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MER (Marketing Efficiency Ratio)

MER (also called blended ROAS) is total revenue divided by total marketing spend over the same period. Use it as a top-down efficiency check, then move to the full guide when you need to judge whether blended performance is actually strong enough to scale.

Use this page for the fast definition. If you need to decide whether blended efficiency is really strong enough to scale, read the full MER guide next.

Read the full MER guide
Written by MetricKit EditorialReviewed by MetricKit Editorial ReviewUpdated 2026-01-23
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Definition

MER (also called blended ROAS) is total revenue divided by total marketing spend over the same period. Use it as a top-down efficiency check, then move to the full guide when you need to judge whether blended performance is actually strong enough to scale.

Formula

MER = total revenue / total marketing spend

Example

If total revenue is $500k and total marketing spend is $100k, MER = $500k / $100k = 5.0.

Common mistakes

  • Using MER alone to optimize channel budgets (it hides what's working).
  • Not adjusting for seasonality, promos, and pricing changes.

Measured as

MER = total revenue / total marketing spend

Misused when

  • Using MER alone to optimize channel budgets (it hides what's working).
  • Not adjusting for seasonality, promos, and pricing changes.

Operator takeaway

  • Use MER (Marketing Efficiency Ratio) only inside a stable attribution rule, conversion definition, and time window so campaign comparisons stay honest.
  • If performance changes, check whether the metric moved for a real business reason or because the measurement setup changed underneath you.

Next decision

  • Quantify the impact with MER Calculator if you need to turn the definition into an operating assumption.
  • Read MER (blended ROAS): how to use it without fooling yourself if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.

Where to use this on MetricKit

Calculators

  • MER Calculator: Calculate MER (Marketing Efficiency Ratio / blended ROAS) and estimate break-even and target MER from margin assumptions.
  • ROAS Calculator: Calculate Return on Ad Spend (ROAS) and estimate contribution profit after ad spend.

Guides