Articles

How to calculate marketing efficiency ratio

2026-05-20 11:54 · Paid Marketing

Learn the MER formula, see a simple example, and understand how marketing efficiency ratio fits into blended performance reporting.

Marketing efficiency ratio, usually shortened to MER, compares total revenue with total marketing spend.

The MER formula is:

MER = total revenue / total marketing spend

For example, if an ecommerce business generates $200,000 in total revenue and spends $50,000 on marketing during the same period, MER is 4.00x. That means each dollar of marketing spend supported four dollars of revenue.

MER is useful when you want a blended view instead of a channel-by-channel view. Paid search, paid social, email, organic search, affiliates, and retargeting can all influence each other. MER gives one broad efficiency number for the full marketing engine.

The key is to keep the reporting window consistent. Use revenue and marketing spend from the same period, and be clear about whether marketing spend includes only ad spend or broader marketing costs.

Use the MER Calculator at /tools/mer-calculator for quick checks. Then compare MER with ROAS, ROI, AOV, LTV, CAC, and profit margin to understand whether growth is efficient and sustainable.