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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.

Network6.144.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
6.144.0.0
Broadcast address
6.159.255.255
First usable
6.144.0.1
Last usable
6.159.255.254
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 06900000 · Integer 110100480 to 111149055
Reverse DNS zones
144.6.in-addr.arpa
145.6.in-addr.arpa
146.6.in-addr.arpa
147.6.in-addr.arpa
148.6.in-addr.arpa
149.6.in-addr.arpa
150.6.in-addr.arpa
151.6.in-addr.arpa
152.6.in-addr.arpa
153.6.in-addr.arpa
154.6.in-addr.arpa
155.6.in-addr.arpa
156.6.in-addr.arpa
157.6.in-addr.arpa
158.6.in-addr.arpa
159.6.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
Address00000110.10010000.00000000.000000006.144.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00000110.10010000.00000000.000000006.144.0.0
Broadcast00000110.10011111.11111111.111111116.159.255.255
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)

6.144.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
16.144.0.0/206.144.0.1 to 6.144.15.2546.144.15.2554,094
26.144.16.0/206.144.16.1 to 6.144.31.2546.144.31.2554,094
36.144.32.0/206.144.32.1 to 6.144.47.2546.144.47.2554,094
46.144.48.0/206.144.48.1 to 6.144.63.2546.144.63.2554,094
56.144.64.0/206.144.64.1 to 6.144.79.2546.144.79.2554,094
66.144.80.0/206.144.80.1 to 6.144.95.2546.144.95.2554,094
76.144.96.0/206.144.96.1 to 6.144.111.2546.144.111.2554,094
86.144.112.0/206.144.112.1 to 6.144.127.2546.144.127.2554,094
96.144.128.0/206.144.128.1 to 6.144.143.2546.144.143.2554,094
106.144.144.0/206.144.144.1 to 6.144.159.2546.144.159.2554,094
116.144.160.0/206.144.160.1 to 6.144.175.2546.144.175.2554,094
126.144.176.0/206.144.176.1 to 6.144.191.2546.144.191.2554,094
136.144.192.0/206.144.192.1 to 6.144.207.2546.144.207.2554,094
146.144.208.0/206.144.208.1 to 6.144.223.2546.144.223.2554,094
156.144.224.0/206.144.224.1 to 6.144.239.2546.144.239.2554,094
166.144.240.0/206.144.240.1 to 6.144.255.2546.144.255.2554,094
176.145.0.0/206.145.0.1 to 6.145.15.2546.145.15.2554,094
186.145.16.0/206.145.16.1 to 6.145.31.2546.145.31.2554,094
196.145.32.0/206.145.32.1 to 6.145.47.2546.145.47.2554,094
206.145.48.0/206.145.48.1 to 6.145.63.2546.145.63.2554,094
216.145.64.0/206.145.64.1 to 6.145.79.2546.145.79.2554,094
226.145.80.0/206.145.80.1 to 6.145.95.2546.145.95.2554,094
236.145.96.0/206.145.96.1 to 6.145.111.2546.145.111.2554,094
246.145.112.0/206.145.112.1 to 6.145.127.2546.145.127.2554,094
256.145.128.0/206.145.128.1 to 6.145.143.2546.145.143.2554,094
266.145.144.0/206.145.144.1 to 6.145.159.2546.145.159.2554,094
276.145.160.0/206.145.160.1 to 6.145.175.2546.145.175.2554,094
286.145.176.0/206.145.176.1 to 6.145.191.2546.145.191.2554,094
296.145.192.0/206.145.192.1 to 6.145.207.2546.145.207.2554,094
306.145.208.0/206.145.208.1 to 6.145.223.2546.145.223.2554,094
316.145.224.0/206.145.224.1 to 6.145.239.2546.145.239.2554,094
326.145.240.0/206.145.240.1 to 6.145.255.2546.145.255.2554,094
336.146.0.0/206.146.0.1 to 6.146.15.2546.146.15.2554,094
346.146.16.0/206.146.16.1 to 6.146.31.2546.146.31.2554,094
356.146.32.0/206.146.32.1 to 6.146.47.2546.146.47.2554,094
366.146.48.0/206.146.48.1 to 6.146.63.2546.146.63.2554,094
376.146.64.0/206.146.64.1 to 6.146.79.2546.146.79.2554,094
386.146.80.0/206.146.80.1 to 6.146.95.2546.146.95.2554,094
396.146.96.0/206.146.96.1 to 6.146.111.2546.146.111.2554,094
406.146.112.0/206.146.112.1 to 6.146.127.2546.146.127.2554,094
416.146.128.0/206.146.128.1 to 6.146.143.2546.146.143.2554,094
426.146.144.0/206.146.144.1 to 6.146.159.2546.146.159.2554,094
436.146.160.0/206.146.160.1 to 6.146.175.2546.146.175.2554,094
446.146.176.0/206.146.176.1 to 6.146.191.2546.146.191.2554,094
456.146.192.0/206.146.192.1 to 6.146.207.2546.146.207.2554,094
466.146.208.0/206.146.208.1 to 6.146.223.2546.146.223.2554,094
476.146.224.0/206.146.224.1 to 6.146.239.2546.146.239.2554,094
486.146.240.0/206.146.240.1 to 6.146.255.2546.146.255.2554,094
496.147.0.0/206.147.0.1 to 6.147.15.2546.147.15.2554,094
506.147.16.0/206.147.16.1 to 6.147.31.2546.147.31.2554,094
516.147.32.0/206.147.32.1 to 6.147.47.2546.147.47.2554,094
526.147.48.0/206.147.48.1 to 6.147.63.2546.147.63.2554,094
536.147.64.0/206.147.64.1 to 6.147.79.2546.147.79.2554,094
546.147.80.0/206.147.80.1 to 6.147.95.2546.147.95.2554,094
556.147.96.0/206.147.96.1 to 6.147.111.2546.147.111.2554,094
566.147.112.0/206.147.112.1 to 6.147.127.2546.147.127.2554,094
576.147.128.0/206.147.128.1 to 6.147.143.2546.147.143.2554,094
586.147.144.0/206.147.144.1 to 6.147.159.2546.147.159.2554,094
596.147.160.0/206.147.160.1 to 6.147.175.2546.147.175.2554,094
606.147.176.0/206.147.176.1 to 6.147.191.2546.147.191.2554,094
616.147.192.0/206.147.192.1 to 6.147.207.2546.147.207.2554,094
626.147.208.0/206.147.208.1 to 6.147.223.2546.147.223.2554,094
636.147.224.0/206.147.224.1 to 6.147.239.2546.147.239.2554,094
646.147.240.0/206.147.240.1 to 6.147.255.2546.147.255.2554,094
656.148.0.0/206.148.0.1 to 6.148.15.2546.148.15.2554,094
666.148.16.0/206.148.16.1 to 6.148.31.2546.148.31.2554,094
676.148.32.0/206.148.32.1 to 6.148.47.2546.148.47.2554,094
686.148.48.0/206.148.48.1 to 6.148.63.2546.148.63.2554,094
696.148.64.0/206.148.64.1 to 6.148.79.2546.148.79.2554,094
706.148.80.0/206.148.80.1 to 6.148.95.2546.148.95.2554,094
716.148.96.0/206.148.96.1 to 6.148.111.2546.148.111.2554,094
726.148.112.0/206.148.112.1 to 6.148.127.2546.148.127.2554,094
736.148.128.0/206.148.128.1 to 6.148.143.2546.148.143.2554,094
746.148.144.0/206.148.144.1 to 6.148.159.2546.148.159.2554,094
756.148.160.0/206.148.160.1 to 6.148.175.2546.148.175.2554,094
766.148.176.0/206.148.176.1 to 6.148.191.2546.148.191.2554,094
776.148.192.0/206.148.192.1 to 6.148.207.2546.148.207.2554,094
786.148.208.0/206.148.208.1 to 6.148.223.2546.148.223.2554,094
796.148.224.0/206.148.224.1 to 6.148.239.2546.148.239.2554,094
806.148.240.0/206.148.240.1 to 6.148.255.2546.148.255.2554,094
816.149.0.0/206.149.0.1 to 6.149.15.2546.149.15.2554,094
826.149.16.0/206.149.16.1 to 6.149.31.2546.149.31.2554,094
836.149.32.0/206.149.32.1 to 6.149.47.2546.149.47.2554,094
846.149.48.0/206.149.48.1 to 6.149.63.2546.149.63.2554,094
856.149.64.0/206.149.64.1 to 6.149.79.2546.149.79.2554,094
866.149.80.0/206.149.80.1 to 6.149.95.2546.149.95.2554,094
876.149.96.0/206.149.96.1 to 6.149.111.2546.149.111.2554,094
886.149.112.0/206.149.112.1 to 6.149.127.2546.149.127.2554,094
896.149.128.0/206.149.128.1 to 6.149.143.2546.149.143.2554,094
906.149.144.0/206.149.144.1 to 6.149.159.2546.149.159.2554,094
916.149.160.0/206.149.160.1 to 6.149.175.2546.149.175.2554,094
926.149.176.0/206.149.176.1 to 6.149.191.2546.149.191.2554,094
936.149.192.0/206.149.192.1 to 6.149.207.2546.149.207.2554,094
946.149.208.0/206.149.208.1 to 6.149.223.2546.149.223.2554,094
956.149.224.0/206.149.224.1 to 6.149.239.2546.149.239.2554,094
966.149.240.0/206.149.240.1 to 6.149.255.2546.149.255.2554,094
976.150.0.0/206.150.0.1 to 6.150.15.2546.150.15.2554,094
986.150.16.0/206.150.16.1 to 6.150.31.2546.150.31.2554,094
996.150.32.0/206.150.32.1 to 6.150.47.2546.150.47.2554,094
1006.150.48.0/206.150.48.1 to 6.150.63.2546.150.63.2554,094
1016.150.64.0/206.150.64.1 to 6.150.79.2546.150.79.2554,094
1026.150.80.0/206.150.80.1 to 6.150.95.2546.150.95.2554,094
1036.150.96.0/206.150.96.1 to 6.150.111.2546.150.111.2554,094
1046.150.112.0/206.150.112.1 to 6.150.127.2546.150.127.2554,094
1056.150.128.0/206.150.128.1 to 6.150.143.2546.150.143.2554,094
1066.150.144.0/206.150.144.1 to 6.150.159.2546.150.159.2554,094
1076.150.160.0/206.150.160.1 to 6.150.175.2546.150.175.2554,094
1086.150.176.0/206.150.176.1 to 6.150.191.2546.150.191.2554,094
1096.150.192.0/206.150.192.1 to 6.150.207.2546.150.207.2554,094
1106.150.208.0/206.150.208.1 to 6.150.223.2546.150.223.2554,094
1116.150.224.0/206.150.224.1 to 6.150.239.2546.150.239.2554,094
1126.150.240.0/206.150.240.1 to 6.150.255.2546.150.255.2554,094
1136.151.0.0/206.151.0.1 to 6.151.15.2546.151.15.2554,094
1146.151.16.0/206.151.16.1 to 6.151.31.2546.151.31.2554,094
1156.151.32.0/206.151.32.1 to 6.151.47.2546.151.47.2554,094
1166.151.48.0/206.151.48.1 to 6.151.63.2546.151.63.2554,094
1176.151.64.0/206.151.64.1 to 6.151.79.2546.151.79.2554,094
1186.151.80.0/206.151.80.1 to 6.151.95.2546.151.95.2554,094
1196.151.96.0/206.151.96.1 to 6.151.111.2546.151.111.2554,094
1206.151.112.0/206.151.112.1 to 6.151.127.2546.151.127.2554,094
1216.151.128.0/206.151.128.1 to 6.151.143.2546.151.143.2554,094
1226.151.144.0/206.151.144.1 to 6.151.159.2546.151.159.2554,094
1236.151.160.0/206.151.160.1 to 6.151.175.2546.151.175.2554,094
1246.151.176.0/206.151.176.1 to 6.151.191.2546.151.191.2554,094
1256.151.192.0/206.151.192.1 to 6.151.207.2546.151.207.2554,094
1266.151.208.0/206.151.208.1 to 6.151.223.2546.151.223.2554,094
1276.151.224.0/206.151.224.1 to 6.151.239.2546.151.239.2554,094
1286.151.240.0/206.151.240.1 to 6.151.255.2546.151.255.2554,094
1296.152.0.0/206.152.0.1 to 6.152.15.2546.152.15.2554,094
1306.152.16.0/206.152.16.1 to 6.152.31.2546.152.31.2554,094
1316.152.32.0/206.152.32.1 to 6.152.47.2546.152.47.2554,094
1326.152.48.0/206.152.48.1 to 6.152.63.2546.152.63.2554,094
1336.152.64.0/206.152.64.1 to 6.152.79.2546.152.79.2554,094
1346.152.80.0/206.152.80.1 to 6.152.95.2546.152.95.2554,094
1356.152.96.0/206.152.96.1 to 6.152.111.2546.152.111.2554,094
1366.152.112.0/206.152.112.1 to 6.152.127.2546.152.127.2554,094
1376.152.128.0/206.152.128.1 to 6.152.143.2546.152.143.2554,094
1386.152.144.0/206.152.144.1 to 6.152.159.2546.152.159.2554,094
1396.152.160.0/206.152.160.1 to 6.152.175.2546.152.175.2554,094
1406.152.176.0/206.152.176.1 to 6.152.191.2546.152.191.2554,094
1416.152.192.0/206.152.192.1 to 6.152.207.2546.152.207.2554,094
1426.152.208.0/206.152.208.1 to 6.152.223.2546.152.223.2554,094
1436.152.224.0/206.152.224.1 to 6.152.239.2546.152.239.2554,094
1446.152.240.0/206.152.240.1 to 6.152.255.2546.152.255.2554,094
1456.153.0.0/206.153.0.1 to 6.153.15.2546.153.15.2554,094
1466.153.16.0/206.153.16.1 to 6.153.31.2546.153.31.2554,094
1476.153.32.0/206.153.32.1 to 6.153.47.2546.153.47.2554,094
1486.153.48.0/206.153.48.1 to 6.153.63.2546.153.63.2554,094
1496.153.64.0/206.153.64.1 to 6.153.79.2546.153.79.2554,094
1506.153.80.0/206.153.80.1 to 6.153.95.2546.153.95.2554,094
1516.153.96.0/206.153.96.1 to 6.153.111.2546.153.111.2554,094
1526.153.112.0/206.153.112.1 to 6.153.127.2546.153.127.2554,094
1536.153.128.0/206.153.128.1 to 6.153.143.2546.153.143.2554,094
1546.153.144.0/206.153.144.1 to 6.153.159.2546.153.159.2554,094
1556.153.160.0/206.153.160.1 to 6.153.175.2546.153.175.2554,094
1566.153.176.0/206.153.176.1 to 6.153.191.2546.153.191.2554,094
1576.153.192.0/206.153.192.1 to 6.153.207.2546.153.207.2554,094
1586.153.208.0/206.153.208.1 to 6.153.223.2546.153.223.2554,094
1596.153.224.0/206.153.224.1 to 6.153.239.2546.153.239.2554,094
1606.153.240.0/206.153.240.1 to 6.153.255.2546.153.255.2554,094
1616.154.0.0/206.154.0.1 to 6.154.15.2546.154.15.2554,094
1626.154.16.0/206.154.16.1 to 6.154.31.2546.154.31.2554,094
1636.154.32.0/206.154.32.1 to 6.154.47.2546.154.47.2554,094
1646.154.48.0/206.154.48.1 to 6.154.63.2546.154.63.2554,094
1656.154.64.0/206.154.64.1 to 6.154.79.2546.154.79.2554,094
1666.154.80.0/206.154.80.1 to 6.154.95.2546.154.95.2554,094
1676.154.96.0/206.154.96.1 to 6.154.111.2546.154.111.2554,094
1686.154.112.0/206.154.112.1 to 6.154.127.2546.154.127.2554,094
1696.154.128.0/206.154.128.1 to 6.154.143.2546.154.143.2554,094
1706.154.144.0/206.154.144.1 to 6.154.159.2546.154.159.2554,094
1716.154.160.0/206.154.160.1 to 6.154.175.2546.154.175.2554,094
1726.154.176.0/206.154.176.1 to 6.154.191.2546.154.191.2554,094
1736.154.192.0/206.154.192.1 to 6.154.207.2546.154.207.2554,094
1746.154.208.0/206.154.208.1 to 6.154.223.2546.154.223.2554,094
1756.154.224.0/206.154.224.1 to 6.154.239.2546.154.239.2554,094
1766.154.240.0/206.154.240.1 to 6.154.255.2546.154.255.2554,094
1776.155.0.0/206.155.0.1 to 6.155.15.2546.155.15.2554,094
1786.155.16.0/206.155.16.1 to 6.155.31.2546.155.31.2554,094
1796.155.32.0/206.155.32.1 to 6.155.47.2546.155.47.2554,094
1806.155.48.0/206.155.48.1 to 6.155.63.2546.155.63.2554,094
1816.155.64.0/206.155.64.1 to 6.155.79.2546.155.79.2554,094
1826.155.80.0/206.155.80.1 to 6.155.95.2546.155.95.2554,094
1836.155.96.0/206.155.96.1 to 6.155.111.2546.155.111.2554,094
1846.155.112.0/206.155.112.1 to 6.155.127.2546.155.127.2554,094
1856.155.128.0/206.155.128.1 to 6.155.143.2546.155.143.2554,094
1866.155.144.0/206.155.144.1 to 6.155.159.2546.155.159.2554,094
1876.155.160.0/206.155.160.1 to 6.155.175.2546.155.175.2554,094
1886.155.176.0/206.155.176.1 to 6.155.191.2546.155.191.2554,094
1896.155.192.0/206.155.192.1 to 6.155.207.2546.155.207.2554,094
1906.155.208.0/206.155.208.1 to 6.155.223.2546.155.223.2554,094
1916.155.224.0/206.155.224.1 to 6.155.239.2546.155.239.2554,094
1926.155.240.0/206.155.240.1 to 6.155.255.2546.155.255.2554,094
1936.156.0.0/206.156.0.1 to 6.156.15.2546.156.15.2554,094
1946.156.16.0/206.156.16.1 to 6.156.31.2546.156.31.2554,094
1956.156.32.0/206.156.32.1 to 6.156.47.2546.156.47.2554,094
1966.156.48.0/206.156.48.1 to 6.156.63.2546.156.63.2554,094
1976.156.64.0/206.156.64.1 to 6.156.79.2546.156.79.2554,094
1986.156.80.0/206.156.80.1 to 6.156.95.2546.156.95.2554,094
1996.156.96.0/206.156.96.1 to 6.156.111.2546.156.111.2554,094
2006.156.112.0/206.156.112.1 to 6.156.127.2546.156.127.2554,094
2016.156.128.0/206.156.128.1 to 6.156.143.2546.156.143.2554,094
2026.156.144.0/206.156.144.1 to 6.156.159.2546.156.159.2554,094
2036.156.160.0/206.156.160.1 to 6.156.175.2546.156.175.2554,094
2046.156.176.0/206.156.176.1 to 6.156.191.2546.156.191.2554,094
2056.156.192.0/206.156.192.1 to 6.156.207.2546.156.207.2554,094
2066.156.208.0/206.156.208.1 to 6.156.223.2546.156.223.2554,094
2076.156.224.0/206.156.224.1 to 6.156.239.2546.156.239.2554,094
2086.156.240.0/206.156.240.1 to 6.156.255.2546.156.255.2554,094
2096.157.0.0/206.157.0.1 to 6.157.15.2546.157.15.2554,094
2106.157.16.0/206.157.16.1 to 6.157.31.2546.157.31.2554,094
2116.157.32.0/206.157.32.1 to 6.157.47.2546.157.47.2554,094
2126.157.48.0/206.157.48.1 to 6.157.63.2546.157.63.2554,094
2136.157.64.0/206.157.64.1 to 6.157.79.2546.157.79.2554,094
2146.157.80.0/206.157.80.1 to 6.157.95.2546.157.95.2554,094
2156.157.96.0/206.157.96.1 to 6.157.111.2546.157.111.2554,094
2166.157.112.0/206.157.112.1 to 6.157.127.2546.157.127.2554,094
2176.157.128.0/206.157.128.1 to 6.157.143.2546.157.143.2554,094
2186.157.144.0/206.157.144.1 to 6.157.159.2546.157.159.2554,094
2196.157.160.0/206.157.160.1 to 6.157.175.2546.157.175.2554,094
2206.157.176.0/206.157.176.1 to 6.157.191.2546.157.191.2554,094
2216.157.192.0/206.157.192.1 to 6.157.207.2546.157.207.2554,094
2226.157.208.0/206.157.208.1 to 6.157.223.2546.157.223.2554,094
2236.157.224.0/206.157.224.1 to 6.157.239.2546.157.239.2554,094
2246.157.240.0/206.157.240.1 to 6.157.255.2546.157.255.2554,094
2256.158.0.0/206.158.0.1 to 6.158.15.2546.158.15.2554,094
2266.158.16.0/206.158.16.1 to 6.158.31.2546.158.31.2554,094
2276.158.32.0/206.158.32.1 to 6.158.47.2546.158.47.2554,094
2286.158.48.0/206.158.48.1 to 6.158.63.2546.158.63.2554,094
2296.158.64.0/206.158.64.1 to 6.158.79.2546.158.79.2554,094
2306.158.80.0/206.158.80.1 to 6.158.95.2546.158.95.2554,094
2316.158.96.0/206.158.96.1 to 6.158.111.2546.158.111.2554,094
2326.158.112.0/206.158.112.1 to 6.158.127.2546.158.127.2554,094
2336.158.128.0/206.158.128.1 to 6.158.143.2546.158.143.2554,094
2346.158.144.0/206.158.144.1 to 6.158.159.2546.158.159.2554,094
2356.158.160.0/206.158.160.1 to 6.158.175.2546.158.175.2554,094
2366.158.176.0/206.158.176.1 to 6.158.191.2546.158.191.2554,094
2376.158.192.0/206.158.192.1 to 6.158.207.2546.158.207.2554,094
2386.158.208.0/206.158.208.1 to 6.158.223.2546.158.223.2554,094
2396.158.224.0/206.158.224.1 to 6.158.239.2546.158.239.2554,094
2406.158.240.0/206.158.240.1 to 6.158.255.2546.158.255.2554,094
2416.159.0.0/206.159.0.1 to 6.159.15.2546.159.15.2554,094
2426.159.16.0/206.159.16.1 to 6.159.31.2546.159.31.2554,094
2436.159.32.0/206.159.32.1 to 6.159.47.2546.159.47.2554,094
2446.159.48.0/206.159.48.1 to 6.159.63.2546.159.63.2554,094
2456.159.64.0/206.159.64.1 to 6.159.79.2546.159.79.2554,094
2466.159.80.0/206.159.80.1 to 6.159.95.2546.159.95.2554,094
2476.159.96.0/206.159.96.1 to 6.159.111.2546.159.111.2554,094
2486.159.112.0/206.159.112.1 to 6.159.127.2546.159.127.2554,094
2496.159.128.0/206.159.128.1 to 6.159.143.2546.159.143.2554,094
2506.159.144.0/206.159.144.1 to 6.159.159.2546.159.159.2554,094
2516.159.160.0/206.159.160.1 to 6.159.175.2546.159.175.2554,094
2526.159.176.0/206.159.176.1 to 6.159.191.2546.159.191.2554,094
2536.159.192.0/206.159.192.1 to 6.159.207.2546.159.207.2554,094
2546.159.208.0/206.159.208.1 to 6.159.223.2546.159.223.2554,094
2556.159.224.0/206.159.224.1 to 6.159.239.2546.159.239.2554,094
2566.159.240.0/206.159.240.1 to 6.159.255.2546.159.255.2554,094

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.