This paper presents an application that allows you to calculate the main parameters that define an IP address based on the host's IP address and his subnet mask. Computed parameters are: network address or subnet of which the IP address, the number of bits borrowed, the number of subnets created, the number of hosts in each subnet, broadcast address and list all subnets created. These parameters are calculated taking into account both class division and using the CIDR. Application also converts the decimal IP address value in binary, integer and hexadecimal.