The 30-Day AWS Cost Audit: A Step-by-Step Playbook
A practical week-by-week guide to auditing and optimizing AWS costs. Week 1: Visibility. Week 2: Quick wins. Week 3: Right-sizing. Week 4: Commitments.
The 30-Day AWS Cost Audit
A step-by-step playbook for reducing your cloud bill
Most AWS cost optimization guides are either too vague ("look for waste") or too overwhelming ("here are 147 things to check"). This playbook is different: it's a structured 30-day plan with specific daily and weekly tasks.
Follow it step by step, and by day 30 you'll have visibility into your costs, eliminated obvious waste, right-sized your resources, and set up ongoing optimization processes.
The 4-Week Structure
Visibility
Understand where your money goes
Quick Wins
Low-risk, high-impact changes
Right-Sizing
Optimize active resources
Commitments
Lock in discounts
Week 1: Visibility
Understand where your money goes before you try to cut it
Set Up Cost Explorer & Billing Alerts
Tasks:
- Enable Cost Explorer in AWS Console
- Set up budget alerts at 50%, 80%, 100% of monthly target
- Enable Cost Anomaly Detection
- Export last 6 months of data to CSV
Why This Matters:
You can't manage what you don't measure. Most AWS users never look at Cost Explorer until something goes wrong.
Analyze Cost Breakdown by Service
Tasks:
- Identify top 5 services by cost
- Compare month-over-month growth rates
- Flag any unexpected services on the bill
- Document findings in a spreadsheet
What to Look For:
- • EC2 usually dominates (30-50%)
- • RDS is often #2
- • Watch for data transfer costs
- • CloudWatch can be surprisingly high
Inventory All Resources
Tasks:
- List all EC2 instances with sizes and utilization
- List all RDS instances
- Note which are tagged vs untagged
- Create a "resource owner" spreadsheet
Pro Tip:
Use AWS Resource Groups Tag Editor to get a complete inventory across all regions at once.
Create Cost Dashboard & Baseline
Tasks:
- Create a simple cost dashboard (spreadsheet or tool)
- Document current monthly spend as baseline
- Set a target for end of 30 days (e.g., 20% reduction)
- Share baseline with stakeholders
Week 1 Deliverable:
A documented baseline of current costs, top services, and a target reduction percentage.
Week 2: Quick Wins
Low-risk changes that deliver immediate savings
Delete Orphaned Resources
Tasks:
- Find and delete unattached EBS volumes
- Release unassociated Elastic IPs
- Remove empty S3 buckets
- Delete idle load balancers (no healthy targets)
Expected Savings:
5-15% of total bill. These are "free money" optimizations—zero risk, immediate savings.
Clean Up Old Snapshots
Tasks:
- List all EBS snapshots older than 90 days
- Identify snapshots of deleted volumes
- Delete unnecessary snapshots (keep recent + monthly)
- Set up AWS Backup with retention policies
Expected Savings:
$0.05/GB/month. If you have 1TB of old snapshots, that's $50/month.
Upgrade GP2 to GP3 Storage
Tasks:
- List all gp2 EBS volumes
- Upgrade to gp3 (zero downtime)
- Update Terraform/CloudFormation for new resources
Expected Savings:
20% reduction in EBS costs. $0.10/GB → $0.08/GB, plus better performance.
Optimize CloudWatch Logs
Tasks:
- Set retention policies on all log groups (7-30 days)
- Find largest log groups by storage
- Review Lambda function log levels
- Consider exporting old logs to S3
Expected Savings:
50-80% reduction in CloudWatch costs. Often one of the biggest quick wins.
Review & Document Week 2 Savings
Tasks:
- Calculate total estimated monthly savings
- Document all changes made
- Update cost dashboard with projected new baseline
- Share wins with stakeholders
Week 2 Deliverable:
A documented list of quick wins with estimated monthly savings. Target: 10-20% reduction.
Week 3: Right-Sizing
Optimize resources that are running but oversized
Analyze EC2 Utilization
Tasks:
- Check AWS Compute Optimizer recommendations
- Review CloudWatch CPU metrics (look for <30%)
- Check memory utilization (requires CloudWatch agent)
- Create list of right-sizing candidates
Rule of Thumb:
If average CPU is below 30% consistently, the instance is likely oversized by at least one size class.
Right-Size EC2 Instances
Tasks:
- Start with dev/staging environments
- Downsize oversized instances (one size at a time)
- Monitor for 24-48 hours after each change
- Update to latest generation (m4 → m6i)
Expected Savings:
20-40% reduction in EC2 costs. This is often the biggest single optimization.
Right-Size RDS Databases
Tasks:
- Review RDS CPU and connection metrics
- Identify idle or over-provisioned databases
- Consider Aurora Serverless for variable workloads
- Schedule maintenance window for resizing
Caution:
RDS right-sizing requires brief downtime. Plan changes during maintenance windows.
Review & Document Week 3 Savings
Tasks:
- Document all instances resized
- Calculate cost impact of changes
- Note any changes that need to be reverted
- Update baseline with new projected costs
Week 3 Deliverable:
A list of right-sized resources with before/after costs. Target: Additional 10-20% savings.
Week 4: Commitments & Sustainability
Lock in discounts and set up ongoing optimization
Evaluate Savings Plans / Reserved Instances
Tasks:
- Review Cost Explorer RI/SP recommendations
- Calculate stable baseline usage (60-70% of avg)
- Compare Compute SP vs EC2 SP vs RIs
- Get approval for commitment purchases
Recommendation:
Start with Compute Savings Plans for EC2/Lambda/Fargate. Use RDS Reserved Instances for databases. Don't over-commit!
Purchase Commitments
Tasks:
- Purchase Compute Savings Plans (start at 60% of baseline)
- Purchase RDS Reserved Instances for stable databases
- Document all purchases and expiration dates
- Set calendar reminders for renewal reviews
Expected Savings:
30-50% additional savings on committed usage. This compounds with right-sizing.
Set Up Ongoing Governance
Tasks:
- Enable AWS Config rules for tag compliance
- Set up weekly cost anomaly review process
- Create monthly cost review meeting cadence
- Document tagging standards and enforce via SCPs
Why This Matters:
Cost optimization isn't a one-time project. Without ongoing governance, waste creeps back within 3-6 months.
Final Review & Report
Tasks:
- Compare Day 30 costs to Day 1 baseline
- Create executive summary of all changes
- Document lessons learned
- Present results to stakeholders
- Plan next optimization cycle (quarterly)
Week 4 Deliverable:
A comprehensive report showing: baseline, changes made, savings achieved, and ongoing governance plan.
Expected Results After 30 Days
Breakdown of Savings by Week
Start Your 30-Day Audit Today
Get a head start with our free AWS Cost Analyzer. Upload your Cost Explorer CSV and see exactly where your money is going—the perfect Day 1 activity.
Start My Free AnalysisResults in 5 minutes • Perfect for Day 1
The Bottom Line
AWS cost optimization isn't complicated—it's just systematic. This 30-day playbook breaks down the process into manageable daily tasks. Follow it step by step, and you'll achieve significant savings while building the processes to maintain them long-term.