> ## 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: Measure Registration Efficiency

> Track cost per sign up to measure how efficiently your ads drive new registrations. Calculate average ad spend per sign up event for your Shopify store.

<Tip>
  Cost per Sign Up measures the average ad spend required to generate one sign up (registration) event on your site.
</Tip>

## Formula

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

### Formula Components

| Metric                                                                    | Definition                                                       |
| ------------------------------------------------------------------------- | ---------------------------------------------------------------- |
| [**Channel Spend**](/reference/metrics/advertising/blended/blended-spend) | Total advertising spend across all channels                      |
| [**Sign Ups**](/reference/metrics/funnel/engagement/sign-up)              | Total sign up (registration) events tracked by the Upstack pixel |

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

***

## Example

Your store spent **\$8,000** on ads in February and tracked **1,600** sign up events.

| Metric               | Value      | Calculation          |
| -------------------- | ---------- | -------------------- |
| Channel Spend        | \$8,000    | Total ad spend       |
| Sign Ups             | 1,600      | Total sign up events |
| **Cost per Sign Up** | **\$5.00** | \$8,000 ÷ 1,600      |

***

## How It Works

The Upstack pixel captures sign up events when visitors register for an account on your site. Cost per Sign Up divides your total ad spend by the number of registration events, showing how efficiently your ads drive new account creation. Lower values indicate more cost-effective acquisition of registered users who can be nurtured through email and remarketing.

***

## When to Use

| Scenario                             | Action                                                           |
| ------------------------------------ | ---------------------------------------------------------------- |
| Evaluating acquisition campaigns     | Compare Cost per Sign Up across campaigns targeting new visitors |
| Measuring membership program ROI     | Track if registration-focused ads efficiently drive new signups  |
| Assessing lead generation efficiency | Monitor cost to acquire new registered contacts                  |
| Optimizing top-of-funnel spend       | Find channels with lowest Cost per Sign Up for budget allocation |

***

## Related Metrics

| Metric                                                                | Relationship                                                   |
| --------------------------------------------------------------------- | -------------------------------------------------------------- |
| [Sign Ups](/reference/metrics/funnel/engagement/sign-up)              | The denominator in this calculation                            |
| [Cost per Login](/reference/metrics/funnel/engagement/cost-per-login) | Similar cost efficiency metric for existing account engagement |
| [Conversions](/reference/metrics/funnel/conversions/conversions)      | Ultimate purchase goal after registration                      |

[See all Engagement metrics →](/reference/metrics/funnel/engagement)