> ## 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.

# MER: Marketing Efficiency Ratio

> Track what percentage of revenue you spend on advertising. Calculate MER to monitor ad spend efficiency—lower MER means more revenue per dollar spent.

<Tip>
  MER (Marketing Efficiency Ratio) measures what percentage of your total revenue is spent on advertising—lower is better.
</Tip>

## Formula

<Info>
  **Marketing Efficiency Ratio** = ( **Total Ad Spend** ÷ **Total Revenue** ) × 100
</Info>

### Formula Components

| Metric                                                                                   | Definition                                              |
| ---------------------------------------------------------------------------------------- | ------------------------------------------------------- |
| [**Total Ad Spend**](/reference/metrics/advertising/blended/blended-spend/blended-spend) | Sum of advertising spend across all connected platforms |
| [**Total Revenue**](/reference/metrics/orders/revenue/total-revenue)                     | Complete order revenue including shipping and taxes     |

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

***

## Example

Your store generated **\$250,000** in order revenue while spending **\$50,000** on ads:

| Total Revenue | Total Ad Spend | MER |
| ------------- | -------------- | --- |
| \$250,000     | \$50,000       | 20% |
| \$250,000     | \$75,000       | 30% |
| \$250,000     | \$30,000       | 12% |

A 20% MER means you spent \$0.20 on ads for every \$1.00 of revenue. Lower MER indicates better efficiency—you're keeping more of each revenue dollar.

***

## How It Works

MER divides your total advertising spend by your total order revenue, then multiplies by 100 to express it as a percentage. Unlike ROAS (which is Revenue ÷ Spend), MER shows the inverse—what fraction of your revenue goes to advertising. Lower MER values indicate better efficiency.

***

## When to Use

| Scenario                   | Action                                                |
| -------------------------- | ----------------------------------------------------- |
| Setting efficiency targets | Define maximum acceptable ad spend as % of revenue    |
| Comparing time periods     | Track if marketing efficiency improves over time      |
| Budget planning            | Determine how much revenue to reinvest in ads         |
| Profitability analysis     | Combine with margin data to ensure ads are profitable |

***

## Related Metrics

| Metric                                                                              | Relationship                                       |
| ----------------------------------------------------------------------------------- | -------------------------------------------------- |
| [ROAS](/reference/metrics/orders/performance/roas)                                  | Inverse metric: Revenue ÷ Spend (higher is better) |
| [Total Revenue](/reference/metrics/orders/revenue/total-revenue)                    | The denominator in MER calculation                 |
| [Blended Spend](/reference/metrics/advertising/blended/blended-spend/blended-spend) | The numerator in MER calculation                   |
| [CAC](/reference/metrics/orders/performance/cac)                                    | Cost per new customer acquired                     |

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