.99.255.2547.99.255.25516,382
1457.100.0.0/187.100.0.1 to 7.100.63.2547.100.63.25516,382
1467.100.64.0/187.100.64.1 to 7.100.127.2547.100.127.25516,382
1477.100.128.0/187.100.128.1 to 7.100.191.2547.100.191.25516,382
1487.100.192.0/187.100.192.1 to 7.100.255.2547.100.255.25516,382
1497.101.0.0/187.101.0.1 to 7.101.63.2547.101.63.25516,382
1507.101.64.0/187.101.64.1 to 7.101.127.2547.101.127.25516,382
1517.101.128.0/187.101.128.1 to 7.101.191.2547.101.191.25516,382
1527.101.192.0/187.101.192.1 to 7.101.255.2547.101.255.25516,382
1537.102.0.0/187.102.0.1 to 7.102.63.2547.102.63.25516,382
1547.102.64.0/187.102.64.1 to 7.102.127.2547.102.127.25516,382
1557.102.128.0/187.102.128.1 to 7.102.191.2547.102.191.25516,382
1567.102.192.0/187.102.192.1 to 7.102.255.2547.102.255.25516,382
1577.103.0.0/187.103.0.1 to 7.103.63.2547.103.63.25516,382
1587.103.64.0/187.103.64.1 to 7.103.127.2547.103.127.25516,382
1597.103.128.0/187.103.128.1 to 7.103.191.2547.103.191.25516,382
1607.103.192.0/187.103.192.1 to 7.103.255.2547.103.255.25516,382
1617.104.0.0/187.104.0.1 to 7.104.63.2547.104.63.25516,382
1627.104.64.0/187.104.64.1 to 7.104.127.2547.104.127.25516,382
1637.104.128.0/187.104.128.1 to 7.104.191.2547.104.191.25516,382
1647.104.192.0/187.104.192.1 to 7.104.255.2547.104.255.25516,382
1657.105.0.0/187.105.0.1 to 7.105.63.2547.105.63.25516,382
1667.105.64.0/187.105.64.1 to 7.105.127.2547.105.127.25516,382
1677.105.128.0/187.105.128.1 to 7.105.191.2547.105.191.25516,382
1687.105.192.0/187.105.192.1 to 7.105.255.2547.105.255.25516,382
1697.106.0.0/187.106.0.1 to 7.106.63.2547.106.63.25516,382
1707.106.64.0/187.106.64.1 to 7.106.127.2547.106.127.25516,382
1717.106.128.0/187.106.128.1 to 7.106.191.2547.106.191.25516,382
1727.106.192.0/187.106.192.1 to 7.106.255.2547.106.255.25516,382
1737.107.0.0/187.107.0.1 to 7.107.63.2547.107.63.25516,382
1747.107.64.0/187.107.64.1 to 7.107.127.2547.107.127.25516,382
1757.107.128.0/187.107.128.1 to 7.107.191.2547.107.191.25516,382
1767.107.192.0/187.107.192.1 to 7.107.255.2547.107.255.25516,382
1777.108.0.0/187.108.0.1 to 7.108.63.2547.108.63.25516,382
1787.108.64.0/187.108.64.1 to 7.108.127.2547.108.127.25516,382
1797.108.128.0/187.108.128.1 to 7.108.191.2547.108.191.25516,382
1807.108.192.0/187.108.192.1 to 7.108.255.2547.108.255.25516,382
1817.109.0.0/187.109.0.1 to 7.109.63.2547.109.63.25516,382
1827.109.64.0/187.109.64.1 to 7.109.127.2547.109.127.25516,382
1837.109.128.0/187.109.128.1 to 7.109.191.2547.109.191.25516,382
1847.109.192.0/187.109.192.1 to 7.109.255.2547.109.255.25516,382
1857.110.0.0/187.110.0.1 to 7.110.63.2547.110.63.25516,382
1867.110.64.0/187.110.64.1 to 7.110.127.2547.110.127.25516,382
1877.110.128.0/187.110.128.1 to 7.110.191.2547.110.191.25516,382
1887.110.192.0/187.110.192.1 to 7.110.255.2547.110.255.25516,382
1897.111.0.0/187.111.0.1 to 7.111.63.2547.111.63.25516,382
1907.111.64.0/187.111.64.1 to 7.111.127.2547.111.127.25516,382
1917.111.128.0/187.111.128.1 to 7.111.191.2547.111.191.25516,382
1927.111.192.0/187.111.192.1 to 7.111.255.2547.111.255.25516,382
1937.112.0.0/187.112.0.1 to 7.112.63.2547.112.63.25516,382
1947.112.64.0/187.112.64.1 to 7.112.127.2547.112.127.25516,382
1957.112.128.0/187.112.128.1 to 7.112.191.2547.112.191.25516,382
1967.112.192.0/187.112.192.1 to 7.112.255.2547.112.255.25516,382
1977.113.0.0/187.113.0.1 to 7.113.63.2547.113.63.25516,382
1987.113.64.0/187.113.64.1 to 7.113.127.2547.113.127.25516,382
1997.113.128.0/187.113.128.1 to 7.113.191.2547.113.191.25516,382
2007.113.192.0/187.113.192.1 to 7.113.255.2547.113.255.25516,382
2017.114.0.0/187.114.0.1 to 7.114.63.2547.114.63.25516,382
2027.114.64.0/187.114.64.1 to 7.114.127.2547.114.127.25516,382
2037.114.128.0/187.114.128.1 to 7.114.191.2547.114.191.25516,382
2047.114.192.0/187.114.192.1 to 7.114.255.2547.114.255.25516,382
2057.115.0.0/187.115.0.1 to 7.115.63.2547.115.63.25516,382
2067.115.64.0/187.115.64.1 to 7.115.127.2547.115.127.25516,382
2077.115.128.0/187.115.128.1 to 7.115.191.2547.115.191.25516,382
2087.115.192.0/187.115.192.1 to 7.115.255.2547.115.255.25516,382
2097.116.0.0/187.116.0.1 to 7.116.63.2547.116.63.25516,382
2107.116.64.0/187.116.64.1 to 7.116.127.2547.116.127.25516,382
2117.116.128.0/187.116.128.1 to 7.116.191.2547.116.191.25516,382
2127.116.192.0/187.116.192.1 to 7.116.255.2547.116.255.25516,382
2137.117.0.0/187.117.0.1 to 7.117.63.2547.117.63.25516,382
2147.117.64.0/187.117.64.1 to 7.117.127.2547.117.127.25516,382
2157.117.128.0/187.117.128.1 to 7.117.191.2547.117.191.25516,382
2167.117.192.0/187.117.192.1 to 7.117.255.2547.117.255.25516,382
2177.118.0.0/187.118.0.1 to 7.118.63.2547.118.63.25516,382
2187.118.64.0/187.118.64.1 to 7.118.127.2547.118.127.25516,382
2197.118.128.0/187.118.128.1 to 7.118.191.2547.118.191.25516,382
2207.118.192.0/187.118.192.1 to 7.118.255.2547.118.255.25516,382
2217.119.0.0/187.119.0.1 to 7.119.63.2547.119.63.25516,382
2227.119.64.0/187.119.64.1 to 7.119.127.2547.119.127.25516,382
2237.119.128.0/187.119.128.1 to 7.119.191.2547.119.191.25516,382
2247.119.192.0/187.119.192.1 to 7.119.255.2547.119.255.25516,382
2257.120.0.0/187.120.0.1 to 7.120.63.2547.120.63.25516,382
2267.120.64.0/187.120.64.1 to 7.120.127.2547.120.127.25516,382
2277.120.128.0/187.120.128.1 to 7.120.191.2547.120.191.25516,382
2287.120.192.0/187.120.192.1 to 7.120.255.2547.120.255.25516,382
2297.121.0.0/187.121.0.1 to 7.121.63.2547.121.63.25516,382
2307.121.64.0/187.121.64.1 to 7.121.127.2547.121.127.25516,382
2317.121.128.0/187.121.128.1 to 7.121.191.2547.121.191.25516,382
2327.121.192.0/187.121.192.1 to 7.121.255.2547.121.255.25516,382
2337.122.0.0/187.122.0.1 to 7.122.63.2547.122.63.25516,382
2347.122.64.0/187.122.64.1 to 7.122.127.2547.122.127.25516,382
2357.122.128.0/187.122.128.1 to 7.122.191.2547.122.191.25516,382
2367.122.192.0/187.122.192.1 to 7.122.255.2547.122.255.25516,382
2377.123.0.0/187.123.0.1 to 7.123.63.2547.123.63.25516,382
2387.123.64.0/187.123.64.1 to 7.123.127.2547.123.127.25516,382
2397.123.128.0/187.123.128.1 to 7.123.191.2547.123.191.25516,382
2407.123.192.0/187.123.192.1 to 7.123.255.2547.123.255.25516,382
2417.124.0.0/187.124.0.1 to 7.124.63.2547.124.63.25516,382
2427.124.64.0/187.124.64.1 to 7.124.127.2547.124.127.25516,382
2437.124.128.0/187.124.128.1 to 7.124.191.2547.124.191.25516,382
2447.124.192.0/187.124.192.1 to 7.124.255.2547.124.255.25516,382
2457.125.0.0/187.125.0.1 to 7.125.63.2547.125.63.25516,382
2467.125.64.0/187.125.64.1 to 7.125.127.2547.125.127.25516,382
2477.125.128.0/187.125.128.1 to 7.125.191.2547.125.191.25516,382
2487.125.192.0/187.125.192.1 to 7.125.255.2547.125.255.25516,382
2497.126.0.0/187.126.0.1 to 7.126.63.2547.126.63.25516,382
2507.126.64.0/187.126.64.1 to 7.126.127.2547.126.127.25516,382
2517.126.128.0/187.126.128.1 to 7.126.191.2547.126.191.25516,382
2527.126.192.0/187.126.192.1 to 7.126.255.2547.126.255.25516,382
2537.127.0.0/187.127.0.1 to 7.127.63.2547.127.63.25516,382
2547.127.64.0/187.127.64.1 to 7.127.127.2547.127.127.25516,382
2557.127.128.0/187.127.128.1 to 7.127.191.2547.127.191.25516,382
2567.127.192.0/187.127.192.1 to 7.127.255.2547.127.255.25516,382

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.