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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.

Network4.136.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
4.136.0.0
Broadcast address
4.136.255.255
First usable
4.136.0.1
Last usable
4.136.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 04880000 · Integer 76021760 to 76087295
Reverse DNS zone
136.4.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000100.10001000..00000000.000000004.136.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00000100.10001000..00000000.000000004.136.0.0
Broadcast00000100.10001000..11111111.111111114.136.255.255
Split into smaller subnets/26
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

4.136.0.0/16 makes 1,024 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.136.0.0/264.136.0.1 to 4.136.0.624.136.0.6362
24.136.0.64/264.136.0.65 to 4.136.0.1264.136.0.12762
34.136.0.128/264.136.0.129 to 4.136.0.1904.136.0.19162
44.136.0.192/264.136.0.193 to 4.136.0.2544.136.0.25562
54.136.1.0/264.136.1.1 to 4.136.1.624.136.1.6362
64.136.1.64/264.136.1.65 to 4.136.1.1264.136.1.12762
74.136.1.128/264.136.1.129 to 4.136.1.1904.136.1.19162
84.136.1.192/264.136.1.193 to 4.136.1.2544.136.1.25562
94.136.2.0/264.136.2.1 to 4.136.2.624.136.2.6362
104.136.2.64/264.136.2.65 to 4.136.2.1264.136.2.12762
114.136.2.128/264.136.2.129 to 4.136.2.1904.136.2.19162
124.136.2.192/264.136.2.193 to 4.136.2.2544.136.2.25562
134.136.3.0/264.136.3.1 to 4.136.3.624.136.3.6362
144.136.3.64/264.136.3.65 to 4.136.3.1264.136.3.12762
154.136.3.128/264.136.3.129 to 4.136.3.1904.136.3.19162
164.136.3.192/264.136.3.193 to 4.136.3.2544.136.3.25562
174.136.4.0/264.136.4.1 to 4.136.4.624.136.4.6362
184.136.4.64/264.136.4.65 to 4.136.4.1264.136.4.12762
194.136.4.128/264.136.4.129 to 4.136.4.1904.136.4.19162
204.136.4.192/264.136.4.193 to 4.136.4.2544.136.4.25562
214.136.5.0/264.136.5.1 to 4.136.5.624.136.5.6362
224.136.5.64/264.136.5.65 to 4.136.5.1264.136.5.12762
234.136.5.128/264.136.5.129 to 4.136.5.1904.136.5.19162
244.136.5.192/264.136.5.193 to 4.136.5.2544.136.5.25562
254.136.6.0/264.136.6.1 to 4.136.6.624.136.6.6362
264.136.6.64/264.136.6.65 to 4.136.6.1264.136.6.12762
274.136.6.128/264.136.6.129 to 4.136.6.1904.136.6.19162
284.136.6.192/264.136.6.193 to 4.136.6.2544.136.6.25562
294.136.7.0/264.136.7.1 to 4.136.7.624.136.7.6362
304.136.7.64/264.136.7.65 to 4.136.7.1264.136.7.12762
314.136.7.128/264.136.7.129 to 4.136.7.1904.136.7.19162
324.136.7.192/264.136.7.193 to 4.136.7.2544.136.7.25562
334.136.8.0/264.136.8.1 to 4.136.8.624.136.8.6362
344.136.8.64/264.136.8.65 to 4.136.8.1264.136.8.12762
354.136.8.128/264.136.8.129 to 4.136.8.1904.136.8.19162
364.136.8.192/264.136.8.193 to 4.136.8.2544.136.8.25562
374.136.9.0/264.136.9.1 to 4.136.9.624.136.9.6362
384.136.9.64/264.136.9.65 to 4.136.9.1264.136.9.12762
394.136.9.128/264.136.9.129 to 4.136.9.1904.136.9.19162
404.136.9.192/264.136.9.193 to 4.136.9.2544.136.9.25562
414.136.10.0/264.136.10.1 to 4.136.10.624.136.10.6362
424.136.10.64/264.136.10.65 to 4.136.10.1264.136.10.12762
434.136.10.128/264.136.10.129 to 4.136.10.1904.136.10.19162
444.136.10.192/264.136.10.193 to 4.136.10.2544.136.10.25562
454.136.11.0/264.136.11.1 to 4.136.11.624.136.11.6362
464.136.11.64/264.136.11.65 to 4.136.11.1264.136.11.12762
474.136.11.128/264.136.11.129 to 4.136.11.1904.136.11.19162
484.136.11.192/264.136.11.193 to 4.136.11.2544.136.11.25562
494.136.12.0/264.136.12.1 to 4.136.12.624.136.12.6362
504.136.12.64/264.136.12.65 to 4.136.12.1264.136.12.12762
514.136.12.128/264.136.12.129 to 4.136.12.1904.136.12.19162
524.136.12.192/264.136.12.193 to 4.136.12.2544.136.12.25562
534.136.13.0/264.136.13.1 to 4.136.13.624.136.13.6362
544.136.13.64/264.136.13.65 to 4.136.13.1264.136.13.12762
554.136.13.128/264.136.13.129 to 4.136.13.1904.136.13.19162
564.136.13.192/264.136.13.193 to 4.136.13.2544.136.13.25562
574.136.14.0/264.136.14.1 to 4.136.14.624.136.14.6362
584.136.14.64/264.136.14.65 to 4.136.14.1264.136.14.12762
594.136.14.128/264.136.14.129 to 4.136.14.1904.136.14.19162
604.136.14.192/264.136.14.193 to 4.136.14.2544.136.14.25562
614.136.15.0/264.136.15.1 to 4.136.15.624.136.15.6362
624.136.15.64/264.136.15.65 to 4.136.15.1264.136.15.12762
634.136.15.128/264.136.15.129 to 4.136.15.1904.136.15.19162
644.136.15.192/264.136.15.193 to 4.136.15.2544.136.15.25562
654.136.16.0/264.136.16.1 to 4.136.16.624.136.16.6362
664.136.16.64/264.136.16.65 to 4.136.16.1264.136.16.12762
674.136.16.128/264.136.16.129 to 4.136.16.1904.136.16.19162
684.136.16.192/264.136.16.193 to 4.136.16.2544.136.16.25562
694.136.17.0/264.136.17.1 to 4.136.17.624.136.17.6362
704.136.17.64/264.136.17.65 to 4.136.17.1264.136.17.12762
714.136.17.128/264.136.17.129 to 4.136.17.1904.136.17.19162
724.136.17.192/264.136.17.193 to 4.136.17.2544.136.17.25562
734.136.18.0/264.136.18.1 to 4.136.18.624.136.18.6362
744.136.18.64/264.136.18.65 to 4.136.18.1264.136.18.12762
754.136.18.128/264.136.18.129 to 4.136.18.1904.136.18.19162
764.136.18.192/264.136.18.193 to 4.136.18.2544.136.18.25562
774.136.19.0/264.136.19.1 to 4.136.19.624.136.19.6362
784.136.19.64/264.136.19.65 to 4.136.19.1264.136.19.12762
794.136.19.128/264.136.19.129 to 4.136.19.1904.136.19.19162
804.136.19.192/264.136.19.193 to 4.136.19.2544.136.19.25562
814.136.20.0/264.136.20.1 to 4.136.20.624.136.20.6362
824.136.20.64/264.136.20.65 to 4.136.20.1264.136.20.12762
834.136.20.128/264.136.20.129 to 4.136.20.1904.136.20.19162
844.136.20.192/264.136.20.193 to 4.136.20.2544.136.20.25562
854.136.21.0/264.136.21.1 to 4.136.21.624.136.21.6362
864.136.21.64/264.136.21.65 to 4.136.21.1264.136.21.12762
874.136.21.128/264.136.21.129 to 4.136.21.1904.136.21.19162
884.136.21.192/264.136.21.193 to 4.136.21.2544.136.21.25562
894.136.22.0/264.136.22.1 to 4.136.22.624.136.22.6362
904.136.22.64/264.136.22.65 to 4.136.22.1264.136.22.12762
914.136.22.128/264.136.22.129 to 4.136.22.1904.136.22.19162
924.136.22.192/264.136.22.193 to 4.136.22.2544.136.22.25562
934.136.23.0/264.136.23.1 to 4.136.23.624.136.23.6362
944.136.23.64/264.136.23.65 to 4.136.23.1264.136.23.12762
954.136.23.128/264.136.23.129 to 4.136.23.1904.136.23.19162
964.136.23.192/264.136.23.193 to 4.136.23.2544.136.23.25562
974.136.24.0/264.136.24.1 to 4.136.24.624.136.24.6362
984.136.24.64/264.136.24.65 to 4.136.24.1264.136.24.12762
994.136.24.128/264.136.24.129 to 4.136.24.1904.136.24.19162
1004.136.24.192/264.136.24.193 to 4.136.24.2544.136.24.25562
1014.136.25.0/264.136.25.1 to 4.136.25.624.136.25.6362
1024.136.25.64/264.136.25.65 to 4.136.25.1264.136.25.12762
1034.136.25.128/264.136.25.129 to 4.136.25.1904.136.25.19162
1044.136.25.192/264.136.25.193 to 4.136.25.2544.136.25.25562
1054.136.26.0/264.136.26.1 to 4.136.26.624.136.26.6362
1064.136.26.64/264.136.26.65 to 4.136.26.1264.136.26.12762
1074.136.26.128/264.136.26.129 to 4.136.26.1904.136.26.19162
1084.136.26.192/264.136.26.193 to 4.136.26.2544.136.26.25562
1094.136.27.0/264.136.27.1 to 4.136.27.624.136.27.6362
1104.136.27.64/264.136.27.65 to 4.136.27.1264.136.27.12762
1114.136.27.128/264.136.27.129 to 4.136.27.1904.136.27.19162
1124.136.27.192/264.136.27.193 to 4.136.27.2544.136.27.25562
1134.136.28.0/264.136.28.1 to 4.136.28.624.136.28.6362
1144.136.28.64/264.136.28.65 to 4.136.28.1264.136.28.12762
1154.136.28.128/264.136.28.129 to 4.136.28.1904.136.28.19162
1164.136.28.192/264.136.28.193 to 4.136.28.2544.136.28.25562
1174.136.29.0/264.136.29.1 to 4.136.29.624.136.29.6362
1184.136.29.64/264.136.29.65 to 4.136.29.1264.136.29.12762
1194.136.29.128/264.136.29.129 to 4.136.29.1904.136.29.19162
1204.136.29.192/264.136.29.193 to 4.136.29.2544.136.29.25562
1214.136.30.0/264.136.30.1 to 4.136.30.624.136.30.6362
1224.136.30.64/264.136.30.65 to 4.136.30.1264.136.30.12762
1234.136.30.128/264.136.30.129 to 4.136.30.1904.136.30.19162
1244.136.30.192/264.136.30.193 to 4.136.30.2544.136.30.25562
1254.136.31.0/264.136.31.1 to 4.136.31.624.136.31.6362
1264.136.31.64/264.136.31.65 to 4.136.31.1264.136.31.12762
1274.136.31.128/264.136.31.129 to 4.136.31.1904.136.31.19162
1284.136.31.192/264.136.31.193 to 4.136.31.2544.136.31.25562
1294.136.32.0/264.136.32.1 to 4.136.32.624.136.32.6362
1304.136.32.64/264.136.32.65 to 4.136.32.1264.136.32.12762
1314.136.32.128/264.136.32.129 to 4.136.32.1904.136.32.19162
1324.136.32.192/264.136.32.193 to 4.136.32.2544.136.32.25562
1334.136.33.0/264.136.33.1 to 4.136.33.624.136.33.6362
1344.136.33.64/264.136.33.65 to 4.136.33.1264.136.33.12762
1354.136.33.128/264.136.33.129 to 4.136.33.1904.136.33.19162
1364.136.33.192/264.136.33.193 to 4.136.33.2544.136.33.25562
1374.136.34.0/264.136.34.1 to 4.136.34.624.136.34.6362
1384.136.34.64/264.136.34.65 to 4.136.34.1264.136.34.12762
1394.136.34.128/264.136.34.129 to 4.136.34.1904.136.34.19162
1404.136.34.192/264.136.34.193 to 4.136.34.2544.136.34.25562
1414.136.35.0/264.136.35.1 to 4.136.35.624.136.35.6362
1424.136.35.64/264.136.35.65 to 4.136.35.1264.136.35.12762
1434.136.35.128/264.136.35.129 to 4.136.35.1904.136.35.19162
1444.136.35.192/264.136.35.193 to 4.136.35.2544.136.35.25562
1454.136.36.0/264.136.36.1 to 4.136.36.624.136.36.6362
1464.136.36.64/264.136.36.65 to 4.136.36.1264.136.36.12762
1474.136.36.128/264.136.36.129 to 4.136.36.1904.136.36.19162
1484.136.36.192/264.136.36.193 to 4.136.36.2544.136.36.25562
1494.136.37.0/264.136.37.1 to 4.136.37.624.136.37.6362
1504.136.37.64/264.136.37.65 to 4.136.37.1264.136.37.12762
1514.136.37.128/264.136.37.129 to 4.136.37.1904.136.37.19162
1524.136.37.192/264.136.37.193 to 4.136.37.2544.136.37.25562
1534.136.38.0/264.136.38.1 to 4.136.38.624.136.38.6362
1544.136.38.64/264.136.38.65 to 4.136.38.1264.136.38.12762
1554.136.38.128/264.136.38.129 to 4.136.38.1904.136.38.19162
1564.136.38.192/264.136.38.193 to 4.136.38.2544.136.38.25562
1574.136.39.0/264.136.39.1 to 4.136.39.624.136.39.6362
1584.136.39.64/264.136.39.65 to 4.136.39.1264.136.39.12762
1594.136.39.128/264.136.39.129 to 4.136.39.1904.136.39.19162
1604.136.39.192/264.136.39.193 to 4.136.39.2544.136.39.25562
1614.136.40.0/264.136.40.1 to 4.136.40.624.136.40.6362
1624.136.40.64/264.136.40.65 to 4.136.40.1264.136.40.12762
1634.136.40.128/264.136.40.129 to 4.136.40.1904.136.40.19162
1644.136.40.192/264.136.40.193 to 4.136.40.2544.136.40.25562
1654.136.41.0/264.136.41.1 to 4.136.41.624.136.41.6362
1664.136.41.64/264.136.41.65 to 4.136.41.1264.136.41.12762
1674.136.41.128/264.136.41.129 to 4.136.41.1904.136.41.19162
1684.136.41.192/264.136.41.193 to 4.136.41.2544.136.41.25562
1694.136.42.0/264.136.42.1 to 4.136.42.624.136.42.6362
1704.136.42.64/264.136.42.65 to 4.136.42.1264.136.42.12762
1714.136.42.128/264.136.42.129 to 4.136.42.1904.136.42.19162
1724.136.42.192/264.136.42.193 to 4.136.42.2544.136.42.25562
1734.136.43.0/264.136.43.1 to 4.136.43.624.136.43.6362
1744.136.43.64/264.136.43.65 to 4.136.43.1264.136.43.12762
1754.136.43.128/264.136.43.129 to 4.136.43.1904.136.43.19162
1764.136.43.192/264.136.43.193 to 4.136.43.2544.136.43.25562
1774.136.44.0/264.136.44.1 to 4.136.44.624.136.44.6362
1784.136.44.64/264.136.44.65 to 4.136.44.1264.136.44.12762
1794.136.44.128/264.136.44.129 to 4.136.44.1904.136.44.19162
1804.136.44.192/264.136.44.193 to 4.136.44.2544.136.44.25562
1814.136.45.0/264.136.45.1 to 4.136.45.624.136.45.6362
1824.136.45.64/264.136.45.65 to 4.136.45.1264.136.45.12762
1834.136.45.128/264.136.45.129 to 4.136.45.1904.136.45.19162
1844.136.45.192/264.136.45.193 to 4.136.45.2544.136.45.25562
1854.136.46.0/264.136.46.1 to 4.136.46.624.136.46.6362
1864.136.46.64/264.136.46.65 to 4.136.46.1264.136.46.12762
1874.136.46.128/264.136.46.129 to 4.136.46.1904.136.46.19162
1884.136.46.192/264.136.46.193 to 4.136.46.2544.136.46.25562
1894.136.47.0/264.136.47.1 to 4.136.47.624.136.47.6362
1904.136.47.64/264.136.47.65 to 4.136.47.1264.136.47.12762
1914.136.47.128/264.136.47.129 to 4.136.47.1904.136.47.19162
1924.136.47.192/264.136.47.193 to 4.136.47.2544.136.47.25562
1934.136.48.0/264.136.48.1 to 4.136.48.624.136.48.6362
1944.136.48.64/264.136.48.65 to 4.136.48.1264.136.48.12762
1954.136.48.128/264.136.48.129 to 4.136.48.1904.136.48.19162
1964.136.48.192/264.136.48.193 to 4.136.48.2544.136.48.25562
1974.136.49.0/264.136.49.1 to 4.136.49.624.136.49.6362
1984.136.49.64/264.136.49.65 to 4.136.49.1264.136.49.12762
1994.136.49.128/264.136.49.129 to 4.136.49.1904.136.49.19162
2004.136.49.192/264.136.49.193 to 4.136.49.2544.136.49.25562
2014.136.50.0/264.136.50.1 to 4.136.50.624.136.50.6362
2024.136.50.64/264.136.50.65 to 4.136.50.1264.136.50.12762
2034.136.50.128/264.136.50.129 to 4.136.50.1904.136.50.19162
2044.136.50.192/264.136.50.193 to 4.136.50.2544.136.50.25562
2054.136.51.0/264.136.51.1 to 4.136.51.624.136.51.6362
2064.136.51.64/264.136.51.65 to 4.136.51.1264.136.51.12762
2074.136.51.128/264.136.51.129 to 4.136.51.1904.136.51.19162
2084.136.51.192/264.136.51.193 to 4.136.51.2544.136.51.25562
2094.136.52.0/264.136.52.1 to 4.136.52.624.136.52.6362
2104.136.52.64/264.136.52.65 to 4.136.52.1264.136.52.12762
2114.136.52.128/264.136.52.129 to 4.136.52.1904.136.52.19162
2124.136.52.192/264.136.52.193 to 4.136.52.2544.136.52.25562
2134.136.53.0/264.136.53.1 to 4.136.53.624.136.53.6362
2144.136.53.64/264.136.53.65 to 4.136.53.1264.136.53.12762
2154.136.53.128/264.136.53.129 to 4.136.53.1904.136.53.19162
2164.136.53.192/264.136.53.193 to 4.136.53.2544.136.53.25562
2174.136.54.0/264.136.54.1 to 4.136.54.624.136.54.6362
2184.136.54.64/264.136.54.65 to 4.136.54.1264.136.54.12762
2194.136.54.128/264.136.54.129 to 4.136.54.1904.136.54.19162
2204.136.54.192/264.136.54.193 to 4.136.54.2544.136.54.25562
2214.136.55.0/264.136.55.1 to 4.136.55.624.136.55.6362
2224.136.55.64/264.136.55.65 to 4.136.55.1264.136.55.12762
2234.136.55.128/264.136.55.129 to 4.136.55.1904.136.55.19162
2244.136.55.192/264.136.55.193 to 4.136.55.2544.136.55.25562
2254.136.56.0/264.136.56.1 to 4.136.56.624.136.56.6362
2264.136.56.64/264.136.56.65 to 4.136.56.1264.136.56.12762
2274.136.56.128/264.136.56.129 to 4.136.56.1904.136.56.19162
2284.136.56.192/264.136.56.193 to 4.136.56.2544.136.56.25562
2294.136.57.0/264.136.57.1 to 4.136.57.624.136.57.6362
2304.136.57.64/264.136.57.65 to 4.136.57.1264.136.57.12762
2314.136.57.128/264.136.57.129 to 4.136.57.1904.136.57.19162
2324.136.57.192/264.136.57.193 to 4.136.57.2544.136.57.25562
2334.136.58.0/264.136.58.1 to 4.136.58.624.136.58.6362
2344.136.58.64/264.136.58.65 to 4.136.58.1264.136.58.12762
2354.136.58.128/264.136.58.129 to 4.136.58.1904.136.58.19162
2364.136.58.192/264.136.58.193 to 4.136.58.2544.136.58.25562
2374.136.59.0/264.136.59.1 to 4.136.59.624.136.59.6362
2384.136.59.64/264.136.59.65 to 4.136.59.1264.136.59.12762
2394.136.59.128/264.136.59.129 to 4.136.59.1904.136.59.19162
2404.136.59.192/264.136.59.193 to 4.136.59.2544.136.59.25562
2414.136.60.0/264.136.60.1 to 4.136.60.624.136.60.6362
2424.136.60.64/264.136.60.65 to 4.136.60.1264.136.60.12762
2434.136.60.128/264.136.60.129 to 4.136.60.1904.136.60.19162
2444.136.60.192/264.136.60.193 to 4.136.60.2544.136.60.25562
2454.136.61.0/264.136.61.1 to 4.136.61.624.136.61.6362
2464.136.61.64/264.136.61.65 to 4.136.61.1264.136.61.12762
2474.136.61.128/264.136.61.129 to 4.136.61.1904.136.61.19162
2484.136.61.192/264.136.61.193 to 4.136.61.2544.136.61.25562
2494.136.62.0/264.136.62.1 to 4.136.62.624.136.62.6362
2504.136.62.64/264.136.62.65 to 4.136.62.1264.136.62.12762
2514.136.62.128/264.136.62.129 to 4.136.62.1904.136.62.19162
2524.136.62.192/264.136.62.193 to 4.136.62.2544.136.62.25562
2534.136.63.0/264.136.63.1 to 4.136.63.624.136.63.6362
2544.136.63.64/264.136.63.65 to 4.136.63.1264.136.63.12762
2554.136.63.128/264.136.63.129 to 4.136.63.1904.136.63.19162
2564.136.63.192/264.136.63.193 to 4.136.63.2544.136.63.25562

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.