Do HTTP headers count towards S3 Data transfer?

The HTTP headers returned with the S3 object do count towards the data transfer pricing. When you request a 100B file from S3, the total data transferred includes the file contents as well as the HTTP headers.

To analyze your S3 data transfer costs in more detail:

Check your S3 usage report to identify the buckets and operations responsible for high data transfer charges.
Review the S3 server access logs associated with those buckets to get detailed information on the requests, including the amount of data transferred.
    You can use Amazon Athena to query the server access logs, for example:

    SELECT SUM(bytessent) as uploadtotal, SUM(objectsize) as downloadtotal, SUM(bytessent + objectsize) AS total 
    FROM s3_access_logs_db.mybucket_logs
    WHERE remoteIP='1.2.3.4' 
      AND parse_datetime(requestdatetime,'dd MMM yyyy:HH:mm:ss Z') 
      BETWEEN parse_datetime('2024-06-1','yyyy-MM-dd') 
      AND parse_datetime('2024-06-15','yyyy-MM-dd');

For more information on analyzing S3 data transfer costs, please refer to the AWS documentation on Understanding your AWS billing and usage reports for Amazon S3 

https://aws.amazon.com/s3/pricing/

https://repost.aws/knowledge-center/s3-data-transfer-costs

I hope this helps provide some guidance on analyzing your S3 data transfer costs.