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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network0.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
0.64.0.0
Broadcast address
0.127.255.255
First usable
0.64.0.1
Last usable
0.127.255.254
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
This network 0.0.0.0/8
Not routed; 0.0.0.0 means "any address" in settings
Old class
A (default /8)
As numbers
Hex 00400000 · Integer 4194304 to 8388607
Reverse DNS zones
64.0.in-addr.arpa
65.0.in-addr.arpa
66.0.in-addr.arpa
67.0.in-addr.arpa
68.0.in-addr.arpa
69.0.in-addr.arpa
70.0.in-addr.arpa
71.0.in-addr.arpa
72.0.in-addr.arpa
73.0.in-addr.arpa
74.0.in-addr.arpa
75.0.in-addr.arpa
76.0.in-addr.arpa
77.0.in-addr.arpa
78.0.in-addr.arpa
79.0.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
Address00000000.01000000.00000000.000000000.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00000000.01000000.00000000.000000000.64.0.0
Broadcast00000000.01111111.11111111.111111110.127.255.255
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)

0.64.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.64.0.0/180.64.0.1 to 0.64.63.2540.64.63.25516,382
20.64.64.0/180.64.64.1 to 0.64.127.2540.64.127.25516,382
30.64.128.0/180.64.128.1 to 0.64.191.2540.64.191.25516,382
40.64.192.0/180.64.192.1 to 0.64.255.2540.64.255.25516,382
50.65.0.0/180.65.0.1 to 0.65.63.2540.65.63.25516,382
60.65.64.0/180.65.64.1 to 0.65.127.2540.65.127.25516,382
70.65.128.0/180.65.128.1 to 0.65.191.2540.65.191.25516,382
80.65.192.0/180.65.192.1 to 0.65.255.2540.65.255.25516,382
90.66.0.0/180.66.0.1 to 0.66.63.2540.66.63.25516,382
100.66.64.0/180.66.64.1 to 0.66.127.2540.66.127.25516,382
110.66.128.0/180.66.128.1 to 0.66.191.2540.66.191.25516,382
120.66.192.0/180.66.192.1 to 0.66.255.2540.66.255.25516,382
130.67.0.0/180.67.0.1 to 0.67.63.2540.67.63.25516,382
140.67.64.0/180.67.64.1 to 0.67.127.2540.67.127.25516,382
150.67.128.0/180.67.128.1 to 0.67.191.2540.67.191.25516,382
160.67.192.0/180.67.192.1 to 0.67.255.2540.67.255.25516,382
170.68.0.0/180.68.0.1 to 0.68.63.2540.68.63.25516,382
180.68.64.0/180.68.64.1 to 0.68.127.2540.68.127.25516,382
190.68.128.0/180.68.128.1 to 0.68.191.2540.68.191.25516,382
200.68.192.0/180.68.192.1 to 0.68.255.2540.68.255.25516,382
210.69.0.0/180.69.0.1 to 0.69.63.2540.69.63.25516,382
220.69.64.0/180.69.64.1 to 0.69.127.2540.69.127.25516,382
230.69.128.0/180.69.128.1 to 0.69.191.2540.69.191.25516,382
240.69.192.0/180.69.192.1 to 0.69.255.2540.69.255.25516,382
250.70.0.0/180.70.0.1 to 0.70.63.2540.70.63.25516,382
260.70.64.0/180.70.64.1 to 0.70.127.2540.70.127.25516,382
270.70.128.0/180.70.128.1 to 0.70.191.2540.70.191.25516,382
280.70.192.0/180.70.192.1 to 0.70.255.2540.70.255.25516,382
290.71.0.0/180.71.0.1 to 0.71.63.2540.71.63.25516,382
300.71.64.0/180.71.64.1 to 0.71.127.2540.71.127.25516,382
310.71.128.0/180.71.128.1 to 0.71.191.2540.71.191.25516,382
320.71.192.0/180.71.192.1 to 0.71.255.2540.71.255.25516,382
330.72.0.0/180.72.0.1 to 0.72.63.2540.72.63.25516,382
340.72.64.0/180.72.64.1 to 0.72.127.2540.72.127.25516,382
350.72.128.0/180.72.128.1 to 0.72.191.2540.72.191.25516,382
360.72.192.0/180.72.192.1 to 0.72.255.2540.72.255.25516,382
370.73.0.0/180.73.0.1 to 0.73.63.2540.73.63.25516,382
380.73.64.0/180.73.64.1 to 0.73.127.2540.73.127.25516,382
390.73.128.0/180.73.128.1 to 0.73.191.2540.73.191.25516,382
400.73.192.0/180.73.192.1 to 0.73.255.2540.73.255.25516,382
410.74.0.0/180.74.0.1 to 0.74.63.2540.74.63.25516,382
420.74.64.0/180.74.64.1 to 0.74.127.2540.74.127.25516,382
430.74.128.0/180.74.128.1 to 0.74.191.2540.74.191.25516,382
440.74.192.0/180.74.192.1 to 0.74.255.2540.74.255.25516,382
450.75.0.0/180.75.0.1 to 0.75.63.2540.75.63.25516,382
460.75.64.0/180.75.64.1 to 0.75.127.2540.75.127.25516,382
470.75.128.0/180.75.128.1 to 0.75.191.2540.75.191.25516,382
480.75.192.0/180.75.192.1 to 0.75.255.2540.75.255.25516,382
490.76.0.0/180.76.0.1 to 0.76.63.2540.76.63.25516,382
500.76.64.0/180.76.64.1 to 0.76.127.2540.76.127.25516,382
510.76.128.0/180.76.128.1 to 0.76.191.2540.76.191.25516,382
520.76.192.0/180.76.192.1 to 0.76.255.2540.76.255.25516,382
530.77.0.0/180.77.0.1 to 0.77.63.2540.77.63.25516,382
540.77.64.0/180.77.64.1 to 0.77.127.2540.77.127.25516,382
550.77.128.0/180.77.128.1 to 0.77.191.2540.77.191.25516,382
560.77.192.0/180.77.192.1 to 0.77.255.2540.77.255.25516,382
570.78.0.0/180.78.0.1 to 0.78.63.2540.78.63.25516,382
580.78.64.0/180.78.64.1 to 0.78.127.2540.78.127.25516,382
590.78.128.0/180.78.128.1 to 0.78.191.2540.78.191.25516,382
600.78.192.0/180.78.192.1 to 0.78.255.2540.78.255.25516,382
610.79.0.0/180.79.0.1 to 0.79.63.2540.79.63.25516,382
620.79.64.0/180.79.64.1 to 0.79.127.2540.79.127.25516,382
630.79.128.0/180.79.128.1 to 0.79.191.2540.79.191.25516,382
640.79.192.0/180.79.192.1 to 0.79.255.2540.79.255.25516,382
650.80.0.0/180.80.0.1 to 0.80.63.2540.80.63.25516,382
660.80.64.0/180.80.64.1 to 0.80.127.2540.80.127.25516,382
670.80.128.0/180.80.128.1 to 0.80.191.2540.80.191.25516,382
680.80.192.0/180.80.192.1 to 0.80.255.2540.80.255.25516,382
690.81.0.0/180.81.0.1 to 0.81.63.2540.81.63.25516,382
700.81.64.0/180.81.64.1 to 0.81.127.2540.81.127.25516,382
710.81.128.0/180.81.128.1 to 0.81.191.2540.81.191.25516,382
720.81.192.0/180.81.192.1 to 0.81.255.2540.81.255.25516,382
730.82.0.0/180.82.0.1 to 0.82.63.2540.82.63.25516,382
740.82.64.0/180.82.64.1 to 0.82.127.2540.82.127.25516,382
750.82.128.0/180.82.128.1 to 0.82.191.2540.82.191.25516,382
760.82.192.0/180.82.192.1 to 0.82.255.2540.82.255.25516,382
770.83.0.0/180.83.0.1 to 0.83.63.2540.83.63.25516,382
780.83.64.0/180.83.64.1 to 0.83.127.2540.83.127.25516,382
790.83.128.0/180.83.128.1 to 0.83.191.2540.83.191.25516,382
800.83.192.0/180.83.192.1 to 0.83.255.2540.83.255.25516,382
810.84.0.0/180.84.0.1 to 0.84.63.2540.84.63.25516,382
820.84.64.0/180.84.64.1 to 0.84.127.2540.84.127.25516,382
830.84.128.0/180.84.128.1 to 0.84.191.2540.84.191.25516,382
840.84.192.0/180.84.192.1 to 0.84.255.2540.84.255.25516,382
850.85.0.0/180.85.0.1 to 0.85.63.2540.85.63.25516,382
860.85.64.0/180.85.64.1 to 0.85.127.2540.85.127.25516,382
870.85.128.0/180.85.128.1 to 0.85.191.2540.85.191.25516,382
880.85.192.0/180.85.192.1 to 0.85.255.2540.85.255.25516,382
890.86.0.0/180.86.0.1 to 0.86.63.2540.86.63.25516,382
900.86.64.0/180.86.64.1 to 0.86.127.2540.86.127.25516,382
910.86.128.0/180.86.128.1 to 0.86.191.2540.86.191.25516,382
920.86.192.0/180.86.192.1 to 0.86.255.2540.86.255.25516,382
930.87.0.0/180.87.0.1 to 0.87.63.2540.87.63.25516,382
940.87.64.0/180.87.64.1 to 0.87.127.2540.87.127.25516,382
950.87.128.0/180.87.128.1 to 0.87.191.2540.87.191.25516,382
960.87.192.0/180.87.192.1 to 0.87.255.2540.87.255.25516,382
970.88.0.0/180.88.0.1 to 0.88.63.2540.88.63.25516,382
980.88.64.0/180.88.64.1 to 0.88.127.2540.88.127.25516,382
990.88.128.0/180.88.128.1 to 0.88.191.2540.88.191.25516,382
1000.88.192.0/180.88.192.1 to 0.88.255.2540.88.255.25516,382
1010.89.0.0/180.89.0.1 to 0.89.63.2540.89.63.25516,382
1020.89.64.0/180.89.64.1 to 0.89.127.2540.89.127.25516,382
1030.89.128.0/180.89.128.1 to 0.89.191.2540.89.191.25516,382
1040.89.192.0/180.89.192.1 to 0.89.255.2540.89.255.25516,382
1050.90.0.0/180.90.0.1 to 0.90.63.2540.90.63.25516,382
1060.90.64.0/180.90.64.1 to 0.90.127.2540.90.127.25516,382
1070.90.128.0/180.90.128.1 to 0.90.191.2540.90.191.25516,382
1080.90.192.0/180.90.192.1 to 0.90.255.2540.90.255.25516,382
1090.91.0.0/180.91.0.1 to 0.91.63.2540.91.63.25516,382
1100.91.64.0/180.91.64.1 to 0.91.127.2540.91.127.25516,382
1110.91.128.0/180.91.128.1 to 0.91.191.2540.91.191.25516,382
1120.91.192.0/180.91.192.1 to 0.91.255.2540.91.255.25516,382
1130.92.0.0/180.92.0.1 to 0.92.63.2540.92.63.25516,382
1140.92.64.0/180.92.64.1 to 0.92.127.2540.92.127.25516,382
1150.92.128.0/180.92.128.1 to 0.92.191.2540.92.191.25516,382
1160.92.192.0/180.92.192.1 to 0.92.255.2540.92.255.25516,382
1170.93.0.0/180.93.0.1 to 0.93.63.2540.93.63.25516,382
1180.93.64.0/180.93.64.1 to 0.93.127.2540.93.127.25516,382
1190.93.128.0/180.93.128.1 to 0.93.191.2540.93.191.25516,382
1200.93.192.0/180.93.192.1 to 0.93.255.2540.93.255.25516,382
1210.94.0.0/180.94.0.1 to 0.94.63.2540.94.63.25516,382
1220.94.64.0/180.94.64.1 to 0.94.127.2540.94.127.25516,382
1230.94.128.0/180.94.128.1 to 0.94.191.2540.94.191.25516,382
1240.94.192.0/180.94.192.1 to 0.94.255.2540.94.255.25516,382
1250.95.0.0/180.95.0.1 to 0.95.63.2540.95.63.25516,382
1260.95.64.0/180.95.64.1 to 0.95.127.2540.95.127.25516,382
1270.95.128.0/180.95.128.1 to 0.95.191.2540.95.191.25516,382
1280.95.192.0/180.95.192.1 to 0.95.255.2540.95.255.25516,382
1290.96.0.0/180.96.0.1 to 0.96.63.2540.96.63.25516,382
1300.96.64.0/180.96.64.1 to 0.96.127.2540.96.127.25516,382
1310.96.128.0/180.96.128.1 to 0.96.191.2540.96.191.25516,382
1320.96.192.0/180.96.192.1 to 0.96.255.2540.96.255.25516,382
1330.97.0.0/180.97.0.1 to 0.97.63.2540.97.63.25516,382
1340.97.64.0/180.97.64.1 to 0.97.127.2540.97.127.25516,382
1350.97.128.0/180.97.128.1 to 0.97.191.2540.97.191.25516,382
1360.97.192.0/180.97.192.1 to 0.97.255.2540.97.255.25516,382
1370.98.0.0/180.98.0.1 to 0.98.63.2540.98.63.25516,382
1380.98.64.0/180.98.64.1 to 0.98.127.2540.98.127.25516,382
1390.98.128.0/180.98.128.1 to 0.98.191.2540.98.191.25516,382
1400.98.192.0/180.98.192.1 to 0.98.255.2540.98.255.25516,382
1410.99.0.0/180.99.0.1 to 0.99.63.2540.99.63.25516,382
1420.99.64.0/180.99.64.1 to 0.99.127.2540.99.127.25516,382
1430.99.128.0/180.99.128.1 to 0.99.191.2540.99.191.25516,382
1440.99.192.0/180.99.192.1 to 0.99.255.2540.99.255.25516,382
1450.100.0.0/180.100.0.1 to 0.100.63.2540.100.63.25516,382
1460.100.64.0/180.100.64.1 to 0.100.127.2540.100.127.25516,382
1470.100.128.0/180.100.128.1 to 0.100.191.2540.100.191.25516,382
1480.100.192.0/180.100.192.1 to 0.100.255.2540.100.255.25516,382
1490.101.0.0/180.101.0.1 to 0.101.63.2540.101.63.25516,382
1500.101.64.0/180.101.64.1 to 0.101.127.2540.101.127.25516,382
1510.101.128.0/180.101.128.1 to 0.101.191.2540.101.191.25516,382
1520.101.192.0/180.101.192.1 to 0.101.255.2540.101.255.25516,382
1530.102.0.0/180.102.0.1 to 0.102.63.2540.102.63.25516,382
1540.102.64.0/180.102.64.1 to 0.102.127.2540.102.127.25516,382
1550.102.128.0/180.102.128.1 to 0.102.191.2540.102.191.25516,382
1560.102.192.0/180.102.192.1 to 0.102.255.2540.102.255.25516,382
1570.103.0.0/180.103.0.1 to 0.103.63.2540.103.63.25516,382
1580.103.64.0/180.103.64.1 to 0.103.127.2540.103.127.25516,382
1590.103.128.0/180.103.128.1 to 0.103.191.2540.103.191.25516,382
1600.103.192.0/180.103.192.1 to 0.103.255.2540.103.255.25516,382
1610.104.0.0/180.104.0.1 to 0.104.63.2540.104.63.25516,382
1620.104.64.0/180.104.64.1 to 0.104.127.2540.104.127.25516,382
1630.104.128.0/180.104.128.1 to 0.104.191.2540.104.191.25516,382
1640.104.192.0/180.104.192.1 to 0.104.255.2540.104.255.25516,382
1650.105.0.0/180.105.0.1 to 0.105.63.2540.105.63.25516,382
1660.105.64.0/180.105.64.1 to 0.105.127.2540.105.127.25516,382
1670.105.128.0/180.105.128.1 to 0.105.191.2540.105.191.25516,382
1680.105.192.0/180.105.192.1 to 0.105.255.2540.105.255.25516,382
1690.106.0.0/180.106.0.1 to 0.106.63.2540.106.63.25516,382
1700.106.64.0/180.106.64.1 to 0.106.127.2540.106.127.25516,382
1710.106.128.0/180.106.128.1 to 0.106.191.2540.106.191.25516,382
1720.106.192.0/180.106.192.1 to 0.106.255.2540.106.255.25516,382
1730.107.0.0/180.107.0.1 to 0.107.63.2540.107.63.25516,382
1740.107.64.0/180.107.64.1 to 0.107.127.2540.107.127.25516,382
1750.107.128.0/180.107.128.1 to 0.107.191.2540.107.191.25516,382
1760.107.192.0/180.107.192.1 to 0.107.255.2540.107.255.25516,382
1770.108.0.0/180.108.0.1 to 0.108.63.2540.108.63.25516,382
1780.108.64.0/180.108.64.1 to 0.108.127.2540.108.127.25516,382
1790.108.128.0/180.108.128.1 to 0.108.191.2540.108.191.25516,382
1800.108.192.0/180.108.192.1 to 0.108.255.2540.108.255.25516,382
1810.109.0.0/180.109.0.1 to 0.109.63.2540.109.63.25516,382
1820.109.64.0/180.109.64.1 to 0.109.127.2540.109.127.25516,382
1830.109.128.0/180.109.128.1 to 0.109.191.2540.109.191.25516,382
1840.109.192.0/180.109.192.1 to 0.109.255.2540.109.255.25516,382
1850.110.0.0/180.110.0.1 to 0.110.63.2540.110.63.25516,382
1860.110.64.0/180.110.64.1 to 0.110.127.2540.110.127.25516,382
1870.110.128.0/180.110.128.1 to 0.110.191.2540.110.191.25516,382
1880.110.192.0/180.110.192.1 to 0.110.255.2540.110.255.25516,382
1890.111.0.0/180.111.0.1 to 0.111.63.2540.111.63.25516,382
1900.111.64.0/180.111.64.1 to 0.111.127.2540.111.127.25516,382
1910.111.128.0/180.111.128.1 to 0.111.191.2540.111.191.25516,382
1920.111.192.0/180.111.192.1 to 0.111.255.2540.111.255.25516,382
1930.112.0.0/180.112.0.1 to 0.112.63.2540.112.63.25516,382
1940.112.64.0/180.112.64.1 to 0.112.127.2540.112.127.25516,382
1950.112.128.0/180.112.128.1 to 0.112.191.2540.112.191.25516,382
1960.112.192.0/180.112.192.1 to 0.112.255.2540.112.255.25516,382
1970.113.0.0/180.113.0.1 to 0.113.63.2540.113.63.25516,382
1980.113.64.0/180.113.64.1 to 0.113.127.2540.113.127.25516,382
1990.113.128.0/180.113.128.1 to 0.113.191.2540.113.191.25516,382
2000.113.192.0/180.113.192.1 to 0.113.255.2540.113.255.25516,382
2010.114.0.0/180.114.0.1 to 0.114.63.2540.114.63.25516,382
2020.114.64.0/180.114.64.1 to 0.114.127.2540.114.127.25516,382
2030.114.128.0/180.114.128.1 to 0.114.191.2540.114.191.25516,382
2040.114.192.0/180.114.192.1 to 0.114.255.2540.114.255.25516,382
2050.115.0.0/180.115.0.1 to 0.115.63.2540.115.63.25516,382
2060.115.64.0/180.115.64.1 to 0.115.127.2540.115.127.25516,382
2070.115.128.0/180.115.128.1 to 0.115.191.2540.115.191.25516,382
2080.115.192.0/180.115.192.1 to 0.115.255.2540.115.255.25516,382
2090.116.0.0/180.116.0.1 to 0.116.63.2540.116.63.25516,382
2100.116.64.0/180.116.64.1 to 0.116.127.2540.116.127.25516,382
2110.116.128.0/180.116.128.1 to 0.116.191.2540.116.191.25516,382
2120.116.192.0/180.116.192.1 to 0.116.255.2540.116.255.25516,382
2130.117.0.0/180.117.0.1 to 0.117.63.2540.117.63.25516,382
2140.117.64.0/180.117.64.1 to 0.117.127.2540.117.127.25516,382
2150.117.128.0/180.117.128.1 to 0.117.191.2540.117.191.25516,382
2160.117.192.0/180.117.192.1 to 0.117.255.2540.117.255.25516,382
2170.118.0.0/180.118.0.1 to 0.118.63.2540.118.63.25516,382
2180.118.64.0/180.118.64.1 to 0.118.127.2540.118.127.25516,382
2190.118.128.0/180.118.128.1 to 0.118.191.2540.118.191.25516,382
2200.118.192.0/180.118.192.1 to 0.118.255.2540.118.255.25516,382
2210.119.0.0/180.119.0.1 to 0.119.63.2540.119.63.25516,382
2220.119.64.0/180.119.64.1 to 0.119.127.2540.119.127.25516,382
2230.119.128.0/180.119.128.1 to 0.119.191.2540.119.191.25516,382
2240.119.192.0/180.119.192.1 to 0.119.255.2540.119.255.25516,382
2250.120.0.0/180.120.0.1 to 0.120.63.2540.120.63.25516,382
2260.120.64.0/180.120.64.1 to 0.120.127.2540.120.127.25516,382
2270.120.128.0/180.120.128.1 to 0.120.191.2540.120.191.25516,382
2280.120.192.0/180.120.192.1 to 0.120.255.2540.120.255.25516,382
2290.121.0.0/180.121.0.1 to 0.121.63.2540.121.63.25516,382
2300.121.64.0/180.121.64.1 to 0.121.127.2540.121.127.25516,382
2310.121.128.0/180.121.128.1 to 0.121.191.2540.121.191.25516,382
2320.121.192.0/180.121.192.1 to 0.121.255.2540.121.255.25516,382
2330.122.0.0/180.122.0.1 to 0.122.63.2540.122.63.25516,382
2340.122.64.0/180.122.64.1 to 0.122.127.2540.122.127.25516,382
2350.122.128.0/180.122.128.1 to 0.122.191.2540.122.191.25516,382
2360.122.192.0/180.122.192.1 to 0.122.255.2540.122.255.25516,382
2370.123.0.0/180.123.0.1 to 0.123.63.2540.123.63.25516,382
2380.123.64.0/180.123.64.1 to 0.123.127.2540.123.127.25516,382
2390.123.128.0/180.123.128.1 to 0.123.191.2540.123.191.25516,382
2400.123.192.0/180.123.192.1 to 0.123.255.2540.123.255.25516,382
2410.124.0.0/180.124.0.1 to 0.124.63.2540.124.63.25516,382
2420.124.64.0/180.124.64.1 to 0.124.127.2540.124.127.25516,382
2430.124.128.0/180.124.128.1 to 0.124.191.2540.124.191.25516,382
2440.124.192.0/180.124.192.1 to 0.124.255.2540.124.255.25516,382
2450.125.0.0/180.125.0.1 to 0.125.63.2540.125.63.25516,382
2460.125.64.0/180.125.64.1 to 0.125.127.2540.125.127.25516,382
2470.125.128.0/180.125.128.1 to 0.125.191.2540.125.191.25516,382
2480.125.192.0/180.125.192.1 to 0.125.255.2540.125.255.25516,382
2490.126.0.0/180.126.0.1 to 0.126.63.2540.126.63.25516,382
2500.126.64.0/180.126.64.1 to 0.126.127.2540.126.127.25516,382
2510.126.128.0/180.126.128.1 to 0.126.191.2540.126.191.25516,382
2520.126.192.0/180.126.192.1 to 0.126.255.2540.126.255.25516,382
2530.127.0.0/180.127.0.1 to 0.127.63.2540.127.63.25516,382
2540.127.64.0/180.127.64.1 to 0.127.127.2540.127.127.25516,382
2550.127.128.0/180.127.128.1 to 0.127.191.2540.127.191.25516,382
2560.127.192.0/180.127.192.1 to 0.127.255.2540.127.255.25516,382

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.