URL normalization is a process of transforming URL strings into canonical form. Through this process, duplicate URL representations for web pages can be reduced significantly. There are a number of normalization methods. In this paper, we describe four metrics for evaluating normalization methods. The reliability and consistency of a URL is also considered in our evaluation. With the metrics proposed, we evaluate seven normalization methods. The evaluation results on over 25 million URLs, extracted from the web, are reported in this paper.