> ## 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 Add Payment Info: Measure Payment Step Efficiency

> Track cost per add payment info to measure checkout payment step efficiency. Calculate your average ad spend per payment info submission event.

<Tip>
  Cost per Add Payment Info measures the average advertising spend required to generate one payment info submission event tracked by the Upstack pixel.
</Tip>

## Formula

<Info>
  **Cost per Add Payment Info** = **Channel Spend** ÷ **Add Payment Info Events**
</Info>

### Formula Components

| Metric                                                                         | Definition                                                  |
| ------------------------------------------------------------------------------ | ----------------------------------------------------------- |
| **Channel Spend**                                                              | Total advertising spend across all connected ad platforms   |
| [**Add Payment Info**](/reference/metrics/funnel/conversions/add-payment-info) | Payment info submission events tracked by the Upstack pixel |

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

***

## Example

Your Shopify store spent **\$12,000 on ads** in March and the Upstack pixel tracked **4,800 add payment info events**.

| Week      | Ad Spend     | Add Payment Info | Cost/Add Payment Info |
| --------- | ------------ | ---------------- | --------------------- |
| Week 1    | \$2,800      | 1,120            | \$2.50                |
| Week 2    | \$3,200      | 1,280            | \$2.50                |
| Week 3    | \$2,900      | 1,160            | \$2.50                |
| Week 4    | \$3,100      | 1,240            | \$2.50                |
| **Total** | **\$12,000** | **4,800**        | **\$2.50**            |

***

## How It Works

Upstack calculates Cost per Add Payment Info by dividing your total advertising spend across all channels by the number of payment info submission events tracked by the pixel. This metric measures how efficiently your ads drive visitors to the payment stage of checkout—a high-intent action that indicates strong purchase likelihood.

***

## When to Use

| Scenario                   | Action                                                                         |
| -------------------------- | ------------------------------------------------------------------------------ |
| Funnel efficiency analysis | Compare against cost per purchase to measure payment-to-purchase drop-off cost |
| Budget optimization        | Identify channels that drive payment info submissions most efficiently         |
| Checkout optimization      | Monitor how checkout UX changes affect acquisition costs at payment stage      |
| Campaign targeting         | Evaluate which audiences reach payment stage at lower cost                     |

***

## Related Metrics

| Metric                                                                                 | Relationship                               |
| -------------------------------------------------------------------------------------- | ------------------------------------------ |
| [Add Payment Info](/reference/metrics/funnel/conversions/add-payment-info)             | Count of payment info events (denominator) |
| [Add Payment Info Value](/reference/metrics/funnel/conversions/add-payment-info-value) | Monetary value of payment info events      |
| [Cost per Purchase](/reference/metrics/funnel/conversions/cost-per-purchase)           | Next funnel stage cost efficiency          |

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