Explanation
Why the waste happens and who it affects.
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.
Billing model
The pricing dimensions that drive this cost.
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 60-second minimum for Linux, Windows, RHEL and Ubuntu Pro; SLES is billed per full hour
- Storage and data transfer
How to detect
5 checks to find it in your estate.
- 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
How to fix
How to remove the waste.
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.
Documentation
Vendor references for pricing and configuration.