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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.

Network4.16.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
4.16.0.0
Broadcast address
4.23.255.255
First usable
4.16.0.1
Last usable
4.23.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
A (default /8)
As numbers
Hex 04100000 · Integer 68157440 to 68681727
Reverse DNS zones
16.4.in-addr.arpa
17.4.in-addr.arpa
18.4.in-addr.arpa
19.4.in-addr.arpa
20.4.in-addr.arpa
21.4.in-addr.arpa
22.4.in-addr.arpa
23.4.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000100.00010000.00000000.000000004.16.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network00000100.00010000.00000000.000000004.16.0.0
Broadcast00000100.00010111.11111111.111111114.23.255.255
Split into smaller subnets/25
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

4.16.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
14.16.0.0/254.16.0.1 to 4.16.0.1264.16.0.127126
24.16.0.128/254.16.0.129 to 4.16.0.2544.16.0.255126
34.16.1.0/254.16.1.1 to 4.16.1.1264.16.1.127126
44.16.1.128/254.16.1.129 to 4.16.1.2544.16.1.255126
54.16.2.0/254.16.2.1 to 4.16.2.1264.16.2.127126
64.16.2.128/254.16.2.129 to 4.16.2.2544.16.2.255126
74.16.3.0/254.16.3.1 to 4.16.3.1264.16.3.127126
84.16.3.128/254.16.3.129 to 4.16.3.2544.16.3.255126
94.16.4.0/254.16.4.1 to 4.16.4.1264.16.4.127126
104.16.4.128/254.16.4.129 to 4.16.4.2544.16.4.255126
114.16.5.0/254.16.5.1 to 4.16.5.1264.16.5.127126
124.16.5.128/254.16.5.129 to 4.16.5.2544.16.5.255126
134.16.6.0/254.16.6.1 to 4.16.6.1264.16.6.127126
144.16.6.128/254.16.6.129 to 4.16.6.2544.16.6.255126
154.16.7.0/254.16.7.1 to 4.16.7.1264.16.7.127126
164.16.7.128/254.16.7.129 to 4.16.7.2544.16.7.255126
174.16.8.0/254.16.8.1 to 4.16.8.1264.16.8.127126
184.16.8.128/254.16.8.129 to 4.16.8.2544.16.8.255126
194.16.9.0/254.16.9.1 to 4.16.9.1264.16.9.127126
204.16.9.128/254.16.9.129 to 4.16.9.2544.16.9.255126
214.16.10.0/254.16.10.1 to 4.16.10.1264.16.10.127126
224.16.10.128/254.16.10.129 to 4.16.10.2544.16.10.255126
234.16.11.0/254.16.11.1 to 4.16.11.1264.16.11.127126
244.16.11.128/254.16.11.129 to 4.16.11.2544.16.11.255126
254.16.12.0/254.16.12.1 to 4.16.12.1264.16.12.127126
264.16.12.128/254.16.12.129 to 4.16.12.2544.16.12.255126
274.16.13.0/254.16.13.1 to 4.16.13.1264.16.13.127126
284.16.13.128/254.16.13.129 to 4.16.13.2544.16.13.255126
294.16.14.0/254.16.14.1 to 4.16.14.1264.16.14.127126
304.16.14.128/254.16.14.129 to 4.16.14.2544.16.14.255126
314.16.15.0/254.16.15.1 to 4.16.15.1264.16.15.127126
324.16.15.128/254.16.15.129 to 4.16.15.2544.16.15.255126
334.16.16.0/254.16.16.1 to 4.16.16.1264.16.16.127126
344.16.16.128/254.16.16.129 to 4.16.16.2544.16.16.255126
354.16.17.0/254.16.17.1 to 4.16.17.1264.16.17.127126
364.16.17.128/254.16.17.129 to 4.16.17.2544.16.17.255126
374.16.18.0/254.16.18.1 to 4.16.18.1264.16.18.127126
384.16.18.128/254.16.18.129 to 4.16.18.2544.16.18.255126
394.16.19.0/254.16.19.1 to 4.16.19.1264.16.19.127126
404.16.19.128/254.16.19.129 to 4.16.19.2544.16.19.255126
414.16.20.0/254.16.20.1 to 4.16.20.1264.16.20.127126
424.16.20.128/254.16.20.129 to 4.16.20.2544.16.20.255126
434.16.21.0/254.16.21.1 to 4.16.21.1264.16.21.127126
444.16.21.128/254.16.21.129 to 4.16.21.2544.16.21.255126
454.16.22.0/254.16.22.1 to 4.16.22.1264.16.22.127126
464.16.22.128/254.16.22.129 to 4.16.22.2544.16.22.255126
474.16.23.0/254.16.23.1 to 4.16.23.1264.16.23.127126
484.16.23.128/254.16.23.129 to 4.16.23.2544.16.23.255126
494.16.24.0/254.16.24.1 to 4.16.24.1264.16.24.127126
504.16.24.128/254.16.24.129 to 4.16.24.2544.16.24.255126
514.16.25.0/254.16.25.1 to 4.16.25.1264.16.25.127126
524.16.25.128/254.16.25.129 to 4.16.25.2544.16.25.255126
534.16.26.0/254.16.26.1 to 4.16.26.1264.16.26.127126
544.16.26.128/254.16.26.129 to 4.16.26.2544.16.26.255126
554.16.27.0/254.16.27.1 to 4.16.27.1264.16.27.127126
564.16.27.128/254.16.27.129 to 4.16.27.2544.16.27.255126
574.16.28.0/254.16.28.1 to 4.16.28.1264.16.28.127126
584.16.28.128/254.16.28.129 to 4.16.28.2544.16.28.255126
594.16.29.0/254.16.29.1 to 4.16.29.1264.16.29.127126
604.16.29.128/254.16.29.129 to 4.16.29.2544.16.29.255126
614.16.30.0/254.16.30.1 to 4.16.30.1264.16.30.127126
624.16.30.128/254.16.30.129 to 4.16.30.2544.16.30.255126
634.16.31.0/254.16.31.1 to 4.16.31.1264.16.31.127126
644.16.31.128/254.16.31.129 to 4.16.31.2544.16.31.255126
654.16.32.0/254.16.32.1 to 4.16.32.1264.16.32.127126
664.16.32.128/254.16.32.129 to 4.16.32.2544.16.32.255126
674.16.33.0/254.16.33.1 to 4.16.33.1264.16.33.127126
684.16.33.128/254.16.33.129 to 4.16.33.2544.16.33.255126
694.16.34.0/254.16.34.1 to 4.16.34.1264.16.34.127126
704.16.34.128/254.16.34.129 to 4.16.34.2544.16.34.255126
714.16.35.0/254.16.35.1 to 4.16.35.1264.16.35.127126
724.16.35.128/254.16.35.129 to 4.16.35.2544.16.35.255126
734.16.36.0/254.16.36.1 to 4.16.36.1264.16.36.127126
744.16.36.128/254.16.36.129 to 4.16.36.2544.16.36.255126
754.16.37.0/254.16.37.1 to 4.16.37.1264.16.37.127126
764.16.37.128/254.16.37.129 to 4.16.37.2544.16.37.255126
774.16.38.0/254.16.38.1 to 4.16.38.1264.16.38.127126
784.16.38.128/254.16.38.129 to 4.16.38.2544.16.38.255126
794.16.39.0/254.16.39.1 to 4.16.39.1264.16.39.127126
804.16.39.128/254.16.39.129 to 4.16.39.2544.16.39.255126
814.16.40.0/254.16.40.1 to 4.16.40.1264.16.40.127126
824.16.40.128/254.16.40.129 to 4.16.40.2544.16.40.255126
834.16.41.0/254.16.41.1 to 4.16.41.1264.16.41.127126
844.16.41.128/254.16.41.129 to 4.16.41.2544.16.41.255126
854.16.42.0/254.16.42.1 to 4.16.42.1264.16.42.127126
864.16.42.128/254.16.42.129 to 4.16.42.2544.16.42.255126
874.16.43.0/254.16.43.1 to 4.16.43.1264.16.43.127126
884.16.43.128/254.16.43.129 to 4.16.43.2544.16.43.255126
894.16.44.0/254.16.44.1 to 4.16.44.1264.16.44.127126
904.16.44.128/254.16.44.129 to 4.16.44.2544.16.44.255126
914.16.45.0/254.16.45.1 to 4.16.45.1264.16.45.127126
924.16.45.128/254.16.45.129 to 4.16.45.2544.16.45.255126
934.16.46.0/254.16.46.1 to 4.16.46.1264.16.46.127126
944.16.46.128/254.16.46.129 to 4.16.46.2544.16.46.255126
954.16.47.0/254.16.47.1 to 4.16.47.1264.16.47.127126
964.16.47.128/254.16.47.129 to 4.16.47.2544.16.47.255126
974.16.48.0/254.16.48.1 to 4.16.48.1264.16.48.127126
984.16.48.128/254.16.48.129 to 4.16.48.2544.16.48.255126
994.16.49.0/254.16.49.1 to 4.16.49.1264.16.49.127126
1004.16.49.128/254.16.49.129 to 4.16.49.2544.16.49.255126
1014.16.50.0/254.16.50.1 to 4.16.50.1264.16.50.127126
1024.16.50.128/254.16.50.129 to 4.16.50.2544.16.50.255126
1034.16.51.0/254.16.51.1 to 4.16.51.1264.16.51.127126
1044.16.51.128/254.16.51.129 to 4.16.51.2544.16.51.255126
1054.16.52.0/254.16.52.1 to 4.16.52.1264.16.52.127126
1064.16.52.128/254.16.52.129 to 4.16.52.2544.16.52.255126
1074.16.53.0/254.16.53.1 to 4.16.53.1264.16.53.127126
1084.16.53.128/254.16.53.129 to 4.16.53.2544.16.53.255126
1094.16.54.0/254.16.54.1 to 4.16.54.1264.16.54.127126
1104.16.54.128/254.16.54.129 to 4.16.54.2544.16.54.255126
1114.16.55.0/254.16.55.1 to 4.16.55.1264.16.55.127126
1124.16.55.128/254.16.55.129 to 4.16.55.2544.16.55.255126
1134.16.56.0/254.16.56.1 to 4.16.56.1264.16.56.127126
1144.16.56.128/254.16.56.129 to 4.16.56.2544.16.56.255126
1154.16.57.0/254.16.57.1 to 4.16.57.1264.16.57.127126
1164.16.57.128/254.16.57.129 to 4.16.57.2544.16.57.255126
1174.16.58.0/254.16.58.1 to 4.16.58.1264.16.58.127126
1184.16.58.128/254.16.58.129 to 4.16.58.2544.16.58.255126
1194.16.59.0/254.16.59.1 to 4.16.59.1264.16.59.127126
1204.16.59.128/254.16.59.129 to 4.16.59.2544.16.59.255126
1214.16.60.0/254.16.60.1 to 4.16.60.1264.16.60.127126
1224.16.60.128/254.16.60.129 to 4.16.60.2544.16.60.255126
1234.16.61.0/254.16.61.1 to 4.16.61.1264.16.61.127126
1244.16.61.128/254.16.61.129 to 4.16.61.2544.16.61.255126
1254.16.62.0/254.16.62.1 to 4.16.62.1264.16.62.127126
1264.16.62.128/254.16.62.129 to 4.16.62.2544.16.62.255126
1274.16.63.0/254.16.63.1 to 4.16.63.1264.16.63.127126
1284.16.63.128/254.16.63.129 to 4.16.63.2544.16.63.255126
1294.16.64.0/254.16.64.1 to 4.16.64.1264.16.64.127126
1304.16.64.128/254.16.64.129 to 4.16.64.2544.16.64.255126
1314.16.65.0/254.16.65.1 to 4.16.65.1264.16.65.127126
1324.16.65.128/254.16.65.129 to 4.16.65.2544.16.65.255126
1334.16.66.0/254.16.66.1 to 4.16.66.1264.16.66.127126
1344.16.66.128/254.16.66.129 to 4.16.66.2544.16.66.255126
1354.16.67.0/254.16.67.1 to 4.16.67.1264.16.67.127126
1364.16.67.128/254.16.67.129 to 4.16.67.2544.16.67.255126
1374.16.68.0/254.16.68.1 to 4.16.68.1264.16.68.127126
1384.16.68.128/254.16.68.129 to 4.16.68.2544.16.68.255126
1394.16.69.0/254.16.69.1 to 4.16.69.1264.16.69.127126
1404.16.69.128/254.16.69.129 to 4.16.69.2544.16.69.255126
1414.16.70.0/254.16.70.1 to 4.16.70.1264.16.70.127126
1424.16.70.128/254.16.70.129 to 4.16.70.2544.16.70.255126
1434.16.71.0/254.16.71.1 to 4.16.71.1264.16.71.127126
1444.16.71.128/254.16.71.129 to 4.16.71.2544.16.71.255126
1454.16.72.0/254.16.72.1 to 4.16.72.1264.16.72.127126
1464.16.72.128/254.16.72.129 to 4.16.72.2544.16.72.255126
1474.16.73.0/254.16.73.1 to 4.16.73.1264.16.73.127126
1484.16.73.128/254.16.73.129 to 4.16.73.2544.16.73.255126
1494.16.74.0/254.16.74.1 to 4.16.74.1264.16.74.127126
1504.16.74.128/254.16.74.129 to 4.16.74.2544.16.74.255126
1514.16.75.0/254.16.75.1 to 4.16.75.1264.16.75.127126
1524.16.75.128/254.16.75.129 to 4.16.75.2544.16.75.255126
1534.16.76.0/254.16.76.1 to 4.16.76.1264.16.76.127126
1544.16.76.128/254.16.76.129 to 4.16.76.2544.16.76.255126
1554.16.77.0/254.16.77.1 to 4.16.77.1264.16.77.127126
1564.16.77.128/254.16.77.129 to 4.16.77.2544.16.77.255126
1574.16.78.0/254.16.78.1 to 4.16.78.1264.16.78.127126
1584.16.78.128/254.16.78.129 to 4.16.78.2544.16.78.255126
1594.16.79.0/254.16.79.1 to 4.16.79.1264.16.79.127126
1604.16.79.128/254.16.79.129 to 4.16.79.2544.16.79.255126
1614.16.80.0/254.16.80.1 to 4.16.80.1264.16.80.127126
1624.16.80.128/254.16.80.129 to 4.16.80.2544.16.80.255126
1634.16.81.0/254.16.81.1 to 4.16.81.1264.16.81.127126
1644.16.81.128/254.16.81.129 to 4.16.81.2544.16.81.255126
1654.16.82.0/254.16.82.1 to 4.16.82.1264.16.82.127126
1664.16.82.128/254.16.82.129 to 4.16.82.2544.16.82.255126
1674.16.83.0/254.16.83.1 to 4.16.83.1264.16.83.127126
1684.16.83.128/254.16.83.129 to 4.16.83.2544.16.83.255126
1694.16.84.0/254.16.84.1 to 4.16.84.1264.16.84.127126
1704.16.84.128/254.16.84.129 to 4.16.84.2544.16.84.255126
1714.16.85.0/254.16.85.1 to 4.16.85.1264.16.85.127126
1724.16.85.128/254.16.85.129 to 4.16.85.2544.16.85.255126
1734.16.86.0/254.16.86.1 to 4.16.86.1264.16.86.127126
1744.16.86.128/254.16.86.129 to 4.16.86.2544.16.86.255126
1754.16.87.0/254.16.87.1 to 4.16.87.1264.16.87.127126
1764.16.87.128/254.16.87.129 to 4.16.87.2544.16.87.255126
1774.16.88.0/254.16.88.1 to 4.16.88.1264.16.88.127126
1784.16.88.128/254.16.88.129 to 4.16.88.2544.16.88.255126
1794.16.89.0/254.16.89.1 to 4.16.89.1264.16.89.127126
1804.16.89.128/254.16.89.129 to 4.16.89.2544.16.89.255126
1814.16.90.0/254.16.90.1 to 4.16.90.1264.16.90.127126
1824.16.90.128/254.16.90.129 to 4.16.90.2544.16.90.255126
1834.16.91.0/254.16.91.1 to 4.16.91.1264.16.91.127126
1844.16.91.128/254.16.91.129 to 4.16.91.2544.16.91.255126
1854.16.92.0/254.16.92.1 to 4.16.92.1264.16.92.127126
1864.16.92.128/254.16.92.129 to 4.16.92.2544.16.92.255126
1874.16.93.0/254.16.93.1 to 4.16.93.1264.16.93.127126
1884.16.93.128/254.16.93.129 to 4.16.93.2544.16.93.255126
1894.16.94.0/254.16.94.1 to 4.16.94.1264.16.94.127126
1904.16.94.128/254.16.94.129 to 4.16.94.2544.16.94.255126
1914.16.95.0/254.16.95.1 to 4.16.95.1264.16.95.127126
1924.16.95.128/254.16.95.129 to 4.16.95.2544.16.95.255126
1934.16.96.0/254.16.96.1 to 4.16.96.1264.16.96.127126
1944.16.96.128/254.16.96.129 to 4.16.96.2544.16.96.255126
1954.16.97.0/254.16.97.1 to 4.16.97.1264.16.97.127126
1964.16.97.128/254.16.97.129 to 4.16.97.2544.16.97.255126
1974.16.98.0/254.16.98.1 to 4.16.98.1264.16.98.127126
1984.16.98.128/254.16.98.129 to 4.16.98.2544.16.98.255126
1994.16.99.0/254.16.99.1 to 4.16.99.1264.16.99.127126
2004.16.99.128/254.16.99.129 to 4.16.99.2544.16.99.255126
2014.16.100.0/254.16.100.1 to 4.16.100.1264.16.100.127126
2024.16.100.128/254.16.100.129 to 4.16.100.2544.16.100.255126
2034.16.101.0/254.16.101.1 to 4.16.101.1264.16.101.127126
2044.16.101.128/254.16.101.129 to 4.16.101.2544.16.101.255126
2054.16.102.0/254.16.102.1 to 4.16.102.1264.16.102.127126
2064.16.102.128/254.16.102.129 to 4.16.102.2544.16.102.255126
2074.16.103.0/254.16.103.1 to 4.16.103.1264.16.103.127126
2084.16.103.128/254.16.103.129 to 4.16.103.2544.16.103.255126
2094.16.104.0/254.16.104.1 to 4.16.104.1264.16.104.127126
2104.16.104.128/254.16.104.129 to 4.16.104.2544.16.104.255126
2114.16.105.0/254.16.105.1 to 4.16.105.1264.16.105.127126
2124.16.105.128/254.16.105.129 to 4.16.105.2544.16.105.255126
2134.16.106.0/254.16.106.1 to 4.16.106.1264.16.106.127126
2144.16.106.128/254.16.106.129 to 4.16.106.2544.16.106.255126
2154.16.107.0/254.16.107.1 to 4.16.107.1264.16.107.127126
2164.16.107.128/254.16.107.129 to 4.16.107.2544.16.107.255126
2174.16.108.0/254.16.108.1 to 4.16.108.1264.16.108.127126
2184.16.108.128/254.16.108.129 to 4.16.108.2544.16.108.255126
2194.16.109.0/254.16.109.1 to 4.16.109.1264.16.109.127126
2204.16.109.128/254.16.109.129 to 4.16.109.2544.16.109.255126
2214.16.110.0/254.16.110.1 to 4.16.110.1264.16.110.127126
2224.16.110.128/254.16.110.129 to 4.16.110.2544.16.110.255126
2234.16.111.0/254.16.111.1 to 4.16.111.1264.16.111.127126
2244.16.111.128/254.16.111.129 to 4.16.111.2544.16.111.255126
2254.16.112.0/254.16.112.1 to 4.16.112.1264.16.112.127126
2264.16.112.128/254.16.112.129 to 4.16.112.2544.16.112.255126
2274.16.113.0/254.16.113.1 to 4.16.113.1264.16.113.127126
2284.16.113.128/254.16.113.129 to 4.16.113.2544.16.113.255126
2294.16.114.0/254.16.114.1 to 4.16.114.1264.16.114.127126
2304.16.114.128/254.16.114.129 to 4.16.114.2544.16.114.255126
2314.16.115.0/254.16.115.1 to 4.16.115.1264.16.115.127126
2324.16.115.128/254.16.115.129 to 4.16.115.2544.16.115.255126
2334.16.116.0/254.16.116.1 to 4.16.116.1264.16.116.127126
2344.16.116.128/254.16.116.129 to 4.16.116.2544.16.116.255126
2354.16.117.0/254.16.117.1 to 4.16.117.1264.16.117.127126
2364.16.117.128/254.16.117.129 to 4.16.117.2544.16.117.255126
2374.16.118.0/254.16.118.1 to 4.16.118.1264.16.118.127126
2384.16.118.128/254.16.118.129 to 4.16.118.2544.16.118.255126
2394.16.119.0/254.16.119.1 to 4.16.119.1264.16.119.127126
2404.16.119.128/254.16.119.129 to 4.16.119.2544.16.119.255126
2414.16.120.0/254.16.120.1 to 4.16.120.1264.16.120.127126
2424.16.120.128/254.16.120.129 to 4.16.120.2544.16.120.255126
2434.16.121.0/254.16.121.1 to 4.16.121.1264.16.121.127126
2444.16.121.128/254.16.121.129 to 4.16.121.2544.16.121.255126
2454.16.122.0/254.16.122.1 to 4.16.122.1264.16.122.127126
2464.16.122.128/254.16.122.129 to 4.16.122.2544.16.122.255126
2474.16.123.0/254.16.123.1 to 4.16.123.1264.16.123.127126
2484.16.123.128/254.16.123.129 to 4.16.123.2544.16.123.255126
2494.16.124.0/254.16.124.1 to 4.16.124.1264.16.124.127126
2504.16.124.128/254.16.124.129 to 4.16.124.2544.16.124.255126
2514.16.125.0/254.16.125.1 to 4.16.125.1264.16.125.127126
2524.16.125.128/254.16.125.129 to 4.16.125.2544.16.125.255126
2534.16.126.0/254.16.126.1 to 4.16.126.1264.16.126.127126
2544.16.126.128/254.16.126.129 to 4.16.126.2544.16.126.255126
2554.16.127.0/254.16.127.1 to 4.16.127.1264.16.127.127126
2564.16.127.128/254.16.127.129 to 4.16.127.2544.16.127.255126

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.