AWS Backup pricing for EFS explanation

I noticed the costs for backing up EFS in Ireland region is as follows:

Resource Type Warm Storage Cold Storage
Amazon EFS File System Backup $0.05 per GB-Month $0.01 per GB-Month
Amazon EBS Volume Snapshot $0.05 per GB-Month n/a†
Amazon RDS Database Snapshot $0.095 per GB-Month n/a†

The example given for US East (N. Virginia) region is:

Total usage (GB-Hours) = (400 GB x 15 days x (24 hours / day)) + (800 GB x 15 days x (24 hours / day)) = 432,000 GB-Hours
We add up GB-Hours and convert to GB-Month to calculate monthly charges:
Total Monthly Storage Charge = 600 GB-Month x $0.05 = $30

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

How is the 432,000 GB-Hours arrived at?

My EFS metered size is 350 GiB. How much would it cost per month if I backup daily and weekly?

Edited by: ec-confounder on Mar 20, 2020 5:53 AM

Edited by: ec-confounder on Mar 20, 2020 5:54 AM