Convert revenue once before adding currencies

Adding a euro amount to a dollar amount produces a number, not a comparable revenue total. This lab makes the conversion direction visible and tests the sensitivity of a mixed-currency total. The exchange rate is an editable teaching assumption, not a current market quote.

Define the calculation before using it

Choose a reporting currency and specify the number of reporting-currency units received for one source-currency unit. Apply that rate to the source amount before adding revenue already expressed in the reporting currency. Preserve whether the rate represents transaction-time conversion, a settlement rate or an accounting convention. A rate without its direction is an easy source of silent reciprocal errors.

Work through the synthetic example

The example converts 1,000 source units at 1.10 reporting units each, then adds 500 reporting units already on hand. The total is 1,600. The calculator varies the conversion assumption so the reader can see how much of a comparison depends on FX rather than player behaviour. It does not recommend any particular accounting rate.

Use the artifact and preserve its assumptions

Open the editable calculator to change the inputs and inspect the sensitivity view. The CSV records synthetic inputs and expected outputs; the JSON fixture keeps the equations available for reproduction. These calculations have been checked against the stated example. No measured campaign data is included.

The sensitivity rows vary only fx by 20% below and above the entered value. They are scenarios, not confidence limits or a forecast distribution. A row outside the model’s constraints is labelled rather than turned into a plausible-looking result. Save the chosen inputs with the decision so another reader can distinguish a changed assumption from a changed formula.

Evidence and limits

Google’s export schema identifies event_value_in_usd as a currency-converted value. That makes the revenue basis consequential: an already converted field should not be converted a second time. See Google Analytics BigQuery Export schema, especially “event_date, event_timestamp, event_value_in_usd and event_params fields”.

Use an approved rate source and consistent timing for a real reconciliation. Platform-reported converted revenue may already include conversion; applying the worksheet to it again would double-convert the value.

Background: UA metrics explained: CPI, ROAS, LTV and payback and Reading an MMP dashboard without fooling yourself. These existing articles provide context; the present calculation does not verify every archived claim.