This document describes a tool called Overprov for detecting cluster overprovisioning. The tool analyzes metrics from clusters to check for signs of overprovisioning based on simple rules. It is designed to save costs in the long run by identifying when clusters have extra resources that are not being used. The tool can analyze multiple metrics for different cluster types and products. It has a modular structure so new analyzers can be added to check additional metrics. The tool generates daily reports but is not meant for instantaneous autoscaling decisions. It includes examples of using the tool to analyze Cassandra and Elasticsearch clusters.