Cost analysis FAQs

Overview

This article answers the most common questions about cost analysis in Cost Analyzer — including cost groups, analysis views, forecasting, filters, and cost dimensions.

Business value

Understanding how cost analysis works in Cost Analyzer helps teams structure their cost data correctly, interpret analysis views accurately, and use forecasting to make informed spend decisions.

How it works

Cost Analyzer organizes Azure spend into cost groups, which define the scope of analysis — by subscription, resource group, tag, or cost dimension. Within a cost group, analysis views provide filtered, customizable perspectives on cost data. Forecasting projects future spend based on historical patterns. All analysis operates on data retrieved from the Azure Cost Management API during the import cycle.

FAQs

1. What is a cost group and how is it different from an Azure subscription?
   A cost group is a logical container in Cost Analyzer that defines a scope for cost analysis, budgeting, and monitoring. It can span one or more subscriptions, resource groups, or be filtered by tags and resource types. An Azure subscription is the billing boundary in Azure itself. A cost group gives you the flexibility to organize spend in ways that reflect your teams and products — not just Azure's billing structure.

2. Can a single resource appear in more than one cost group?
   Yes. Cost groups are analytical constructs, not exclusive partitions. The same subscription or resource group can be included in multiple cost groups. This is useful when you need to view the same resource from different organizational perspectives — for example, by team and by environment simultaneously. Be aware that overlapping cost groups will double-count spend if both are summed together.

3. What cost dimensions are available for filtering in analysis views?
   Cost Analyzer supports filtering by subscription, resource group, resource type, resource name, location, and resource tags. The available dimensions depend on the data present in the connected subscriptions. Tag-based dimensions are only available if resources in the subscription are consistently tagged.

4. How far back does cost history go in Cost Analyzer?
   Cost Analyzer imports data from Azure Cost Management, which retains billing data for up to 13 months by default. The available history in Cost Analyzer depends on how long the subscription has been connected and whether there are gaps in the import history. Older data may not be available for subscriptions connected recently.

5. Why does my forecast look flat or show no projection?
   Forecasting requires a minimum of 7–14 days of complete import history. A new cost group, a recently connected subscription, or a period with import gaps may not have sufficient data to generate a projection. Resolve any import gaps and allow the import cycle to rebuild history before expecting forecast data to appear.

6. Can I save an analysis view and reuse it across monitors and reports?
   Yes. Saved analysis views in Cost Analyzer can be referenced when configuring budget monitors, anomaly detection, and scheduled reports. Saving a view preserves its filter configuration — subscription scope, date range, dimensions, and groupings — so you can reuse the same perspective without rebuilding filters each time.

7. What is the difference between actual cost and amortized cost?
   Actual cost reflects charges as they appear on the Azure invoice — reservation purchases show as a lump sum in the month of purchase. Amortized cost spreads reservation and savings plan fees evenly across the period they cover, giving a more accurate picture of daily spend for committed resources. Use amortized cost when analyzing workloads covered by reservations or savings plans to avoid misleading spikes in the month of purchase.

Related articles

• Cost analysis
• Cost management groups
• Getting started FAQs
• Budgets and alerts FAQs