> ## 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.

# Google Cost per Purchase: Acquisition Efficiency

> Track your Google Ads cost per purchase to measure acquisition efficiency. Calculate how much you spend to drive each conversion through Google campaigns.

<Tip>
  Google Cost per Purchase measures how much you spend on average to drive each purchase through your Google Ads campaigns.
</Tip>

## Formula

<Info>
  **Google Cost per Purchase** = [**Google Spend**](/reference/metrics/advertising/google/google-spend/google-spend) ÷ [**Google Purchases**](/reference/metrics/advertising/google/google-conversions/google-purchases)
</Info>

### Formula Components

| Metric                                                                                            | Definition                                    |
| ------------------------------------------------------------------------------------------------- | --------------------------------------------- |
| [**Google Spend**](/reference/metrics/advertising/google/google-spend/google-spend)               | Total amount billed by Google for advertising |
| [**Google Purchases**](/reference/metrics/advertising/google/google-conversions/google-purchases) | Number of purchases attributed to Google ads  |

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

***

## Example

A home decor store spent **\$4,200** on Google Ads in March and drove **84 purchases**.

| Metric                | Value       | Calculation            |
| --------------------- | ----------- | ---------------------- |
| Google Spend          | \$4,200     | Total ad spend         |
| Google Purchases      | 84          | Attributed conversions |
| **Cost per Purchase** | **\$50.00** | \$4,200 ÷ 84           |

***

## How It Works

Google Cost per Purchase divides your total Google Ads spend by the number of purchases attributed to those campaigns. Lower values indicate more efficient acquisition—you're spending less to acquire each customer through Google.

***

## When to Use

| Scenario                  | Action                                                    |
| ------------------------- | --------------------------------------------------------- |
| High cost per purchase    | Pause underperforming campaigns or ad groups              |
| Compare campaign types    | Evaluate Search vs Shopping vs Performance Max efficiency |
| Budget allocation         | Shift spend to campaigns with lower acquisition costs     |
| Cross-platform comparison | Compare against Meta or TikTok cost per purchase          |

***

## Related Metrics

| Metric                                                                                        | Relationship                    |
| --------------------------------------------------------------------------------------------- | ------------------------------- |
| [Google Spend](/reference/metrics/advertising/google/google-spend/google-spend)               | Numerator in calculation        |
| [Google Purchases](/reference/metrics/advertising/google/google-conversions/google-purchases) | Denominator in calculation      |
| [Google ROAS](/reference/metrics/advertising/google/google-efficiency/google-roas)            | Revenue-based efficiency metric |

[See all Google Efficiency metrics →](/reference/metrics/advertising/google/google-efficiency)