> ## 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.

# Blended Cost per Add to Cart: Cross-Platform ATC Efficiency

> Track your blended cost per add to cart across Meta, Google, and TikTok ads. Measure cross-platform efficiency for cart actions.

<Tip>
  Blended Cost per Add to Cart measures how much you spend across all ad platforms to generate one add-to-cart event.
</Tip>

## Formula

<Info>
  **Blended Cost per Add to Cart** = [**Blended Spend**](/reference/metrics/advertising/blended/blended-spend/blended-spend) ÷ [**Blended Add to Carts**](/reference/metrics/advertising/blended/blended-conversions/blended-add-to-carts)
</Info>

### Formula Components

| Metric                                                                                                      | Definition                                                  |
| ----------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------- |
| [**Blended Spend**](/reference/metrics/advertising/blended/blended-spend/blended-spend)                     | Total advertising spend across all connected ad platforms   |
| [**Blended Add to Carts**](/reference/metrics/advertising/blended/blended-conversions/blended-add-to-carts) | Total add-to-cart events attributed across all ad platforms |

| Metadata        |                                                                                                     |
| --------------- | --------------------------------------------------------------------------------------------------- |
| **Type**        | Currency                                                                                            |
| **Data Source** | [Meta Ads](/sources/facebook-ads), [Google Ads](/sources/google-ads), [TikTok Ads](/sources/tiktok) |
| **Aggregation** | Ratio                                                                                               |

***

## Example

Your store spent **\$15,000** across all ad platforms last month and generated **3,000** add-to-cart events.

| Metric                           | Value      |
| -------------------------------- | ---------- |
| Blended Spend                    | \$15,000   |
| Blended Add to Carts             | 3,000      |
| **Blended Cost per Add to Cart** | **\$5.00** |

***

## How It Works

Blended Cost per Add to Cart divides your total advertising spend across Meta, Google, and TikTok by the total add-to-cart events attributed to those platforms. This gives you a unified view of how efficiently your combined ad spend drives cart actions, regardless of which platform generated them.

***

## When to Use

| Scenario                    | Action                                                                                   |
| --------------------------- | ---------------------------------------------------------------------------------------- |
| Budget allocation           | Compare blended cost per ATC against platform-specific costs to identify efficiency gaps |
| Funnel optimization         | Track how cost per cart action changes relative to cost per purchase                     |
| Campaign scaling            | Monitor if increased spend maintains efficient cost per cart action                      |
| Cross-platform benchmarking | Evaluate overall ad efficiency without platform-specific bias                            |

***

## Related Metrics

| Metric                                                                                                            | Relationship                                             |
| ----------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------- |
| [Blended Spend](/reference/metrics/advertising/blended/blended-spend/blended-spend)                               | Numerator — total ad spend across platforms              |
| [Blended Add to Carts](/reference/metrics/advertising/blended/blended-conversions/blended-add-to-carts)           | Denominator — total cart events across platforms         |
| [Blended Cost per Purchase](/reference/metrics/advertising/blended/blended-conversions/blended-cost-per-purchase) | Downstream efficiency — cost to convert cart to purchase |
| [Blended ROAS](/reference/metrics/advertising/blended/blended-efficiency/blended-roas)                            | Revenue efficiency — return on combined ad spend         |

[See all Blended Conversions metrics →](/reference/metrics/advertising/blended/blended-conversions)