# Underutilized instances in EC2 Auto Scaling group Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/underutilized-instances-in-ec2-auto-scaling-group Oversized instances within Auto Scaling Groups lead to inflated baseline costs, even when scaling adjusts the number of instances dynamically. By: PointFive Updated: 2026-09-28 [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) # Underutilized Instances in EC2 Auto Scaling Group The short version Oversized instances within Auto Scaling Groups lead to inflated baseline costs, even when scaling adjusts the number of instances dynamically. PointFive Research Cloud cost research at PointFive AWS service [AWS EC2](https://www.pointfive.co/efficiency-hub/cloud-services/aws-ec2) Category [Compute](https://www.pointfive.co/efficiency-hub/service-category/compute) Reference CER-0014 Type Overprovisioned Resource ## Explanation Why the waste happens and who it affects. When workloads consistently use only a fraction of the available CPU, memory, or network capacity, there is an opportunity to downsize to smaller, less expensive instance types without sacrificing performance. Right-sizing helps balance capacity and efficiency, reducing compute spend while preserving workload stability. ## Billing model The pricing dimensions that drive this cost. EC2 instances are billed per second (60-second minimum) for Linux, Windows, RHEL, and Ubuntu Pro, and per full hour for SLES, based on instance type, operating system, and purchase model (e.g., On-Demand, Reserved Instances, Spot Instances). Larger instance types incur higher charges regardless of whether the workload fully utilizes the available resources. ## How to detect 5 checks to find it in your estate. - Identify Auto Scaling Groups where instances exhibit low average CPU, memory, or network utilization relative to their capacity. - Review instance sizing in relation to historical workload peaks and scaling behavior. - Assess whether smaller, more cost-effective instance types could support the same workload with acceptable performance. - Evaluate launch templates (and migrate any remaining launch configurations, which are deprecated) to determine if default instance types were selected without performance optimization. - Confirm with application and infrastructure owners that resizing aligns with performance, availability, and SLA requirements ## How to fix 4 ways to remove the waste. - Evaluate smaller instance types that better match the workload's actual resource requirements. - Update the launch template for the Auto Scaling Group to use the selected instance type, and deploy changes during a low-traffic window if needed. - After downsizing, monitor performance metrics to ensure the workload continues to meet application and SLA expectations. - Regularly reassess instance sizing as usage patterns evolve to maintain ongoing cost efficiency. ## Documentation Vendor references for pricing and configuration. - [Amazon EC2 Pricing aws.amazon.com](https://aws.amazon.com/ec2/pricing/) - [Auto Scaling launch templates docs.aws.amazon.com](https://docs.aws.amazon.com/autoscaling/ec2/userguide/launch-templates.html) - [Viewing EC2 Auto Scaling group recommendations docs.aws.amazon.com](https://docs.aws.amazon.com/compute-optimizer/latest/ug/view-asg-recommendations.html) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - AWS EC2 CER-0047 ### [Underutilized EC2 Instance](https://www.pointfive.co/efficiency-hub/inefficiencies/underutilized-ec2-instance) EC2 instances are often overprovisioned based on rough estimates, legacy patterns, or performance buffer assumptions. If an instance consistently uses only a small fraction of its provisioned CPU or memory, it likely represents an... Compute - AWS EC2 CER-0327 ### [Spot Instance Overreliance Without Effective Cost-Per-Performance Analysis](https://www.pointfive.co/efficiency-hub/inefficiencies/spot-instance-overreliance-without-cost-per-performance-analysis) Organizations frequently pursue aggressive Spot Instance adoption based on headline discount percentages - up to 90% off On-Demand pricing - without evaluating the effective cost per unit of work completed. While Spot pricing can deliver... Compute - AWS EC2 CER-0324 ### [Excessive On-Demand Compute Spend Due to Low Savings Plan and Reserved Instance Coverage](https://www.pointfive.co/efficiency-hub/inefficiencies/excessive-on-demand-compute-spend-due-to-low-savings-plan-and-reserved-instance-coverage) AWS compute services charge the full published On-Demand rate when no commitment-based discount - such as a Savings Plan (SP) or Reserved Instance (RI) - is in effect. On-Demand pricing provides maximum flexibility, but it is also the most... Compute --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.