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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.

Network2.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
2.0.0.0
Broadcast address
3.255.255.255
First usable
2.0.0.1
Last usable
3.255.255.254
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 02000000 · Integer 33554432 to 67108863
Reverse DNS zones
2.in-addr.arpa
3.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
Address00000010.00000000.00000000.000000002.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00000010.00000000.00000000.000000002.0.0.0
Broadcast00000011.11111111.11111111.111111113.255.255.255
Split into smaller subnets/17
/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)

2.0.0.0/7 makes 1,024 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.0.0.0/172.0.0.1 to 2.0.127.2542.0.127.25532,766
22.0.128.0/172.0.128.1 to 2.0.255.2542.0.255.25532,766
32.1.0.0/172.1.0.1 to 2.1.127.2542.1.127.25532,766
42.1.128.0/172.1.128.1 to 2.1.255.2542.1.255.25532,766
52.2.0.0/172.2.0.1 to 2.2.127.2542.2.127.25532,766
62.2.128.0/172.2.128.1 to 2.2.255.2542.2.255.25532,766
72.3.0.0/172.3.0.1 to 2.3.127.2542.3.127.25532,766
82.3.128.0/172.3.128.1 to 2.3.255.2542.3.255.25532,766
92.4.0.0/172.4.0.1 to 2.4.127.2542.4.127.25532,766
102.4.128.0/172.4.128.1 to 2.4.255.2542.4.255.25532,766
112.5.0.0/172.5.0.1 to 2.5.127.2542.5.127.25532,766
122.5.128.0/172.5.128.1 to 2.5.255.2542.5.255.25532,766
132.6.0.0/172.6.0.1 to 2.6.127.2542.6.127.25532,766
142.6.128.0/172.6.128.1 to 2.6.255.2542.6.255.25532,766
152.7.0.0/172.7.0.1 to 2.7.127.2542.7.127.25532,766
162.7.128.0/172.7.128.1 to 2.7.255.2542.7.255.25532,766
172.8.0.0/172.8.0.1 to 2.8.127.2542.8.127.25532,766
182.8.128.0/172.8.128.1 to 2.8.255.2542.8.255.25532,766
192.9.0.0/172.9.0.1 to 2.9.127.2542.9.127.25532,766
202.9.128.0/172.9.128.1 to 2.9.255.2542.9.255.25532,766
212.10.0.0/172.10.0.1 to 2.10.127.2542.10.127.25532,766
222.10.128.0/172.10.128.1 to 2.10.255.2542.10.255.25532,766
232.11.0.0/172.11.0.1 to 2.11.127.2542.11.127.25532,766
242.11.128.0/172.11.128.1 to 2.11.255.2542.11.255.25532,766
252.12.0.0/172.12.0.1 to 2.12.127.2542.12.127.25532,766
262.12.128.0/172.12.128.1 to 2.12.255.2542.12.255.25532,766
272.13.0.0/172.13.0.1 to 2.13.127.2542.13.127.25532,766
282.13.128.0/172.13.128.1 to 2.13.255.2542.13.255.25532,766
292.14.0.0/172.14.0.1 to 2.14.127.2542.14.127.25532,766
302.14.128.0/172.14.128.1 to 2.14.255.2542.14.255.25532,766
312.15.0.0/172.15.0.1 to 2.15.127.2542.15.127.25532,766
322.15.128.0/172.15.128.1 to 2.15.255.2542.15.255.25532,766
332.16.0.0/172.16.0.1 to 2.16.127.2542.16.127.25532,766
342.16.128.0/172.16.128.1 to 2.16.255.2542.16.255.25532,766
352.17.0.0/172.17.0.1 to 2.17.127.2542.17.127.25532,766
362.17.128.0/172.17.128.1 to 2.17.255.2542.17.255.25532,766
372.18.0.0/172.18.0.1 to 2.18.127.2542.18.127.25532,766
382.18.128.0/172.18.128.1 to 2.18.255.2542.18.255.25532,766
392.19.0.0/172.19.0.1 to 2.19.127.2542.19.127.25532,766
402.19.128.0/172.19.128.1 to 2.19.255.2542.19.255.25532,766
412.20.0.0/172.20.0.1 to 2.20.127.2542.20.127.25532,766
422.20.128.0/172.20.128.1 to 2.20.255.2542.20.255.25532,766
432.21.0.0/172.21.0.1 to 2.21.127.2542.21.127.25532,766
442.21.128.0/172.21.128.1 to 2.21.255.2542.21.255.25532,766
452.22.0.0/172.22.0.1 to 2.22.127.2542.22.127.25532,766
462.22.128.0/172.22.128.1 to 2.22.255.2542.22.255.25532,766
472.23.0.0/172.23.0.1 to 2.23.127.2542.23.127.25532,766
482.23.128.0/172.23.128.1 to 2.23.255.2542.23.255.25532,766
492.24.0.0/172.24.0.1 to 2.24.127.2542.24.127.25532,766
502.24.128.0/172.24.128.1 to 2.24.255.2542.24.255.25532,766
512.25.0.0/172.25.0.1 to 2.25.127.2542.25.127.25532,766
522.25.128.0/172.25.128.1 to 2.25.255.2542.25.255.25532,766
532.26.0.0/172.26.0.1 to 2.26.127.2542.26.127.25532,766
542.26.128.0/172.26.128.1 to 2.26.255.2542.26.255.25532,766
552.27.0.0/172.27.0.1 to 2.27.127.2542.27.127.25532,766
562.27.128.0/172.27.128.1 to 2.27.255.2542.27.255.25532,766
572.28.0.0/172.28.0.1 to 2.28.127.2542.28.127.25532,766
582.28.128.0/172.28.128.1 to 2.28.255.2542.28.255.25532,766
592.29.0.0/172.29.0.1 to 2.29.127.2542.29.127.25532,766
602.29.128.0/172.29.128.1 to 2.29.255.2542.29.255.25532,766
612.30.0.0/172.30.0.1 to 2.30.127.2542.30.127.25532,766
622.30.128.0/172.30.128.1 to 2.30.255.2542.30.255.25532,766
632.31.0.0/172.31.0.1 to 2.31.127.2542.31.127.25532,766
642.31.128.0/172.31.128.1 to 2.31.255.2542.31.255.25532,766
652.32.0.0/172.32.0.1 to 2.32.127.2542.32.127.25532,766
662.32.128.0/172.32.128.1 to 2.32.255.2542.32.255.25532,766
672.33.0.0/172.33.0.1 to 2.33.127.2542.33.127.25532,766
682.33.128.0/172.33.128.1 to 2.33.255.2542.33.255.25532,766
692.34.0.0/172.34.0.1 to 2.34.127.2542.34.127.25532,766
702.34.128.0/172.34.128.1 to 2.34.255.2542.34.255.25532,766
712.35.0.0/172.35.0.1 to 2.35.127.2542.35.127.25532,766
722.35.128.0/172.35.128.1 to 2.35.255.2542.35.255.25532,766
732.36.0.0/172.36.0.1 to 2.36.127.2542.36.127.25532,766
742.36.128.0/172.36.128.1 to 2.36.255.2542.36.255.25532,766
752.37.0.0/172.37.0.1 to 2.37.127.2542.37.127.25532,766
762.37.128.0/172.37.128.1 to 2.37.255.2542.37.255.25532,766
772.38.0.0/172.38.0.1 to 2.38.127.2542.38.127.25532,766
782.38.128.0/172.38.128.1 to 2.38.255.2542.38.255.25532,766
792.39.0.0/172.39.0.1 to 2.39.127.2542.39.127.25532,766
802.39.128.0/172.39.128.1 to 2.39.255.2542.39.255.25532,766
812.40.0.0/172.40.0.1 to 2.40.127.2542.40.127.25532,766
822.40.128.0/172.40.128.1 to 2.40.255.2542.40.255.25532,766
832.41.0.0/172.41.0.1 to 2.41.127.2542.41.127.25532,766
842.41.128.0/172.41.128.1 to 2.41.255.2542.41.255.25532,766
852.42.0.0/172.42.0.1 to 2.42.127.2542.42.127.25532,766
862.42.128.0/172.42.128.1 to 2.42.255.2542.42.255.25532,766
872.43.0.0/172.43.0.1 to 2.43.127.2542.43.127.25532,766
882.43.128.0/172.43.128.1 to 2.43.255.2542.43.255.25532,766
892.44.0.0/172.44.0.1 to 2.44.127.2542.44.127.25532,766
902.44.128.0/172.44.128.1 to 2.44.255.2542.44.255.25532,766
912.45.0.0/172.45.0.1 to 2.45.127.2542.45.127.25532,766
922.45.128.0/172.45.128.1 to 2.45.255.2542.45.255.25532,766
932.46.0.0/172.46.0.1 to 2.46.127.2542.46.127.25532,766
942.46.128.0/172.46.128.1 to 2.46.255.2542.46.255.25532,766
952.47.0.0/172.47.0.1 to 2.47.127.2542.47.127.25532,766
962.47.128.0/172.47.128.1 to 2.47.255.2542.47.255.25532,766
972.48.0.0/172.48.0.1 to 2.48.127.2542.48.127.25532,766
982.48.128.0/172.48.128.1 to 2.48.255.2542.48.255.25532,766
992.49.0.0/172.49.0.1 to 2.49.127.2542.49.127.25532,766
1002.49.128.0/172.49.128.1 to 2.49.255.2542.49.255.25532,766
1012.50.0.0/172.50.0.1 to 2.50.127.2542.50.127.25532,766
1022.50.128.0/172.50.128.1 to 2.50.255.2542.50.255.25532,766
1032.51.0.0/172.51.0.1 to 2.51.127.2542.51.127.25532,766
1042.51.128.0/172.51.128.1 to 2.51.255.2542.51.255.25532,766
1052.52.0.0/172.52.0.1 to 2.52.127.2542.52.127.25532,766
1062.52.128.0/172.52.128.1 to 2.52.255.2542.52.255.25532,766
1072.53.0.0/172.53.0.1 to 2.53.127.2542.53.127.25532,766
1082.53.128.0/172.53.128.1 to 2.53.255.2542.53.255.25532,766
1092.54.0.0/172.54.0.1 to 2.54.127.2542.54.127.25532,766
1102.54.128.0/172.54.128.1 to 2.54.255.2542.54.255.25532,766
1112.55.0.0/172.55.0.1 to 2.55.127.2542.55.127.25532,766
1122.55.128.0/172.55.128.1 to 2.55.255.2542.55.255.25532,766
1132.56.0.0/172.56.0.1 to 2.56.127.2542.56.127.25532,766
1142.56.128.0/172.56.128.1 to 2.56.255.2542.56.255.25532,766
1152.57.0.0/172.57.0.1 to 2.57.127.2542.57.127.25532,766
1162.57.128.0/172.57.128.1 to 2.57.255.2542.57.255.25532,766
1172.58.0.0/172.58.0.1 to 2.58.127.2542.58.127.25532,766
1182.58.128.0/172.58.128.1 to 2.58.255.2542.58.255.25532,766
1192.59.0.0/172.59.0.1 to 2.59.127.2542.59.127.25532,766
1202.59.128.0/172.59.128.1 to 2.59.255.2542.59.255.25532,766
1212.60.0.0/172.60.0.1 to 2.60.127.2542.60.127.25532,766
1222.60.128.0/172.60.128.1 to 2.60.255.2542.60.255.25532,766
1232.61.0.0/172.61.0.1 to 2.61.127.2542.61.127.25532,766
1242.61.128.0/172.61.128.1 to 2.61.255.2542.61.255.25532,766
1252.62.0.0/172.62.0.1 to 2.62.127.2542.62.127.25532,766
1262.62.128.0/172.62.128.1 to 2.62.255.2542.62.255.25532,766
1272.63.0.0/172.63.0.1 to 2.63.127.2542.63.127.25532,766
1282.63.128.0/172.63.128.1 to 2.63.255.2542.63.255.25532,766
1292.64.0.0/172.64.0.1 to 2.64.127.2542.64.127.25532,766
1302.64.128.0/172.64.128.1 to 2.64.255.2542.64.255.25532,766
1312.65.0.0/172.65.0.1 to 2.65.127.2542.65.127.25532,766
1322.65.128.0/172.65.128.1 to 2.65.255.2542.65.255.25532,766
1332.66.0.0/172.66.0.1 to 2.66.127.2542.66.127.25532,766
1342.66.128.0/172.66.128.1 to 2.66.255.2542.66.255.25532,766
1352.67.0.0/172.67.0.1 to 2.67.127.2542.67.127.25532,766
1362.67.128.0/172.67.128.1 to 2.67.255.2542.67.255.25532,766
1372.68.0.0/172.68.0.1 to 2.68.127.2542.68.127.25532,766
1382.68.128.0/172.68.128.1 to 2.68.255.2542.68.255.25532,766
1392.69.0.0/172.69.0.1 to 2.69.127.2542.69.127.25532,766
1402.69.128.0/172.69.128.1 to 2.69.255.2542.69.255.25532,766
1412.70.0.0/172.70.0.1 to 2.70.127.2542.70.127.25532,766
1422.70.128.0/172.70.128.1 to 2.70.255.2542.70.255.25532,766
1432.71.0.0/172.71.0.1 to 2.71.127.2542.71.127.25532,766
1442.71.128.0/172.71.128.1 to 2.71.255.2542.71.255.25532,766
1452.72.0.0/172.72.0.1 to 2.72.127.2542.72.127.25532,766
1462.72.128.0/172.72.128.1 to 2.72.255.2542.72.255.25532,766
1472.73.0.0/172.73.0.1 to 2.73.127.2542.73.127.25532,766
1482.73.128.0/172.73.128.1 to 2.73.255.2542.73.255.25532,766
1492.74.0.0/172.74.0.1 to 2.74.127.2542.74.127.25532,766
1502.74.128.0/172.74.128.1 to 2.74.255.2542.74.255.25532,766
1512.75.0.0/172.75.0.1 to 2.75.127.2542.75.127.25532,766
1522.75.128.0/172.75.128.1 to 2.75.255.2542.75.255.25532,766
1532.76.0.0/172.76.0.1 to 2.76.127.2542.76.127.25532,766
1542.76.128.0/172.76.128.1 to 2.76.255.2542.76.255.25532,766
1552.77.0.0/172.77.0.1 to 2.77.127.2542.77.127.25532,766
1562.77.128.0/172.77.128.1 to 2.77.255.2542.77.255.25532,766
1572.78.0.0/172.78.0.1 to 2.78.127.2542.78.127.25532,766
1582.78.128.0/172.78.128.1 to 2.78.255.2542.78.255.25532,766
1592.79.0.0/172.79.0.1 to 2.79.127.2542.79.127.25532,766
1602.79.128.0/172.79.128.1 to 2.79.255.2542.79.255.25532,766
1612.80.0.0/172.80.0.1 to 2.80.127.2542.80.127.25532,766
1622.80.128.0/172.80.128.1 to 2.80.255.2542.80.255.25532,766
1632.81.0.0/172.81.0.1 to 2.81.127.2542.81.127.25532,766
1642.81.128.0/172.81.128.1 to 2.81.255.2542.81.255.25532,766
1652.82.0.0/172.82.0.1 to 2.82.127.2542.82.127.25532,766
1662.82.128.0/172.82.128.1 to 2.82.255.2542.82.255.25532,766
1672.83.0.0/172.83.0.1 to 2.83.127.2542.83.127.25532,766
1682.83.128.0/172.83.128.1 to 2.83.255.2542.83.255.25532,766
1692.84.0.0/172.84.0.1 to 2.84.127.2542.84.127.25532,766
1702.84.128.0/172.84.128.1 to 2.84.255.2542.84.255.25532,766
1712.85.0.0/172.85.0.1 to 2.85.127.2542.85.127.25532,766
1722.85.128.0/172.85.128.1 to 2.85.255.2542.85.255.25532,766
1732.86.0.0/172.86.0.1 to 2.86.127.2542.86.127.25532,766
1742.86.128.0/172.86.128.1 to 2.86.255.2542.86.255.25532,766
1752.87.0.0/172.87.0.1 to 2.87.127.2542.87.127.25532,766
1762.87.128.0/172.87.128.1 to 2.87.255.2542.87.255.25532,766
1772.88.0.0/172.88.0.1 to 2.88.127.2542.88.127.25532,766
1782.88.128.0/172.88.128.1 to 2.88.255.2542.88.255.25532,766
1792.89.0.0/172.89.0.1 to 2.89.127.2542.89.127.25532,766
1802.89.128.0/172.89.128.1 to 2.89.255.2542.89.255.25532,766
1812.90.0.0/172.90.0.1 to 2.90.127.2542.90.127.25532,766
1822.90.128.0/172.90.128.1 to 2.90.255.2542.90.255.25532,766
1832.91.0.0/172.91.0.1 to 2.91.127.2542.91.127.25532,766
1842.91.128.0/172.91.128.1 to 2.91.255.2542.91.255.25532,766
1852.92.0.0/172.92.0.1 to 2.92.127.2542.92.127.25532,766
1862.92.128.0/172.92.128.1 to 2.92.255.2542.92.255.25532,766
1872.93.0.0/172.93.0.1 to 2.93.127.2542.93.127.25532,766
1882.93.128.0/172.93.128.1 to 2.93.255.2542.93.255.25532,766
1892.94.0.0/172.94.0.1 to 2.94.127.2542.94.127.25532,766
1902.94.128.0/172.94.128.1 to 2.94.255.2542.94.255.25532,766
1912.95.0.0/172.95.0.1 to 2.95.127.2542.95.127.25532,766
1922.95.128.0/172.95.128.1 to 2.95.255.2542.95.255.25532,766
1932.96.0.0/172.96.0.1 to 2.96.127.2542.96.127.25532,766
1942.96.128.0/172.96.128.1 to 2.96.255.2542.96.255.25532,766
1952.97.0.0/172.97.0.1 to 2.97.127.2542.97.127.25532,766
1962.97.128.0/172.97.128.1 to 2.97.255.2542.97.255.25532,766
1972.98.0.0/172.98.0.1 to 2.98.127.2542.98.127.25532,766
1982.98.128.0/172.98.128.1 to 2.98.255.2542.98.255.25532,766
1992.99.0.0/172.99.0.1 to 2.99.127.2542.99.127.25532,766
2002.99.128.0/172.99.128.1 to 2.99.255.2542.99.255.25532,766
2012.100.0.0/172.100.0.1 to 2.100.127.2542.100.127.25532,766
2022.100.128.0/172.100.128.1 to 2.100.255.2542.100.255.25532,766
2032.101.0.0/172.101.0.1 to 2.101.127.2542.101.127.25532,766
2042.101.128.0/172.101.128.1 to 2.101.255.2542.101.255.25532,766
2052.102.0.0/172.102.0.1 to 2.102.127.2542.102.127.25532,766
2062.102.128.0/172.102.128.1 to 2.102.255.2542.102.255.25532,766
2072.103.0.0/172.103.0.1 to 2.103.127.2542.103.127.25532,766
2082.103.128.0/172.103.128.1 to 2.103.255.2542.103.255.25532,766
2092.104.0.0/172.104.0.1 to 2.104.127.2542.104.127.25532,766
2102.104.128.0/172.104.128.1 to 2.104.255.2542.104.255.25532,766
2112.105.0.0/172.105.0.1 to 2.105.127.2542.105.127.25532,766
2122.105.128.0/172.105.128.1 to 2.105.255.2542.105.255.25532,766
2132.106.0.0/172.106.0.1 to 2.106.127.2542.106.127.25532,766
2142.106.128.0/172.106.128.1 to 2.106.255.2542.106.255.25532,766
2152.107.0.0/172.107.0.1 to 2.107.127.2542.107.127.25532,766
2162.107.128.0/172.107.128.1 to 2.107.255.2542.107.255.25532,766
2172.108.0.0/172.108.0.1 to 2.108.127.2542.108.127.25532,766
2182.108.128.0/172.108.128.1 to 2.108.255.2542.108.255.25532,766
2192.109.0.0/172.109.0.1 to 2.109.127.2542.109.127.25532,766
2202.109.128.0/172.109.128.1 to 2.109.255.2542.109.255.25532,766
2212.110.0.0/172.110.0.1 to 2.110.127.2542.110.127.25532,766
2222.110.128.0/172.110.128.1 to 2.110.255.2542.110.255.25532,766
2232.111.0.0/172.111.0.1 to 2.111.127.2542.111.127.25532,766
2242.111.128.0/172.111.128.1 to 2.111.255.2542.111.255.25532,766
2252.112.0.0/172.112.0.1 to 2.112.127.2542.112.127.25532,766
2262.112.128.0/172.112.128.1 to 2.112.255.2542.112.255.25532,766
2272.113.0.0/172.113.0.1 to 2.113.127.2542.113.127.25532,766
2282.113.128.0/172.113.128.1 to 2.113.255.2542.113.255.25532,766
2292.114.0.0/172.114.0.1 to 2.114.127.2542.114.127.25532,766
2302.114.128.0/172.114.128.1 to 2.114.255.2542.114.255.25532,766
2312.115.0.0/172.115.0.1 to 2.115.127.2542.115.127.25532,766
2322.115.128.0/172.115.128.1 to 2.115.255.2542.115.255.25532,766
2332.116.0.0/172.116.0.1 to 2.116.127.2542.116.127.25532,766
2342.116.128.0/172.116.128.1 to 2.116.255.2542.116.255.25532,766
2352.117.0.0/172.117.0.1 to 2.117.127.2542.117.127.25532,766
2362.117.128.0/172.117.128.1 to 2.117.255.2542.117.255.25532,766
2372.118.0.0/172.118.0.1 to 2.118.127.2542.118.127.25532,766
2382.118.128.0/172.118.128.1 to 2.118.255.2542.118.255.25532,766
2392.119.0.0/172.119.0.1 to 2.119.127.2542.119.127.25532,766
2402.119.128.0/172.119.128.1 to 2.119.255.2542.119.255.25532,766
2412.120.0.0/172.120.0.1 to 2.120.127.2542.120.127.25532,766
2422.120.128.0/172.120.128.1 to 2.120.255.2542.120.255.25532,766
2432.121.0.0/172.121.0.1 to 2.121.127.2542.121.127.25532,766
2442.121.128.0/172.121.128.1 to 2.121.255.2542.121.255.25532,766
2452.122.0.0/172.122.0.1 to 2.122.127.2542.122.127.25532,766
2462.122.128.0/172.122.128.1 to 2.122.255.2542.122.255.25532,766
2472.123.0.0/172.123.0.1 to 2.123.127.2542.123.127.25532,766
2482.123.128.0/172.123.128.1 to 2.123.255.2542.123.255.25532,766
2492.124.0.0/172.124.0.1 to 2.124.127.2542.124.127.25532,766
2502.124.128.0/172.124.128.1 to 2.124.255.2542.124.255.25532,766
2512.125.0.0/172.125.0.1 to 2.125.127.2542.125.127.25532,766
2522.125.128.0/172.125.128.1 to 2.125.255.2542.125.255.25532,766
2532.126.0.0/172.126.0.1 to 2.126.127.2542.126.127.25532,766
2542.126.128.0/172.126.128.1 to 2.126.255.2542.126.255.25532,766
2552.127.0.0/172.127.0.1 to 2.127.127.2542.127.127.25532,766
2562.127.128.0/172.127.128.1 to 2.127.255.2542.127.255.25532,766

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.