# Average Wait Time - Specific Phone Line

**Voice - Calls**  
*Calculated Metric*  
Calculates the average wait time for inbound calls to a specific phone number so you can monitor line-level KPIs.

## Business value & use cases
Helps managers track whether certain phone lines are creating longer waits than others, especially when displaying KPIs for a single line on a dashboard. Can highlight where demand is outpacing staffing or routing capacity and pairs well with a [Target KPI Value](/content/best-practice/zendesk-explore-custom-metrics/library/target-kpi-value/index.html) set to the desired average wait time.

## Dataset and dependencies
- **Dataset**: Voice - Calls  
- **Type**: Calculated Metric  
- **Dependencies**: None, though often paired with a custom Target KPI Value for the same phone line.

## The code

Unlock to view full code  
Not sure how to work with the code? Check our [getting started guides](/content/best-practice/zendesk-explore-custom-metrics/guides/index.html).

## Implementation steps
1. Go to Explore → Report Builder > Voice → Calls Dataset → Start Report.  
2. Select the Calculator icon for Calculations.  
3. Choose Standard calculated metric.  
4. Paste in the code above.  
5. Replace +448001234123 with the [phone number you want to track](/content/best-practice/zendesk-explore-custom-metrics/library/phone-line-name/index.html).  
6. Validate and save.  
7. Add the report to a dashboard alongside any other KPIs for that line.

## Validation tips
- Check that only calls from the specified number are included.  
- Compare results against a report filtered directly by that phone number to confirm accuracy.  
- Test with different numbers if you plan to track multiple lines.

## Caveats and considerations
You must create a separate version of this metric for each phone number you want to track. Best used when each line represents a distinct queue or customer journey worth monitoring. On a line-specific dashboard, pair alongside metrics such as call volume or [completion rate](/content/best-practice/zendesk-explore-custom-metrics/library/inbound-completion-rate-within-agents-control/index.html) to give a fuller view of line-level performance.

## Example chart

Example dashboard tile tracking average wait time alongside line-level KPIs

## Related metrics / attributes
[**Phone Line Name**  
Voice - Calls  
*Calculated Attribute*  
Replaces raw Voice phone numbers with readable names so charts and tables are easier to interpret.

[**Target KPI Value**  
Support - Tickets  
*Calculated Metric*  
Creates a constant numeric metric (for example 0.9 for 90%) that you can reuse as a KPI threshold across reports and dashboards.

## Now share real-time data with your team
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