Viewing resource recommendations - AWS Compute Optimizer

Viewing resource recommendations

The recommendations page in the AWS Compute Optimizer console lists your running resources, their findings classifications, instance type, and hourly prices for the selected purchasing option. The top recommendation from Compute Optimizer is listed next to each of your resources, and it includes the recommended instance type and the hourly price for the selected purchasing option. Use the recommendations page to compare your running resources with recommended resources, which can help you to decide if you should up-size or down-size your resources.

The recommendations are refreshed daily. They're generated by analyzing your resource’s specifications and utilization metrics over a period of the last 14 days. For more information, see Metrics analyzed by AWS Compute Optimizer. Keep in mind that recommendations could take up to 12 hours to be generated, and sufficient metric data must be accumulated. For more information, see Metric requirements.

Supported resources and requirements

Compute Optimizer generates recommendations for Amazon Elastic Compute Cloud (Amazon EC2) instances and Amazon EC2 Auto Scaling groups that meet a specific set of requirements, and that have accumulated sufficient metric data. For more information, see Supported resources and requirements.

Findings classifications

The findings classifications on the recommendations page provide a summary of how each of your resources performed during the analyzed period, such as whether they were over-provisioned or under-provisioned. The classifications differ based on the AWS service of the resource. For more information, see Findings classifications.

Prices and purchasing options

In the recommendations page, you can choose to view the hourly prices for your running instances and the recommended instance types under different Amazon EC2 purchasing options. Use the pricing information to get an idea of the price difference between your running resources and the recommended resources. It also shows the price difference between your running instance's current purchasing option, and the purchasing option that you select on the recommendations page.


The prices listed on the recommendations page might not reflect the actual prices you pay for your resources. For more information about finding the actual price of your running resources, see Amazon EC2 Usage Reports in the Amazon Elastic Compute Cloud User Guide.

The following purchasing options can be selected on the recommendations page:

  • On-Demand Instances - An On-Demand Instance is an instance that you use on demand. You have full control over its lifecycle—you decide when to launch, stop, hibernate, start, reboot, and terminate it. No longer-term commitments or upfront payments are needed. For more information about On-Demand Instances, see On-Demand Instances in the Amazon Elastic Compute Cloud User Guide. For more information about pricing, see Amazon EC2 On-Demand Instance Pricing.

  • Reserved Instances (one-year or three-year commitment, no upfront) - Reserved Instances provide you with significant savings on your Amazon EC2 costs compared to On-Demand Instance pricing. Reserved Instances are not physical instances, but rather a billing discount applied to the use of On-Demand Instances in your account. For more information about Reserved Instances, see Reserved Instances in the Amazon Elastic Compute Cloud User Guide. For more information about pricing, see Amazon EC2 Reserved Instance Pricing.

For more information about purchasing options, see Instance Purchasing Options in the Amazon Elastic Compute Cloud User Guide.

Estimated monthly savings

The EC2 instances recommendations page also lists the On-Demand hours, Reserved Instance (RI) hours, and Savings Plans hours for each of your running instances. These data columns represent the subset of the total running hours that each instance was On-Demand, was covered by an AWS reservation, and was covered by Savings Plans over the look-back period (up to the last 14 days). That data is used to calculate an Estimated monthly savings for each of your recommendations, which is also displayed in the recommendations page.

To calculate the estimated monthly savings, we first examine the instance running in the look-back period to identify if it was partially or fully covered by an RI or running On-Demand. Another factor is whether the RI is size-flexible. The cost to run the instance is calculated based on the On-Demand hours and the rate of the instance type.

For each recommendation, we calculate the cost to operate a new instance. We assume that a size-flexible RI will cover the new instance in the same way as the previous instance. Savings are calculated based on the number of On-Demand running hours and the difference in On-Demand rates. If the RI isn't size-flexible, the savings calculation is based on if the instance hours during the look-back period are operated as On-Demand.

Recommendations are provided regardless of estimated monthly savings. Even if the estimated savings is less than zero, you might be able to convert your existing Convertible RIs to cover the recommended instance types.


Recommendations don't capture second-order effects of rightsizing, such as the resulting RI hour’s availability and how they will apply to other instances. Potential savings based on reallocation of the RI hours aren't included in the calculation.

Viewing recommendations

Use the following procedure to view recommendations for your resources.

To view recommendations

  1. Open the Compute Optimizer console at

  2. Choose one of the recommendation page options listed in the navigation pane, such as EC2 instances or Auto Scaling groups.

    The recommendations page lists the specifications and findings classifications of your running resources, along with the specifications of the recommended resources. The resources listed are from the AWS Region that is currently selected, in the selected account.

  3. You can perform the following actions on the recommendations page:

    • To filter recommendations to one or more AWS Regions, enter the name of the Region in the Filter by one or more Regions text box, or choose one or more Regions in the drop-down list that appears.

    • To view recommendations for resources in another account, choose Account, and then select a different account ID.

      This option is available only if you are signed in to a management account of an organization, and you opted in all member accounts within the organization.

    • To clear the selected filters, choose Clear filters next to the filter.

    • To change the purchasing option that is displayed, choose Settings (the gear icon), then choose On-Demand Instances, Reserved Instances, standard 1-year no upfront, or Reserved Instances, standard 3-year no upfront.

    • To view the resource details, such as additional recommendations and a comparison of utilization metrics, choose the findings classification listed next to the desired resource. For more information, see Viewing resource details.