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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.

Network4.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
4.0.0.0
Broadcast address
5.255.255.255
First usable
4.0.0.1
Last usable
5.255.255.254
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 04000000 · Integer 67108864 to 100663295
Reverse DNS zones
4.in-addr.arpa
5.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
Address00000100.00000000.00000000.000000004.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000100.00000000.00000000.000000004.0.0.0
Broadcast00000101.11111111.11111111.111111115.255.255.255
Split into smaller subnets/18
/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)

4.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.0.0.0/184.0.0.1 to 4.0.63.2544.0.63.25516,382
24.0.64.0/184.0.64.1 to 4.0.127.2544.0.127.25516,382
34.0.128.0/184.0.128.1 to 4.0.191.2544.0.191.25516,382
44.0.192.0/184.0.192.1 to 4.0.255.2544.0.255.25516,382
54.1.0.0/184.1.0.1 to 4.1.63.2544.1.63.25516,382
64.1.64.0/184.1.64.1 to 4.1.127.2544.1.127.25516,382
74.1.128.0/184.1.128.1 to 4.1.191.2544.1.191.25516,382
84.1.192.0/184.1.192.1 to 4.1.255.2544.1.255.25516,382
94.2.0.0/184.2.0.1 to 4.2.63.2544.2.63.25516,382
104.2.64.0/184.2.64.1 to 4.2.127.2544.2.127.25516,382
114.2.128.0/184.2.128.1 to 4.2.191.2544.2.191.25516,382
124.2.192.0/184.2.192.1 to 4.2.255.2544.2.255.25516,382
134.3.0.0/184.3.0.1 to 4.3.63.2544.3.63.25516,382
144.3.64.0/184.3.64.1 to 4.3.127.2544.3.127.25516,382
154.3.128.0/184.3.128.1 to 4.3.191.2544.3.191.25516,382
164.3.192.0/184.3.192.1 to 4.3.255.2544.3.255.25516,382
174.4.0.0/184.4.0.1 to 4.4.63.2544.4.63.25516,382
184.4.64.0/184.4.64.1 to 4.4.127.2544.4.127.25516,382
194.4.128.0/184.4.128.1 to 4.4.191.2544.4.191.25516,382
204.4.192.0/184.4.192.1 to 4.4.255.2544.4.255.25516,382
214.5.0.0/184.5.0.1 to 4.5.63.2544.5.63.25516,382
224.5.64.0/184.5.64.1 to 4.5.127.2544.5.127.25516,382
234.5.128.0/184.5.128.1 to 4.5.191.2544.5.191.25516,382
244.5.192.0/184.5.192.1 to 4.5.255.2544.5.255.25516,382
254.6.0.0/184.6.0.1 to 4.6.63.2544.6.63.25516,382
264.6.64.0/184.6.64.1 to 4.6.127.2544.6.127.25516,382
274.6.128.0/184.6.128.1 to 4.6.191.2544.6.191.25516,382
284.6.192.0/184.6.192.1 to 4.6.255.2544.6.255.25516,382
294.7.0.0/184.7.0.1 to 4.7.63.2544.7.63.25516,382
304.7.64.0/184.7.64.1 to 4.7.127.2544.7.127.25516,382
314.7.128.0/184.7.128.1 to 4.7.191.2544.7.191.25516,382
324.7.192.0/184.7.192.1 to 4.7.255.2544.7.255.25516,382
334.8.0.0/184.8.0.1 to 4.8.63.2544.8.63.25516,382
344.8.64.0/184.8.64.1 to 4.8.127.2544.8.127.25516,382
354.8.128.0/184.8.128.1 to 4.8.191.2544.8.191.25516,382
364.8.192.0/184.8.192.1 to 4.8.255.2544.8.255.25516,382
374.9.0.0/184.9.0.1 to 4.9.63.2544.9.63.25516,382
384.9.64.0/184.9.64.1 to 4.9.127.2544.9.127.25516,382
394.9.128.0/184.9.128.1 to 4.9.191.2544.9.191.25516,382
404.9.192.0/184.9.192.1 to 4.9.255.2544.9.255.25516,382
414.10.0.0/184.10.0.1 to 4.10.63.2544.10.63.25516,382
424.10.64.0/184.10.64.1 to 4.10.127.2544.10.127.25516,382
434.10.128.0/184.10.128.1 to 4.10.191.2544.10.191.25516,382
444.10.192.0/184.10.192.1 to 4.10.255.2544.10.255.25516,382
454.11.0.0/184.11.0.1 to 4.11.63.2544.11.63.25516,382
464.11.64.0/184.11.64.1 to 4.11.127.2544.11.127.25516,382
474.11.128.0/184.11.128.1 to 4.11.191.2544.11.191.25516,382
484.11.192.0/184.11.192.1 to 4.11.255.2544.11.255.25516,382
494.12.0.0/184.12.0.1 to 4.12.63.2544.12.63.25516,382
504.12.64.0/184.12.64.1 to 4.12.127.2544.12.127.25516,382
514.12.128.0/184.12.128.1 to 4.12.191.2544.12.191.25516,382
524.12.192.0/184.12.192.1 to 4.12.255.2544.12.255.25516,382
534.13.0.0/184.13.0.1 to 4.13.63.2544.13.63.25516,382
544.13.64.0/184.13.64.1 to 4.13.127.2544.13.127.25516,382
554.13.128.0/184.13.128.1 to 4.13.191.2544.13.191.25516,382
564.13.192.0/184.13.192.1 to 4.13.255.2544.13.255.25516,382
574.14.0.0/184.14.0.1 to 4.14.63.2544.14.63.25516,382
584.14.64.0/184.14.64.1 to 4.14.127.2544.14.127.25516,382
594.14.128.0/184.14.128.1 to 4.14.191.2544.14.191.25516,382
604.14.192.0/184.14.192.1 to 4.14.255.2544.14.255.25516,382
614.15.0.0/184.15.0.1 to 4.15.63.2544.15.63.25516,382
624.15.64.0/184.15.64.1 to 4.15.127.2544.15.127.25516,382
634.15.128.0/184.15.128.1 to 4.15.191.2544.15.191.25516,382
644.15.192.0/184.15.192.1 to 4.15.255.2544.15.255.25516,382
654.16.0.0/184.16.0.1 to 4.16.63.2544.16.63.25516,382
664.16.64.0/184.16.64.1 to 4.16.127.2544.16.127.25516,382
674.16.128.0/184.16.128.1 to 4.16.191.2544.16.191.25516,382
684.16.192.0/184.16.192.1 to 4.16.255.2544.16.255.25516,382
694.17.0.0/184.17.0.1 to 4.17.63.2544.17.63.25516,382
704.17.64.0/184.17.64.1 to 4.17.127.2544.17.127.25516,382
714.17.128.0/184.17.128.1 to 4.17.191.2544.17.191.25516,382
724.17.192.0/184.17.192.1 to 4.17.255.2544.17.255.25516,382
734.18.0.0/184.18.0.1 to 4.18.63.2544.18.63.25516,382
744.18.64.0/184.18.64.1 to 4.18.127.2544.18.127.25516,382
754.18.128.0/184.18.128.1 to 4.18.191.2544.18.191.25516,382
764.18.192.0/184.18.192.1 to 4.18.255.2544.18.255.25516,382
774.19.0.0/184.19.0.1 to 4.19.63.2544.19.63.25516,382
784.19.64.0/184.19.64.1 to 4.19.127.2544.19.127.25516,382
794.19.128.0/184.19.128.1 to 4.19.191.2544.19.191.25516,382
804.19.192.0/184.19.192.1 to 4.19.255.2544.19.255.25516,382
814.20.0.0/184.20.0.1 to 4.20.63.2544.20.63.25516,382
824.20.64.0/184.20.64.1 to 4.20.127.2544.20.127.25516,382
834.20.128.0/184.20.128.1 to 4.20.191.2544.20.191.25516,382
844.20.192.0/184.20.192.1 to 4.20.255.2544.20.255.25516,382
854.21.0.0/184.21.0.1 to 4.21.63.2544.21.63.25516,382
864.21.64.0/184.21.64.1 to 4.21.127.2544.21.127.25516,382
874.21.128.0/184.21.128.1 to 4.21.191.2544.21.191.25516,382
884.21.192.0/184.21.192.1 to 4.21.255.2544.21.255.25516,382
894.22.0.0/184.22.0.1 to 4.22.63.2544.22.63.25516,382
904.22.64.0/184.22.64.1 to 4.22.127.2544.22.127.25516,382
914.22.128.0/184.22.128.1 to 4.22.191.2544.22.191.25516,382
924.22.192.0/184.22.192.1 to 4.22.255.2544.22.255.25516,382
934.23.0.0/184.23.0.1 to 4.23.63.2544.23.63.25516,382
944.23.64.0/184.23.64.1 to 4.23.127.2544.23.127.25516,382
954.23.128.0/184.23.128.1 to 4.23.191.2544.23.191.25516,382
964.23.192.0/184.23.192.1 to 4.23.255.2544.23.255.25516,382
974.24.0.0/184.24.0.1 to 4.24.63.2544.24.63.25516,382
984.24.64.0/184.24.64.1 to 4.24.127.2544.24.127.25516,382
994.24.128.0/184.24.128.1 to 4.24.191.2544.24.191.25516,382
1004.24.192.0/184.24.192.1 to 4.24.255.2544.24.255.25516,382
1014.25.0.0/184.25.0.1 to 4.25.63.2544.25.63.25516,382
1024.25.64.0/184.25.64.1 to 4.25.127.2544.25.127.25516,382
1034.25.128.0/184.25.128.1 to 4.25.191.2544.25.191.25516,382
1044.25.192.0/184.25.192.1 to 4.25.255.2544.25.255.25516,382
1054.26.0.0/184.26.0.1 to 4.26.63.2544.26.63.25516,382
1064.26.64.0/184.26.64.1 to 4.26.127.2544.26.127.25516,382
1074.26.128.0/184.26.128.1 to 4.26.191.2544.26.191.25516,382
1084.26.192.0/184.26.192.1 to 4.26.255.2544.26.255.25516,382
1094.27.0.0/184.27.0.1 to 4.27.63.2544.27.63.25516,382
1104.27.64.0/184.27.64.1 to 4.27.127.2544.27.127.25516,382
1114.27.128.0/184.27.128.1 to 4.27.191.2544.27.191.25516,382
1124.27.192.0/184.27.192.1 to 4.27.255.2544.27.255.25516,382
1134.28.0.0/184.28.0.1 to 4.28.63.2544.28.63.25516,382
1144.28.64.0/184.28.64.1 to 4.28.127.2544.28.127.25516,382
1154.28.128.0/184.28.128.1 to 4.28.191.2544.28.191.25516,382
1164.28.192.0/184.28.192.1 to 4.28.255.2544.28.255.25516,382
1174.29.0.0/184.29.0.1 to 4.29.63.2544.29.63.25516,382
1184.29.64.0/184.29.64.1 to 4.29.127.2544.29.127.25516,382
1194.29.128.0/184.29.128.1 to 4.29.191.2544.29.191.25516,382
1204.29.192.0/184.29.192.1 to 4.29.255.2544.29.255.25516,382
1214.30.0.0/184.30.0.1 to 4.30.63.2544.30.63.25516,382
1224.30.64.0/184.30.64.1 to 4.30.127.2544.30.127.25516,382
1234.30.128.0/184.30.128.1 to 4.30.191.2544.30.191.25516,382
1244.30.192.0/184.30.192.1 to 4.30.255.2544.30.255.25516,382
1254.31.0.0/184.31.0.1 to 4.31.63.2544.31.63.25516,382
1264.31.64.0/184.31.64.1 to 4.31.127.2544.31.127.25516,382
1274.31.128.0/184.31.128.1 to 4.31.191.2544.31.191.25516,382
1284.31.192.0/184.31.192.1 to 4.31.255.2544.31.255.25516,382
1294.32.0.0/184.32.0.1 to 4.32.63.2544.32.63.25516,382
1304.32.64.0/184.32.64.1 to 4.32.127.2544.32.127.25516,382
1314.32.128.0/184.32.128.1 to 4.32.191.2544.32.191.25516,382
1324.32.192.0/184.32.192.1 to 4.32.255.2544.32.255.25516,382
1334.33.0.0/184.33.0.1 to 4.33.63.2544.33.63.25516,382
1344.33.64.0/184.33.64.1 to 4.33.127.2544.33.127.25516,382
1354.33.128.0/184.33.128.1 to 4.33.191.2544.33.191.25516,382
1364.33.192.0/184.33.192.1 to 4.33.255.2544.33.255.25516,382
1374.34.0.0/184.34.0.1 to 4.34.63.2544.34.63.25516,382
1384.34.64.0/184.34.64.1 to 4.34.127.2544.34.127.25516,382
1394.34.128.0/184.34.128.1 to 4.34.191.2544.34.191.25516,382
1404.34.192.0/184.34.192.1 to 4.34.255.2544.34.255.25516,382
1414.35.0.0/184.35.0.1 to 4.35.63.2544.35.63.25516,382
1424.35.64.0/184.35.64.1 to 4.35.127.2544.35.127.25516,382
1434.35.128.0/184.35.128.1 to 4.35.191.2544.35.191.25516,382
1444.35.192.0/184.35.192.1 to 4.35.255.2544.35.255.25516,382
1454.36.0.0/184.36.0.1 to 4.36.63.2544.36.63.25516,382
1464.36.64.0/184.36.64.1 to 4.36.127.2544.36.127.25516,382
1474.36.128.0/184.36.128.1 to 4.36.191.2544.36.191.25516,382
1484.36.192.0/184.36.192.1 to 4.36.255.2544.36.255.25516,382
1494.37.0.0/184.37.0.1 to 4.37.63.2544.37.63.25516,382
1504.37.64.0/184.37.64.1 to 4.37.127.2544.37.127.25516,382
1514.37.128.0/184.37.128.1 to 4.37.191.2544.37.191.25516,382
1524.37.192.0/184.37.192.1 to 4.37.255.2544.37.255.25516,382
1534.38.0.0/184.38.0.1 to 4.38.63.2544.38.63.25516,382
1544.38.64.0/184.38.64.1 to 4.38.127.2544.38.127.25516,382
1554.38.128.0/184.38.128.1 to 4.38.191.2544.38.191.25516,382
1564.38.192.0/184.38.192.1 to 4.38.255.2544.38.255.25516,382
1574.39.0.0/184.39.0.1 to 4.39.63.2544.39.63.25516,382
1584.39.64.0/184.39.64.1 to 4.39.127.2544.39.127.25516,382
1594.39.128.0/184.39.128.1 to 4.39.191.2544.39.191.25516,382
1604.39.192.0/184.39.192.1 to 4.39.255.2544.39.255.25516,382
1614.40.0.0/184.40.0.1 to 4.40.63.2544.40.63.25516,382
1624.40.64.0/184.40.64.1 to 4.40.127.2544.40.127.25516,382
1634.40.128.0/184.40.128.1 to 4.40.191.2544.40.191.25516,382
1644.40.192.0/184.40.192.1 to 4.40.255.2544.40.255.25516,382
1654.41.0.0/184.41.0.1 to 4.41.63.2544.41.63.25516,382
1664.41.64.0/184.41.64.1 to 4.41.127.2544.41.127.25516,382
1674.41.128.0/184.41.128.1 to 4.41.191.2544.41.191.25516,382
1684.41.192.0/184.41.192.1 to 4.41.255.2544.41.255.25516,382
1694.42.0.0/184.42.0.1 to 4.42.63.2544.42.63.25516,382
1704.42.64.0/184.42.64.1 to 4.42.127.2544.42.127.25516,382
1714.42.128.0/184.42.128.1 to 4.42.191.2544.42.191.25516,382
1724.42.192.0/184.42.192.1 to 4.42.255.2544.42.255.25516,382
1734.43.0.0/184.43.0.1 to 4.43.63.2544.43.63.25516,382
1744.43.64.0/184.43.64.1 to 4.43.127.2544.43.127.25516,382
1754.43.128.0/184.43.128.1 to 4.43.191.2544.43.191.25516,382
1764.43.192.0/184.43.192.1 to 4.43.255.2544.43.255.25516,382
1774.44.0.0/184.44.0.1 to 4.44.63.2544.44.63.25516,382
1784.44.64.0/184.44.64.1 to 4.44.127.2544.44.127.25516,382
1794.44.128.0/184.44.128.1 to 4.44.191.2544.44.191.25516,382
1804.44.192.0/184.44.192.1 to 4.44.255.2544.44.255.25516,382
1814.45.0.0/184.45.0.1 to 4.45.63.2544.45.63.25516,382
1824.45.64.0/184.45.64.1 to 4.45.127.2544.45.127.25516,382
1834.45.128.0/184.45.128.1 to 4.45.191.2544.45.191.25516,382
1844.45.192.0/184.45.192.1 to 4.45.255.2544.45.255.25516,382
1854.46.0.0/184.46.0.1 to 4.46.63.2544.46.63.25516,382
1864.46.64.0/184.46.64.1 to 4.46.127.2544.46.127.25516,382
1874.46.128.0/184.46.128.1 to 4.46.191.2544.46.191.25516,382
1884.46.192.0/184.46.192.1 to 4.46.255.2544.46.255.25516,382
1894.47.0.0/184.47.0.1 to 4.47.63.2544.47.63.25516,382
1904.47.64.0/184.47.64.1 to 4.47.127.2544.47.127.25516,382
1914.47.128.0/184.47.128.1 to 4.47.191.2544.47.191.25516,382
1924.47.192.0/184.47.192.1 to 4.47.255.2544.47.255.25516,382
1934.48.0.0/184.48.0.1 to 4.48.63.2544.48.63.25516,382
1944.48.64.0/184.48.64.1 to 4.48.127.2544.48.127.25516,382
1954.48.128.0/184.48.128.1 to 4.48.191.2544.48.191.25516,382
1964.48.192.0/184.48.192.1 to 4.48.255.2544.48.255.25516,382
1974.49.0.0/184.49.0.1 to 4.49.63.2544.49.63.25516,382
1984.49.64.0/184.49.64.1 to 4.49.127.2544.49.127.25516,382
1994.49.128.0/184.49.128.1 to 4.49.191.2544.49.191.25516,382
2004.49.192.0/184.49.192.1 to 4.49.255.2544.49.255.25516,382
2014.50.0.0/184.50.0.1 to 4.50.63.2544.50.63.25516,382
2024.50.64.0/184.50.64.1 to 4.50.127.2544.50.127.25516,382
2034.50.128.0/184.50.128.1 to 4.50.191.2544.50.191.25516,382
2044.50.192.0/184.50.192.1 to 4.50.255.2544.50.255.25516,382
2054.51.0.0/184.51.0.1 to 4.51.63.2544.51.63.25516,382
2064.51.64.0/184.51.64.1 to 4.51.127.2544.51.127.25516,382
2074.51.128.0/184.51.128.1 to 4.51.191.2544.51.191.25516,382
2084.51.192.0/184.51.192.1 to 4.51.255.2544.51.255.25516,382
2094.52.0.0/184.52.0.1 to 4.52.63.2544.52.63.25516,382
2104.52.64.0/184.52.64.1 to 4.52.127.2544.52.127.25516,382
2114.52.128.0/184.52.128.1 to 4.52.191.2544.52.191.25516,382
2124.52.192.0/184.52.192.1 to 4.52.255.2544.52.255.25516,382
2134.53.0.0/184.53.0.1 to 4.53.63.2544.53.63.25516,382
2144.53.64.0/184.53.64.1 to 4.53.127.2544.53.127.25516,382
2154.53.128.0/184.53.128.1 to 4.53.191.2544.53.191.25516,382
2164.53.192.0/184.53.192.1 to 4.53.255.2544.53.255.25516,382
2174.54.0.0/184.54.0.1 to 4.54.63.2544.54.63.25516,382
2184.54.64.0/184.54.64.1 to 4.54.127.2544.54.127.25516,382
2194.54.128.0/184.54.128.1 to 4.54.191.2544.54.191.25516,382
2204.54.192.0/184.54.192.1 to 4.54.255.2544.54.255.25516,382
2214.55.0.0/184.55.0.1 to 4.55.63.2544.55.63.25516,382
2224.55.64.0/184.55.64.1 to 4.55.127.2544.55.127.25516,382
2234.55.128.0/184.55.128.1 to 4.55.191.2544.55.191.25516,382
2244.55.192.0/184.55.192.1 to 4.55.255.2544.55.255.25516,382
2254.56.0.0/184.56.0.1 to 4.56.63.2544.56.63.25516,382
2264.56.64.0/184.56.64.1 to 4.56.127.2544.56.127.25516,382
2274.56.128.0/184.56.128.1 to 4.56.191.2544.56.191.25516,382
2284.56.192.0/184.56.192.1 to 4.56.255.2544.56.255.25516,382
2294.57.0.0/184.57.0.1 to 4.57.63.2544.57.63.25516,382
2304.57.64.0/184.57.64.1 to 4.57.127.2544.57.127.25516,382
2314.57.128.0/184.57.128.1 to 4.57.191.2544.57.191.25516,382
2324.57.192.0/184.57.192.1 to 4.57.255.2544.57.255.25516,382
2334.58.0.0/184.58.0.1 to 4.58.63.2544.58.63.25516,382
2344.58.64.0/184.58.64.1 to 4.58.127.2544.58.127.25516,382
2354.58.128.0/184.58.128.1 to 4.58.191.2544.58.191.25516,382
2364.58.192.0/184.58.192.1 to 4.58.255.2544.58.255.25516,382
2374.59.0.0/184.59.0.1 to 4.59.63.2544.59.63.25516,382
2384.59.64.0/184.59.64.1 to 4.59.127.2544.59.127.25516,382
2394.59.128.0/184.59.128.1 to 4.59.191.2544.59.191.25516,382
2404.59.192.0/184.59.192.1 to 4.59.255.2544.59.255.25516,382
2414.60.0.0/184.60.0.1 to 4.60.63.2544.60.63.25516,382
2424.60.64.0/184.60.64.1 to 4.60.127.2544.60.127.25516,382
2434.60.128.0/184.60.128.1 to 4.60.191.2544.60.191.25516,382
2444.60.192.0/184.60.192.1 to 4.60.255.2544.60.255.25516,382
2454.61.0.0/184.61.0.1 to 4.61.63.2544.61.63.25516,382
2464.61.64.0/184.61.64.1 to 4.61.127.2544.61.127.25516,382
2474.61.128.0/184.61.128.1 to 4.61.191.2544.61.191.25516,382
2484.61.192.0/184.61.192.1 to 4.61.255.2544.61.255.25516,382
2494.62.0.0/184.62.0.1 to 4.62.63.2544.62.63.25516,382
2504.62.64.0/184.62.64.1 to 4.62.127.2544.62.127.25516,382
2514.62.128.0/184.62.128.1 to 4.62.191.2544.62.191.25516,382
2524.62.192.0/184.62.192.1 to 4.62.255.2544.62.255.25516,382
2534.63.0.0/184.63.0.1 to 4.63.63.2544.63.63.25516,382
2544.63.64.0/184.63.64.1 to 4.63.127.2544.63.127.25516,382
2554.63.128.0/184.63.128.1 to 4.63.191.2544.63.191.25516,382
2564.63.192.0/184.63.192.1 to 4.63.255.2544.63.255.25516,382

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.