The best elucidations to software development problems are regularly touted as object-oriented processes. The popularity of object-oriented design metrics is essential in software engineering for measuring the software complexity, estimating size, quality and project efforts. There are various approaches through which we can find the software cost estimation and predicates on various kinds of deliverable items. Object-oriented metrics assures to reduce cost and the maintenance effort by serving as early predictors to estimate software faults. Such an early quantification augments the quality of the final software. This paper reviews object-oriented metrics. A comparison table is maintained via which we can analyze the difference between all the object-oriented metrics effectively.