AWS Cost Analysis: The 5 Biggest Cost Traps and How to Find Them

The AWS bill is growing, but nobody knows exactly why. A typical scenario in companies with organically grown cloud infrastructure. The good news: in nearly every AWS environment, there is 20-40% savings potential — if you know where to look.

The 5 Most Common AWS Cost Traps

1. Oversized EC2 Instances

The classic: an m5.2xlarge has been running for months with an average CPU utilization of 8%. This happens when instances are sized for load spikes that never materialize. AWS Cost Explorer and Compute Optimizer provide concrete rightsizing recommendations based on 14 days of CloudWatch metrics.

Typical savings potential: 30-50% of EC2 costs by switching to appropriate instance types and Graviton processors.

2. Forgotten EBS Snapshots and Volumes

Every time an EC2 instance is terminated, the associated EBS snapshots persist — and continue to cost money. In larger environments, hundreds of orphaned snapshots quickly add up to four-figure monthly amounts.

Quick Win: A simple script that identifies all snapshots without an associated AMI or volume often saves three-figure amounts per month immediately.

3. Unused Elastic IPs and Load Balancers

An Elastic IP not assigned to a running instance costs $3.60 per month. Sounds like little — but 50 forgotten EIPs are $180 monthly for nothing. The same applies to Application Load Balancers that still exist but no longer route any traffic.

4. Missing Reserved Instances and Savings Plans

On-demand prices are the most expensive way to use AWS. Yet in many companies, 80% of workloads run without any reservation. Meanwhile, 1-year no-upfront Reserved Instances already offer 30-40% savings — with no upfront payment and full flexibility with Convertible RIs.

5. Data Transfer Costs

AWS data transfer is one of the most frequently underestimated cost drivers. Data between Availability Zones costs $0.01/GB in both directions. For an EKS cluster with cross-AZ traffic, this can quickly add up to $500-1,000 per month.

Solution: Topology-aware routing in Kubernetes and VPC endpoints for AWS services eliminate a large portion of unnecessary cross-AZ traffic.

A Systematic Approach Instead of Individual Measures

Individual quick wins are good, but sustainable cost management requires structure. A proven approach:

• Tagging Strategy: Every resource gets tags for team, project, and environment — the foundation for cost allocation.
• Monthly Cost Reviews: A 30-minute review of the top 10 cost drivers with concrete action items.
• AWS Budgets: Automatic alerts at 80% and 100% of the planned budget per team or project.
• Cost Anomaly Detection: AWS's own service that automatically detects and reports unusual cost spikes.

The most important step is the first one: creating transparency. Those who understand their AWS costs can control them.