> ## Documentation Index
> Fetch the complete documentation index at: https://docs.upstackdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Subscription Churned Cost: Wasted CAC from Churn

> Calculate advertising cost associated with churned subscriptions. Measure CAC lost to subscriber attrition.

<Tip>
  Subscription Churned Cost measures the advertising spend associated with subscriptions that churned.
</Tip>

## Formula

<Info>
  **Subscription Churned Cost** = **Ad Spend** ÷ **Subscription Churned**
</Info>

### Formula Components

| Metric                                                                                 | Definition                                         |
| -------------------------------------------------------------------------------------- | -------------------------------------------------- |
| [**Ad Spend**](/reference/metrics/advertising/blended/blended-spend)                   | Total advertising cost from connected ad platforms |
| [**Subscription Churned**](/reference/metrics/funnel/conversions/subscription-churned) | Count of churned subscriptions                     |

| Metadata        |                         |
| --------------- | ----------------------- |
| **Type**        | Currency                |
| **Data Source** | [Upstack Pixel](/pixel) |
| **Aggregation** | Ratio                   |

***

## Example

You spent **\$10,000** on advertising in January and had **89 churned subscriptions**.

| Metric                    | Value    | Notes                    |
| ------------------------- | -------- | ------------------------ |
| Ad Spend                  | \$10,000 | Monthly advertising cost |
| Subscription Churned      | 89       | Lost subscriptions       |
| Subscription Churned Cost | \$112.36 | Ad spend per churned sub |

***

## How It Works

This metric divides your total ad spend by the number of churned subscriptions. While not a direct causation metric, it helps contextualize acquisition cost against retention performance.

***

## When to Use

| Scenario                 | Action                                         |
| ------------------------ | ---------------------------------------------- |
| Channel quality analysis | Identify sources with high churn attribution   |
| CAC efficiency           | Compare acquisition cost to retention outcomes |
| Win-back budgeting       | Allocate spend to reduce churn impact          |
| Cohort performance       | Analyze churn rates by acquisition channel     |

***

## Related Metrics

| Metric                                                                                         | Relationship                        |
| ---------------------------------------------------------------------------------------------- | ----------------------------------- |
| [Subscription Churned](/reference/metrics/funnel/conversions/subscription-churned)             | The denominator in this calculation |
| [Subscription Churned Value](/reference/metrics/funnel/conversions/subscription-churned-value) | Revenue lost to churn               |
| [Subscription Created Cost](/reference/metrics/funnel/conversions/subscription-created-cost)   | Cost to acquire new subs            |

[See all Conversions metrics →](/reference/metrics/funnel/conversions)