Blended ROAS
Also known as: blended return on ad spend
Total attributed revenue across all paid channels divided by total paid spend.
Blended ROAS is the compromise metric between per-platform reporting (fast but lies) and MER (true but slow). Most performance teams review daily by platform, weekly by blended, and monthly by MER.
Definition
Blended ROAS aggregates paid-attributed revenue and paid spend across every channel — Meta, Google, TikTok, etc. — into a single ratio, without double-counting per-platform views.
Why it matters
Adding platform ROAS numbers double-counts because both Meta and Google claim the same purchase. Blended ROAS fixes that at the paid-media layer.
Formula
Blended ROAS = Sum(Paid-attributed Revenue) ÷ Sum(Paid Spend)
Why platform ROAS overstates
Meta and Google each attribute the same purchase to themselves. If both apply a 7-day view-through window, a customer who saw a Meta ad and later clicked a Google ad is a conversion in both platforms. Summing platform ROAS would count the revenue twice; blended ROAS uses shop-side revenue instead.
$60k Meta + $28k Google + $9k TikTok spend; paid-attributed revenue $310k → Blended ROAS = 3.2.
Common mistakes
- ✕Summing individual platform ROAS — always double-counts.
- ✕Confusing blended ROAS with MER (MER uses total revenue).
- ✕Not deduping platform reporting against a common source of truth.