Blended ROAS vs Platform ROAS: Why Meta and Google Both Claim the Same Sale

The double-counting problem

Ask Meta Ads Manager and Google Ads how many sales they drove last month, add the two numbers, and you will almost always get more orders than your store actually shipped. That is not a bug in either platform — it is how attribution works when every platform grades its own homework. A customer who clicked an Instagram ad on Monday and a Google Shopping ad on Wednesday before buying on Friday is a 'conversion' in both dashboards.

Each platform measures its own contribution using its own attribution window — Meta defaults to 7-day click / 1-day view, Google to data-driven attribution across its own surfaces. Neither can see the other's touchpoints, so both claim the order. The more channels you run, the bigger the overlap, and the more your platform-reported ROAS inflates relative to reality.

What blended ROAS actually measures

Blended ROAS is total store revenue divided by total advertising spend across every channel — Meta plus Google plus anything else — for the same period. It ignores attribution entirely, which is exactly why it cannot be gamed: revenue comes from your commerce platform (Shopify, in most D2C stacks), spend comes from the ad accounts, and neither side gets to argue about credit.

A brand spending ₹1,00,000 across Meta and Google that books ₹4,00,000 in net revenue has a blended ROAS of 4.0 — regardless of what either platform claims. If Meta reports 5.2 and Google reports 3.8 at the same time, those numbers are answering a different question: 'of the orders I saw, how much revenue per rupee of my spend?' Useful for optimising within the channel; useless for judging the business.

When to use which number

Platform ROAS still matters — inside the platform. Comparing two Meta campaigns against each other with Meta's attribution is fair, because both are measured the same way. Shifting budget between ad sets, killing fatigued creative, picking audiences: platform metrics are the right tool.

Blended ROAS is the executive number: it decides whether the overall advertising program makes money, how much headroom you have to scale, and whether this month beat last month. Finance should never see a platform ROAS without the blended number next to it.

• Optimising within a channel → platform ROAS
• Judging overall ad profitability → blended ROAS
• Reporting to founders or finance → blended ROAS, with platform numbers as supporting detail
• Diagnosing channel overlap → compare the sum of platform conversions to real orders

The COD complication

In India there is a second layer: cash-on-delivery. A COD order that gets refused at the door was 'revenue' in every ad dashboard and in naive blended ROAS too. Mature teams track a realised variant — prepaid revenue plus delivered COD revenue — alongside booked revenue, so RTO (return to origin) losses do not hide inside a flattering ROAS.

The practical setup: blended ROAS on booked revenue for pace, realised P&L for truth, platform ROAS for in-channel optimisation. Three numbers, three jobs.