How are RI and SP savings calculated and how can I be sure they are correct?

AWS RI and SP Savings Calculation Method

AWS measures RI and SP savings as the difference between spend with RIs and SPs vs. spend if compute ran at on-demand rates. Savings values are impacted by a number of factors including utilization, coverage, and discount rates.

Note: Because RIs and SPs can be unutilized, it is possible to have negative savings (i.e., you paid more with RIs and SPs than if you had run at on-demand rates).

Authoritative System of Record

While the ProsperOps platform is responsible for ingesting compute usage telemetry and programmatically optimizing RIs and SPs to generate savings outcomes, ProsperOps considers AWS as the authoritative system of record for all RI and SP savings generated.  The savings values shown in our Console will match AWS at all times.


ProsperOps makes it simple to audit the savings values provided in our Console by including pre-configured deep links to AWS Cost Explorer. These links allow you to easily compare ProsperOps values against authoritative AWS RI and SP savings data. These links are available in the savings summary panel at the top of the Savings Dashboard, as shown below. Savings values can be audited at any time and will match AWS whether the data is estimated mid-month or the month has been finalized by AWS.