> ## 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.

# Overall Browser Coverage: Deduplication Key Coverage

> Track combined deduplication key coverage across all browser events to prevent duplicate conversion reporting in Meta ads.

<Tip>
  Overall Browser Coverage measures the percentage of browser pixel events that include a deduplication key, reflecting how well your setup prevents duplicate conversion reporting.
</Tip>

## Formula

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

### Formula Components

| Metric                             | Definition                                                          |
| ---------------------------------- | ------------------------------------------------------------------- |
| **Browser Events with Dedupe Key** | Count of browser pixel events containing a deduplication identifier |
| **Total Browser Events**           | Total count of browser pixel events sent to Meta                    |

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

***

## Example

Your store sends **12,450 browser events** to Meta, with **11,580 including deduplication keys**.

| Metric                       | Value     | Interpretation                |
| ---------------------------- | --------- | ----------------------------- |
| Events with Dedupe Key       | 11,580    | Browser events with event IDs |
| Total Browser Events         | 12,450    | All browser pixel events      |
| **Overall Browser Coverage** | **93.0%** | Strong deduplication coverage |

***

## How It Works

When both browser pixel and server Conversions API send the same conversion event, Meta uses deduplication keys to avoid double-counting. This metric shows the percentage of your browser events that include the required identifier (typically `event_id`) for accurate deduplication.

***

## When to Use

| Scenario                      | Action                                             |
| ----------------------------- | -------------------------------------------------- |
| Coverage below 90%            | Check pixel configuration for missing event IDs    |
| Seeing duplicate conversions  | Verify browser events include matching dedupe keys |
| Setting up redundant tracking | Ensure browser and server events share identifiers |
| Auditing data quality         | Compare with server coverage for full picture      |

***

## Related Metrics

| Metric                                                                                 | Relationship                                 |
| -------------------------------------------------------------------------------------- | -------------------------------------------- |
| [Browser Dedupe Coverage](/reference/metrics/data-quality/emq/browser-dedupe-coverage) | Per-event breakdown of browser deduplication |
| [Server Dedupe Coverage](/reference/metrics/data-quality/emq/server-dedupe-coverage)   | Server-side deduplication key coverage       |

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