> ## 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.

# Cost per Sign Up: Ad Spend Efficiency for Sign Up Events

> Track the average cost to acquire a sign up through your advertising. Calculate ad spend efficiency for sign up conversions tracked by Upstack.

<Tip>
  Cost per Sign Up measures the average advertising spend required to generate one sign up event tracked by the Upstack pixel.
</Tip>

## Formula

<Info>
  **Cost per Sign Up** = **Channel Spend** ÷ **Sign Up Events**
</Info>

### Formula Components

| Metric             | Definition                                                |
| ------------------ | --------------------------------------------------------- |
| **Channel Spend**  | Total advertising spend across all connected ad platforms |
| **Sign Up Events** | Total sign up events tracked by the Upstack pixel         |

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

***

## Example

Your store spent **\$2,500** on advertising in April and tracked **500 sign ups**:

| Week      | Spend       | Sign Ups | Cost per Sign Up |
| --------- | ----------- | -------- | ---------------- |
| Week 1    | \$600       | 150      | \$4.00           |
| Week 2    | \$650       | 130      | \$5.00           |
| Week 3    | \$625       | 125      | \$5.00           |
| Week 4    | \$625       | 95       | \$6.58           |
| **Total** | **\$2,500** | **500**  | **\$5.00**       |

***

## How It Works

Cost per Sign Up divides your total advertising spend by the number of sign up events captured by the Upstack pixel. This efficiency metric helps you understand how much you're paying to acquire each new sign up through your paid channels.

***

## When to Use

| Scenario                      | Action                                                                 |
| ----------------------------- | ---------------------------------------------------------------------- |
| Evaluating lead gen campaigns | Compare cost per sign up across campaigns to find best performers      |
| Setting acquisition targets   | Use historical cost per sign up to forecast sign up volume from budget |
| Optimizing ad creative        | Identify which creatives drive lower cost sign ups                     |
| Budget allocation             | Shift spend toward channels with lower cost per sign up                |

***

## Related Metrics

| Metric             | Relationship                                             |
| ------------------ | -------------------------------------------------------- |
| **Sign Up Events** | Denominator — total sign ups tracked by Upstack          |
| **Channel Spend**  | Numerator — advertising cost driving sign ups            |
| **Sign Up Value**  | Measures total value of sign ups; pair with cost for ROI |

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