What are 'EC2 - Unused RI' costs?

Products

• CloudHealth

Issue/Introduction

‘EC2 - Unused RI’ represents the cost of reservations that you’ve paid for, but haven’t yet utilized.

When you purchase reservations with AWS, you are agreeing to pay for full monthly usage of those reservations, even if you don't fully utilize them.  The portion that you haven’t used is categorized as Unused RI within the platform. 

You may notice on the 1st of the month that there is a spike in ‘EC2 - Unused RI’ costs on reports.  Since AWS charges you for your reservations, regardless of whether they are used or not, the platform reflects your unused RI costs at the beginning of the month as you would be obligated to pay no matter what.

However, you’ll notice that day by day, this ‘EC2 - Unused RI’ cost will decrease as your ‘EC2 - Compute’ charges increase.  This is because your RIs are being consumed and applied to your instances.

At the end of the month, any remaining ‘EC2 - Unused RI’ costs will be a reflection of the total number of hours that were not applied to instances.