# Cost Delta

Cost Delta helps you quickly identify unexpected changes in your cloud spend. By comparing your current cost against a historical baseline, OneLens highlights spikes or drops that deserve your attention.

## Set Up Cost Delta Thresholds and Filters

Start by defining what counts as a significant cost change for you.

* **Thresholds**: Set thresholds as a percentage or absolute value to control when OneLens flags a delta.
* **Filters**: Focus on what matters to you—filter by account, service, region, or cost center.
* **Frequency**: Decide how often you want OneLens to check for deltas—daily, weekly, or custom.

## View a Cost Delta

When OneLens detects a cost delta, it’s immediately available in your dashboard. Each delta card shows you:

* Which account, service, region, or cost center was affected
* The current spends vs. historical spend
* The delta value and percentage
* When the change was first noticed

You can sort, search, and filter the list to quickly zero in on the changes that matter most to you.

## Understand a Cost Delta

To help you understand what’s driving the delta, OneLens gives you the full context:

* **Spend Trend**: View how the cost evolved over time.
* **Breakdown by Dimension**: Drill down by usage type, instance type, resource, or tag.
* **Baseline Comparison**: See how your current cost compares with historical norms.

## Finding the Root Cause

### Top 10 Resource Root Cause

OneLens surfaces the top 10 resources contributing to the delta. You can immediately see which resources are behind the cost shift and how much each one contributed.

### AI-Based Hint

You also get an AI-generated hint that helps explain the delta using patterns from your data—such as usage anomalies, sudden scaling, or policy violations. It’s designed to save you time during investigation.

## Act on a Cost Delta

* **Acknowledge**: Indicate that the delta is under review to prevent duplicate investigations.
* **Document**: Add notes or links to create a record of the investigation.
* **Assign**: Assign the delta to the appropriate individual or team for follow-up.
* **Dismiss**: Dismiss expected or irrelevant deltas.
* **Resolve**: Mark as resolved once addressed to keep the view clean and focused.


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