AWS Cost Explorer
A cost management tool that visualizes and analyzes AWS usage costs and consumption through graphs and filters, with the ability to forecast future costs
Overview
AWS Cost Explorer is a tool for visually analyzing AWS usage costs and consumption. It displays daily and monthly cost trends in graphs and can break down costs by service, account, region, tag, and other dimensions. It includes cost forecasting up to 12 months ahead, Reserved Instance and Savings Plans purchase recommendations, unused resource detection, and other analysis features directly tied to cost optimization. You can also retrieve cost data via API to build custom dashboards and alert systems.
Cost Allocation Tags and Grouping Design
To maximize Cost Explorer's analytical power, cost allocation tag design is essential. AWS provides service-level and region-level cost breakdowns by default, but tracking costs by project, team, or environment (production/development) requires cost allocation tags. Standardizing tag keys such as Environment, Project, Team, and Owner, and enforcing naming conventions through Organizations tag policies, is the recommended practice. After defining tags, you must activate them in the Billing console for them to appear in Cost Explorer - a step that is often overlooked. The grouping feature can display costs in a service-by-account matrix, instantly identifying which account's service is driving cost increases. Filtering by specific linked accounts, purchase options (On-Demand, Reserved, Spot), or usage types enables more precise analysis. For organizations with many accounts, grouping by linked account first and then drilling into service-level details provides the fastest path to identifying cost anomalies.
Cost Anomaly Detection and Budget Alerts
Enabling Cost Anomaly Detection allows machine learning to learn normal cost patterns and automatically detect unusual cost spikes, sending notifications via SNS or email. You can create monitors scoped to specific services, linked accounts, or cost allocation tags, with configurable thresholds for alert sensitivity. This is far more effective than static budget thresholds alone, as it adapts to your actual spending patterns and seasonal variations. AWS Budgets complements anomaly detection by setting hard spending limits with automated actions - for example, triggering an SNS notification when 80% of the monthly budget is consumed, and executing a Lambda function to stop non-essential EC2 instances when 100% is reached. Both Cost Explorer and Azure Cost Management support budget alerts, but Cost Explorer's integration with AWS Budgets for automated remediation actions provides a practical advantage over Azure's alert-only approach. AWS cost optimization books (Amazon) are a helpful resource for further reading.
Savings Plans Recommendations and Weekly Cost Reviews
The most effective practical use of Cost Explorer is establishing a weekly cost review habit. Every Monday, review the previous week's cost trends and check for abnormal increases or unexpected new line items. The Savings Plans recommendation feature suggests the optimal Savings Plans type (Compute or EC2 Instance) and term (1-year or 3-year, with or without upfront payment) based on usage patterns from the past 7, 30, or 60 days. Compute Savings Plans offer the most flexibility, applying discounts across EC2, Fargate, and Lambda regardless of instance family or region, while EC2 Instance Savings Plans provide deeper discounts but are locked to a specific instance family and region. For data export, the Cost Explorer API returns cost data in JSON format, enabling custom dashboards and automated reporting pipelines. One caveat is that Cost Explorer data has up to a 24-hour delay, making it unsuitable for real-time cost monitoring. When real-time visibility is needed, combine it with CloudWatch Billing metrics for immediate threshold alerts.