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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.

Network3.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
3.0.0.0
Broadcast address
3.255.255.255
First usable
3.0.0.1
Last usable
3.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 03000000 · Integer 50331648 to 67108863
Reverse DNS zone
3.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000011..00000000.00000000.000000003.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00000011..00000000.00000000.000000003.0.0.0
Broadcast00000011..11111111.11111111.111111113.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

3.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
13.0.0.0/183.0.0.1 to 3.0.63.2543.0.63.25516,382
23.0.64.0/183.0.64.1 to 3.0.127.2543.0.127.25516,382
33.0.128.0/183.0.128.1 to 3.0.191.2543.0.191.25516,382
43.0.192.0/183.0.192.1 to 3.0.255.2543.0.255.25516,382
53.1.0.0/183.1.0.1 to 3.1.63.2543.1.63.25516,382
63.1.64.0/183.1.64.1 to 3.1.127.2543.1.127.25516,382
73.1.128.0/183.1.128.1 to 3.1.191.2543.1.191.25516,382
83.1.192.0/183.1.192.1 to 3.1.255.2543.1.255.25516,382
93.2.0.0/183.2.0.1 to 3.2.63.2543.2.63.25516,382
103.2.64.0/183.2.64.1 to 3.2.127.2543.2.127.25516,382
113.2.128.0/183.2.128.1 to 3.2.191.2543.2.191.25516,382
123.2.192.0/183.2.192.1 to 3.2.255.2543.2.255.25516,382
133.3.0.0/183.3.0.1 to 3.3.63.2543.3.63.25516,382
143.3.64.0/183.3.64.1 to 3.3.127.2543.3.127.25516,382
153.3.128.0/183.3.128.1 to 3.3.191.2543.3.191.25516,382
163.3.192.0/183.3.192.1 to 3.3.255.2543.3.255.25516,382
173.4.0.0/183.4.0.1 to 3.4.63.2543.4.63.25516,382
183.4.64.0/183.4.64.1 to 3.4.127.2543.4.127.25516,382
193.4.128.0/183.4.128.1 to 3.4.191.2543.4.191.25516,382
203.4.192.0/183.4.192.1 to 3.4.255.2543.4.255.25516,382
213.5.0.0/183.5.0.1 to 3.5.63.2543.5.63.25516,382
223.5.64.0/183.5.64.1 to 3.5.127.2543.5.127.25516,382
233.5.128.0/183.5.128.1 to 3.5.191.2543.5.191.25516,382
243.5.192.0/183.5.192.1 to 3.5.255.2543.5.255.25516,382
253.6.0.0/183.6.0.1 to 3.6.63.2543.6.63.25516,382
263.6.64.0/183.6.64.1 to 3.6.127.2543.6.127.25516,382
273.6.128.0/183.6.128.1 to 3.6.191.2543.6.191.25516,382
283.6.192.0/183.6.192.1 to 3.6.255.2543.6.255.25516,382
293.7.0.0/183.7.0.1 to 3.7.63.2543.7.63.25516,382
303.7.64.0/183.7.64.1 to 3.7.127.2543.7.127.25516,382
313.7.128.0/183.7.128.1 to 3.7.191.2543.7.191.25516,382
323.7.192.0/183.7.192.1 to 3.7.255.2543.7.255.25516,382
333.8.0.0/183.8.0.1 to 3.8.63.2543.8.63.25516,382
343.8.64.0/183.8.64.1 to 3.8.127.2543.8.127.25516,382
353.8.128.0/183.8.128.1 to 3.8.191.2543.8.191.25516,382
363.8.192.0/183.8.192.1 to 3.8.255.2543.8.255.25516,382
373.9.0.0/183.9.0.1 to 3.9.63.2543.9.63.25516,382
383.9.64.0/183.9.64.1 to 3.9.127.2543.9.127.25516,382
393.9.128.0/183.9.128.1 to 3.9.191.2543.9.191.25516,382
403.9.192.0/183.9.192.1 to 3.9.255.2543.9.255.25516,382
413.10.0.0/183.10.0.1 to 3.10.63.2543.10.63.25516,382
423.10.64.0/183.10.64.1 to 3.10.127.2543.10.127.25516,382
433.10.128.0/183.10.128.1 to 3.10.191.2543.10.191.25516,382
443.10.192.0/183.10.192.1 to 3.10.255.2543.10.255.25516,382
453.11.0.0/183.11.0.1 to 3.11.63.2543.11.63.25516,382
463.11.64.0/183.11.64.1 to 3.11.127.2543.11.127.25516,382
473.11.128.0/183.11.128.1 to 3.11.191.2543.11.191.25516,382
483.11.192.0/183.11.192.1 to 3.11.255.2543.11.255.25516,382
493.12.0.0/183.12.0.1 to 3.12.63.2543.12.63.25516,382
503.12.64.0/183.12.64.1 to 3.12.127.2543.12.127.25516,382
513.12.128.0/183.12.128.1 to 3.12.191.2543.12.191.25516,382
523.12.192.0/183.12.192.1 to 3.12.255.2543.12.255.25516,382
533.13.0.0/183.13.0.1 to 3.13.63.2543.13.63.25516,382
543.13.64.0/183.13.64.1 to 3.13.127.2543.13.127.25516,382
553.13.128.0/183.13.128.1 to 3.13.191.2543.13.191.25516,382
563.13.192.0/183.13.192.1 to 3.13.255.2543.13.255.25516,382
573.14.0.0/183.14.0.1 to 3.14.63.2543.14.63.25516,382
583.14.64.0/183.14.64.1 to 3.14.127.2543.14.127.25516,382
593.14.128.0/183.14.128.1 to 3.14.191.2543.14.191.25516,382
603.14.192.0/183.14.192.1 to 3.14.255.2543.14.255.25516,382
613.15.0.0/183.15.0.1 to 3.15.63.2543.15.63.25516,382
623.15.64.0/183.15.64.1 to 3.15.127.2543.15.127.25516,382
633.15.128.0/183.15.128.1 to 3.15.191.2543.15.191.25516,382
643.15.192.0/183.15.192.1 to 3.15.255.2543.15.255.25516,382
653.16.0.0/183.16.0.1 to 3.16.63.2543.16.63.25516,382
663.16.64.0/183.16.64.1 to 3.16.127.2543.16.127.25516,382
673.16.128.0/183.16.128.1 to 3.16.191.2543.16.191.25516,382
683.16.192.0/183.16.192.1 to 3.16.255.2543.16.255.25516,382
693.17.0.0/183.17.0.1 to 3.17.63.2543.17.63.25516,382
703.17.64.0/183.17.64.1 to 3.17.127.2543.17.127.25516,382
713.17.128.0/183.17.128.1 to 3.17.191.2543.17.191.25516,382
723.17.192.0/183.17.192.1 to 3.17.255.2543.17.255.25516,382
733.18.0.0/183.18.0.1 to 3.18.63.2543.18.63.25516,382
743.18.64.0/183.18.64.1 to 3.18.127.2543.18.127.25516,382
753.18.128.0/183.18.128.1 to 3.18.191.2543.18.191.25516,382
763.18.192.0/183.18.192.1 to 3.18.255.2543.18.255.25516,382
773.19.0.0/183.19.0.1 to 3.19.63.2543.19.63.25516,382
783.19.64.0/183.19.64.1 to 3.19.127.2543.19.127.25516,382
793.19.128.0/183.19.128.1 to 3.19.191.2543.19.191.25516,382
803.19.192.0/183.19.192.1 to 3.19.255.2543.19.255.25516,382
813.20.0.0/183.20.0.1 to 3.20.63.2543.20.63.25516,382
823.20.64.0/183.20.64.1 to 3.20.127.2543.20.127.25516,382
833.20.128.0/183.20.128.1 to 3.20.191.2543.20.191.25516,382
843.20.192.0/183.20.192.1 to 3.20.255.2543.20.255.25516,382
853.21.0.0/183.21.0.1 to 3.21.63.2543.21.63.25516,382
863.21.64.0/183.21.64.1 to 3.21.127.2543.21.127.25516,382
873.21.128.0/183.21.128.1 to 3.21.191.2543.21.191.25516,382
883.21.192.0/183.21.192.1 to 3.21.255.2543.21.255.25516,382
893.22.0.0/183.22.0.1 to 3.22.63.2543.22.63.25516,382
903.22.64.0/183.22.64.1 to 3.22.127.2543.22.127.25516,382
913.22.128.0/183.22.128.1 to 3.22.191.2543.22.191.25516,382
923.22.192.0/183.22.192.1 to 3.22.255.2543.22.255.25516,382
933.23.0.0/183.23.0.1 to 3.23.63.2543.23.63.25516,382
943.23.64.0/183.23.64.1 to 3.23.127.2543.23.127.25516,382
953.23.128.0/183.23.128.1 to 3.23.191.2543.23.191.25516,382
963.23.192.0/183.23.192.1 to 3.23.255.2543.23.255.25516,382
973.24.0.0/183.24.0.1 to 3.24.63.2543.24.63.25516,382
983.24.64.0/183.24.64.1 to 3.24.127.2543.24.127.25516,382
993.24.128.0/183.24.128.1 to 3.24.191.2543.24.191.25516,382
1003.24.192.0/183.24.192.1 to 3.24.255.2543.24.255.25516,382
1013.25.0.0/183.25.0.1 to 3.25.63.2543.25.63.25516,382
1023.25.64.0/183.25.64.1 to 3.25.127.2543.25.127.25516,382
1033.25.128.0/183.25.128.1 to 3.25.191.2543.25.191.25516,382
1043.25.192.0/183.25.192.1 to 3.25.255.2543.25.255.25516,382
1053.26.0.0/183.26.0.1 to 3.26.63.2543.26.63.25516,382
1063.26.64.0/183.26.64.1 to 3.26.127.2543.26.127.25516,382
1073.26.128.0/183.26.128.1 to 3.26.191.2543.26.191.25516,382
1083.26.192.0/183.26.192.1 to 3.26.255.2543.26.255.25516,382
1093.27.0.0/183.27.0.1 to 3.27.63.2543.27.63.25516,382
1103.27.64.0/183.27.64.1 to 3.27.127.2543.27.127.25516,382
1113.27.128.0/183.27.128.1 to 3.27.191.2543.27.191.25516,382
1123.27.192.0/183.27.192.1 to 3.27.255.2543.27.255.25516,382
1133.28.0.0/183.28.0.1 to 3.28.63.2543.28.63.25516,382
1143.28.64.0/183.28.64.1 to 3.28.127.2543.28.127.25516,382
1153.28.128.0/183.28.128.1 to 3.28.191.2543.28.191.25516,382
1163.28.192.0/183.28.192.1 to 3.28.255.2543.28.255.25516,382
1173.29.0.0/183.29.0.1 to 3.29.63.2543.29.63.25516,382
1183.29.64.0/183.29.64.1 to 3.29.127.2543.29.127.25516,382
1193.29.128.0/183.29.128.1 to 3.29.191.2543.29.191.25516,382
1203.29.192.0/183.29.192.1 to 3.29.255.2543.29.255.25516,382
1213.30.0.0/183.30.0.1 to 3.30.63.2543.30.63.25516,382
1223.30.64.0/183.30.64.1 to 3.30.127.2543.30.127.25516,382
1233.30.128.0/183.30.128.1 to 3.30.191.2543.30.191.25516,382
1243.30.192.0/183.30.192.1 to 3.30.255.2543.30.255.25516,382
1253.31.0.0/183.31.0.1 to 3.31.63.2543.31.63.25516,382
1263.31.64.0/183.31.64.1 to 3.31.127.2543.31.127.25516,382
1273.31.128.0/183.31.128.1 to 3.31.191.2543.31.191.25516,382
1283.31.192.0/183.31.192.1 to 3.31.255.2543.31.255.25516,382
1293.32.0.0/183.32.0.1 to 3.32.63.2543.32.63.25516,382
1303.32.64.0/183.32.64.1 to 3.32.127.2543.32.127.25516,382
1313.32.128.0/183.32.128.1 to 3.32.191.2543.32.191.25516,382
1323.32.192.0/183.32.192.1 to 3.32.255.2543.32.255.25516,382
1333.33.0.0/183.33.0.1 to 3.33.63.2543.33.63.25516,382
1343.33.64.0/183.33.64.1 to 3.33.127.2543.33.127.25516,382
1353.33.128.0/183.33.128.1 to 3.33.191.2543.33.191.25516,382
1363.33.192.0/183.33.192.1 to 3.33.255.2543.33.255.25516,382
1373.34.0.0/183.34.0.1 to 3.34.63.2543.34.63.25516,382
1383.34.64.0/183.34.64.1 to 3.34.127.2543.34.127.25516,382
1393.34.128.0/183.34.128.1 to 3.34.191.2543.34.191.25516,382
1403.34.192.0/183.34.192.1 to 3.34.255.2543.34.255.25516,382
1413.35.0.0/183.35.0.1 to 3.35.63.2543.35.63.25516,382
1423.35.64.0/183.35.64.1 to 3.35.127.2543.35.127.25516,382
1433.35.128.0/183.35.128.1 to 3.35.191.2543.35.191.25516,382
1443.35.192.0/183.35.192.1 to 3.35.255.2543.35.255.25516,382
1453.36.0.0/183.36.0.1 to 3.36.63.2543.36.63.25516,382
1463.36.64.0/183.36.64.1 to 3.36.127.2543.36.127.25516,382
1473.36.128.0/183.36.128.1 to 3.36.191.2543.36.191.25516,382
1483.36.192.0/183.36.192.1 to 3.36.255.2543.36.255.25516,382
1493.37.0.0/183.37.0.1 to 3.37.63.2543.37.63.25516,382
1503.37.64.0/183.37.64.1 to 3.37.127.2543.37.127.25516,382
1513.37.128.0/183.37.128.1 to 3.37.191.2543.37.191.25516,382
1523.37.192.0/183.37.192.1 to 3.37.255.2543.37.255.25516,382
1533.38.0.0/183.38.0.1 to 3.38.63.2543.38.63.25516,382
1543.38.64.0/183.38.64.1 to 3.38.127.2543.38.127.25516,382
1553.38.128.0/183.38.128.1 to 3.38.191.2543.38.191.25516,382
1563.38.192.0/183.38.192.1 to 3.38.255.2543.38.255.25516,382
1573.39.0.0/183.39.0.1 to 3.39.63.2543.39.63.25516,382
1583.39.64.0/183.39.64.1 to 3.39.127.2543.39.127.25516,382
1593.39.128.0/183.39.128.1 to 3.39.191.2543.39.191.25516,382
1603.39.192.0/183.39.192.1 to 3.39.255.2543.39.255.25516,382
1613.40.0.0/183.40.0.1 to 3.40.63.2543.40.63.25516,382
1623.40.64.0/183.40.64.1 to 3.40.127.2543.40.127.25516,382
1633.40.128.0/183.40.128.1 to 3.40.191.2543.40.191.25516,382
1643.40.192.0/183.40.192.1 to 3.40.255.2543.40.255.25516,382
1653.41.0.0/183.41.0.1 to 3.41.63.2543.41.63.25516,382
1663.41.64.0/183.41.64.1 to 3.41.127.2543.41.127.25516,382
1673.41.128.0/183.41.128.1 to 3.41.191.2543.41.191.25516,382
1683.41.192.0/183.41.192.1 to 3.41.255.2543.41.255.25516,382
1693.42.0.0/183.42.0.1 to 3.42.63.2543.42.63.25516,382
1703.42.64.0/183.42.64.1 to 3.42.127.2543.42.127.25516,382
1713.42.128.0/183.42.128.1 to 3.42.191.2543.42.191.25516,382
1723.42.192.0/183.42.192.1 to 3.42.255.2543.42.255.25516,382
1733.43.0.0/183.43.0.1 to 3.43.63.2543.43.63.25516,382
1743.43.64.0/183.43.64.1 to 3.43.127.2543.43.127.25516,382
1753.43.128.0/183.43.128.1 to 3.43.191.2543.43.191.25516,382
1763.43.192.0/183.43.192.1 to 3.43.255.2543.43.255.25516,382
1773.44.0.0/183.44.0.1 to 3.44.63.2543.44.63.25516,382
1783.44.64.0/183.44.64.1 to 3.44.127.2543.44.127.25516,382
1793.44.128.0/183.44.128.1 to 3.44.191.2543.44.191.25516,382
1803.44.192.0/183.44.192.1 to 3.44.255.2543.44.255.25516,382
1813.45.0.0/183.45.0.1 to 3.45.63.2543.45.63.25516,382
1823.45.64.0/183.45.64.1 to 3.45.127.2543.45.127.25516,382
1833.45.128.0/183.45.128.1 to 3.45.191.2543.45.191.25516,382
1843.45.192.0/183.45.192.1 to 3.45.255.2543.45.255.25516,382
1853.46.0.0/183.46.0.1 to 3.46.63.2543.46.63.25516,382
1863.46.64.0/183.46.64.1 to 3.46.127.2543.46.127.25516,382
1873.46.128.0/183.46.128.1 to 3.46.191.2543.46.191.25516,382
1883.46.192.0/183.46.192.1 to 3.46.255.2543.46.255.25516,382
1893.47.0.0/183.47.0.1 to 3.47.63.2543.47.63.25516,382
1903.47.64.0/183.47.64.1 to 3.47.127.2543.47.127.25516,382
1913.47.128.0/183.47.128.1 to 3.47.191.2543.47.191.25516,382
1923.47.192.0/183.47.192.1 to 3.47.255.2543.47.255.25516,382
1933.48.0.0/183.48.0.1 to 3.48.63.2543.48.63.25516,382
1943.48.64.0/183.48.64.1 to 3.48.127.2543.48.127.25516,382
1953.48.128.0/183.48.128.1 to 3.48.191.2543.48.191.25516,382
1963.48.192.0/183.48.192.1 to 3.48.255.2543.48.255.25516,382
1973.49.0.0/183.49.0.1 to 3.49.63.2543.49.63.25516,382
1983.49.64.0/183.49.64.1 to 3.49.127.2543.49.127.25516,382
1993.49.128.0/183.49.128.1 to 3.49.191.2543.49.191.25516,382
2003.49.192.0/183.49.192.1 to 3.49.255.2543.49.255.25516,382
2013.50.0.0/183.50.0.1 to 3.50.63.2543.50.63.25516,382
2023.50.64.0/183.50.64.1 to 3.50.127.2543.50.127.25516,382
2033.50.128.0/183.50.128.1 to 3.50.191.2543.50.191.25516,382
2043.50.192.0/183.50.192.1 to 3.50.255.2543.50.255.25516,382
2053.51.0.0/183.51.0.1 to 3.51.63.2543.51.63.25516,382
2063.51.64.0/183.51.64.1 to 3.51.127.2543.51.127.25516,382
2073.51.128.0/183.51.128.1 to 3.51.191.2543.51.191.25516,382
2083.51.192.0/183.51.192.1 to 3.51.255.2543.51.255.25516,382
2093.52.0.0/183.52.0.1 to 3.52.63.2543.52.63.25516,382
2103.52.64.0/183.52.64.1 to 3.52.127.2543.52.127.25516,382
2113.52.128.0/183.52.128.1 to 3.52.191.2543.52.191.25516,382
2123.52.192.0/183.52.192.1 to 3.52.255.2543.52.255.25516,382
2133.53.0.0/183.53.0.1 to 3.53.63.2543.53.63.25516,382
2143.53.64.0/183.53.64.1 to 3.53.127.2543.53.127.25516,382
2153.53.128.0/183.53.128.1 to 3.53.191.2543.53.191.25516,382
2163.53.192.0/183.53.192.1 to 3.53.255.2543.53.255.25516,382
2173.54.0.0/183.54.0.1 to 3.54.63.2543.54.63.25516,382
2183.54.64.0/183.54.64.1 to 3.54.127.2543.54.127.25516,382
2193.54.128.0/183.54.128.1 to 3.54.191.2543.54.191.25516,382
2203.54.192.0/183.54.192.1 to 3.54.255.2543.54.255.25516,382
2213.55.0.0/183.55.0.1 to 3.55.63.2543.55.63.25516,382
2223.55.64.0/183.55.64.1 to 3.55.127.2543.55.127.25516,382
2233.55.128.0/183.55.128.1 to 3.55.191.2543.55.191.25516,382
2243.55.192.0/183.55.192.1 to 3.55.255.2543.55.255.25516,382
2253.56.0.0/183.56.0.1 to 3.56.63.2543.56.63.25516,382
2263.56.64.0/183.56.64.1 to 3.56.127.2543.56.127.25516,382
2273.56.128.0/183.56.128.1 to 3.56.191.2543.56.191.25516,382
2283.56.192.0/183.56.192.1 to 3.56.255.2543.56.255.25516,382
2293.57.0.0/183.57.0.1 to 3.57.63.2543.57.63.25516,382
2303.57.64.0/183.57.64.1 to 3.57.127.2543.57.127.25516,382
2313.57.128.0/183.57.128.1 to 3.57.191.2543.57.191.25516,382
2323.57.192.0/183.57.192.1 to 3.57.255.2543.57.255.25516,382
2333.58.0.0/183.58.0.1 to 3.58.63.2543.58.63.25516,382
2343.58.64.0/183.58.64.1 to 3.58.127.2543.58.127.25516,382
2353.58.128.0/183.58.128.1 to 3.58.191.2543.58.191.25516,382
2363.58.192.0/183.58.192.1 to 3.58.255.2543.58.255.25516,382
2373.59.0.0/183.59.0.1 to 3.59.63.2543.59.63.25516,382
2383.59.64.0/183.59.64.1 to 3.59.127.2543.59.127.25516,382
2393.59.128.0/183.59.128.1 to 3.59.191.2543.59.191.25516,382
2403.59.192.0/183.59.192.1 to 3.59.255.2543.59.255.25516,382
2413.60.0.0/183.60.0.1 to 3.60.63.2543.60.63.25516,382
2423.60.64.0/183.60.64.1 to 3.60.127.2543.60.127.25516,382
2433.60.128.0/183.60.128.1 to 3.60.191.2543.60.191.25516,382
2443.60.192.0/183.60.192.1 to 3.60.255.2543.60.255.25516,382
2453.61.0.0/183.61.0.1 to 3.61.63.2543.61.63.25516,382
2463.61.64.0/183.61.64.1 to 3.61.127.2543.61.127.25516,382
2473.61.128.0/183.61.128.1 to 3.61.191.2543.61.191.25516,382
2483.61.192.0/183.61.192.1 to 3.61.255.2543.61.255.25516,382
2493.62.0.0/183.62.0.1 to 3.62.63.2543.62.63.25516,382
2503.62.64.0/183.62.64.1 to 3.62.127.2543.62.127.25516,382
2513.62.128.0/183.62.128.1 to 3.62.191.2543.62.191.25516,382
2523.62.192.0/183.62.192.1 to 3.62.255.2543.62.255.25516,382
2533.63.0.0/183.63.0.1 to 3.63.63.2543.63.63.25516,382
2543.63.64.0/183.63.64.1 to 3.63.127.2543.63.127.25516,382
2553.63.128.0/183.63.128.1 to 3.63.191.2543.63.191.25516,382
2563.63.192.0/183.63.192.1 to 3.63.255.2543.63.255.25516,382

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.