AWS
EC2 Rightsizing: The Complete Guide to Saving Money
Step-by-step guide to rightsizing your EC2 instances. Learn how to identify oversized instances, analyze metrics, and implement changes safely.
CloudSavvy Team
Cloud Cost Experts
January 12, 2026
9 min read
What is EC2 Rightsizing?
Rightsizing is the process of matching your EC2 instance types and sizes to your workload performance and capacity requirements at the lowest possible cost.
Why Rightsizing Matters
Studies show that 35-45% of cloud resources are over-provisioned. This translates to:
- Wasted compute capacity
- Unnecessary spending
- Missed optimization opportunities
Identifying Rightsizing Opportunities
Key Metrics to Analyze
CPU Utilization:
- Average below 20%: Likely oversized
- Peak below 50%: Consider downsizing
- Consistent 70%+: Appropriately sized
- Requires CloudWatch agent installation
- Analyze peak vs. average usage
- Consider memory-optimized instances if memory-bound
- Check if hitting network limits
- Consider enhanced networking instances if constrained
Analysis Period
- Minimum 14 days of data
- Include peak usage periods
- Account for batch jobs and scheduled tasks
Safe Rightsizing Process
- Baseline: Document current configuration and performance
- Analyze: Review 2+ weeks of metrics
- Test: Resize in non-production first
- Monitor: Watch for performance issues
- Iterate: Make incremental changes
AWS Tools for Rightsizing
AWS Compute Optimizer:
- ML-based recommendations
- Considers multiple metrics
- Provides confidence levels
- Historical metrics
- Custom dashboards
- Alarm configuration
- Rightsizing recommendations
- Savings estimates
- Reservation coverage
CloudSavvy Rightsizing Features
CloudSavvy enhances rightsizing with:
- Recommendations across AWS and Azure
- Estimated savings for each suggestion
- One-click analysis reports
- Historical trend analysis
Common Rightsizing Mistakes
Avoid these pitfalls:
- Rightsizing without sufficient data
- Ignoring memory metrics
- Not considering burst workloads
- Failing to test changes
- Making too many changes at once
Conclusion
EC2 rightsizing is one of the highest-impact optimizations you can make. Start with your largest instances, analyze metrics carefully, and make changes incrementally.