One key aspect to note is that the Current Monthly Price
in the Rightsizing report is the List Price, so it might be significantly higher than the cost in the Cost History Report.
Example how the Current Monthly Price
is calculated:
If an instance has run for 10 hours in the last 5 days, we extrapolate this for 30 days i.e. total monthly hours for the instance would be (10/5)*30 and we multiply this by that instance type's on-demand rate to calculate it's monthly price. We add this across all instances for 'Current Monthly Price'.
The platform does a similar computation for Projected Monthly Price
Projected Monthly Savings
= Current Monthly Price
- Projected Monthly Price