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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.

Network0.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
0.0.0.0
Broadcast address
1.255.255.255
First usable
0.0.0.1
Last usable
1.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 00000000 · Integer 0 to 33554431
Reverse DNS zones
0.in-addr.arpa
1.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000000.00000000.00000000.000000000.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000000.00000000.00000000.000000000.0.0.0
Broadcast00000001.11111111.11111111.111111111.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

0.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.0.0.0/190.0.0.1 to 0.0.31.2540.0.31.2558,190
20.0.32.0/190.0.32.1 to 0.0.63.2540.0.63.2558,190
30.0.64.0/190.0.64.1 to 0.0.95.2540.0.95.2558,190
40.0.96.0/190.0.96.1 to 0.0.127.2540.0.127.2558,190
50.0.128.0/190.0.128.1 to 0.0.159.2540.0.159.2558,190
60.0.160.0/190.0.160.1 to 0.0.191.2540.0.191.2558,190
70.0.192.0/190.0.192.1 to 0.0.223.2540.0.223.2558,190
80.0.224.0/190.0.224.1 to 0.0.255.2540.0.255.2558,190
90.1.0.0/190.1.0.1 to 0.1.31.2540.1.31.2558,190
100.1.32.0/190.1.32.1 to 0.1.63.2540.1.63.2558,190
110.1.64.0/190.1.64.1 to 0.1.95.2540.1.95.2558,190
120.1.96.0/190.1.96.1 to 0.1.127.2540.1.127.2558,190
130.1.128.0/190.1.128.1 to 0.1.159.2540.1.159.2558,190
140.1.160.0/190.1.160.1 to 0.1.191.2540.1.191.2558,190
150.1.192.0/190.1.192.1 to 0.1.223.2540.1.223.2558,190
160.1.224.0/190.1.224.1 to 0.1.255.2540.1.255.2558,190
170.2.0.0/190.2.0.1 to 0.2.31.2540.2.31.2558,190
180.2.32.0/190.2.32.1 to 0.2.63.2540.2.63.2558,190
190.2.64.0/190.2.64.1 to 0.2.95.2540.2.95.2558,190
200.2.96.0/190.2.96.1 to 0.2.127.2540.2.127.2558,190
210.2.128.0/190.2.128.1 to 0.2.159.2540.2.159.2558,190
220.2.160.0/190.2.160.1 to 0.2.191.2540.2.191.2558,190
230.2.192.0/190.2.192.1 to 0.2.223.2540.2.223.2558,190
240.2.224.0/190.2.224.1 to 0.2.255.2540.2.255.2558,190
250.3.0.0/190.3.0.1 to 0.3.31.2540.3.31.2558,190
260.3.32.0/190.3.32.1 to 0.3.63.2540.3.63.2558,190
270.3.64.0/190.3.64.1 to 0.3.95.2540.3.95.2558,190
280.3.96.0/190.3.96.1 to 0.3.127.2540.3.127.2558,190
290.3.128.0/190.3.128.1 to 0.3.159.2540.3.159.2558,190
300.3.160.0/190.3.160.1 to 0.3.191.2540.3.191.2558,190
310.3.192.0/190.3.192.1 to 0.3.223.2540.3.223.2558,190
320.3.224.0/190.3.224.1 to 0.3.255.2540.3.255.2558,190
330.4.0.0/190.4.0.1 to 0.4.31.2540.4.31.2558,190
340.4.32.0/190.4.32.1 to 0.4.63.2540.4.63.2558,190
350.4.64.0/190.4.64.1 to 0.4.95.2540.4.95.2558,190
360.4.96.0/190.4.96.1 to 0.4.127.2540.4.127.2558,190
370.4.128.0/190.4.128.1 to 0.4.159.2540.4.159.2558,190
380.4.160.0/190.4.160.1 to 0.4.191.2540.4.191.2558,190
390.4.192.0/190.4.192.1 to 0.4.223.2540.4.223.2558,190
400.4.224.0/190.4.224.1 to 0.4.255.2540.4.255.2558,190
410.5.0.0/190.5.0.1 to 0.5.31.2540.5.31.2558,190
420.5.32.0/190.5.32.1 to 0.5.63.2540.5.63.2558,190
430.5.64.0/190.5.64.1 to 0.5.95.2540.5.95.2558,190
440.5.96.0/190.5.96.1 to 0.5.127.2540.5.127.2558,190
450.5.128.0/190.5.128.1 to 0.5.159.2540.5.159.2558,190
460.5.160.0/190.5.160.1 to 0.5.191.2540.5.191.2558,190
470.5.192.0/190.5.192.1 to 0.5.223.2540.5.223.2558,190
480.5.224.0/190.5.224.1 to 0.5.255.2540.5.255.2558,190
490.6.0.0/190.6.0.1 to 0.6.31.2540.6.31.2558,190
500.6.32.0/190.6.32.1 to 0.6.63.2540.6.63.2558,190
510.6.64.0/190.6.64.1 to 0.6.95.2540.6.95.2558,190
520.6.96.0/190.6.96.1 to 0.6.127.2540.6.127.2558,190
530.6.128.0/190.6.128.1 to 0.6.159.2540.6.159.2558,190
540.6.160.0/190.6.160.1 to 0.6.191.2540.6.191.2558,190
550.6.192.0/190.6.192.1 to 0.6.223.2540.6.223.2558,190
560.6.224.0/190.6.224.1 to 0.6.255.2540.6.255.2558,190
570.7.0.0/190.7.0.1 to 0.7.31.2540.7.31.2558,190
580.7.32.0/190.7.32.1 to 0.7.63.2540.7.63.2558,190
590.7.64.0/190.7.64.1 to 0.7.95.2540.7.95.2558,190
600.7.96.0/190.7.96.1 to 0.7.127.2540.7.127.2558,190
610.7.128.0/190.7.128.1 to 0.7.159.2540.7.159.2558,190
620.7.160.0/190.7.160.1 to 0.7.191.2540.7.191.2558,190
630.7.192.0/190.7.192.1 to 0.7.223.2540.7.223.2558,190
640.7.224.0/190.7.224.1 to 0.7.255.2540.7.255.2558,190
650.8.0.0/190.8.0.1 to 0.8.31.2540.8.31.2558,190
660.8.32.0/190.8.32.1 to 0.8.63.2540.8.63.2558,190
670.8.64.0/190.8.64.1 to 0.8.95.2540.8.95.2558,190
680.8.96.0/190.8.96.1 to 0.8.127.2540.8.127.2558,190
690.8.128.0/190.8.128.1 to 0.8.159.2540.8.159.2558,190
700.8.160.0/190.8.160.1 to 0.8.191.2540.8.191.2558,190
710.8.192.0/190.8.192.1 to 0.8.223.2540.8.223.2558,190
720.8.224.0/190.8.224.1 to 0.8.255.2540.8.255.2558,190
730.9.0.0/190.9.0.1 to 0.9.31.2540.9.31.2558,190
740.9.32.0/190.9.32.1 to 0.9.63.2540.9.63.2558,190
750.9.64.0/190.9.64.1 to 0.9.95.2540.9.95.2558,190
760.9.96.0/190.9.96.1 to 0.9.127.2540.9.127.2558,190
770.9.128.0/190.9.128.1 to 0.9.159.2540.9.159.2558,190
780.9.160.0/190.9.160.1 to 0.9.191.2540.9.191.2558,190
790.9.192.0/190.9.192.1 to 0.9.223.2540.9.223.2558,190
800.9.224.0/190.9.224.1 to 0.9.255.2540.9.255.2558,190
810.10.0.0/190.10.0.1 to 0.10.31.2540.10.31.2558,190
820.10.32.0/190.10.32.1 to 0.10.63.2540.10.63.2558,190
830.10.64.0/190.10.64.1 to 0.10.95.2540.10.95.2558,190
840.10.96.0/190.10.96.1 to 0.10.127.2540.10.127.2558,190
850.10.128.0/190.10.128.1 to 0.10.159.2540.10.159.2558,190
860.10.160.0/190.10.160.1 to 0.10.191.2540.10.191.2558,190
870.10.192.0/190.10.192.1 to 0.10.223.2540.10.223.2558,190
880.10.224.0/190.10.224.1 to 0.10.255.2540.10.255.2558,190
890.11.0.0/190.11.0.1 to 0.11.31.2540.11.31.2558,190
900.11.32.0/190.11.32.1 to 0.11.63.2540.11.63.2558,190
910.11.64.0/190.11.64.1 to 0.11.95.2540.11.95.2558,190
920.11.96.0/190.11.96.1 to 0.11.127.2540.11.127.2558,190
930.11.128.0/190.11.128.1 to 0.11.159.2540.11.159.2558,190
940.11.160.0/190.11.160.1 to 0.11.191.2540.11.191.2558,190
950.11.192.0/190.11.192.1 to 0.11.223.2540.11.223.2558,190
960.11.224.0/190.11.224.1 to 0.11.255.2540.11.255.2558,190
970.12.0.0/190.12.0.1 to 0.12.31.2540.12.31.2558,190
980.12.32.0/190.12.32.1 to 0.12.63.2540.12.63.2558,190
990.12.64.0/190.12.64.1 to 0.12.95.2540.12.95.2558,190
1000.12.96.0/190.12.96.1 to 0.12.127.2540.12.127.2558,190
1010.12.128.0/190.12.128.1 to 0.12.159.2540.12.159.2558,190
1020.12.160.0/190.12.160.1 to 0.12.191.2540.12.191.2558,190
1030.12.192.0/190.12.192.1 to 0.12.223.2540.12.223.2558,190
1040.12.224.0/190.12.224.1 to 0.12.255.2540.12.255.2558,190
1050.13.0.0/190.13.0.1 to 0.13.31.2540.13.31.2558,190
1060.13.32.0/190.13.32.1 to 0.13.63.2540.13.63.2558,190
1070.13.64.0/190.13.64.1 to 0.13.95.2540.13.95.2558,190
1080.13.96.0/190.13.96.1 to 0.13.127.2540.13.127.2558,190
1090.13.128.0/190.13.128.1 to 0.13.159.2540.13.159.2558,190
1100.13.160.0/190.13.160.1 to 0.13.191.2540.13.191.2558,190
1110.13.192.0/190.13.192.1 to 0.13.223.2540.13.223.2558,190
1120.13.224.0/190.13.224.1 to 0.13.255.2540.13.255.2558,190
1130.14.0.0/190.14.0.1 to 0.14.31.2540.14.31.2558,190
1140.14.32.0/190.14.32.1 to 0.14.63.2540.14.63.2558,190
1150.14.64.0/190.14.64.1 to 0.14.95.2540.14.95.2558,190
1160.14.96.0/190.14.96.1 to 0.14.127.2540.14.127.2558,190
1170.14.128.0/190.14.128.1 to 0.14.159.2540.14.159.2558,190
1180.14.160.0/190.14.160.1 to 0.14.191.2540.14.191.2558,190
1190.14.192.0/190.14.192.1 to 0.14.223.2540.14.223.2558,190
1200.14.224.0/190.14.224.1 to 0.14.255.2540.14.255.2558,190
1210.15.0.0/190.15.0.1 to 0.15.31.2540.15.31.2558,190
1220.15.32.0/190.15.32.1 to 0.15.63.2540.15.63.2558,190
1230.15.64.0/190.15.64.1 to 0.15.95.2540.15.95.2558,190
1240.15.96.0/190.15.96.1 to 0.15.127.2540.15.127.2558,190
1250.15.128.0/190.15.128.1 to 0.15.159.2540.15.159.2558,190
1260.15.160.0/190.15.160.1 to 0.15.191.2540.15.191.2558,190
1270.15.192.0/190.15.192.1 to 0.15.223.2540.15.223.2558,190
1280.15.224.0/190.15.224.1 to 0.15.255.2540.15.255.2558,190
1290.16.0.0/190.16.0.1 to 0.16.31.2540.16.31.2558,190
1300.16.32.0/190.16.32.1 to 0.16.63.2540.16.63.2558,190
1310.16.64.0/190.16.64.1 to 0.16.95.2540.16.95.2558,190
1320.16.96.0/190.16.96.1 to 0.16.127.2540.16.127.2558,190
1330.16.128.0/190.16.128.1 to 0.16.159.2540.16.159.2558,190
1340.16.160.0/190.16.160.1 to 0.16.191.2540.16.191.2558,190
1350.16.192.0/190.16.192.1 to 0.16.223.2540.16.223.2558,190
1360.16.224.0/190.16.224.1 to 0.16.255.2540.16.255.2558,190
1370.17.0.0/190.17.0.1 to 0.17.31.2540.17.31.2558,190
1380.17.32.0/190.17.32.1 to 0.17.63.2540.17.63.2558,190
1390.17.64.0/190.17.64.1 to 0.17.95.2540.17.95.2558,190
1400.17.96.0/190.17.96.1 to 0.17.127.2540.17.127.2558,190
1410.17.128.0/190.17.128.1 to 0.17.159.2540.17.159.2558,190
1420.17.160.0/190.17.160.1 to 0.17.191.2540.17.191.2558,190
1430.17.192.0/190.17.192.1 to 0.17.223.2540.17.223.2558,190
1440.17.224.0/190.17.224.1 to 0.17.255.2540.17.255.2558,190
1450.18.0.0/190.18.0.1 to 0.18.31.2540.18.31.2558,190
1460.18.32.0/190.18.32.1 to 0.18.63.2540.18.63.2558,190
1470.18.64.0/190.18.64.1 to 0.18.95.2540.18.95.2558,190
1480.18.96.0/190.18.96.1 to 0.18.127.2540.18.127.2558,190
1490.18.128.0/190.18.128.1 to 0.18.159.2540.18.159.2558,190
1500.18.160.0/190.18.160.1 to 0.18.191.2540.18.191.2558,190
1510.18.192.0/190.18.192.1 to 0.18.223.2540.18.223.2558,190
1520.18.224.0/190.18.224.1 to 0.18.255.2540.18.255.2558,190
1530.19.0.0/190.19.0.1 to 0.19.31.2540.19.31.2558,190
1540.19.32.0/190.19.32.1 to 0.19.63.2540.19.63.2558,190
1550.19.64.0/190.19.64.1 to 0.19.95.2540.19.95.2558,190
1560.19.96.0/190.19.96.1 to 0.19.127.2540.19.127.2558,190
1570.19.128.0/190.19.128.1 to 0.19.159.2540.19.159.2558,190
1580.19.160.0/190.19.160.1 to 0.19.191.2540.19.191.2558,190
1590.19.192.0/190.19.192.1 to 0.19.223.2540.19.223.2558,190
1600.19.224.0/190.19.224.1 to 0.19.255.2540.19.255.2558,190
1610.20.0.0/190.20.0.1 to 0.20.31.2540.20.31.2558,190
1620.20.32.0/190.20.32.1 to 0.20.63.2540.20.63.2558,190
1630.20.64.0/190.20.64.1 to 0.20.95.2540.20.95.2558,190
1640.20.96.0/190.20.96.1 to 0.20.127.2540.20.127.2558,190
1650.20.128.0/190.20.128.1 to 0.20.159.2540.20.159.2558,190
1660.20.160.0/190.20.160.1 to 0.20.191.2540.20.191.2558,190
1670.20.192.0/190.20.192.1 to 0.20.223.2540.20.223.2558,190
1680.20.224.0/190.20.224.1 to 0.20.255.2540.20.255.2558,190
1690.21.0.0/190.21.0.1 to 0.21.31.2540.21.31.2558,190
1700.21.32.0/190.21.32.1 to 0.21.63.2540.21.63.2558,190
1710.21.64.0/190.21.64.1 to 0.21.95.2540.21.95.2558,190
1720.21.96.0/190.21.96.1 to 0.21.127.2540.21.127.2558,190
1730.21.128.0/190.21.128.1 to 0.21.159.2540.21.159.2558,190
1740.21.160.0/190.21.160.1 to 0.21.191.2540.21.191.2558,190
1750.21.192.0/190.21.192.1 to 0.21.223.2540.21.223.2558,190
1760.21.224.0/190.21.224.1 to 0.21.255.2540.21.255.2558,190
1770.22.0.0/190.22.0.1 to 0.22.31.2540.22.31.2558,190
1780.22.32.0/190.22.32.1 to 0.22.63.2540.22.63.2558,190
1790.22.64.0/190.22.64.1 to 0.22.95.2540.22.95.2558,190
1800.22.96.0/190.22.96.1 to 0.22.127.2540.22.127.2558,190
1810.22.128.0/190.22.128.1 to 0.22.159.2540.22.159.2558,190
1820.22.160.0/190.22.160.1 to 0.22.191.2540.22.191.2558,190
1830.22.192.0/190.22.192.1 to 0.22.223.2540.22.223.2558,190
1840.22.224.0/190.22.224.1 to 0.22.255.2540.22.255.2558,190
1850.23.0.0/190.23.0.1 to 0.23.31.2540.23.31.2558,190
1860.23.32.0/190.23.32.1 to 0.23.63.2540.23.63.2558,190
1870.23.64.0/190.23.64.1 to 0.23.95.2540.23.95.2558,190
1880.23.96.0/190.23.96.1 to 0.23.127.2540.23.127.2558,190
1890.23.128.0/190.23.128.1 to 0.23.159.2540.23.159.2558,190
1900.23.160.0/190.23.160.1 to 0.23.191.2540.23.191.2558,190
1910.23.192.0/190.23.192.1 to 0.23.223.2540.23.223.2558,190
1920.23.224.0/190.23.224.1 to 0.23.255.2540.23.255.2558,190
1930.24.0.0/190.24.0.1 to 0.24.31.2540.24.31.2558,190
1940.24.32.0/190.24.32.1 to 0.24.63.2540.24.63.2558,190
1950.24.64.0/190.24.64.1 to 0.24.95.2540.24.95.2558,190
1960.24.96.0/190.24.96.1 to 0.24.127.2540.24.127.2558,190
1970.24.128.0/190.24.128.1 to 0.24.159.2540.24.159.2558,190
1980.24.160.0/190.24.160.1 to 0.24.191.2540.24.191.2558,190
1990.24.192.0/190.24.192.1 to 0.24.223.2540.24.223.2558,190
2000.24.224.0/190.24.224.1 to 0.24.255.2540.24.255.2558,190
2010.25.0.0/190.25.0.1 to 0.25.31.2540.25.31.2558,190
2020.25.32.0/190.25.32.1 to 0.25.63.2540.25.63.2558,190
2030.25.64.0/190.25.64.1 to 0.25.95.2540.25.95.2558,190
2040.25.96.0/190.25.96.1 to 0.25.127.2540.25.127.2558,190
2050.25.128.0/190.25.128.1 to 0.25.159.2540.25.159.2558,190
2060.25.160.0/190.25.160.1 to 0.25.191.2540.25.191.2558,190
2070.25.192.0/190.25.192.1 to 0.25.223.2540.25.223.2558,190
2080.25.224.0/190.25.224.1 to 0.25.255.2540.25.255.2558,190
2090.26.0.0/190.26.0.1 to 0.26.31.2540.26.31.2558,190
2100.26.32.0/190.26.32.1 to 0.26.63.2540.26.63.2558,190
2110.26.64.0/190.26.64.1 to 0.26.95.2540.26.95.2558,190
2120.26.96.0/190.26.96.1 to 0.26.127.2540.26.127.2558,190
2130.26.128.0/190.26.128.1 to 0.26.159.2540.26.159.2558,190
2140.26.160.0/190.26.160.1 to 0.26.191.2540.26.191.2558,190
2150.26.192.0/190.26.192.1 to 0.26.223.2540.26.223.2558,190
2160.26.224.0/190.26.224.1 to 0.26.255.2540.26.255.2558,190
2170.27.0.0/190.27.0.1 to 0.27.31.2540.27.31.2558,190
2180.27.32.0/190.27.32.1 to 0.27.63.2540.27.63.2558,190
2190.27.64.0/190.27.64.1 to 0.27.95.2540.27.95.2558,190
2200.27.96.0/190.27.96.1 to 0.27.127.2540.27.127.2558,190
2210.27.128.0/190.27.128.1 to 0.27.159.2540.27.159.2558,190
2220.27.160.0/190.27.160.1 to 0.27.191.2540.27.191.2558,190
2230.27.192.0/190.27.192.1 to 0.27.223.2540.27.223.2558,190
2240.27.224.0/190.27.224.1 to 0.27.255.2540.27.255.2558,190
2250.28.0.0/190.28.0.1 to 0.28.31.2540.28.31.2558,190
2260.28.32.0/190.28.32.1 to 0.28.63.2540.28.63.2558,190
2270.28.64.0/190.28.64.1 to 0.28.95.2540.28.95.2558,190
2280.28.96.0/190.28.96.1 to 0.28.127.2540.28.127.2558,190
2290.28.128.0/190.28.128.1 to 0.28.159.2540.28.159.2558,190
2300.28.160.0/190.28.160.1 to 0.28.191.2540.28.191.2558,190
2310.28.192.0/190.28.192.1 to 0.28.223.2540.28.223.2558,190
2320.28.224.0/190.28.224.1 to 0.28.255.2540.28.255.2558,190
2330.29.0.0/190.29.0.1 to 0.29.31.2540.29.31.2558,190
2340.29.32.0/190.29.32.1 to 0.29.63.2540.29.63.2558,190
2350.29.64.0/190.29.64.1 to 0.29.95.2540.29.95.2558,190
2360.29.96.0/190.29.96.1 to 0.29.127.2540.29.127.2558,190
2370.29.128.0/190.29.128.1 to 0.29.159.2540.29.159.2558,190
2380.29.160.0/190.29.160.1 to 0.29.191.2540.29.191.2558,190
2390.29.192.0/190.29.192.1 to 0.29.223.2540.29.223.2558,190
2400.29.224.0/190.29.224.1 to 0.29.255.2540.29.255.2558,190
2410.30.0.0/190.30.0.1 to 0.30.31.2540.30.31.2558,190
2420.30.32.0/190.30.32.1 to 0.30.63.2540.30.63.2558,190
2430.30.64.0/190.30.64.1 to 0.30.95.2540.30.95.2558,190
2440.30.96.0/190.30.96.1 to 0.30.127.2540.30.127.2558,190
2450.30.128.0/190.30.128.1 to 0.30.159.2540.30.159.2558,190
2460.30.160.0/190.30.160.1 to 0.30.191.2540.30.191.2558,190
2470.30.192.0/190.30.192.1 to 0.30.223.2540.30.223.2558,190
2480.30.224.0/190.30.224.1 to 0.30.255.2540.30.255.2558,190
2490.31.0.0/190.31.0.1 to 0.31.31.2540.31.31.2558,190
2500.31.32.0/190.31.32.1 to 0.31.63.2540.31.63.2558,190
2510.31.64.0/190.31.64.1 to 0.31.95.2540.31.95.2558,190
2520.31.96.0/190.31.96.1 to 0.31.127.2540.31.127.2558,190
2530.31.128.0/190.31.128.1 to 0.31.159.2540.31.159.2558,190
2540.31.160.0/190.31.160.1 to 0.31.191.2540.31.191.2558,190
2550.31.192.0/190.31.192.1 to 0.31.223.2540.31.223.2558,190
2560.31.224.0/190.31.224.1 to 0.31.255.2540.31.255.2558,190

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.