Multi-currency attribution
When conversions happen in different currencies, attribution must convert each conversion value into a single reporting currency before credit and ROAS can be compared. Platforms apply exchange rates (often daily) at value capture, so the same sale can report slightly different amounts depending on when and at what rate it was converted. Getting currency handling right is a prerequisite for trustworthy cross-market attribution and ROAS.
Why currency enters attribution
Value-based attribution and ROAS divide credited value by spend. If conversions arrive in euros, yen, and dollars, those values cannot be summed or compared until they share a currency.
Platforms convert each conversion value to the account's reporting currency using an exchange rate — commonly a daily rate at the time the value is recorded — so all credit is expressed in one unit.
Where it goes wrong
Rate timing is the catch: the rate used at capture may differ from the rate at the actual sale or at booking in finance systems, so analytics and finance can disagree on the 'same' revenue. Daily rate changes also make identical sales report different converted values on different days.
Best practice is to store the original value and currency on the conversion, document which rate source and timing the platform uses, and reconcile to finance rather than assuming a single true number.
- Each conversion value converted to one reporting currency
- Rates are typically daily and applied at value capture
- Store original value + currency; reconcile to finance
How it appears in analytics and logs
If cross-market ROAS looks volatile without volume changes, currency conversion timing or rate differences — not performance — may be moving the numbers.
Diagnostic use case
Compare conversion value and ROAS fairly across markets by ensuring every conversion is converted to one reporting currency at a consistent rate.
What WebmasterID can help detect
WebmasterID can record the original transaction value and currency on first-party conversion events, so conversion is explicit rather than guessed downstream.
Common mistakes
- Summing conversion values across currencies without converting.
- Assuming analytics' converted revenue matches finance exactly.
- Ignoring that daily rates shift identical sales' reported value.
Privacy and accuracy notes
Currency conversion operates on aggregated value totals, not personal data. Educational, not legal advice on financial reporting.
Related pages
- Value-based attribution
Value-based attribution assigns the monetary value of a conversion — not just a count of one — across the touchpoints in the path. It matters because optimizing for conversion counts treats a low-value and a high-value sale identically; distributing value lets bidding and analysis favor the channels that bring more revenue, provided conversion values are passed accurately.
- Marketing ROI vs ROAS
Return on ad spend (ROAS) and marketing return on investment (ROI) are often conflated but measure different things. ROAS is revenue divided by advertising spend — a top-line efficiency ratio. Marketing ROI is profit (or net gain) divided by the full cost of the marketing — a bottom-line return. A campaign can have a high ROAS yet a poor ROI once margins and total costs are included. This page defines both formulas and when each applies.
- Attribution data discrepancies
Attribution data discrepancies are the routine mismatches between conversion numbers reported by different tools — an ad platform versus site analytics, or two analytics products. They arise from different attribution models, lookback and reporting windows, time zones, deduplication rules, bot filtering, and consent handling. Most discrepancies are structural and expected, so the goal is to explain them, not eliminate them.
- Attribution analytics
Record original value and currency on conversions.
Sources and verification notes
- Google Ads Help — Conversion value and currencyDocuments conversion value with currency codes and conversion.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.