Underutilized EC2 Instance

Service Category

Compute

Cloud Provider

AWS

Service Name

AWS EC2

Inefficiency Type

Overprovisioned Resource

Explanation

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 opportunity for rightsizing. These inefficiencies persist unless usage is periodically reviewed and instance types are adjusted to align with actual workload requirements.

Relevant Billing Model

EC2 instances are billed based on:

Instance type and size — Larger or more specialized instances incur higher hourly or per-second costs
Uptime — Charged per second with a one-minute minimum (Linux); hourly for Windows or certain older usage types
Storage and data transfer

Detection

Review average CPU and memory utilization of running EC2 instances.
Determine whether actual usage justifies the selected instance type or size
Confirm whether performance buffers, licensing rules, or other constraints require overprovisioning
Check whether the workload could be better served with burstable instances (e.g., T family) or smaller sizes within the same family
Validate with application owners whether the instance can be safely resized

Remediation

Resize the EC2 instance to a smaller type that better matches observed usage. Consider using burstable instances for smaller workloads with spiky or inconsistent usage. Review Auto Scaling policies to allow dynamic adjustment when necessary.

Relevant Documentation

AWS EC2 Pricing