MER (marketing efficiency ratio)

MER is total store revenue divided by total marketing spend over the same period. It ignores which ad platform claims the sale.

Stock photos and example labels, not customers.

Definition

MER is total store revenue divided by total marketing spend over the same period. It ignores which ad platform claims the sale.

FormulaMER = total revenue / total marketing spend

Example with made-up numbers: A store books 80,000 in revenue in a month and spends 20,000 across all ad platforms. MER = 80,000 / 20,000 = 4.0.

How to use it

Because MER uses the store's own revenue and all spend across channels, it avoids the double counting that happens when Meta, Google and TikTok each claim the same order. That makes it the steadier number for a monthly client review.

Some tools show the reciprocal (spend divided by revenue) under the same name. Always write the formula next to the number, and keep the period and the currency the same on both sides.