What is MER?

MER is the number your accountant would recognise. It ignores attribution entirely and asks a simpler question: for all the money that went into marketing this month, how much revenue did the business take?

Its strength is that nobody can inflate it. Platform ROAS figures overlap — Meta and Google will both claim the same purchase, and the sum of their reported revenue routinely exceeds what the business actually earned. MER has no such problem because it starts from the real total. When a founder tells us their Meta ads report 6x but the bank account disagrees, MER is the number we reach for first.

It is close to, but not the same as, blended ROAS. Both start from real total revenue rather than what a platform claims. The difference is the denominator: MER divides by all marketing cost — agency fees, tools, influencer and affiliate payouts, creative production — while blended ROAS divides by ad spend alone. So MER is the truer business number and blended ROAS is the more practical media number, and MER will always be the lower of the two.

Its weakness is that it cannot tell you where to put the next rupee. It is a health check, not a decision tool. The workable combination is MER as the number the business is steered by, and in-platform metrics as the numbers each account is optimised by, with a clear understanding that they will never reconcile exactly and are not supposed to.