What is marketing efficiency ratio (MER)? Formula, examples, and targets to hit

Marketing efficiency ratio, or MER, measures the performance of your marketing spend. It’s one of the most important metrics marketers use to measure impact.

And while that might sound similar to return on ad spend, ROAS is slightly different in that it’s typically channel-specific and attribution-dependent.

Keep reading to learn how to calculate MER, improve marketing efficiency, and understand marketing efficiency examples.

Key takeaways

• Marketing Efficiency Ratio (MER) evaluates total advertising spend as a proportion of the revenue generated from all orders:
• The Triple Whale formula is MER = Blended Ad Spend ÷ Order Revenue.
• Note: For the inverse ratio (Order Revenue ÷ Blended Ad Spend), use Blended ROAS. Many marketers calculate MER this way and report it as a multiplier, so confirm which convention a benchmark or report uses before you compare.

‍What is marketing efficiency ratio (MER) and why is it important?

What is MER? It’s a calculation used to determine how efficient (or effective) your marketing efforts are from a high-level, holistic view of your business.

Depending on the calculation you use, MER tells you what percentage of revenue is spent on ads — regardless of which platform drove the conversion.

Ideally, your MER should be a low percentage. When it is, you’re generating better results from your ad campaigns while spending less on marketing overall. This big-picture insight helps you evaluate if your marketing strategy is effective and when to make changes if it isn’t as successful as you’d like it to be.

How to calculate MER

Now that you know the MER definition, you’re ready to learn the MER formula.

To calculate MER, take your total marketing spend and divide it by your total revenue derived from marketing over the same timeframe.

At Triple Whale, the marketing efficiency ratio formula looks like:

MER = Blended Ad Spend ÷ Order Revenue

The result will be a decimal number that you can use as a percentage.

As a reminder, that’s different from the ROAS formula, which involves dividing your revenue from ads by the cost of those ads.

Which revenue and costs should you include?

Pick what counts as “spend” before you run the numbers. MER works with your ad spend alone or with your total marketing costs, and each gives you a different answer.

Start with ad spend

That’s what you pay platforms like Meta, Google, and TikTok. It’s the version Triple Whale reports and the one most benchmarks use, so it’s the easiest to compare. Keep salaries, agency fees, and software out of it.

Track total marketing cost on its own

Some brands also measure a fuller view that adds team, agency, creative, and tools. It’s useful for budgeting. Give it a different name so it stays separate from MER.

Line up your numbers

Spend and revenue should cover the same time period, stores, channels, and currency. If your revenue includes Amazon sales but your spend only covers your DTC ads, your MER will look better than it is.

Stick with one revenue figure

Triple Whale uses order revenue: what customers paid at checkout, before refunds. If you use something else, like net sales, note it. Switching definitions makes this month’s MER impossible to compare with last month’s.

out disclosure changes your MER and breaks comparisons with benchmarks.

Now, there are a couple of ways you may see MER represented.

MER as a percentage

At Triple Whale, your MER is displayed as a percentage, so let's start here.

Say you’re an automotive company that has generated the following:

• Total Ad Spend of $100,000
• Total Revenue of $300,000

Your MER calculation would be:
100,000 ÷ 300,000 = .33 or simply 33%

Instead of saying “MER is 33%” most buyers mentally translate it to: “Ads are 33% of revenue."

MER as a decimal

The MER formula produces a decimal. Using the automotive example:

$100,000 ÷ $300,000 = 0.33

A decimal MER reads as “ad spend per dollar of revenue.” At 0.33, you spend 33 cents on ads for every $1 in Order Revenue. You’ll see this format when you query MER in the SQL Editor or pull it through the API. Multiply by 100 to convert it to the percentage shown in the Triple Whale dashboard.

MER calculation examples

MER in marketing can be used for several different purposes. Here are a few examples to show you how.

Tracking

You can calculate (or view) your MER anytime to track how effective your paid media is.

Perhaps your brand spent $2,000 on marketing overall last month, and you made $8,000 in revenue from marketing. Your MER calculation would look like:

MER = $2,000 ÷ $8,000 = 0.25 (25%)If you discover your MER is higher than your goal, you can keep doing what you’re doing. If it’s lower than your goal, you may decide to cut back on spending on the platforms you’re least confident in or launch new ads.

Forecasting

Let’s say you want to hit $100,000 in revenue next month. You know your mode average order value (AOV) is $200. With some simple math, you can use your mode AOV to come up with a target MER and then budget your marketing spend accordingly.

Here’s what that looks like:

• First, divide your revenue goal by your AOV to determine how many orders you’ll need next month to hit your target:
  • $100,000/$200 = 500 orders
• Let’s say a reasonable goal for your cost per acquisition is $30.
• Now you’re ready to calculate your budget by multiplying your orders by your CPA:
  • 500 x $30 = $15,000
• Finally, you’re ready to calculate your target MER by dividing your (hypothetical) total revenue by your (hypothetical) total marketing spend:
  • 15,000÷100,000=0.15 (15%)
• Now you know how efficient your marketing needs to be if you want to reach your revenue goal.

Budgeting

You can also use MER to set a budget for your marketing spend if you have different data handy.

Let’s say your business is shooting for $10,000,000 in revenue this year. You typically have a MER of 20%. You can use these two numbers to figure out a reasonable budget for your paid media strategy:

Target MER is 20%:

• 0.20=Spend÷Revenue

Solve for spend:

• Spend=Revenue×MER
• Spend=10,000,000×0.20
• Spend=2,000,000

Now you know you’ll need $2,000,000 for your total marketing spend to hit that revenue goal this year.

What is a ‘good’ MER?

Much like a good ROAS, there is no one universally “good” MER for every business and brand. A lower MER is generally better, because it means you're spending less.

Ultimately, if you’re trying to answer the question “What is a good marketing efficiency ratio?” you’re going to have to adjust your benchmark based on your business’s industry, size, and goals.

In 2026, the median MER for our Triple Whale customers is 39%.

Continuing as a percentage, here is the median MER by industry among Triple Whale brands over the last 90 days:

How to reduce MER: The Ekster example

A rising MER means ad spend is eating a larger share of revenue. Brands often accept that early on, when paid media drives most new customers. As you scale, the goal shifts to growing revenue faster than spend.

Premium wallet brand Ekster made that shift a priority. Managing Director Jan Meijer set out to move the business from high marketing spend ratios toward more efficient spending, with a larger share of revenue coming from existing customers and organic sales.

Here’s how the team approached it:

• Complete the cost side. Ekster added influencer campaigns and other off-platform spend to Triple Whale as custom spend, so Blended Ad Spend reflected everything they paid to acquire customers.
• Compare attribution models before moving budget. The team reviewed Total Impact, last-click, first-click, and other windows side by side, then shifted budget toward channels that held up across models.
• Give finance and marketing one source of truth. Shared data replaced the debate between the growth-minded commercial team and the cautious operations team.

The result: a 20% year-over-year improvement in MER alongside 50%+ revenue growth. Ekster lowered MER without cutting its way there. Revenue grew faster than spend.

How to monitor MER and avoid its limitations

We’re big MER fans at Triple Whale, but the metric has blind spots. It measures all spend against all revenue, so it can’t show you what’s happening at the channel, campaign, ad set, or ad level. A MER you’re happy with still won’t tell you which channels to scale or cut.

For that, you need marketing attribution, marketing mix modeling (MMM), or incrementality testing, the most reliable way to measure what your paid media adds.

MER also reflects revenue in the current period. It leaves out the long-term value you build through customer retention and loyalty, so pair it with LTV when you plan for future growth.

When MER moves, check the inputs before you change budget:

• Revenue mix: A shift toward returning customers, wholesale, or marketplace sales changes MER without any change in ad performance.
• Discounting: Heavy promotions shrink revenue per order, which can raise MER even when ads perform as planned.
• Returns: If your revenue figure is measured before refunds, a high-return period can make MER look better than your realized revenue supports.
• Seasonality and market conditions: Compare against the same period last year, and expect MER to rise during high-cost windows like BFCM.
• Reporting lag: Ad platforms can restate spend, and orders can change after the fact. Give a period time to settle before you act on it.

Split out new customers

Divide ad spend by new-customer revenue alone to see how efficient your acquisition is, separate from the lift existing customers give your overall MER.

Avoid cutting your way to a lower MER

Pulling spend lowers MER fast, and new-customer volume falls with it. A lower ratio paired with shrinking revenue is a warning sign. Aim for what Ekster achieved: revenue growing faster than spend.

MER vs. ROAS and blended ROAS

Triple Whale defines MER differently from the traditional marketing formula:

MER = Blended Ad Spend ÷ Order Revenue

It’s closely related to blended ROAS, which flips the formula:

Blended ROAS = Order Revenue ÷ Blended Ad Spend

• Blended ROAS shows how much order revenue you generate per ad dollar across your channel mix.
• MER shows the percentage of order revenue spent on advertising. They’re two ways to look at the same overall efficiency.
• Blended ad spend provides the cost side of both equations. Monitoring order revenue alongside spend helps you see whether changes come from spending, sales, or both.

MER and ROAS are also similar but different, so let’s get really clear on the differences.

When you’re comparing MER vs. ROAS, the first thing to remember is that ROAS is typically campaign- or channel-specific and attribution-dependent. It can be reported by an ad platform or a third-party attribution tool. MER, on the other hand, gives you a big-picture view of your advertising performance. It includes all order revenue, regardless of attribution.

That means ROAS is more valuable if you want to know how, say, your Instagram ads in particular are performing. MER is more valuable if you’re looking for insight into the overall efficiency of your advertising efforts.

Both metrics use ad spend, but their scope differs. Triple Whale’s MER includes channel ad spend and custom expenses marked as ad spend, not automatically all marketing costs, such as salaries and software subscriptions.

Complementary metrics to consider

Because of the limitations mentioned above, you can gain some helpful context for your MER by considering it alongside other metrics, like the following:

• ROAS: Knowing your return on ad spend will allow you to focus in on the success of specific campaigns in a way that MER doesn’t. Find out how to improve ROAS.
• LTV: Customer lifetime value gives you a picture of long-term earning potential that’s missing if you only consider MER.
• CAC: If MER is the 10,000-foot view of your marketing spend, customer acquisition cost is the on-the-ground perspective. Knowing how much you spend to acquire one customer gives you one of the more granular views of your profitability.
• Conversion rate: Knowing the percentage of your visitors who take a desired action (most likely finalizing a purchase on your site) can help you optimize your customer journey and improve your MER. Check out some of the best strategies for conversation rate optimization.

Conclusion

What is MER in marketing? It shows how much of your revenue goes to advertising. Using the convention in this article, divide Blended Ad Spend by Order Revenue for the same period. Multiply by 100 to express MER as a percentage.

Your MER doesn’t tell you anything about which platforms, channels, or campaigns are most successful. That’s why it’s important to consider MER in the context of other marketing metrics such as your ROAS and LTV.

And if that sounds a little overwhelming, we’ve got you: The Triple Whale data platform surfaces the insights you need to make informed decisions that benefit your brand and your bottom line. Book a demo today.

Frequently asked questions

What does MER mean in marketing?

MER means “marketing efficiency ratio.” It shows how much of your revenue goes to advertising, across every channel, with no attribution required. Think of it as the 10,000-foot view of your marketing spend.

How do you calculate marketing efficiency ratio?

Divide Blended Ad Spend by Order Revenue for the same period. Spend $2,000 on ads, bring in $8,000 in revenue, and your MER is 0.25, or 25%. Ads took a quarter of your revenue.

Is a higher or lower MER better?

Lower. A falling MER means revenue is growing faster than ad spend. Just make sure revenue is climbing too, since cutting spend can shrink MER and your growth along with it.

Is MER the same as blended ROAS?

Close, but inverted. Triple Whale calculates MER as Blended Ad Spend ÷ Order Revenue, and blended ROAS flips it (Order Revenue ÷ Blended Ad Spend). The same $2,000 and $8,000 gives you a 25% MER or a 4.0x blended ROAS. Lower is better for MER, higher is better for blended ROAS.

Heads up: some marketers calculate MER as revenue ÷ spend, which makes it identical to blended ROAS, so check the formula before you compare numbers.