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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.

Network2.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
2.167.0.0
Broadcast address
2.167.255.255
First usable
2.167.0.1
Last usable
2.167.255.254
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 02A70000 · Integer 44498944 to 44564479
Reverse DNS zone
167.2.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000010.10100111..00000000.000000002.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network00000010.10100111..00000000.000000002.167.0.0
Broadcast00000010.10100111..11111111.111111112.167.255.255
Split into smaller subnets/25
/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)

2.167.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.167.0.0/252.167.0.1 to 2.167.0.1262.167.0.127126
22.167.0.128/252.167.0.129 to 2.167.0.2542.167.0.255126
32.167.1.0/252.167.1.1 to 2.167.1.1262.167.1.127126
42.167.1.128/252.167.1.129 to 2.167.1.2542.167.1.255126
52.167.2.0/252.167.2.1 to 2.167.2.1262.167.2.127126
62.167.2.128/252.167.2.129 to 2.167.2.2542.167.2.255126
72.167.3.0/252.167.3.1 to 2.167.3.1262.167.3.127126
82.167.3.128/252.167.3.129 to 2.167.3.2542.167.3.255126
92.167.4.0/252.167.4.1 to 2.167.4.1262.167.4.127126
102.167.4.128/252.167.4.129 to 2.167.4.2542.167.4.255126
112.167.5.0/252.167.5.1 to 2.167.5.1262.167.5.127126
122.167.5.128/252.167.5.129 to 2.167.5.2542.167.5.255126
132.167.6.0/252.167.6.1 to 2.167.6.1262.167.6.127126
142.167.6.128/252.167.6.129 to 2.167.6.2542.167.6.255126
152.167.7.0/252.167.7.1 to 2.167.7.1262.167.7.127126
162.167.7.128/252.167.7.129 to 2.167.7.2542.167.7.255126
172.167.8.0/252.167.8.1 to 2.167.8.1262.167.8.127126
182.167.8.128/252.167.8.129 to 2.167.8.2542.167.8.255126
192.167.9.0/252.167.9.1 to 2.167.9.1262.167.9.127126
202.167.9.128/252.167.9.129 to 2.167.9.2542.167.9.255126
212.167.10.0/252.167.10.1 to 2.167.10.1262.167.10.127126
222.167.10.128/252.167.10.129 to 2.167.10.2542.167.10.255126
232.167.11.0/252.167.11.1 to 2.167.11.1262.167.11.127126
242.167.11.128/252.167.11.129 to 2.167.11.2542.167.11.255126
252.167.12.0/252.167.12.1 to 2.167.12.1262.167.12.127126
262.167.12.128/252.167.12.129 to 2.167.12.2542.167.12.255126
272.167.13.0/252.167.13.1 to 2.167.13.1262.167.13.127126
282.167.13.128/252.167.13.129 to 2.167.13.2542.167.13.255126
292.167.14.0/252.167.14.1 to 2.167.14.1262.167.14.127126
302.167.14.128/252.167.14.129 to 2.167.14.2542.167.14.255126
312.167.15.0/252.167.15.1 to 2.167.15.1262.167.15.127126
322.167.15.128/252.167.15.129 to 2.167.15.2542.167.15.255126
332.167.16.0/252.167.16.1 to 2.167.16.1262.167.16.127126
342.167.16.128/252.167.16.129 to 2.167.16.2542.167.16.255126
352.167.17.0/252.167.17.1 to 2.167.17.1262.167.17.127126
362.167.17.128/252.167.17.129 to 2.167.17.2542.167.17.255126
372.167.18.0/252.167.18.1 to 2.167.18.1262.167.18.127126
382.167.18.128/252.167.18.129 to 2.167.18.2542.167.18.255126
392.167.19.0/252.167.19.1 to 2.167.19.1262.167.19.127126
402.167.19.128/252.167.19.129 to 2.167.19.2542.167.19.255126
412.167.20.0/252.167.20.1 to 2.167.20.1262.167.20.127126
422.167.20.128/252.167.20.129 to 2.167.20.2542.167.20.255126
432.167.21.0/252.167.21.1 to 2.167.21.1262.167.21.127126
442.167.21.128/252.167.21.129 to 2.167.21.2542.167.21.255126
452.167.22.0/252.167.22.1 to 2.167.22.1262.167.22.127126
462.167.22.128/252.167.22.129 to 2.167.22.2542.167.22.255126
472.167.23.0/252.167.23.1 to 2.167.23.1262.167.23.127126
482.167.23.128/252.167.23.129 to 2.167.23.2542.167.23.255126
492.167.24.0/252.167.24.1 to 2.167.24.1262.167.24.127126
502.167.24.128/252.167.24.129 to 2.167.24.2542.167.24.255126
512.167.25.0/252.167.25.1 to 2.167.25.1262.167.25.127126
522.167.25.128/252.167.25.129 to 2.167.25.2542.167.25.255126
532.167.26.0/252.167.26.1 to 2.167.26.1262.167.26.127126
542.167.26.128/252.167.26.129 to 2.167.26.2542.167.26.255126
552.167.27.0/252.167.27.1 to 2.167.27.1262.167.27.127126
562.167.27.128/252.167.27.129 to 2.167.27.2542.167.27.255126
572.167.28.0/252.167.28.1 to 2.167.28.1262.167.28.127126
582.167.28.128/252.167.28.129 to 2.167.28.2542.167.28.255126
592.167.29.0/252.167.29.1 to 2.167.29.1262.167.29.127126
602.167.29.128/252.167.29.129 to 2.167.29.2542.167.29.255126
612.167.30.0/252.167.30.1 to 2.167.30.1262.167.30.127126
622.167.30.128/252.167.30.129 to 2.167.30.2542.167.30.255126
632.167.31.0/252.167.31.1 to 2.167.31.1262.167.31.127126
642.167.31.128/252.167.31.129 to 2.167.31.2542.167.31.255126
652.167.32.0/252.167.32.1 to 2.167.32.1262.167.32.127126
662.167.32.128/252.167.32.129 to 2.167.32.2542.167.32.255126
672.167.33.0/252.167.33.1 to 2.167.33.1262.167.33.127126
682.167.33.128/252.167.33.129 to 2.167.33.2542.167.33.255126
692.167.34.0/252.167.34.1 to 2.167.34.1262.167.34.127126
702.167.34.128/252.167.34.129 to 2.167.34.2542.167.34.255126
712.167.35.0/252.167.35.1 to 2.167.35.1262.167.35.127126
722.167.35.128/252.167.35.129 to 2.167.35.2542.167.35.255126
732.167.36.0/252.167.36.1 to 2.167.36.1262.167.36.127126
742.167.36.128/252.167.36.129 to 2.167.36.2542.167.36.255126
752.167.37.0/252.167.37.1 to 2.167.37.1262.167.37.127126
762.167.37.128/252.167.37.129 to 2.167.37.2542.167.37.255126
772.167.38.0/252.167.38.1 to 2.167.38.1262.167.38.127126
782.167.38.128/252.167.38.129 to 2.167.38.2542.167.38.255126
792.167.39.0/252.167.39.1 to 2.167.39.1262.167.39.127126
802.167.39.128/252.167.39.129 to 2.167.39.2542.167.39.255126
812.167.40.0/252.167.40.1 to 2.167.40.1262.167.40.127126
822.167.40.128/252.167.40.129 to 2.167.40.2542.167.40.255126
832.167.41.0/252.167.41.1 to 2.167.41.1262.167.41.127126
842.167.41.128/252.167.41.129 to 2.167.41.2542.167.41.255126
852.167.42.0/252.167.42.1 to 2.167.42.1262.167.42.127126
862.167.42.128/252.167.42.129 to 2.167.42.2542.167.42.255126
872.167.43.0/252.167.43.1 to 2.167.43.1262.167.43.127126
882.167.43.128/252.167.43.129 to 2.167.43.2542.167.43.255126
892.167.44.0/252.167.44.1 to 2.167.44.1262.167.44.127126
902.167.44.128/252.167.44.129 to 2.167.44.2542.167.44.255126
912.167.45.0/252.167.45.1 to 2.167.45.1262.167.45.127126
922.167.45.128/252.167.45.129 to 2.167.45.2542.167.45.255126
932.167.46.0/252.167.46.1 to 2.167.46.1262.167.46.127126
942.167.46.128/252.167.46.129 to 2.167.46.2542.167.46.255126
952.167.47.0/252.167.47.1 to 2.167.47.1262.167.47.127126
962.167.47.128/252.167.47.129 to 2.167.47.2542.167.47.255126
972.167.48.0/252.167.48.1 to 2.167.48.1262.167.48.127126
982.167.48.128/252.167.48.129 to 2.167.48.2542.167.48.255126
992.167.49.0/252.167.49.1 to 2.167.49.1262.167.49.127126
1002.167.49.128/252.167.49.129 to 2.167.49.2542.167.49.255126
1012.167.50.0/252.167.50.1 to 2.167.50.1262.167.50.127126
1022.167.50.128/252.167.50.129 to 2.167.50.2542.167.50.255126
1032.167.51.0/252.167.51.1 to 2.167.51.1262.167.51.127126
1042.167.51.128/252.167.51.129 to 2.167.51.2542.167.51.255126
1052.167.52.0/252.167.52.1 to 2.167.52.1262.167.52.127126
1062.167.52.128/252.167.52.129 to 2.167.52.2542.167.52.255126
1072.167.53.0/252.167.53.1 to 2.167.53.1262.167.53.127126
1082.167.53.128/252.167.53.129 to 2.167.53.2542.167.53.255126
1092.167.54.0/252.167.54.1 to 2.167.54.1262.167.54.127126
1102.167.54.128/252.167.54.129 to 2.167.54.2542.167.54.255126
1112.167.55.0/252.167.55.1 to 2.167.55.1262.167.55.127126
1122.167.55.128/252.167.55.129 to 2.167.55.2542.167.55.255126
1132.167.56.0/252.167.56.1 to 2.167.56.1262.167.56.127126
1142.167.56.128/252.167.56.129 to 2.167.56.2542.167.56.255126
1152.167.57.0/252.167.57.1 to 2.167.57.1262.167.57.127126
1162.167.57.128/252.167.57.129 to 2.167.57.2542.167.57.255126
1172.167.58.0/252.167.58.1 to 2.167.58.1262.167.58.127126
1182.167.58.128/252.167.58.129 to 2.167.58.2542.167.58.255126
1192.167.59.0/252.167.59.1 to 2.167.59.1262.167.59.127126
1202.167.59.128/252.167.59.129 to 2.167.59.2542.167.59.255126
1212.167.60.0/252.167.60.1 to 2.167.60.1262.167.60.127126
1222.167.60.128/252.167.60.129 to 2.167.60.2542.167.60.255126
1232.167.61.0/252.167.61.1 to 2.167.61.1262.167.61.127126
1242.167.61.128/252.167.61.129 to 2.167.61.2542.167.61.255126
1252.167.62.0/252.167.62.1 to 2.167.62.1262.167.62.127126
1262.167.62.128/252.167.62.129 to 2.167.62.2542.167.62.255126
1272.167.63.0/252.167.63.1 to 2.167.63.1262.167.63.127126
1282.167.63.128/252.167.63.129 to 2.167.63.2542.167.63.255126
1292.167.64.0/252.167.64.1 to 2.167.64.1262.167.64.127126
1302.167.64.128/252.167.64.129 to 2.167.64.2542.167.64.255126
1312.167.65.0/252.167.65.1 to 2.167.65.1262.167.65.127126
1322.167.65.128/252.167.65.129 to 2.167.65.2542.167.65.255126
1332.167.66.0/252.167.66.1 to 2.167.66.1262.167.66.127126
1342.167.66.128/252.167.66.129 to 2.167.66.2542.167.66.255126
1352.167.67.0/252.167.67.1 to 2.167.67.1262.167.67.127126
1362.167.67.128/252.167.67.129 to 2.167.67.2542.167.67.255126
1372.167.68.0/252.167.68.1 to 2.167.68.1262.167.68.127126
1382.167.68.128/252.167.68.129 to 2.167.68.2542.167.68.255126
1392.167.69.0/252.167.69.1 to 2.167.69.1262.167.69.127126
1402.167.69.128/252.167.69.129 to 2.167.69.2542.167.69.255126
1412.167.70.0/252.167.70.1 to 2.167.70.1262.167.70.127126
1422.167.70.128/252.167.70.129 to 2.167.70.2542.167.70.255126
1432.167.71.0/252.167.71.1 to 2.167.71.1262.167.71.127126
1442.167.71.128/252.167.71.129 to 2.167.71.2542.167.71.255126
1452.167.72.0/252.167.72.1 to 2.167.72.1262.167.72.127126
1462.167.72.128/252.167.72.129 to 2.167.72.2542.167.72.255126
1472.167.73.0/252.167.73.1 to 2.167.73.1262.167.73.127126
1482.167.73.128/252.167.73.129 to 2.167.73.2542.167.73.255126
1492.167.74.0/252.167.74.1 to 2.167.74.1262.167.74.127126
1502.167.74.128/252.167.74.129 to 2.167.74.2542.167.74.255126
1512.167.75.0/252.167.75.1 to 2.167.75.1262.167.75.127126
1522.167.75.128/252.167.75.129 to 2.167.75.2542.167.75.255126
1532.167.76.0/252.167.76.1 to 2.167.76.1262.167.76.127126
1542.167.76.128/252.167.76.129 to 2.167.76.2542.167.76.255126
1552.167.77.0/252.167.77.1 to 2.167.77.1262.167.77.127126
1562.167.77.128/252.167.77.129 to 2.167.77.2542.167.77.255126
1572.167.78.0/252.167.78.1 to 2.167.78.1262.167.78.127126
1582.167.78.128/252.167.78.129 to 2.167.78.2542.167.78.255126
1592.167.79.0/252.167.79.1 to 2.167.79.1262.167.79.127126
1602.167.79.128/252.167.79.129 to 2.167.79.2542.167.79.255126
1612.167.80.0/252.167.80.1 to 2.167.80.1262.167.80.127126
1622.167.80.128/252.167.80.129 to 2.167.80.2542.167.80.255126
1632.167.81.0/252.167.81.1 to 2.167.81.1262.167.81.127126
1642.167.81.128/252.167.81.129 to 2.167.81.2542.167.81.255126
1652.167.82.0/252.167.82.1 to 2.167.82.1262.167.82.127126
1662.167.82.128/252.167.82.129 to 2.167.82.2542.167.82.255126
1672.167.83.0/252.167.83.1 to 2.167.83.1262.167.83.127126
1682.167.83.128/252.167.83.129 to 2.167.83.2542.167.83.255126
1692.167.84.0/252.167.84.1 to 2.167.84.1262.167.84.127126
1702.167.84.128/252.167.84.129 to 2.167.84.2542.167.84.255126
1712.167.85.0/252.167.85.1 to 2.167.85.1262.167.85.127126
1722.167.85.128/252.167.85.129 to 2.167.85.2542.167.85.255126
1732.167.86.0/252.167.86.1 to 2.167.86.1262.167.86.127126
1742.167.86.128/252.167.86.129 to 2.167.86.2542.167.86.255126
1752.167.87.0/252.167.87.1 to 2.167.87.1262.167.87.127126
1762.167.87.128/252.167.87.129 to 2.167.87.2542.167.87.255126
1772.167.88.0/252.167.88.1 to 2.167.88.1262.167.88.127126
1782.167.88.128/252.167.88.129 to 2.167.88.2542.167.88.255126
1792.167.89.0/252.167.89.1 to 2.167.89.1262.167.89.127126
1802.167.89.128/252.167.89.129 to 2.167.89.2542.167.89.255126
1812.167.90.0/252.167.90.1 to 2.167.90.1262.167.90.127126
1822.167.90.128/252.167.90.129 to 2.167.90.2542.167.90.255126
1832.167.91.0/252.167.91.1 to 2.167.91.1262.167.91.127126
1842.167.91.128/252.167.91.129 to 2.167.91.2542.167.91.255126
1852.167.92.0/252.167.92.1 to 2.167.92.1262.167.92.127126
1862.167.92.128/252.167.92.129 to 2.167.92.2542.167.92.255126
1872.167.93.0/252.167.93.1 to 2.167.93.1262.167.93.127126
1882.167.93.128/252.167.93.129 to 2.167.93.2542.167.93.255126
1892.167.94.0/252.167.94.1 to 2.167.94.1262.167.94.127126
1902.167.94.128/252.167.94.129 to 2.167.94.2542.167.94.255126
1912.167.95.0/252.167.95.1 to 2.167.95.1262.167.95.127126
1922.167.95.128/252.167.95.129 to 2.167.95.2542.167.95.255126
1932.167.96.0/252.167.96.1 to 2.167.96.1262.167.96.127126
1942.167.96.128/252.167.96.129 to 2.167.96.2542.167.96.255126
1952.167.97.0/252.167.97.1 to 2.167.97.1262.167.97.127126
1962.167.97.128/252.167.97.129 to 2.167.97.2542.167.97.255126
1972.167.98.0/252.167.98.1 to 2.167.98.1262.167.98.127126
1982.167.98.128/252.167.98.129 to 2.167.98.2542.167.98.255126
1992.167.99.0/252.167.99.1 to 2.167.99.1262.167.99.127126
2002.167.99.128/252.167.99.129 to 2.167.99.2542.167.99.255126
2012.167.100.0/252.167.100.1 to 2.167.100.1262.167.100.127126
2022.167.100.128/252.167.100.129 to 2.167.100.2542.167.100.255126
2032.167.101.0/252.167.101.1 to 2.167.101.1262.167.101.127126
2042.167.101.128/252.167.101.129 to 2.167.101.2542.167.101.255126
2052.167.102.0/252.167.102.1 to 2.167.102.1262.167.102.127126
2062.167.102.128/252.167.102.129 to 2.167.102.2542.167.102.255126
2072.167.103.0/252.167.103.1 to 2.167.103.1262.167.103.127126
2082.167.103.128/252.167.103.129 to 2.167.103.2542.167.103.255126
2092.167.104.0/252.167.104.1 to 2.167.104.1262.167.104.127126
2102.167.104.128/252.167.104.129 to 2.167.104.2542.167.104.255126
2112.167.105.0/252.167.105.1 to 2.167.105.1262.167.105.127126
2122.167.105.128/252.167.105.129 to 2.167.105.2542.167.105.255126
2132.167.106.0/252.167.106.1 to 2.167.106.1262.167.106.127126
2142.167.106.128/252.167.106.129 to 2.167.106.2542.167.106.255126
2152.167.107.0/252.167.107.1 to 2.167.107.1262.167.107.127126
2162.167.107.128/252.167.107.129 to 2.167.107.2542.167.107.255126
2172.167.108.0/252.167.108.1 to 2.167.108.1262.167.108.127126
2182.167.108.128/252.167.108.129 to 2.167.108.2542.167.108.255126
2192.167.109.0/252.167.109.1 to 2.167.109.1262.167.109.127126
2202.167.109.128/252.167.109.129 to 2.167.109.2542.167.109.255126
2212.167.110.0/252.167.110.1 to 2.167.110.1262.167.110.127126
2222.167.110.128/252.167.110.129 to 2.167.110.2542.167.110.255126
2232.167.111.0/252.167.111.1 to 2.167.111.1262.167.111.127126
2242.167.111.128/252.167.111.129 to 2.167.111.2542.167.111.255126
2252.167.112.0/252.167.112.1 to 2.167.112.1262.167.112.127126
2262.167.112.128/252.167.112.129 to 2.167.112.2542.167.112.255126
2272.167.113.0/252.167.113.1 to 2.167.113.1262.167.113.127126
2282.167.113.128/252.167.113.129 to 2.167.113.2542.167.113.255126
2292.167.114.0/252.167.114.1 to 2.167.114.1262.167.114.127126
2302.167.114.128/252.167.114.129 to 2.167.114.2542.167.114.255126
2312.167.115.0/252.167.115.1 to 2.167.115.1262.167.115.127126
2322.167.115.128/252.167.115.129 to 2.167.115.2542.167.115.255126
2332.167.116.0/252.167.116.1 to 2.167.116.1262.167.116.127126
2342.167.116.128/252.167.116.129 to 2.167.116.2542.167.116.255126
2352.167.117.0/252.167.117.1 to 2.167.117.1262.167.117.127126
2362.167.117.128/252.167.117.129 to 2.167.117.2542.167.117.255126
2372.167.118.0/252.167.118.1 to 2.167.118.1262.167.118.127126
2382.167.118.128/252.167.118.129 to 2.167.118.2542.167.118.255126
2392.167.119.0/252.167.119.1 to 2.167.119.1262.167.119.127126
2402.167.119.128/252.167.119.129 to 2.167.119.2542.167.119.255126
2412.167.120.0/252.167.120.1 to 2.167.120.1262.167.120.127126
2422.167.120.128/252.167.120.129 to 2.167.120.2542.167.120.255126
2432.167.121.0/252.167.121.1 to 2.167.121.1262.167.121.127126
2442.167.121.128/252.167.121.129 to 2.167.121.2542.167.121.255126
2452.167.122.0/252.167.122.1 to 2.167.122.1262.167.122.127126
2462.167.122.128/252.167.122.129 to 2.167.122.2542.167.122.255126
2472.167.123.0/252.167.123.1 to 2.167.123.1262.167.123.127126
2482.167.123.128/252.167.123.129 to 2.167.123.2542.167.123.255126
2492.167.124.0/252.167.124.1 to 2.167.124.1262.167.124.127126
2502.167.124.128/252.167.124.129 to 2.167.124.2542.167.124.255126
2512.167.125.0/252.167.125.1 to 2.167.125.1262.167.125.127126
2522.167.125.128/252.167.125.129 to 2.167.125.2542.167.125.255126
2532.167.126.0/252.167.126.1 to 2.167.126.1262.167.126.127126
2542.167.126.128/252.167.126.129 to 2.167.126.2542.167.126.255126
2552.167.127.0/252.167.127.1 to 2.167.127.1262.167.127.127126
2562.167.127.128/252.167.127.129 to 2.167.127.2542.167.127.255126

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.