Blended ROAS
Total revenue over total ad spend across all channels: the same calculation as MER.
Blended ROAS is total revenue divided by total ad spend across all channels, the same calculation as MER. The word "blended" is there to contrast it with platform ROAS, which each ad platform reports for itself and tends to over-claim.
You use blended ROAS as the honest, business-level number because platform figures cannot be added together: a shopper who saw two ads before buying is counted by both platforms, so the sum overstates your real return. Blended ROAS counts every sale once. Track it as a weekly trend against last month and last year rather than a single day, because the daily figure is too noisy to act on and the trend is where the honest signal lives.
Its limit is the same as MER's: it tells you the account is healthy or slipping, not which campaign to fix. That is why you run it alongside campaign-level ROAS, the discipline in MER vs ROAS.
Put the number to work: the break-even ROAS calculator turns your margins into the ROAS you need, and a free Due Diligence Audit checks whether the figures you see are the ones you are getting. Back to the glossary.