> ## 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.

# Browser Dedupe Coverage: Pixel Event Deduplication

> Track what percentage of your browser pixel events include a deduplication key. Higher coverage prevents double-counting conversions.

<Tip>
  Browser Dedupe Coverage measures the percentage of browser pixel events that include a deduplication key, preventing double-counting when browser and server events overlap.
</Tip>

## Formula

<Info>
  **Browser Dedupe Coverage** = **Browser Events with Dedupe Key** ÷ **Total Browser Events** × 100
</Info>

### Formula Components

| Metric                             | Definition                                                       |
| ---------------------------------- | ---------------------------------------------------------------- |
| **Browser Events with Dedupe Key** | Browser pixel events that include an event\_id for deduplication |
| **Total Browser Events**           | All browser pixel events sent to Meta                            |

| Metadata        |                                   |
| --------------- | --------------------------------- |
| **Type**        | Percentage                        |
| **Data Source** | [Meta Ads](/sources/facebook-ads) |
| **Aggregation** | Average                           |

***

## Example

A brand's pixel fires **12,450 browser events** in January. **11,830** include a deduplication key.

| Metric                         | Value     |
| ------------------------------ | --------- |
| Browser Events with Dedupe Key | 11,830    |
| Total Browser Events           | 12,450    |
| **Browser Dedupe Coverage**    | **95.0%** |

***

## How It Works

When both your browser pixel and Conversions API send the same event, Meta needs a deduplication key (event\_id) to recognize them as one conversion rather than two. Browser Dedupe Coverage shows how many of your browser events include this key. Higher coverage means more accurate conversion counts and better attribution.

***

## When to Use

| Scenario                        | Action                                                       |
| ------------------------------- | ------------------------------------------------------------ |
| Coverage below 90%              | Verify pixel is sending event\_id with all conversion events |
| Conversion counts seem inflated | Check both browser and server dedupe coverage for gaps       |
| Setting up Conversions API      | Ensure matching event\_ids between browser and server events |
| Optimizing EMQ Score            | Improve dedupe coverage to prevent duplicate conversions     |

***

## Related Metrics

| Metric                                                                                   | Relationship                                                          |
| ---------------------------------------------------------------------------------------- | --------------------------------------------------------------------- |
| [Server Dedupe Coverage](/reference/metrics/data-quality/emq/server-dedupe-coverage)     | Server-side equivalent—both should be high for accurate deduplication |
| [Overall Browser Coverage](/reference/metrics/data-quality/emq/overall-browser-coverage) | Combined deduplication effectiveness across all browser events        |

[See all EMQ metrics →](/reference/metrics/data-quality/emq)