Accessing CloudWatch metrics
You can use the following procedures to view the storage metrics for
            Amazon S3. To get the Amazon S3 metrics involved, you must set a start and end timestamp.
            For metrics for any given 24-hour period, set the time period to 86400 seconds, the
            number of seconds in a day. Also, remember to set the BucketName and
                StorageType dimensions.
For example, if you want to use the AWS CLI to get the average of a specific bucket's size in bytes, you could use the following command:
aws cloudwatch get-metric-statistics --metric-name BucketSizeBytes --namespace AWS/S3 --start-time2016-10-19T00:00:00Z--end-time2016-10-20T00:00:00Z--statistics Average --unit Bytes --regionus-west-2--dimensions Name=BucketName,Value=amzn-s3-demo-bucketName=StorageType,Value=StandardStorage --period86400--output json
This example produces the following output.
{ "Datapoints": [ { "Timestamp": "2016-10-19T00:00:00Z", "Average": 1025328.0, "Unit": "Bytes" } ], "Label": "BucketSizeBytes" }
To view metrics by using the Amazon CloudWatch console
- Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/ - . 
- 
                    In the left navigation pane, choose Metrics. 
- 
                    Choose the S3 namespace. 
- 
                    (Optional) To view a metric, enter the metric name in the search box. 
- 
                    (Optional) To filter by the StorageType dimension, enter the name of the storage class in the search box. 
To view a list of valid metrics stored for your AWS account by using the AWS CLI
- 
                    At a command prompt, use the following command. aws cloudwatch list-metrics --namespace "AWS/S3"
For more information about the permissions required to access CloudWatch dashboards, see Amazon CloudWatch dashboard permissions in the Amazon CloudWatch User Guide.