Object-oriented design is turn out to be more significant in software development environment as stated by the IEEE standard thesaurus of software engineering. It also concludes that software metrics are much more vital in software engineering for determining the software quality characteristics. There are many approaches by virtue of which they can measure the software cost estimation plus predicates on numerous types of deliverable items. Metric tools are used to estimate the measures like lines of code object point, function points, etc. This paper highlights mostly the classification of software quality metrics like size metrics, complexity metrics etc. and different metrics tools.