ip address subnet calculator

IP Multicast address ranges

224.0.0.0 - 224.0.0.255      Well-known multicast addresses, control channels
224.0.1.0 - 238.255.255.255  Globally-scoped (Internet-wide) multicast addresses
239.0.0.0 - 239.255.255.255  Local multicast addresses

Private address ranges

10.0.0.0 - 10.255.255.255  A 24-bit block, /8, class A network
172.16.0.0 - 172.31.255.255  A 20-bit block, /12, set of 16 contiguous class B network numbers
192.168.0.0 - 192.168.255.255  A 16-bit block, /16, set of 255 contiguous 

Overview of common subnets and masks

Mask Hosts  Usable Netmask          Hex Mask
/30  4      2      255.255.255.252  fffffffc  this is 1/64 of a Class C net
/29  8      6      255.255.255.248  fffffff8  this is 1/32 of a Class C net
/28  16     14     255.255.255.240  fffffff0  this is 1/16 of a Class C net
/27  32     30     255.255.255.224  ffffffe0  this is 1/8 of a Class C net
/26  64     62     255.255.255.192  ffffffc0  this is 1/4 of a Class C net
/24  256    254    255.255.255.0    ffffff00  this is a Class C net
/23  512    510    255.255.254.0    fffffe00  these are 2 Class C net
/22  1024   1022   255.255.252.0    fffffc00  these are 4 Class C net
/21  2048   2046   255.255.248.0    fffff800  these are 8 Class C net
/20  4096   4094   255.255.240.0    fffff000  these are 16 Class C net
/19  8192   8190   255.255.224.0    ffffe000  these are 32 Class C net
/18  16384  16382  255.255.192.0    ffffc000  these are 64 Class C net
/17  32768  32766  255.255.128.0    ffff8000  these are 128 Class C net
/16  65536  65534  255.255.0.0      ffff0000  these are 256 Class C net = Class B net