Content revised 21 October 2026.
A calculated metric combines existing values into a measure that answers a business question. Its usefulness depends on correct inputs and a clear denominator.
Write the question and formula
State what decision the measure supports, which values are included and how the result is interpreted. For example, a cost per qualified enquiry needs both the agreed cost scope and a dependable enquiry count.
Check compatibility
Do not combine values from incompatible timeframes or scopes. Decide what happens when the denominator is zero or data is missing. An attractive percentage can be misleading when a small or unsuitable sample drives it.
Use the supported implementation
GA4 offers calculated metrics with permissions and limits described in its current documentation. Check the property’s available options rather than following old Universal Analytics instructions. Keep a record of the formula and owner.
Verify by hand
Test a small known example and compare the manual result with the report. Explain caveats beside the metric. A new formula cannot create revenue or customer-quality evidence that was never collected.
Official guidance: GA4 calculated metrics.