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Managing Reserved Instances and Savings Plans with input metrics such as utilization and coverage doesn’t give a complete picture due to its limitations and can often be misleading. One of the most important Cloud FinOps metrics in business to measure true AWS cost savings is the Effective Savings Rate. To understand how much money businesses save on the cloud one must track the Effective Savings Rate or ESR. It is also considered the AWS metric that matters the most as it provides valuable insight into the level of cost-efficiency. Effective Savings Rate gives an understanding of whether there is scope to reduce cloud spending further.

What is an Effective Savings Rate?

While investing, the output metric that eventually matters is the Return on Investment. ROI is fundamentally how investment performance is evaluated.

The Effective Savings Rate (ESR) measures the ROI for all tools and methods specific to (or across) different cloud providers. ESR is a crucial KPI to measure the actual cloud cost savings performance of different AWS cost savings tools and activities. 

Let us understand by an example. Suppose a business initially spends $200,000 per month on cloud resources. By using discount opportunities, the price gets reduced to $190,000. So the ESR per month is 5 percent of the original cloud bill.
Effective Savings Rate is a crucial KPI that tracks what we are saving in the cloud compared to what we would be spending if there are no changes made for cloud cost optimization.

How to track and measure Effective Savings Rate for businesses?

The Effective Saving Rate, which includes Savings Plans and RIs across EC2, Fargate, and Lambda, can be calculated as follows:

 Effective Savings Rate (ESR) = 1- {Actual Spends Including Discounts/On Demand Equivalent Spend}

Here, Actual Spend Including Discounts refers to the actual amount the business paid with RIs and Savings Plans, amortizing any upfront charges.
On-demand equivalent (ODE) Spend refers to the amount a business would have paid if no discounts were applied. 

There are two key practices for calculating Effective Savings Rate.

  • Negotiating discounted pricing with cloud providers.
  • Leveraging committed-use discount opportunities, such as reserved instances (RIs) which offer resources at a discounted rate in exchange for a fixed period commitment use.

Challenges in Measuring Effective Savings Rate

There are several variables and factors that can influence the Effective Savings Rate and hence calculating ESR is not as easy as it seems. 

A common scenario is that businesses may obtain credits from the cloud provider, which can later be redeemed for free cloud services. If the credits are only available for a limited period, and the ESR calculations are based on them, then the ESR calculation will not be accurate in terms of cloud cost savings. In this case, the ESR calculation will not reflect the cloud cost savings after the credits expire. This may result in overestimating the ROI of your cloud cost optimization efforts.

Another challenge in measuring the Effective Savings Rate is that it measures overall cloud cost savings. However, there can be a case where the savings rates for specific cloud services or products vary significantly from each other. 

The ESR concept is simple but is often more complicated with large savings portfolios of RIs and Savings Plans, dynamic compute fleets (e.g., EC2, Fargate, and Lambda), etc. The more granular the ESR calculations are, the greater understanding we get while assessing how ESR outcomes differ between different clouds, cloud products, and business functions.

Strategies to Improve Effective Savings Rate

If there are multiple clouds, it must also be known how business spending outcomes and FinOps ROI vary between clouds. This will help in understanding which clouds are costing more than they should. For example, if the overall ESR is twenty percent, and one of the cloud accounts for eighteen percent of the savings, we get an insight that there can be an opportunity to save more on another cloud. 

Another important way to get ESR insights is to measure the Effective Savings Rate based on business units. Depending on how each department or team uses cloud resources, and how they approach cost-optimization practices and savings, ESR tracking on a per-business unit basis can be helpful. This practice tells which teams are doing best in cloud cost savings and which teams are obstructing cloud cost optimization. 
Businesses must ensure that they track ESR continuously and over time. Calculating the ESR only once in a few months would not serve the purpose as it will give clarity of fluctuations that occur in between. Continuous ESR tracking also explains the impact of a new product or service launch on the business ROI.


Effective Savings Rate (ESR) comes out as a crucial metric in evaluating the effectiveness of your cloud cost optimization strategies and investment. By breaking down ESR calculation across different cloud providers, services, and business units businesses can achieve a more precise understanding and identify the room for improvement in cloud cost savings.  

If you are looking for a Cloud FinOps partner to help you with cloud cost optimization strategies and ultimately increase the Effective Savings Rate, CloudKeeper can be of great help. Schedule a call with our team today to learn more.

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