ATS SubCalc is a simple and intuitive classful subnet calculator designed for the iPhone for quick and easy use by network engineers on the go.

After being given an IP address, ATS SubCalc will compute the subnet mask, subnet bits, total mask bits, maximum number of subnets, maximum number of hosts, subnet ID, subnet broadcast address, and host range. After this, the subnet mask, subnet bits, max subnets, mask bits, or max hosts can be quickly adjusted by tapping on them, causing the rest of the data to recalculate automatically with a valid classful configuration for the respective IP.