Meta AdsPlatform ROAS divides the revenue a platform credits to its ads by the spend on those ads. Blended ROAS divides all store revenue in the period by all ad spend. The two use different revenue and different spend, so a gap between them is expected.
Where the gap comes from
- Overlap. Several platforms can claim the same order, so their credited revenue adds up to more than the store took.
- Attribution windows. A longer window credits more orders to ads. Check the window each platform used.
- View-through credit. Orders credited after an impression, not a click, depend on the counting rule. Note which rule the report uses.
- Revenue basis. Gross and net revenue, shipping, tax and returns can all differ between the store and a platform.
- Spend basis. Fees, agency charges and spend from other accounts may sit in one number and not in the other.
- Organic and direct orders. Blended ROAS includes every order, including those no ad touched. Platform ROAS only counts orders the platform credits to its ads.
Read the gap, then the trend
- Check the gap size over a steady period first. A gap that stays the same is a counting rule, not a new problem.
- A gap that grows suddenly is worth checking. Look for a tracking change, a new campaign type or a changed window before reading the result.
- Read blended ROAS against the break-even line, with MER next to it. Do not set budgets from platform ROAS alone.
Made-up scenario: the platforms together reported a ROAS of 4.2, while blended ROAS was 2.6. The gap was the same as last quarter, and the platform windows had not changed. The team kept both numbers in the report, each labelled, and judged the budget on blended ROAS against the break-even line.
