Ontology helps semantic web to process and understand large amount of data available in Internet. Ontology uses concepts and their relationship with each other to represent knowledge within a domain. The represented knowledge can be analysed, inferred and reused to make decisions and to derive new knowledge. The developed ontology has to be assessed for quality before using or reusing it. Evaluation becomes a key factor to determine the quality of ontology. Different approaches and methods are used to ensure the quality desired by the user. This article identifies various aspects of ontology, provides a framework for metric based ontology evaluation, elucidates components in the framework and develops a tool based on the framework. The framework checks the syntax, structural and semantic measures of ontology. While a reasoner takes care of the syntax and parser errors, the structural metrics analyses the taxonomy of ontology. Semantic measures deal with the distance of concepts in ontology. Further, competency questions are used to do custom based quality checking of a particular domain. This article provides a systematic way to identify and measure the quality of ontology based on metrics.