You are charged for S3 CloudWatch Metrics based on the number of custom metrics, detailed monitoring needs, and API requests. AWS offers a free tier of basic metrics, but more detailed or custom metrics come with additional charges. It's important to monitor usage and costs through AWS billing tools to avoid unexpected charges.
When you are charged for using S3 CloudWatch Metrics, it is based on several factors. AWS charges for CloudWatch Metrics primarily based on the number of custom metrics and API requests. There are free tier metrics offered by AWS, which include basic monitoring metrics (at 5-minute intervals) for your S3 buckets. However, if you wish for more detailed monitoring (like 1-minute data points) or want to use custom metrics, you will incur additional charges.
Moreover, you will be billed for CloudWatch API requests that you make to retrieve these metrics data. Each AWS service has its pricing for CloudWatch Metrics, and pricing can vary per region. To avoid unexpected charges, you should regularly review your usage and set up billing alerts.
To keep track of costs, AWS provides a detailed billing dashboard, and you can also use AWS Cost Explorer to visualize and manage your AWS spending. If you need more fine-grained information about your utilization and the associated costs of S3 CloudWatch Metrics, you should refer to the Amazon CloudWatch and Amazon S3 pricing pages on the AWS website.