This paper presents a comprehensive class inheritance metrics tool called ClassIN. The tool works for Java projects and presents an analysis with twenty different inheritance metrics including metrics at class level as well as at class hierarchy level. This also helps in identifying class hierarchies that may be more complex from the point of view of software maintenance. Graphical visualization of three important metrics, namely AID, specialization ratio and reuse ratio are also provided for an insight on structure of class hierarchies of a given Java project. This would help developers in identifying classes that may be more prone to faults or high maintenance costs.