> ## 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.

# New Customer CM3 MER: First-Order Contribution Margin Efficiency

> Track new customer CM3 MER for your Shopify store. Measure contribution margin generated per dollar of ad spend on first orders.

<Tip>
  New Customer CM3 MER measures how much contribution margin (after all variable costs including ad spend) you generate from first orders per dollar of ad spend.
</Tip>

## Formula

<Info>
  **New Customer CM3 MER** = **New Customer CM3** ÷ **Ad Spend**
</Info>

### Formula Components

| Metric                                                                                                 | Definition                                       |
| ------------------------------------------------------------------------------------------------------ | ------------------------------------------------ |
| [**New Customer CM3**](/reference/metrics/orders/contribution-margin/new-customer-contribution-margin) | Contribution margin from first-time buyer orders |
| [**Ad Spend**](/reference/metrics/advertising/blended/blended-spend)                                   | Total advertising spend                          |

| Metadata        |                                                                                             |
| --------------- | ------------------------------------------------------------------------------------------- |
| **Type**        | Ratio                                                                                       |
| **Data Source** | [Shopify](/sources/catalog/shopify), [Advertising Platforms](/sources/catalog/facebook-ads) |
| **Aggregation** | Ratio                                                                                       |

***

## Example

Your Shopify store generates **\$7,000** CM3 from new customers and spends **\$15,000** on ads.

| Component                | Value    | Calculation                     |
| ------------------------ | -------- | ------------------------------- |
| New Customer CM3         | \$7,000  | First-order contribution margin |
| Ad Spend                 | \$15,000 | Marketing cost                  |
| **New Customer CM3 MER** | **0.47** | \$7,000 ÷ \$15,000              |

***

## How It Works

New Customer CM3 MER is often below 1.0 because first-order contribution margin already includes ad spend as a deduction. This ratio shows how efficiently you're acquiring customers at the fully-loaded variable cost level.

***

## Interpretation

| Scenario     | Meaning                                                     |
| ------------ | ----------------------------------------------------------- |
| CM3 MER > 0  | First orders contribute positively after all variable costs |
| CM3 MER = 0  | First orders break even on variable costs                   |
| CM3 MER \< 0 | First orders lose money on variable costs                   |

First-order CM3 MER is often low; profitability depends on repeat purchases.

***

## Related Metrics

| Metric                                                                                             | Relationship                    |
| -------------------------------------------------------------------------------------------------- | ------------------------------- |
| [New Customer CM3](/reference/metrics/orders/contribution-margin/new-customer-contribution-margin) | Numerator (contribution margin) |
| [CM3 MER](/reference/metrics/orders/performance/cm3-mer)                                           | Overall CM3 efficiency          |
| [New Customer CM4 MER](/reference/metrics/orders/performance/new-customer-cm4-mer)                 | After fixed costs               |

[See all Performance metrics →](/reference/metrics/orders/performance)