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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/18
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

2.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.0.0.0/182.0.0.1 to 2.0.63.2542.0.63.25516,382
22.0.64.0/182.0.64.1 to 2.0.127.2542.0.127.25516,382
32.0.128.0/182.0.128.1 to 2.0.191.2542.0.191.25516,382
42.0.192.0/182.0.192.1 to 2.0.255.2542.0.255.25516,382
52.1.0.0/182.1.0.1 to 2.1.63.2542.1.63.25516,382
62.1.64.0/182.1.64.1 to 2.1.127.2542.1.127.25516,382
72.1.128.0/182.1.128.1 to 2.1.191.2542.1.191.25516,382
82.1.192.0/182.1.192.1 to 2.1.255.2542.1.255.25516,382
92.2.0.0/182.2.0.1 to 2.2.63.2542.2.63.25516,382
102.2.64.0/182.2.64.1 to 2.2.127.2542.2.127.25516,382
112.2.128.0/182.2.128.1 to 2.2.191.2542.2.191.25516,382
122.2.192.0/182.2.192.1 to 2.2.255.2542.2.255.25516,382
132.3.0.0/182.3.0.1 to 2.3.63.2542.3.63.25516,382
142.3.64.0/182.3.64.1 to 2.3.127.2542.3.127.25516,382
152.3.128.0/182.3.128.1 to 2.3.191.2542.3.191.25516,382
162.3.192.0/182.3.192.1 to 2.3.255.2542.3.255.25516,382
172.4.0.0/182.4.0.1 to 2.4.63.2542.4.63.25516,382
182.4.64.0/182.4.64.1 to 2.4.127.2542.4.127.25516,382
192.4.128.0/182.4.128.1 to 2.4.191.2542.4.191.25516,382
202.4.192.0/182.4.192.1 to 2.4.255.2542.4.255.25516,382
212.5.0.0/182.5.0.1 to 2.5.63.2542.5.63.25516,382
222.5.64.0/182.5.64.1 to 2.5.127.2542.5.127.25516,382
232.5.128.0/182.5.128.1 to 2.5.191.2542.5.191.25516,382
242.5.192.0/182.5.192.1 to 2.5.255.2542.5.255.25516,382
252.6.0.0/182.6.0.1 to 2.6.63.2542.6.63.25516,382
262.6.64.0/182.6.64.1 to 2.6.127.2542.6.127.25516,382
272.6.128.0/182.6.128.1 to 2.6.191.2542.6.191.25516,382
282.6.192.0/182.6.192.1 to 2.6.255.2542.6.255.25516,382
292.7.0.0/182.7.0.1 to 2.7.63.2542.7.63.25516,382
302.7.64.0/182.7.64.1 to 2.7.127.2542.7.127.25516,382
312.7.128.0/182.7.128.1 to 2.7.191.2542.7.191.25516,382
322.7.192.0/182.7.192.1 to 2.7.255.2542.7.255.25516,382
332.8.0.0/182.8.0.1 to 2.8.63.2542.8.63.25516,382
342.8.64.0/182.8.64.1 to 2.8.127.2542.8.127.25516,382
352.8.128.0/182.8.128.1 to 2.8.191.2542.8.191.25516,382
362.8.192.0/182.8.192.1 to 2.8.255.2542.8.255.25516,382
372.9.0.0/182.9.0.1 to 2.9.63.2542.9.63.25516,382
382.9.64.0/182.9.64.1 to 2.9.127.2542.9.127.25516,382
392.9.128.0/182.9.128.1 to 2.9.191.2542.9.191.25516,382
402.9.192.0/182.9.192.1 to 2.9.255.2542.9.255.25516,382
412.10.0.0/182.10.0.1 to 2.10.63.2542.10.63.25516,382
422.10.64.0/182.10.64.1 to 2.10.127.2542.10.127.25516,382
432.10.128.0/182.10.128.1 to 2.10.191.2542.10.191.25516,382
442.10.192.0/182.10.192.1 to 2.10.255.2542.10.255.25516,382
452.11.0.0/182.11.0.1 to 2.11.63.2542.11.63.25516,382
462.11.64.0/182.11.64.1 to 2.11.127.2542.11.127.25516,382
472.11.128.0/182.11.128.1 to 2.11.191.2542.11.191.25516,382
482.11.192.0/182.11.192.1 to 2.11.255.2542.11.255.25516,382
492.12.0.0/182.12.0.1 to 2.12.63.2542.12.63.25516,382
502.12.64.0/182.12.64.1 to 2.12.127.2542.12.127.25516,382
512.12.128.0/182.12.128.1 to 2.12.191.2542.12.191.25516,382
522.12.192.0/182.12.192.1 to 2.12.255.2542.12.255.25516,382
532.13.0.0/182.13.0.1 to 2.13.63.2542.13.63.25516,382
542.13.64.0/182.13.64.1 to 2.13.127.2542.13.127.25516,382
552.13.128.0/182.13.128.1 to 2.13.191.2542.13.191.25516,382
562.13.192.0/182.13.192.1 to 2.13.255.2542.13.255.25516,382
572.14.0.0/182.14.0.1 to 2.14.63.2542.14.63.25516,382
582.14.64.0/182.14.64.1 to 2.14.127.2542.14.127.25516,382
592.14.128.0/182.14.128.1 to 2.14.191.2542.14.191.25516,382
602.14.192.0/182.14.192.1 to 2.14.255.2542.14.255.25516,382
612.15.0.0/182.15.0.1 to 2.15.63.2542.15.63.25516,382
622.15.64.0/182.15.64.1 to 2.15.127.2542.15.127.25516,382
632.15.128.0/182.15.128.1 to 2.15.191.2542.15.191.25516,382
642.15.192.0/182.15.192.1 to 2.15.255.2542.15.255.25516,382
652.16.0.0/182.16.0.1 to 2.16.63.2542.16.63.25516,382
662.16.64.0/182.16.64.1 to 2.16.127.2542.16.127.25516,382
672.16.128.0/182.16.128.1 to 2.16.191.2542.16.191.25516,382
682.16.192.0/182.16.192.1 to 2.16.255.2542.16.255.25516,382
692.17.0.0/182.17.0.1 to 2.17.63.2542.17.63.25516,382
702.17.64.0/182.17.64.1 to 2.17.127.2542.17.127.25516,382
712.17.128.0/182.17.128.1 to 2.17.191.2542.17.191.25516,382
722.17.192.0/182.17.192.1 to 2.17.255.2542.17.255.25516,382
732.18.0.0/182.18.0.1 to 2.18.63.2542.18.63.25516,382
742.18.64.0/182.18.64.1 to 2.18.127.2542.18.127.25516,382
752.18.128.0/182.18.128.1 to 2.18.191.2542.18.191.25516,382
762.18.192.0/182.18.192.1 to 2.18.255.2542.18.255.25516,382
772.19.0.0/182.19.0.1 to 2.19.63.2542.19.63.25516,382
782.19.64.0/182.19.64.1 to 2.19.127.2542.19.127.25516,382
792.19.128.0/182.19.128.1 to 2.19.191.2542.19.191.25516,382
802.19.192.0/182.19.192.1 to 2.19.255.2542.19.255.25516,382
812.20.0.0/182.20.0.1 to 2.20.63.2542.20.63.25516,382
822.20.64.0/182.20.64.1 to 2.20.127.2542.20.127.25516,382
832.20.128.0/182.20.128.1 to 2.20.191.2542.20.191.25516,382
842.20.192.0/182.20.192.1 to 2.20.255.2542.20.255.25516,382
852.21.0.0/182.21.0.1 to 2.21.63.2542.21.63.25516,382
862.21.64.0/182.21.64.1 to 2.21.127.2542.21.127.25516,382
872.21.128.0/182.21.128.1 to 2.21.191.2542.21.191.25516,382
882.21.192.0/182.21.192.1 to 2.21.255.2542.21.255.25516,382
892.22.0.0/182.22.0.1 to 2.22.63.2542.22.63.25516,382
902.22.64.0/182.22.64.1 to 2.22.127.2542.22.127.25516,382
912.22.128.0/182.22.128.1 to 2.22.191.2542.22.191.25516,382
922.22.192.0/182.22.192.1 to 2.22.255.2542.22.255.25516,382
932.23.0.0/182.23.0.1 to 2.23.63.2542.23.63.25516,382
942.23.64.0/182.23.64.1 to 2.23.127.2542.23.127.25516,382
952.23.128.0/182.23.128.1 to 2.23.191.2542.23.191.25516,382
962.23.192.0/182.23.192.1 to 2.23.255.2542.23.255.25516,382
972.24.0.0/182.24.0.1 to 2.24.63.2542.24.63.25516,382
982.24.64.0/182.24.64.1 to 2.24.127.2542.24.127.25516,382
992.24.128.0/182.24.128.1 to 2.24.191.2542.24.191.25516,382
1002.24.192.0/182.24.192.1 to 2.24.255.2542.24.255.25516,382
1012.25.0.0/182.25.0.1 to 2.25.63.2542.25.63.25516,382
1022.25.64.0/182.25.64.1 to 2.25.127.2542.25.127.25516,382
1032.25.128.0/182.25.128.1 to 2.25.191.2542.25.191.25516,382
1042.25.192.0/182.25.192.1 to 2.25.255.2542.25.255.25516,382
1052.26.0.0/182.26.0.1 to 2.26.63.2542.26.63.25516,382
1062.26.64.0/182.26.64.1 to 2.26.127.2542.26.127.25516,382
1072.26.128.0/182.26.128.1 to 2.26.191.2542.26.191.25516,382
1082.26.192.0/182.26.192.1 to 2.26.255.2542.26.255.25516,382
1092.27.0.0/182.27.0.1 to 2.27.63.2542.27.63.25516,382
1102.27.64.0/182.27.64.1 to 2.27.127.2542.27.127.25516,382
1112.27.128.0/182.27.128.1 to 2.27.191.2542.27.191.25516,382
1122.27.192.0/182.27.192.1 to 2.27.255.2542.27.255.25516,382
1132.28.0.0/182.28.0.1 to 2.28.63.2542.28.63.25516,382
1142.28.64.0/182.28.64.1 to 2.28.127.2542.28.127.25516,382
1152.28.128.0/182.28.128.1 to 2.28.191.2542.28.191.25516,382
1162.28.192.0/182.28.192.1 to 2.28.255.2542.28.255.25516,382
1172.29.0.0/182.29.0.1 to 2.29.63.2542.29.63.25516,382
1182.29.64.0/182.29.64.1 to 2.29.127.2542.29.127.25516,382
1192.29.128.0/182.29.128.1 to 2.29.191.2542.29.191.25516,382
1202.29.192.0/182.29.192.1 to 2.29.255.2542.29.255.25516,382
1212.30.0.0/182.30.0.1 to 2.30.63.2542.30.63.25516,382
1222.30.64.0/182.30.64.1 to 2.30.127.2542.30.127.25516,382
1232.30.128.0/182.30.128.1 to 2.30.191.2542.30.191.25516,382
1242.30.192.0/182.30.192.1 to 2.30.255.2542.30.255.25516,382
1252.31.0.0/182.31.0.1 to 2.31.63.2542.31.63.25516,382
1262.31.64.0/182.31.64.1 to 2.31.127.2542.31.127.25516,382
1272.31.128.0/182.31.128.1 to 2.31.191.2542.31.191.25516,382
1282.31.192.0/182.31.192.1 to 2.31.255.2542.31.255.25516,382
1292.32.0.0/182.32.0.1 to 2.32.63.2542.32.63.25516,382
1302.32.64.0/182.32.64.1 to 2.32.127.2542.32.127.25516,382
1312.32.128.0/182.32.128.1 to 2.32.191.2542.32.191.25516,382
1322.32.192.0/182.32.192.1 to 2.32.255.2542.32.255.25516,382
1332.33.0.0/182.33.0.1 to 2.33.63.2542.33.63.25516,382
1342.33.64.0/182.33.64.1 to 2.33.127.2542.33.127.25516,382
1352.33.128.0/182.33.128.1 to 2.33.191.2542.33.191.25516,382
1362.33.192.0/182.33.192.1 to 2.33.255.2542.33.255.25516,382
1372.34.0.0/182.34.0.1 to 2.34.63.2542.34.63.25516,382
1382.34.64.0/182.34.64.1 to 2.34.127.2542.34.127.25516,382
1392.34.128.0/182.34.128.1 to 2.34.191.2542.34.191.25516,382
1402.34.192.0/182.34.192.1 to 2.34.255.2542.34.255.25516,382
1412.35.0.0/182.35.0.1 to 2.35.63.2542.35.63.25516,382
1422.35.64.0/182.35.64.1 to 2.35.127.2542.35.127.25516,382
1432.35.128.0/182.35.128.1 to 2.35.191.2542.35.191.25516,382
1442.35.192.0/182.35.192.1 to 2.35.255.2542.35.255.25516,382
1452.36.0.0/182.36.0.1 to 2.36.63.2542.36.63.25516,382
1462.36.64.0/182.36.64.1 to 2.36.127.2542.36.127.25516,382
1472.36.128.0/182.36.128.1 to 2.36.191.2542.36.191.25516,382
1482.36.192.0/182.36.192.1 to 2.36.255.2542.36.255.25516,382
1492.37.0.0/182.37.0.1 to 2.37.63.2542.37.63.25516,382
1502.37.64.0/182.37.64.1 to 2.37.127.2542.37.127.25516,382
1512.37.128.0/182.37.128.1 to 2.37.191.2542.37.191.25516,382
1522.37.192.0/182.37.192.1 to 2.37.255.2542.37.255.25516,382
1532.38.0.0/182.38.0.1 to 2.38.63.2542.38.63.25516,382
1542.38.64.0/182.38.64.1 to 2.38.127.2542.38.127.25516,382
1552.38.128.0/182.38.128.1 to 2.38.191.2542.38.191.25516,382
1562.38.192.0/182.38.192.1 to 2.38.255.2542.38.255.25516,382
1572.39.0.0/182.39.0.1 to 2.39.63.2542.39.63.25516,382
1582.39.64.0/182.39.64.1 to 2.39.127.2542.39.127.25516,382
1592.39.128.0/182.39.128.1 to 2.39.191.2542.39.191.25516,382
1602.39.192.0/182.39.192.1 to 2.39.255.2542.39.255.25516,382
1612.40.0.0/182.40.0.1 to 2.40.63.2542.40.63.25516,382
1622.40.64.0/182.40.64.1 to 2.40.127.2542.40.127.25516,382
1632.40.128.0/182.40.128.1 to 2.40.191.2542.40.191.25516,382
1642.40.192.0/182.40.192.1 to 2.40.255.2542.40.255.25516,382
1652.41.0.0/182.41.0.1 to 2.41.63.2542.41.63.25516,382
1662.41.64.0/182.41.64.1 to 2.41.127.2542.41.127.25516,382
1672.41.128.0/182.41.128.1 to 2.41.191.2542.41.191.25516,382
1682.41.192.0/182.41.192.1 to 2.41.255.2542.41.255.25516,382
1692.42.0.0/182.42.0.1 to 2.42.63.2542.42.63.25516,382
1702.42.64.0/182.42.64.1 to 2.42.127.2542.42.127.25516,382
1712.42.128.0/182.42.128.1 to 2.42.191.2542.42.191.25516,382
1722.42.192.0/182.42.192.1 to 2.42.255.2542.42.255.25516,382
1732.43.0.0/182.43.0.1 to 2.43.63.2542.43.63.25516,382
1742.43.64.0/182.43.64.1 to 2.43.127.2542.43.127.25516,382
1752.43.128.0/182.43.128.1 to 2.43.191.2542.43.191.25516,382
1762.43.192.0/182.43.192.1 to 2.43.255.2542.43.255.25516,382
1772.44.0.0/182.44.0.1 to 2.44.63.2542.44.63.25516,382
1782.44.64.0/182.44.64.1 to 2.44.127.2542.44.127.25516,382
1792.44.128.0/182.44.128.1 to 2.44.191.2542.44.191.25516,382
1802.44.192.0/182.44.192.1 to 2.44.255.2542.44.255.25516,382
1812.45.0.0/182.45.0.1 to 2.45.63.2542.45.63.25516,382
1822.45.64.0/182.45.64.1 to 2.45.127.2542.45.127.25516,382
1832.45.128.0/182.45.128.1 to 2.45.191.2542.45.191.25516,382
1842.45.192.0/182.45.192.1 to 2.45.255.2542.45.255.25516,382
1852.46.0.0/182.46.0.1 to 2.46.63.2542.46.63.25516,382
1862.46.64.0/182.46.64.1 to 2.46.127.2542.46.127.25516,382
1872.46.128.0/182.46.128.1 to 2.46.191.2542.46.191.25516,382
1882.46.192.0/182.46.192.1 to 2.46.255.2542.46.255.25516,382
1892.47.0.0/182.47.0.1 to 2.47.63.2542.47.63.25516,382
1902.47.64.0/182.47.64.1 to 2.47.127.2542.47.127.25516,382
1912.47.128.0/182.47.128.1 to 2.47.191.2542.47.191.25516,382
1922.47.192.0/182.47.192.1 to 2.47.255.2542.47.255.25516,382
1932.48.0.0/182.48.0.1 to 2.48.63.2542.48.63.25516,382
1942.48.64.0/182.48.64.1 to 2.48.127.2542.48.127.25516,382
1952.48.128.0/182.48.128.1 to 2.48.191.2542.48.191.25516,382
1962.48.192.0/182.48.192.1 to 2.48.255.2542.48.255.25516,382
1972.49.0.0/182.49.0.1 to 2.49.63.2542.49.63.25516,382
1982.49.64.0/182.49.64.1 to 2.49.127.2542.49.127.25516,382
1992.49.128.0/182.49.128.1 to 2.49.191.2542.49.191.25516,382
2002.49.192.0/182.49.192.1 to 2.49.255.2542.49.255.25516,382
2012.50.0.0/182.50.0.1 to 2.50.63.2542.50.63.25516,382
2022.50.64.0/182.50.64.1 to 2.50.127.2542.50.127.25516,382
2032.50.128.0/182.50.128.1 to 2.50.191.2542.50.191.25516,382
2042.50.192.0/182.50.192.1 to 2.50.255.2542.50.255.25516,382
2052.51.0.0/182.51.0.1 to 2.51.63.2542.51.63.25516,382
2062.51.64.0/182.51.64.1 to 2.51.127.2542.51.127.25516,382
2072.51.128.0/182.51.128.1 to 2.51.191.2542.51.191.25516,382
2082.51.192.0/182.51.192.1 to 2.51.255.2542.51.255.25516,382
2092.52.0.0/182.52.0.1 to 2.52.63.2542.52.63.25516,382
2102.52.64.0/182.52.64.1 to 2.52.127.2542.52.127.25516,382
2112.52.128.0/182.52.128.1 to 2.52.191.2542.52.191.25516,382
2122.52.192.0/182.52.192.1 to 2.52.255.2542.52.255.25516,382
2132.53.0.0/182.53.0.1 to 2.53.63.2542.53.63.25516,382
2142.53.64.0/182.53.64.1 to 2.53.127.2542.53.127.25516,382
2152.53.128.0/182.53.128.1 to 2.53.191.2542.53.191.25516,382
2162.53.192.0/182.53.192.1 to 2.53.255.2542.53.255.25516,382
2172.54.0.0/182.54.0.1 to 2.54.63.2542.54.63.25516,382
2182.54.64.0/182.54.64.1 to 2.54.127.2542.54.127.25516,382
2192.54.128.0/182.54.128.1 to 2.54.191.2542.54.191.25516,382
2202.54.192.0/182.54.192.1 to 2.54.255.2542.54.255.25516,382
2212.55.0.0/182.55.0.1 to 2.55.63.2542.55.63.25516,382
2222.55.64.0/182.55.64.1 to 2.55.127.2542.55.127.25516,382
2232.55.128.0/182.55.128.1 to 2.55.191.2542.55.191.25516,382
2242.55.192.0/182.55.192.1 to 2.55.255.2542.55.255.25516,382
2252.56.0.0/182.56.0.1 to 2.56.63.2542.56.63.25516,382
2262.56.64.0/182.56.64.1 to 2.56.127.2542.56.127.25516,382
2272.56.128.0/182.56.128.1 to 2.56.191.2542.56.191.25516,382
2282.56.192.0/182.56.192.1 to 2.56.255.2542.56.255.25516,382
2292.57.0.0/182.57.0.1 to 2.57.63.2542.57.63.25516,382
2302.57.64.0/182.57.64.1 to 2.57.127.2542.57.127.25516,382
2312.57.128.0/182.57.128.1 to 2.57.191.2542.57.191.25516,382
2322.57.192.0/182.57.192.1 to 2.57.255.2542.57.255.25516,382
2332.58.0.0/182.58.0.1 to 2.58.63.2542.58.63.25516,382
2342.58.64.0/182.58.64.1 to 2.58.127.2542.58.127.25516,382
2352.58.128.0/182.58.128.1 to 2.58.191.2542.58.191.25516,382
2362.58.192.0/182.58.192.1 to 2.58.255.2542.58.255.25516,382
2372.59.0.0/182.59.0.1 to 2.59.63.2542.59.63.25516,382
2382.59.64.0/182.59.64.1 to 2.59.127.2542.59.127.25516,382
2392.59.128.0/182.59.128.1 to 2.59.191.2542.59.191.25516,382
2402.59.192.0/182.59.192.1 to 2.59.255.2542.59.255.25516,382
2412.60.0.0/182.60.0.1 to 2.60.63.2542.60.63.25516,382
2422.60.64.0/182.60.64.1 to 2.60.127.2542.60.127.25516,382
2432.60.128.0/182.60.128.1 to 2.60.191.2542.60.191.25516,382
2442.60.192.0/182.60.192.1 to 2.60.255.2542.60.255.25516,382
2452.61.0.0/182.61.0.1 to 2.61.63.2542.61.63.25516,382
2462.61.64.0/182.61.64.1 to 2.61.127.2542.61.127.25516,382
2472.61.128.0/182.61.128.1 to 2.61.191.2542.61.191.25516,382
2482.61.192.0/182.61.192.1 to 2.61.255.2542.61.255.25516,382
2492.62.0.0/182.62.0.1 to 2.62.63.2542.62.63.25516,382
2502.62.64.0/182.62.64.1 to 2.62.127.2542.62.127.25516,382
2512.62.128.0/182.62.128.1 to 2.62.191.2542.62.191.25516,382
2522.62.192.0/182.62.192.1 to 2.62.255.2542.62.255.25516,382
2532.63.0.0/182.63.0.1 to 2.63.63.2542.63.63.25516,382
2542.63.64.0/182.63.64.1 to 2.63.127.2542.63.127.25516,382
2552.63.128.0/182.63.128.1 to 2.63.191.2542.63.191.25516,382
2562.63.192.0/182.63.192.1 to 2.63.255.2542.63.255.25516,382

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.