Calculator

Calculate both views without hiding the denominators

Enter one currency and one reporting window. “All platform-attributed revenue” is the sum of revenue claimed by the ad platforms you are reviewing; it is used only as a diagnostic against observed store revenue.

Formulas

Four ratios that are often confused

Platform ROASplatform-attributed purchase value ÷ that platform's spend

Both numerator and denominator come from the selected advertising platform and inherit its attribution and reporting rules.

Blended ROASobserved store revenue ÷ all paid-media spend

Define store revenue and paid-media coverage explicitly. Include the same brands, countries, currencies, and dates in both.

MERtotal business revenue ÷ total marketing spend

Marketing efficiency ratio can use a broader spend denominator than blended paid-media ROAS. Teams should not assume the labels are universal.

Attribution claim ratiosum of platform-attributed revenue ÷ observed store revenue

A result above 100% signals that attribution claims are not mutually exclusive or otherwise not comparable. It does not quantify causal overlap by itself.

Comparison

Why platform and blended ROAS diverge

Dimension	Platform ROAS	Blended ROAS	Control
Revenue source	Platform-attributed purchase value.	Observed commerce or finance revenue under a written policy.	Label the numerator and source on every chart.
Spend scope	Spend reported by one platform or selected account set.	All paid-media spend in the chosen business scope.	Maintain an account-to-brand and market scope map.
Attribution	Uses the platform’s window, identity, and modeling rules.	Does not need channel attribution in the numerator.	Store the attribution setting with the result.
Overlap	Multiple platforms can claim the same conversion.	Each observed order appears under the commerce revenue policy.	Never create blended revenue by summing platform claims.
Organic demand	May receive credit if a platform interaction qualifies.	Includes revenue regardless of which paid platform claims it.	Interpret blended ROAS as total paid efficiency, not platform causality.
Adjustments	Refund and cancellation handling depends on event collection and platform processing.	Can be defined using observed order and refund facts.	Choose gross, net, or contribution basis consistently.
Date	Credit may follow platform reporting and attribution-date rules.	Revenue may follow order, payment, fulfillment, or refund date.	Compare cohorts and daily time series separately.
Currency	Account reporting currency and platform conversion policy.	Store, presentment, or finance reporting currency.	Convert numerator and denominator with one documented FX policy.

Aggregation rule

Never average row-level ROAS

ROAS is a ratio. To aggregate campaigns, dates, countries, or accounts, sum compatible revenue and spend first, then divide. An unweighted average gives a tiny campaign the same influence as a large one.

Correct combined ROASsum(revenue) ÷ sum(spend)

Only combine rows with compatible revenue definition, attribution setting, currency policy, and scope.

Incorrect shortcutaverage(row-level ROAS)

This usually produces a different number because the rows have different spend weights.

Definition evidence

Check aggregation behavior before rolling up a metric

The Semantic Contract Library exposes source report grains, metrics, and semantic capabilities. Check the Meta Ads connector and Google Ads connector, then use the metric aggregation and grain guide before combining channel results.

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Decision guide

Which number should lead the conversation?

Platform optimizationUse platform ROAS alongside delivery and conversion metrics, while retaining the platform attribution label.

Business pacingUse blended ROAS or a clearly defined MER with observed revenue and comprehensive spend.

Budget comparisonUse both, plus controlled experiments or stronger measurement methods when causal allocation matters.

Creative analysisUse platform-native signals at the appropriate ad or creative grain; avoid treating them as unduplicated business outcomes.

Primary sources: verify conversion value and revenue definitions

ROAS labels are not universal. Validate what each platform places in conversion value and cost, then validate the observed revenue basis independently before comparing or recomputing the ratios.

Related guides

Continue the diagnostic

ROAS vs. MER

See how channel return and marketing efficiency answer different questions.

Meta conversions vs. Shopify orders

Trace attribution and observed-order differences at the source.

Marketing discrepancy decision tree

Classify revenue, conversion, order, and aggregation gaps.

Keep both metrics honest

Make every ROAS number carry its contract

Metric Hive is built to keep source attribution metrics separate from canonical commerce facts and to recompute ratios from compatible base metrics. It can improve consistency and explainability; it cannot make platform attribution equivalent to incremental impact.

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