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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.

Network2.208.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
2.208.0.0
Broadcast address
2.223.255.255
First usable
2.208.0.1
Last usable
2.223.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 02D00000 · Integer 47185920 to 48234495
Reverse DNS zones
208.2.in-addr.arpa
209.2.in-addr.arpa
210.2.in-addr.arpa
211.2.in-addr.arpa
212.2.in-addr.arpa
213.2.in-addr.arpa
214.2.in-addr.arpa
215.2.in-addr.arpa
216.2.in-addr.arpa
217.2.in-addr.arpa
218.2.in-addr.arpa
219.2.in-addr.arpa
220.2.in-addr.arpa
221.2.in-addr.arpa
222.2.in-addr.arpa
223.2.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000010.11010000.00000000.000000002.208.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00000010.11010000.00000000.000000002.208.0.0
Broadcast00000010.11011111.11111111.111111112.223.255.255
Split into smaller subnets/20
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

2.208.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
12.208.0.0/202.208.0.1 to 2.208.15.2542.208.15.2554,094
22.208.16.0/202.208.16.1 to 2.208.31.2542.208.31.2554,094
32.208.32.0/202.208.32.1 to 2.208.47.2542.208.47.2554,094
42.208.48.0/202.208.48.1 to 2.208.63.2542.208.63.2554,094
52.208.64.0/202.208.64.1 to 2.208.79.2542.208.79.2554,094
62.208.80.0/202.208.80.1 to 2.208.95.2542.208.95.2554,094
72.208.96.0/202.208.96.1 to 2.208.111.2542.208.111.2554,094
82.208.112.0/202.208.112.1 to 2.208.127.2542.208.127.2554,094
92.208.128.0/202.208.128.1 to 2.208.143.2542.208.143.2554,094
102.208.144.0/202.208.144.1 to 2.208.159.2542.208.159.2554,094
112.208.160.0/202.208.160.1 to 2.208.175.2542.208.175.2554,094
122.208.176.0/202.208.176.1 to 2.208.191.2542.208.191.2554,094
132.208.192.0/202.208.192.1 to 2.208.207.2542.208.207.2554,094
142.208.208.0/202.208.208.1 to 2.208.223.2542.208.223.2554,094
152.208.224.0/202.208.224.1 to 2.208.239.2542.208.239.2554,094
162.208.240.0/202.208.240.1 to 2.208.255.2542.208.255.2554,094
172.209.0.0/202.209.0.1 to 2.209.15.2542.209.15.2554,094
182.209.16.0/202.209.16.1 to 2.209.31.2542.209.31.2554,094
192.209.32.0/202.209.32.1 to 2.209.47.2542.209.47.2554,094
202.209.48.0/202.209.48.1 to 2.209.63.2542.209.63.2554,094
212.209.64.0/202.209.64.1 to 2.209.79.2542.209.79.2554,094
222.209.80.0/202.209.80.1 to 2.209.95.2542.209.95.2554,094
232.209.96.0/202.209.96.1 to 2.209.111.2542.209.111.2554,094
242.209.112.0/202.209.112.1 to 2.209.127.2542.209.127.2554,094
252.209.128.0/202.209.128.1 to 2.209.143.2542.209.143.2554,094
262.209.144.0/202.209.144.1 to 2.209.159.2542.209.159.2554,094
272.209.160.0/202.209.160.1 to 2.209.175.2542.209.175.2554,094
282.209.176.0/202.209.176.1 to 2.209.191.2542.209.191.2554,094
292.209.192.0/202.209.192.1 to 2.209.207.2542.209.207.2554,094
302.209.208.0/202.209.208.1 to 2.209.223.2542.209.223.2554,094
312.209.224.0/202.209.224.1 to 2.209.239.2542.209.239.2554,094
322.209.240.0/202.209.240.1 to 2.209.255.2542.209.255.2554,094
332.210.0.0/202.210.0.1 to 2.210.15.2542.210.15.2554,094
342.210.16.0/202.210.16.1 to 2.210.31.2542.210.31.2554,094
352.210.32.0/202.210.32.1 to 2.210.47.2542.210.47.2554,094
362.210.48.0/202.210.48.1 to 2.210.63.2542.210.63.2554,094
372.210.64.0/202.210.64.1 to 2.210.79.2542.210.79.2554,094
382.210.80.0/202.210.80.1 to 2.210.95.2542.210.95.2554,094
392.210.96.0/202.210.96.1 to 2.210.111.2542.210.111.2554,094
402.210.112.0/202.210.112.1 to 2.210.127.2542.210.127.2554,094
412.210.128.0/202.210.128.1 to 2.210.143.2542.210.143.2554,094
422.210.144.0/202.210.144.1 to 2.210.159.2542.210.159.2554,094
432.210.160.0/202.210.160.1 to 2.210.175.2542.210.175.2554,094
442.210.176.0/202.210.176.1 to 2.210.191.2542.210.191.2554,094
452.210.192.0/202.210.192.1 to 2.210.207.2542.210.207.2554,094
462.210.208.0/202.210.208.1 to 2.210.223.2542.210.223.2554,094
472.210.224.0/202.210.224.1 to 2.210.239.2542.210.239.2554,094
482.210.240.0/202.210.240.1 to 2.210.255.2542.210.255.2554,094
492.211.0.0/202.211.0.1 to 2.211.15.2542.211.15.2554,094
502.211.16.0/202.211.16.1 to 2.211.31.2542.211.31.2554,094
512.211.32.0/202.211.32.1 to 2.211.47.2542.211.47.2554,094
522.211.48.0/202.211.48.1 to 2.211.63.2542.211.63.2554,094
532.211.64.0/202.211.64.1 to 2.211.79.2542.211.79.2554,094
542.211.80.0/202.211.80.1 to 2.211.95.2542.211.95.2554,094
552.211.96.0/202.211.96.1 to 2.211.111.2542.211.111.2554,094
562.211.112.0/202.211.112.1 to 2.211.127.2542.211.127.2554,094
572.211.128.0/202.211.128.1 to 2.211.143.2542.211.143.2554,094
582.211.144.0/202.211.144.1 to 2.211.159.2542.211.159.2554,094
592.211.160.0/202.211.160.1 to 2.211.175.2542.211.175.2554,094
602.211.176.0/202.211.176.1 to 2.211.191.2542.211.191.2554,094
612.211.192.0/202.211.192.1 to 2.211.207.2542.211.207.2554,094
622.211.208.0/202.211.208.1 to 2.211.223.2542.211.223.2554,094
632.211.224.0/202.211.224.1 to 2.211.239.2542.211.239.2554,094
642.211.240.0/202.211.240.1 to 2.211.255.2542.211.255.2554,094
652.212.0.0/202.212.0.1 to 2.212.15.2542.212.15.2554,094
662.212.16.0/202.212.16.1 to 2.212.31.2542.212.31.2554,094
672.212.32.0/202.212.32.1 to 2.212.47.2542.212.47.2554,094
682.212.48.0/202.212.48.1 to 2.212.63.2542.212.63.2554,094
692.212.64.0/202.212.64.1 to 2.212.79.2542.212.79.2554,094
702.212.80.0/202.212.80.1 to 2.212.95.2542.212.95.2554,094
712.212.96.0/202.212.96.1 to 2.212.111.2542.212.111.2554,094
722.212.112.0/202.212.112.1 to 2.212.127.2542.212.127.2554,094
732.212.128.0/202.212.128.1 to 2.212.143.2542.212.143.2554,094
742.212.144.0/202.212.144.1 to 2.212.159.2542.212.159.2554,094
752.212.160.0/202.212.160.1 to 2.212.175.2542.212.175.2554,094
762.212.176.0/202.212.176.1 to 2.212.191.2542.212.191.2554,094
772.212.192.0/202.212.192.1 to 2.212.207.2542.212.207.2554,094
782.212.208.0/202.212.208.1 to 2.212.223.2542.212.223.2554,094
792.212.224.0/202.212.224.1 to 2.212.239.2542.212.239.2554,094
802.212.240.0/202.212.240.1 to 2.212.255.2542.212.255.2554,094
812.213.0.0/202.213.0.1 to 2.213.15.2542.213.15.2554,094
822.213.16.0/202.213.16.1 to 2.213.31.2542.213.31.2554,094
832.213.32.0/202.213.32.1 to 2.213.47.2542.213.47.2554,094
842.213.48.0/202.213.48.1 to 2.213.63.2542.213.63.2554,094
852.213.64.0/202.213.64.1 to 2.213.79.2542.213.79.2554,094
862.213.80.0/202.213.80.1 to 2.213.95.2542.213.95.2554,094
872.213.96.0/202.213.96.1 to 2.213.111.2542.213.111.2554,094
882.213.112.0/202.213.112.1 to 2.213.127.2542.213.127.2554,094
892.213.128.0/202.213.128.1 to 2.213.143.2542.213.143.2554,094
902.213.144.0/202.213.144.1 to 2.213.159.2542.213.159.2554,094
912.213.160.0/202.213.160.1 to 2.213.175.2542.213.175.2554,094
922.213.176.0/202.213.176.1 to 2.213.191.2542.213.191.2554,094
932.213.192.0/202.213.192.1 to 2.213.207.2542.213.207.2554,094
942.213.208.0/202.213.208.1 to 2.213.223.2542.213.223.2554,094
952.213.224.0/202.213.224.1 to 2.213.239.2542.213.239.2554,094
962.213.240.0/202.213.240.1 to 2.213.255.2542.213.255.2554,094
972.214.0.0/202.214.0.1 to 2.214.15.2542.214.15.2554,094
982.214.16.0/202.214.16.1 to 2.214.31.2542.214.31.2554,094
992.214.32.0/202.214.32.1 to 2.214.47.2542.214.47.2554,094
1002.214.48.0/202.214.48.1 to 2.214.63.2542.214.63.2554,094
1012.214.64.0/202.214.64.1 to 2.214.79.2542.214.79.2554,094
1022.214.80.0/202.214.80.1 to 2.214.95.2542.214.95.2554,094
1032.214.96.0/202.214.96.1 to 2.214.111.2542.214.111.2554,094
1042.214.112.0/202.214.112.1 to 2.214.127.2542.214.127.2554,094
1052.214.128.0/202.214.128.1 to 2.214.143.2542.214.143.2554,094
1062.214.144.0/202.214.144.1 to 2.214.159.2542.214.159.2554,094
1072.214.160.0/202.214.160.1 to 2.214.175.2542.214.175.2554,094
1082.214.176.0/202.214.176.1 to 2.214.191.2542.214.191.2554,094
1092.214.192.0/202.214.192.1 to 2.214.207.2542.214.207.2554,094
1102.214.208.0/202.214.208.1 to 2.214.223.2542.214.223.2554,094
1112.214.224.0/202.214.224.1 to 2.214.239.2542.214.239.2554,094
1122.214.240.0/202.214.240.1 to 2.214.255.2542.214.255.2554,094
1132.215.0.0/202.215.0.1 to 2.215.15.2542.215.15.2554,094
1142.215.16.0/202.215.16.1 to 2.215.31.2542.215.31.2554,094
1152.215.32.0/202.215.32.1 to 2.215.47.2542.215.47.2554,094
1162.215.48.0/202.215.48.1 to 2.215.63.2542.215.63.2554,094
1172.215.64.0/202.215.64.1 to 2.215.79.2542.215.79.2554,094
1182.215.80.0/202.215.80.1 to 2.215.95.2542.215.95.2554,094
1192.215.96.0/202.215.96.1 to 2.215.111.2542.215.111.2554,094
1202.215.112.0/202.215.112.1 to 2.215.127.2542.215.127.2554,094
1212.215.128.0/202.215.128.1 to 2.215.143.2542.215.143.2554,094
1222.215.144.0/202.215.144.1 to 2.215.159.2542.215.159.2554,094
1232.215.160.0/202.215.160.1 to 2.215.175.2542.215.175.2554,094
1242.215.176.0/202.215.176.1 to 2.215.191.2542.215.191.2554,094
1252.215.192.0/202.215.192.1 to 2.215.207.2542.215.207.2554,094
1262.215.208.0/202.215.208.1 to 2.215.223.2542.215.223.2554,094
1272.215.224.0/202.215.224.1 to 2.215.239.2542.215.239.2554,094
1282.215.240.0/202.215.240.1 to 2.215.255.2542.215.255.2554,094
1292.216.0.0/202.216.0.1 to 2.216.15.2542.216.15.2554,094
1302.216.16.0/202.216.16.1 to 2.216.31.2542.216.31.2554,094
1312.216.32.0/202.216.32.1 to 2.216.47.2542.216.47.2554,094
1322.216.48.0/202.216.48.1 to 2.216.63.2542.216.63.2554,094
1332.216.64.0/202.216.64.1 to 2.216.79.2542.216.79.2554,094
1342.216.80.0/202.216.80.1 to 2.216.95.2542.216.95.2554,094
1352.216.96.0/202.216.96.1 to 2.216.111.2542.216.111.2554,094
1362.216.112.0/202.216.112.1 to 2.216.127.2542.216.127.2554,094
1372.216.128.0/202.216.128.1 to 2.216.143.2542.216.143.2554,094
1382.216.144.0/202.216.144.1 to 2.216.159.2542.216.159.2554,094
1392.216.160.0/202.216.160.1 to 2.216.175.2542.216.175.2554,094
1402.216.176.0/202.216.176.1 to 2.216.191.2542.216.191.2554,094
1412.216.192.0/202.216.192.1 to 2.216.207.2542.216.207.2554,094
1422.216.208.0/202.216.208.1 to 2.216.223.2542.216.223.2554,094
1432.216.224.0/202.216.224.1 to 2.216.239.2542.216.239.2554,094
1442.216.240.0/202.216.240.1 to 2.216.255.2542.216.255.2554,094
1452.217.0.0/202.217.0.1 to 2.217.15.2542.217.15.2554,094
1462.217.16.0/202.217.16.1 to 2.217.31.2542.217.31.2554,094
1472.217.32.0/202.217.32.1 to 2.217.47.2542.217.47.2554,094
1482.217.48.0/202.217.48.1 to 2.217.63.2542.217.63.2554,094
1492.217.64.0/202.217.64.1 to 2.217.79.2542.217.79.2554,094
1502.217.80.0/202.217.80.1 to 2.217.95.2542.217.95.2554,094
1512.217.96.0/202.217.96.1 to 2.217.111.2542.217.111.2554,094
1522.217.112.0/202.217.112.1 to 2.217.127.2542.217.127.2554,094
1532.217.128.0/202.217.128.1 to 2.217.143.2542.217.143.2554,094
1542.217.144.0/202.217.144.1 to 2.217.159.2542.217.159.2554,094
1552.217.160.0/202.217.160.1 to 2.217.175.2542.217.175.2554,094
1562.217.176.0/202.217.176.1 to 2.217.191.2542.217.191.2554,094
1572.217.192.0/202.217.192.1 to 2.217.207.2542.217.207.2554,094
1582.217.208.0/202.217.208.1 to 2.217.223.2542.217.223.2554,094
1592.217.224.0/202.217.224.1 to 2.217.239.2542.217.239.2554,094
1602.217.240.0/202.217.240.1 to 2.217.255.2542.217.255.2554,094
1612.218.0.0/202.218.0.1 to 2.218.15.2542.218.15.2554,094
1622.218.16.0/202.218.16.1 to 2.218.31.2542.218.31.2554,094
1632.218.32.0/202.218.32.1 to 2.218.47.2542.218.47.2554,094
1642.218.48.0/202.218.48.1 to 2.218.63.2542.218.63.2554,094
1652.218.64.0/202.218.64.1 to 2.218.79.2542.218.79.2554,094
1662.218.80.0/202.218.80.1 to 2.218.95.2542.218.95.2554,094
1672.218.96.0/202.218.96.1 to 2.218.111.2542.218.111.2554,094
1682.218.112.0/202.218.112.1 to 2.218.127.2542.218.127.2554,094
1692.218.128.0/202.218.128.1 to 2.218.143.2542.218.143.2554,094
1702.218.144.0/202.218.144.1 to 2.218.159.2542.218.159.2554,094
1712.218.160.0/202.218.160.1 to 2.218.175.2542.218.175.2554,094
1722.218.176.0/202.218.176.1 to 2.218.191.2542.218.191.2554,094
1732.218.192.0/202.218.192.1 to 2.218.207.2542.218.207.2554,094
1742.218.208.0/202.218.208.1 to 2.218.223.2542.218.223.2554,094
1752.218.224.0/202.218.224.1 to 2.218.239.2542.218.239.2554,094
1762.218.240.0/202.218.240.1 to 2.218.255.2542.218.255.2554,094
1772.219.0.0/202.219.0.1 to 2.219.15.2542.219.15.2554,094
1782.219.16.0/202.219.16.1 to 2.219.31.2542.219.31.2554,094
1792.219.32.0/202.219.32.1 to 2.219.47.2542.219.47.2554,094
1802.219.48.0/202.219.48.1 to 2.219.63.2542.219.63.2554,094
1812.219.64.0/202.219.64.1 to 2.219.79.2542.219.79.2554,094
1822.219.80.0/202.219.80.1 to 2.219.95.2542.219.95.2554,094
1832.219.96.0/202.219.96.1 to 2.219.111.2542.219.111.2554,094
1842.219.112.0/202.219.112.1 to 2.219.127.2542.219.127.2554,094
1852.219.128.0/202.219.128.1 to 2.219.143.2542.219.143.2554,094
1862.219.144.0/202.219.144.1 to 2.219.159.2542.219.159.2554,094
1872.219.160.0/202.219.160.1 to 2.219.175.2542.219.175.2554,094
1882.219.176.0/202.219.176.1 to 2.219.191.2542.219.191.2554,094
1892.219.192.0/202.219.192.1 to 2.219.207.2542.219.207.2554,094
1902.219.208.0/202.219.208.1 to 2.219.223.2542.219.223.2554,094
1912.219.224.0/202.219.224.1 to 2.219.239.2542.219.239.2554,094
1922.219.240.0/202.219.240.1 to 2.219.255.2542.219.255.2554,094
1932.220.0.0/202.220.0.1 to 2.220.15.2542.220.15.2554,094
1942.220.16.0/202.220.16.1 to 2.220.31.2542.220.31.2554,094
1952.220.32.0/202.220.32.1 to 2.220.47.2542.220.47.2554,094
1962.220.48.0/202.220.48.1 to 2.220.63.2542.220.63.2554,094
1972.220.64.0/202.220.64.1 to 2.220.79.2542.220.79.2554,094
1982.220.80.0/202.220.80.1 to 2.220.95.2542.220.95.2554,094
1992.220.96.0/202.220.96.1 to 2.220.111.2542.220.111.2554,094
2002.220.112.0/202.220.112.1 to 2.220.127.2542.220.127.2554,094
2012.220.128.0/202.220.128.1 to 2.220.143.2542.220.143.2554,094
2022.220.144.0/202.220.144.1 to 2.220.159.2542.220.159.2554,094
2032.220.160.0/202.220.160.1 to 2.220.175.2542.220.175.2554,094
2042.220.176.0/202.220.176.1 to 2.220.191.2542.220.191.2554,094
2052.220.192.0/202.220.192.1 to 2.220.207.2542.220.207.2554,094
2062.220.208.0/202.220.208.1 to 2.220.223.2542.220.223.2554,094
2072.220.224.0/202.220.224.1 to 2.220.239.2542.220.239.2554,094
2082.220.240.0/202.220.240.1 to 2.220.255.2542.220.255.2554,094
2092.221.0.0/202.221.0.1 to 2.221.15.2542.221.15.2554,094
2102.221.16.0/202.221.16.1 to 2.221.31.2542.221.31.2554,094
2112.221.32.0/202.221.32.1 to 2.221.47.2542.221.47.2554,094
2122.221.48.0/202.221.48.1 to 2.221.63.2542.221.63.2554,094
2132.221.64.0/202.221.64.1 to 2.221.79.2542.221.79.2554,094
2142.221.80.0/202.221.80.1 to 2.221.95.2542.221.95.2554,094
2152.221.96.0/202.221.96.1 to 2.221.111.2542.221.111.2554,094
2162.221.112.0/202.221.112.1 to 2.221.127.2542.221.127.2554,094
2172.221.128.0/202.221.128.1 to 2.221.143.2542.221.143.2554,094
2182.221.144.0/202.221.144.1 to 2.221.159.2542.221.159.2554,094
2192.221.160.0/202.221.160.1 to 2.221.175.2542.221.175.2554,094
2202.221.176.0/202.221.176.1 to 2.221.191.2542.221.191.2554,094
2212.221.192.0/202.221.192.1 to 2.221.207.2542.221.207.2554,094
2222.221.208.0/202.221.208.1 to 2.221.223.2542.221.223.2554,094
2232.221.224.0/202.221.224.1 to 2.221.239.2542.221.239.2554,094
2242.221.240.0/202.221.240.1 to 2.221.255.2542.221.255.2554,094
2252.222.0.0/202.222.0.1 to 2.222.15.2542.222.15.2554,094
2262.222.16.0/202.222.16.1 to 2.222.31.2542.222.31.2554,094
2272.222.32.0/202.222.32.1 to 2.222.47.2542.222.47.2554,094
2282.222.48.0/202.222.48.1 to 2.222.63.2542.222.63.2554,094
2292.222.64.0/202.222.64.1 to 2.222.79.2542.222.79.2554,094
2302.222.80.0/202.222.80.1 to 2.222.95.2542.222.95.2554,094
2312.222.96.0/202.222.96.1 to 2.222.111.2542.222.111.2554,094
2322.222.112.0/202.222.112.1 to 2.222.127.2542.222.127.2554,094
2332.222.128.0/202.222.128.1 to 2.222.143.2542.222.143.2554,094
2342.222.144.0/202.222.144.1 to 2.222.159.2542.222.159.2554,094
2352.222.160.0/202.222.160.1 to 2.222.175.2542.222.175.2554,094
2362.222.176.0/202.222.176.1 to 2.222.191.2542.222.191.2554,094
2372.222.192.0/202.222.192.1 to 2.222.207.2542.222.207.2554,094
2382.222.208.0/202.222.208.1 to 2.222.223.2542.222.223.2554,094
2392.222.224.0/202.222.224.1 to 2.222.239.2542.222.239.2554,094
2402.222.240.0/202.222.240.1 to 2.222.255.2542.222.255.2554,094
2412.223.0.0/202.223.0.1 to 2.223.15.2542.223.15.2554,094
2422.223.16.0/202.223.16.1 to 2.223.31.2542.223.31.2554,094
2432.223.32.0/202.223.32.1 to 2.223.47.2542.223.47.2554,094
2442.223.48.0/202.223.48.1 to 2.223.63.2542.223.63.2554,094
2452.223.64.0/202.223.64.1 to 2.223.79.2542.223.79.2554,094
2462.223.80.0/202.223.80.1 to 2.223.95.2542.223.95.2554,094
2472.223.96.0/202.223.96.1 to 2.223.111.2542.223.111.2554,094
2482.223.112.0/202.223.112.1 to 2.223.127.2542.223.127.2554,094
2492.223.128.0/202.223.128.1 to 2.223.143.2542.223.143.2554,094
2502.223.144.0/202.223.144.1 to 2.223.159.2542.223.159.2554,094
2512.223.160.0/202.223.160.1 to 2.223.175.2542.223.175.2554,094
2522.223.176.0/202.223.176.1 to 2.223.191.2542.223.191.2554,094
2532.223.192.0/202.223.192.1 to 2.223.207.2542.223.207.2554,094
2542.223.208.0/202.223.208.1 to 2.223.223.2542.223.223.2554,094
2552.223.224.0/202.223.224.1 to 2.223.239.2542.223.239.2554,094
2562.223.240.0/202.223.240.1 to 2.223.255.2542.223.255.2554,094

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.