Blended ROAS Calculator

Two ROAS figures, one of them wrong

Platform ROAS is revenue a platform believes it caused, divided by what you spent there. Blended ROAS is all revenue you actually collected, divided by everything you spent.

Blended ROAS = total revenue ÷ total ad spend

Add up what each platform claims and the total will usually exceed what you banked. That is not a rounding error. When a customer sees a TikTok video, later clicks a Meta retargeting ad and finally arrives through a branded Google search, all three record a conversion. You received one order.

The gap between the two figures is the amount of double-counting in your reporting, expressed in dollars. Most operators have never measured it, and most are surprised by the size.

Where each number comes from

Ad spend, per channel

From each platform’s billing, not its reporting tab. Billing is what left your account; reporting is what the platform thinks it delivered.

Revenue it claims

The conversion value that platform reports for the period. Copy it faithfully, including the parts you suspect are inflated — the point of this exercise is to measure the inflation, not to correct it first.

Revenue you actually collected

From your store or your bank, for the same period. This single number is what makes the calculation honest, and getting the period boundaries to match matters more than people expect.

One caution on periods: platforms report conversions against the date of the click, not the date of the purchase. A 7-day attribution window means a sale today can be credited to last week. Comparing a calendar month against a click-dated month introduces error that looks like over-attribution but is not.

A worked example

Meta: $6,000 spent, claiming $21,000. TikTok: $3,000 spent, claiming $9,000. Google: $1,000 spent, claiming $5,000. Total spend $10,000, total claimed $35,000. Your store shows $28,000 collected.

Platform arithmetic gives 3.50x. Reality gives 2.80x. The attribution gap is $7,000, meaning the platforms collectively overstated revenue by 25%.

The decision this changes: if your break-even is 2.13x, then at 3.50x you appear to have enormous headroom and would reasonably scale spending. At the true 2.80x you have real but modest room, and a single bad month of CPA inflation eats it. Same account, opposite postures.

Reading the gap

A positive gap — platforms claiming more than you banked — is the normal case. Modest over-claiming is unavoidable with overlapping audiences. Very large over-claiming usually means heavy retargeting counting conversions that would have happened anyway, or attribution windows so long they capture purchases the ad had nothing to do with.

A negative gap is rarer and more interesting: you collected more than your platforms claim. That means real demand they cannot see — word of mouth, organic search, repeat customers — and it usually means you are under-investing, because your true return is better than your dashboards suggest.

Either way, the number to plan against is the blended one, and the number to compare it to is your break-even. Platform ROAS is best treated as a relative signal for comparing campaigns against each other, never as an absolute measure of whether you are making money.

Next steps

Questions

Why do my platforms claim more revenue than I actually made?

Because each one counts a conversion it touched, and customers touch several before buying. Three platforms can each legitimately claim the same order under their own attribution rules. None is lying; they are answering a different question than 'how much money arrived'.

Is blended ROAS the same as MER?

In practice yes — both divide total revenue by total ad spend. The distinction people draw is that blended ROAS tends to be used for a campaign-level roll-up and MER at account level over a period. What matters is that both use collected revenue rather than attributed revenue.

Should I stop looking at platform ROAS?

No, but demote it. It remains the best available signal for comparing one campaign against another inside the same platform. It is simply not a measure of whether the business is profitable — that is what blended is for.

What if my gap is enormous, like 60%?

Check the period alignment first, since click-dated versus purchase-dated reporting produces a false gap. If the periods genuinely match, look at retargeting: campaigns that show ads to people already intending to buy generate the largest share of conversions that would have happened anyway.

Should organic revenue be included?

Yes. Advertising creates demand that arrives later through search, direct and email, and excluding it understates what your spend achieved. If you want to isolate advertising's incremental effect, the tool for that is a holdout test, not a narrower revenue definition.

Sources and last update

Last verified 2026-08-22.

• TrueProfit — What's a Good ROAS in 2026
• EcomCalcTools — Ecommerce ROAS benchmarks by channel

Figures here are planning estimates. Duty applies per 10-digit HTS code and platform fees change without much notice — check your own broker and your own seller account before committing spend. Full workings on the methodology page.