[Home](./index.md) > [@firebase/performance](./performance.md) > [PerformanceTrace](./performance.performancetrace.md) > [putMetric](./performance.performancetrace.putmetric.md) ## PerformanceTrace.putMetric() method Sets the value of the specified custom metric to the given number regardless of whether a metric with that name already exists on the trace instance or not. The value will be floored down to an integer. Signature: ```typescript putMetric(metricName: string, num: number): void; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | metricName | string | Name of the custom metric. | | num | number | Value to of the custom metric. | Returns: void