we propose a novel method for Quality of Service metrification based on Hidden Markov Models. HMM suggest then optimal path for user request. The HMM technique can be used to measure and predict the state or behavior of Web Services in terms of response time, and can be used to rank services quantitatively instead of just qualitatively. We determine the likelihood and usefulness of our approach by doing experiments on real world data sets. The results have shown how our projected method can support the user to automatically select the most predictable Web Service taking into account several metrics, among them, system predictability and response time variability.