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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.

Network8.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
8.0.0.0
Broadcast address
11.255.255.255
First usable
8.0.0.1
Last usable
11.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 08000000 · Integer 134217728 to 201326591
Reverse DNS zones
8.in-addr.arpa
9.in-addr.arpa
10.in-addr.arpa
11.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001000.00000000.00000000.000000008.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network00001000.00000000.00000000.000000008.0.0.0
Broadcast00001011.11111111.11111111.1111111111.255.255.255
Split into smaller subnets/18
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

8.0.0.0/6 makes 4,096 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
18.0.0.0/188.0.0.1 to 8.0.63.2548.0.63.25516,382
28.0.64.0/188.0.64.1 to 8.0.127.2548.0.127.25516,382
38.0.128.0/188.0.128.1 to 8.0.191.2548.0.191.25516,382
48.0.192.0/188.0.192.1 to 8.0.255.2548.0.255.25516,382
58.1.0.0/188.1.0.1 to 8.1.63.2548.1.63.25516,382
68.1.64.0/188.1.64.1 to 8.1.127.2548.1.127.25516,382
78.1.128.0/188.1.128.1 to 8.1.191.2548.1.191.25516,382
88.1.192.0/188.1.192.1 to 8.1.255.2548.1.255.25516,382
98.2.0.0/188.2.0.1 to 8.2.63.2548.2.63.25516,382
108.2.64.0/188.2.64.1 to 8.2.127.2548.2.127.25516,382
118.2.128.0/188.2.128.1 to 8.2.191.2548.2.191.25516,382
128.2.192.0/188.2.192.1 to 8.2.255.2548.2.255.25516,382
138.3.0.0/188.3.0.1 to 8.3.63.2548.3.63.25516,382
148.3.64.0/188.3.64.1 to 8.3.127.2548.3.127.25516,382
158.3.128.0/188.3.128.1 to 8.3.191.2548.3.191.25516,382
168.3.192.0/188.3.192.1 to 8.3.255.2548.3.255.25516,382
178.4.0.0/188.4.0.1 to 8.4.63.2548.4.63.25516,382
188.4.64.0/188.4.64.1 to 8.4.127.2548.4.127.25516,382
198.4.128.0/188.4.128.1 to 8.4.191.2548.4.191.25516,382
208.4.192.0/188.4.192.1 to 8.4.255.2548.4.255.25516,382
218.5.0.0/188.5.0.1 to 8.5.63.2548.5.63.25516,382
228.5.64.0/188.5.64.1 to 8.5.127.2548.5.127.25516,382
238.5.128.0/188.5.128.1 to 8.5.191.2548.5.191.25516,382
248.5.192.0/188.5.192.1 to 8.5.255.2548.5.255.25516,382
258.6.0.0/188.6.0.1 to 8.6.63.2548.6.63.25516,382
268.6.64.0/188.6.64.1 to 8.6.127.2548.6.127.25516,382
278.6.128.0/188.6.128.1 to 8.6.191.2548.6.191.25516,382
288.6.192.0/188.6.192.1 to 8.6.255.2548.6.255.25516,382
298.7.0.0/188.7.0.1 to 8.7.63.2548.7.63.25516,382
308.7.64.0/188.7.64.1 to 8.7.127.2548.7.127.25516,382
318.7.128.0/188.7.128.1 to 8.7.191.2548.7.191.25516,382
328.7.192.0/188.7.192.1 to 8.7.255.2548.7.255.25516,382
338.8.0.0/188.8.0.1 to 8.8.63.2548.8.63.25516,382
348.8.64.0/188.8.64.1 to 8.8.127.2548.8.127.25516,382
358.8.128.0/188.8.128.1 to 8.8.191.2548.8.191.25516,382
368.8.192.0/188.8.192.1 to 8.8.255.2548.8.255.25516,382
378.9.0.0/188.9.0.1 to 8.9.63.2548.9.63.25516,382
388.9.64.0/188.9.64.1 to 8.9.127.2548.9.127.25516,382
398.9.128.0/188.9.128.1 to 8.9.191.2548.9.191.25516,382
408.9.192.0/188.9.192.1 to 8.9.255.2548.9.255.25516,382
418.10.0.0/188.10.0.1 to 8.10.63.2548.10.63.25516,382
428.10.64.0/188.10.64.1 to 8.10.127.2548.10.127.25516,382
438.10.128.0/188.10.128.1 to 8.10.191.2548.10.191.25516,382
448.10.192.0/188.10.192.1 to 8.10.255.2548.10.255.25516,382
458.11.0.0/188.11.0.1 to 8.11.63.2548.11.63.25516,382
468.11.64.0/188.11.64.1 to 8.11.127.2548.11.127.25516,382
478.11.128.0/188.11.128.1 to 8.11.191.2548.11.191.25516,382
488.11.192.0/188.11.192.1 to 8.11.255.2548.11.255.25516,382
498.12.0.0/188.12.0.1 to 8.12.63.2548.12.63.25516,382
508.12.64.0/188.12.64.1 to 8.12.127.2548.12.127.25516,382
518.12.128.0/188.12.128.1 to 8.12.191.2548.12.191.25516,382
528.12.192.0/188.12.192.1 to 8.12.255.2548.12.255.25516,382
538.13.0.0/188.13.0.1 to 8.13.63.2548.13.63.25516,382
548.13.64.0/188.13.64.1 to 8.13.127.2548.13.127.25516,382
558.13.128.0/188.13.128.1 to 8.13.191.2548.13.191.25516,382
568.13.192.0/188.13.192.1 to 8.13.255.2548.13.255.25516,382
578.14.0.0/188.14.0.1 to 8.14.63.2548.14.63.25516,382
588.14.64.0/188.14.64.1 to 8.14.127.2548.14.127.25516,382
598.14.128.0/188.14.128.1 to 8.14.191.2548.14.191.25516,382
608.14.192.0/188.14.192.1 to 8.14.255.2548.14.255.25516,382
618.15.0.0/188.15.0.1 to 8.15.63.2548.15.63.25516,382
628.15.64.0/188.15.64.1 to 8.15.127.2548.15.127.25516,382
638.15.128.0/188.15.128.1 to 8.15.191.2548.15.191.25516,382
648.15.192.0/188.15.192.1 to 8.15.255.2548.15.255.25516,382
658.16.0.0/188.16.0.1 to 8.16.63.2548.16.63.25516,382
668.16.64.0/188.16.64.1 to 8.16.127.2548.16.127.25516,382
678.16.128.0/188.16.128.1 to 8.16.191.2548.16.191.25516,382
688.16.192.0/188.16.192.1 to 8.16.255.2548.16.255.25516,382
698.17.0.0/188.17.0.1 to 8.17.63.2548.17.63.25516,382
708.17.64.0/188.17.64.1 to 8.17.127.2548.17.127.25516,382
718.17.128.0/188.17.128.1 to 8.17.191.2548.17.191.25516,382
728.17.192.0/188.17.192.1 to 8.17.255.2548.17.255.25516,382
738.18.0.0/188.18.0.1 to 8.18.63.2548.18.63.25516,382
748.18.64.0/188.18.64.1 to 8.18.127.2548.18.127.25516,382
758.18.128.0/188.18.128.1 to 8.18.191.2548.18.191.25516,382
768.18.192.0/188.18.192.1 to 8.18.255.2548.18.255.25516,382
778.19.0.0/188.19.0.1 to 8.19.63.2548.19.63.25516,382
788.19.64.0/188.19.64.1 to 8.19.127.2548.19.127.25516,382
798.19.128.0/188.19.128.1 to 8.19.191.2548.19.191.25516,382
808.19.192.0/188.19.192.1 to 8.19.255.2548.19.255.25516,382
818.20.0.0/188.20.0.1 to 8.20.63.2548.20.63.25516,382
828.20.64.0/188.20.64.1 to 8.20.127.2548.20.127.25516,382
838.20.128.0/188.20.128.1 to 8.20.191.2548.20.191.25516,382
848.20.192.0/188.20.192.1 to 8.20.255.2548.20.255.25516,382
858.21.0.0/188.21.0.1 to 8.21.63.2548.21.63.25516,382
868.21.64.0/188.21.64.1 to 8.21.127.2548.21.127.25516,382
878.21.128.0/188.21.128.1 to 8.21.191.2548.21.191.25516,382
888.21.192.0/188.21.192.1 to 8.21.255.2548.21.255.25516,382
898.22.0.0/188.22.0.1 to 8.22.63.2548.22.63.25516,382
908.22.64.0/188.22.64.1 to 8.22.127.2548.22.127.25516,382
918.22.128.0/188.22.128.1 to 8.22.191.2548.22.191.25516,382
928.22.192.0/188.22.192.1 to 8.22.255.2548.22.255.25516,382
938.23.0.0/188.23.0.1 to 8.23.63.2548.23.63.25516,382
948.23.64.0/188.23.64.1 to 8.23.127.2548.23.127.25516,382
958.23.128.0/188.23.128.1 to 8.23.191.2548.23.191.25516,382
968.23.192.0/188.23.192.1 to 8.23.255.2548.23.255.25516,382
978.24.0.0/188.24.0.1 to 8.24.63.2548.24.63.25516,382
988.24.64.0/188.24.64.1 to 8.24.127.2548.24.127.25516,382
998.24.128.0/188.24.128.1 to 8.24.191.2548.24.191.25516,382
1008.24.192.0/188.24.192.1 to 8.24.255.2548.24.255.25516,382
1018.25.0.0/188.25.0.1 to 8.25.63.2548.25.63.25516,382
1028.25.64.0/188.25.64.1 to 8.25.127.2548.25.127.25516,382
1038.25.128.0/188.25.128.1 to 8.25.191.2548.25.191.25516,382
1048.25.192.0/188.25.192.1 to 8.25.255.2548.25.255.25516,382
1058.26.0.0/188.26.0.1 to 8.26.63.2548.26.63.25516,382
1068.26.64.0/188.26.64.1 to 8.26.127.2548.26.127.25516,382
1078.26.128.0/188.26.128.1 to 8.26.191.2548.26.191.25516,382
1088.26.192.0/188.26.192.1 to 8.26.255.2548.26.255.25516,382
1098.27.0.0/188.27.0.1 to 8.27.63.2548.27.63.25516,382
1108.27.64.0/188.27.64.1 to 8.27.127.2548.27.127.25516,382
1118.27.128.0/188.27.128.1 to 8.27.191.2548.27.191.25516,382
1128.27.192.0/188.27.192.1 to 8.27.255.2548.27.255.25516,382
1138.28.0.0/188.28.0.1 to 8.28.63.2548.28.63.25516,382
1148.28.64.0/188.28.64.1 to 8.28.127.2548.28.127.25516,382
1158.28.128.0/188.28.128.1 to 8.28.191.2548.28.191.25516,382
1168.28.192.0/188.28.192.1 to 8.28.255.2548.28.255.25516,382
1178.29.0.0/188.29.0.1 to 8.29.63.2548.29.63.25516,382
1188.29.64.0/188.29.64.1 to 8.29.127.2548.29.127.25516,382
1198.29.128.0/188.29.128.1 to 8.29.191.2548.29.191.25516,382
1208.29.192.0/188.29.192.1 to 8.29.255.2548.29.255.25516,382
1218.30.0.0/188.30.0.1 to 8.30.63.2548.30.63.25516,382
1228.30.64.0/188.30.64.1 to 8.30.127.2548.30.127.25516,382
1238.30.128.0/188.30.128.1 to 8.30.191.2548.30.191.25516,382
1248.30.192.0/188.30.192.1 to 8.30.255.2548.30.255.25516,382
1258.31.0.0/188.31.0.1 to 8.31.63.2548.31.63.25516,382
1268.31.64.0/188.31.64.1 to 8.31.127.2548.31.127.25516,382
1278.31.128.0/188.31.128.1 to 8.31.191.2548.31.191.25516,382
1288.31.192.0/188.31.192.1 to 8.31.255.2548.31.255.25516,382
1298.32.0.0/188.32.0.1 to 8.32.63.2548.32.63.25516,382
1308.32.64.0/188.32.64.1 to 8.32.127.2548.32.127.25516,382
1318.32.128.0/188.32.128.1 to 8.32.191.2548.32.191.25516,382
1328.32.192.0/188.32.192.1 to 8.32.255.2548.32.255.25516,382
1338.33.0.0/188.33.0.1 to 8.33.63.2548.33.63.25516,382
1348.33.64.0/188.33.64.1 to 8.33.127.2548.33.127.25516,382
1358.33.128.0/188.33.128.1 to 8.33.191.2548.33.191.25516,382
1368.33.192.0/188.33.192.1 to 8.33.255.2548.33.255.25516,382
1378.34.0.0/188.34.0.1 to 8.34.63.2548.34.63.25516,382
1388.34.64.0/188.34.64.1 to 8.34.127.2548.34.127.25516,382
1398.34.128.0/188.34.128.1 to 8.34.191.2548.34.191.25516,382
1408.34.192.0/188.34.192.1 to 8.34.255.2548.34.255.25516,382
1418.35.0.0/188.35.0.1 to 8.35.63.2548.35.63.25516,382
1428.35.64.0/188.35.64.1 to 8.35.127.2548.35.127.25516,382
1438.35.128.0/188.35.128.1 to 8.35.191.2548.35.191.25516,382
1448.35.192.0/188.35.192.1 to 8.35.255.2548.35.255.25516,382
1458.36.0.0/188.36.0.1 to 8.36.63.2548.36.63.25516,382
1468.36.64.0/188.36.64.1 to 8.36.127.2548.36.127.25516,382
1478.36.128.0/188.36.128.1 to 8.36.191.2548.36.191.25516,382
1488.36.192.0/188.36.192.1 to 8.36.255.2548.36.255.25516,382
1498.37.0.0/188.37.0.1 to 8.37.63.2548.37.63.25516,382
1508.37.64.0/188.37.64.1 to 8.37.127.2548.37.127.25516,382
1518.37.128.0/188.37.128.1 to 8.37.191.2548.37.191.25516,382
1528.37.192.0/188.37.192.1 to 8.37.255.2548.37.255.25516,382
1538.38.0.0/188.38.0.1 to 8.38.63.2548.38.63.25516,382
1548.38.64.0/188.38.64.1 to 8.38.127.2548.38.127.25516,382
1558.38.128.0/188.38.128.1 to 8.38.191.2548.38.191.25516,382
1568.38.192.0/188.38.192.1 to 8.38.255.2548.38.255.25516,382
1578.39.0.0/188.39.0.1 to 8.39.63.2548.39.63.25516,382
1588.39.64.0/188.39.64.1 to 8.39.127.2548.39.127.25516,382
1598.39.128.0/188.39.128.1 to 8.39.191.2548.39.191.25516,382
1608.39.192.0/188.39.192.1 to 8.39.255.2548.39.255.25516,382
1618.40.0.0/188.40.0.1 to 8.40.63.2548.40.63.25516,382
1628.40.64.0/188.40.64.1 to 8.40.127.2548.40.127.25516,382
1638.40.128.0/188.40.128.1 to 8.40.191.2548.40.191.25516,382
1648.40.192.0/188.40.192.1 to 8.40.255.2548.40.255.25516,382
1658.41.0.0/188.41.0.1 to 8.41.63.2548.41.63.25516,382
1668.41.64.0/188.41.64.1 to 8.41.127.2548.41.127.25516,382
1678.41.128.0/188.41.128.1 to 8.41.191.2548.41.191.25516,382
1688.41.192.0/188.41.192.1 to 8.41.255.2548.41.255.25516,382
1698.42.0.0/188.42.0.1 to 8.42.63.2548.42.63.25516,382
1708.42.64.0/188.42.64.1 to 8.42.127.2548.42.127.25516,382
1718.42.128.0/188.42.128.1 to 8.42.191.2548.42.191.25516,382
1728.42.192.0/188.42.192.1 to 8.42.255.2548.42.255.25516,382
1738.43.0.0/188.43.0.1 to 8.43.63.2548.43.63.25516,382
1748.43.64.0/188.43.64.1 to 8.43.127.2548.43.127.25516,382
1758.43.128.0/188.43.128.1 to 8.43.191.2548.43.191.25516,382
1768.43.192.0/188.43.192.1 to 8.43.255.2548.43.255.25516,382
1778.44.0.0/188.44.0.1 to 8.44.63.2548.44.63.25516,382
1788.44.64.0/188.44.64.1 to 8.44.127.2548.44.127.25516,382
1798.44.128.0/188.44.128.1 to 8.44.191.2548.44.191.25516,382
1808.44.192.0/188.44.192.1 to 8.44.255.2548.44.255.25516,382
1818.45.0.0/188.45.0.1 to 8.45.63.2548.45.63.25516,382
1828.45.64.0/188.45.64.1 to 8.45.127.2548.45.127.25516,382
1838.45.128.0/188.45.128.1 to 8.45.191.2548.45.191.25516,382
1848.45.192.0/188.45.192.1 to 8.45.255.2548.45.255.25516,382
1858.46.0.0/188.46.0.1 to 8.46.63.2548.46.63.25516,382
1868.46.64.0/188.46.64.1 to 8.46.127.2548.46.127.25516,382
1878.46.128.0/188.46.128.1 to 8.46.191.2548.46.191.25516,382
1888.46.192.0/188.46.192.1 to 8.46.255.2548.46.255.25516,382
1898.47.0.0/188.47.0.1 to 8.47.63.2548.47.63.25516,382
1908.47.64.0/188.47.64.1 to 8.47.127.2548.47.127.25516,382
1918.47.128.0/188.47.128.1 to 8.47.191.2548.47.191.25516,382
1928.47.192.0/188.47.192.1 to 8.47.255.2548.47.255.25516,382
1938.48.0.0/188.48.0.1 to 8.48.63.2548.48.63.25516,382
1948.48.64.0/188.48.64.1 to 8.48.127.2548.48.127.25516,382
1958.48.128.0/188.48.128.1 to 8.48.191.2548.48.191.25516,382
1968.48.192.0/188.48.192.1 to 8.48.255.2548.48.255.25516,382
1978.49.0.0/188.49.0.1 to 8.49.63.2548.49.63.25516,382
1988.49.64.0/188.49.64.1 to 8.49.127.2548.49.127.25516,382
1998.49.128.0/188.49.128.1 to 8.49.191.2548.49.191.25516,382
2008.49.192.0/188.49.192.1 to 8.49.255.2548.49.255.25516,382
2018.50.0.0/188.50.0.1 to 8.50.63.2548.50.63.25516,382
2028.50.64.0/188.50.64.1 to 8.50.127.2548.50.127.25516,382
2038.50.128.0/188.50.128.1 to 8.50.191.2548.50.191.25516,382
2048.50.192.0/188.50.192.1 to 8.50.255.2548.50.255.25516,382
2058.51.0.0/188.51.0.1 to 8.51.63.2548.51.63.25516,382
2068.51.64.0/188.51.64.1 to 8.51.127.2548.51.127.25516,382
2078.51.128.0/188.51.128.1 to 8.51.191.2548.51.191.25516,382
2088.51.192.0/188.51.192.1 to 8.51.255.2548.51.255.25516,382
2098.52.0.0/188.52.0.1 to 8.52.63.2548.52.63.25516,382
2108.52.64.0/188.52.64.1 to 8.52.127.2548.52.127.25516,382
2118.52.128.0/188.52.128.1 to 8.52.191.2548.52.191.25516,382
2128.52.192.0/188.52.192.1 to 8.52.255.2548.52.255.25516,382
2138.53.0.0/188.53.0.1 to 8.53.63.2548.53.63.25516,382
2148.53.64.0/188.53.64.1 to 8.53.127.2548.53.127.25516,382
2158.53.128.0/188.53.128.1 to 8.53.191.2548.53.191.25516,382
2168.53.192.0/188.53.192.1 to 8.53.255.2548.53.255.25516,382
2178.54.0.0/188.54.0.1 to 8.54.63.2548.54.63.25516,382
2188.54.64.0/188.54.64.1 to 8.54.127.2548.54.127.25516,382
2198.54.128.0/188.54.128.1 to 8.54.191.2548.54.191.25516,382
2208.54.192.0/188.54.192.1 to 8.54.255.2548.54.255.25516,382
2218.55.0.0/188.55.0.1 to 8.55.63.2548.55.63.25516,382
2228.55.64.0/188.55.64.1 to 8.55.127.2548.55.127.25516,382
2238.55.128.0/188.55.128.1 to 8.55.191.2548.55.191.25516,382
2248.55.192.0/188.55.192.1 to 8.55.255.2548.55.255.25516,382
2258.56.0.0/188.56.0.1 to 8.56.63.2548.56.63.25516,382
2268.56.64.0/188.56.64.1 to 8.56.127.2548.56.127.25516,382
2278.56.128.0/188.56.128.1 to 8.56.191.2548.56.191.25516,382
2288.56.192.0/188.56.192.1 to 8.56.255.2548.56.255.25516,382
2298.57.0.0/188.57.0.1 to 8.57.63.2548.57.63.25516,382
2308.57.64.0/188.57.64.1 to 8.57.127.2548.57.127.25516,382
2318.57.128.0/188.57.128.1 to 8.57.191.2548.57.191.25516,382
2328.57.192.0/188.57.192.1 to 8.57.255.2548.57.255.25516,382
2338.58.0.0/188.58.0.1 to 8.58.63.2548.58.63.25516,382
2348.58.64.0/188.58.64.1 to 8.58.127.2548.58.127.25516,382
2358.58.128.0/188.58.128.1 to 8.58.191.2548.58.191.25516,382
2368.58.192.0/188.58.192.1 to 8.58.255.2548.58.255.25516,382
2378.59.0.0/188.59.0.1 to 8.59.63.2548.59.63.25516,382
2388.59.64.0/188.59.64.1 to 8.59.127.2548.59.127.25516,382
2398.59.128.0/188.59.128.1 to 8.59.191.2548.59.191.25516,382
2408.59.192.0/188.59.192.1 to 8.59.255.2548.59.255.25516,382
2418.60.0.0/188.60.0.1 to 8.60.63.2548.60.63.25516,382
2428.60.64.0/188.60.64.1 to 8.60.127.2548.60.127.25516,382
2438.60.128.0/188.60.128.1 to 8.60.191.2548.60.191.25516,382
2448.60.192.0/188.60.192.1 to 8.60.255.2548.60.255.25516,382
2458.61.0.0/188.61.0.1 to 8.61.63.2548.61.63.25516,382
2468.61.64.0/188.61.64.1 to 8.61.127.2548.61.127.25516,382
2478.61.128.0/188.61.128.1 to 8.61.191.2548.61.191.25516,382
2488.61.192.0/188.61.192.1 to 8.61.255.2548.61.255.25516,382
2498.62.0.0/188.62.0.1 to 8.62.63.2548.62.63.25516,382
2508.62.64.0/188.62.64.1 to 8.62.127.2548.62.127.25516,382
2518.62.128.0/188.62.128.1 to 8.62.191.2548.62.191.25516,382
2528.62.192.0/188.62.192.1 to 8.62.255.2548.62.255.25516,382
2538.63.0.0/188.63.0.1 to 8.63.63.2548.63.63.25516,382
2548.63.64.0/188.63.64.1 to 8.63.127.2548.63.127.25516,382
2558.63.128.0/188.63.128.1 to 8.63.191.2548.63.191.25516,382
2568.63.192.0/188.63.192.1 to 8.63.255.2548.63.255.25516,382

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.