MER (marketing efficiency ratio) is your total store revenue divided by your total marketing spend across every channel. An MER of 3 means ₹3 of revenue for every ₹1 spent on marketing. Because it uses the revenue in your store and the spend on your invoices, it doesn't depend on any platform's attribution. This calculator gives you MER, break-even MER, profit after marketing and a check on Meta's reported ROAS.
How to use this calculator
- Enter total store revenue for a period, from every channel, including organic and repeat orders.
- Enter your Meta ad spend for the same period.
- Enter all other marketing spend: other ad platforms, influencer fees, affiliate commissions and anything else you count as marketing.
- Enter your contribution margin as a percentage of revenue.
- Optionally, enter the purchase value Ads Manager reports for the period.
- Read MER, break-even MER, profit after marketing and Meta's reported ROAS.
How do you calculate MER?
- MER = total revenue ÷ total marketing spend
- Break-even MER = 1 ÷ contribution margin %
- Profit after marketing = total revenue × margin % − total marketing spend
- Meta's reported ROAS = revenue Meta reports ÷ Meta spend
- Meta's claimed share = revenue Meta reports ÷ total revenue
Break-even MER uses the same maths as break-even ROAS, applied to the whole business. If MER sits below it, your marketing costs more than the margin it brings in, whatever any platform says.
Worked example
In rupees. A store makes ₹12,00,000 in a month. It spends ₹2,50,000 on Meta and ₹1,50,000 on everything else, ₹4,00,000 in total. MER = 12,00,000 ÷ 4,00,000 = 3.0. At a 45% margin, break-even MER is 2.22, so marketing pays for itself. Profit after marketing is 5,40,000 − 4,00,000 = ₹1,40,000, before fixed costs. Ads Manager reports ₹8,00,000 of purchase value, a 3.2× ROAS that claims 67% of all revenue.
In dollars. $60,000 of revenue on $15,000 of Meta and $5,000 of other spend is an MER of 3.0. At 40% margin, break-even MER is 2.5, and profit after marketing is $4,000. Meta reports $52,000, a 3.47× ROAS that claims 87% of the store's revenue. With email, organic and repeat orders also selling, that share deserves a hard look.
What does MER tell you about your ROAS?
Platform ROAS and MER answer different questions:
| Platform ROAS | MER | |
|---|---|---|
| Revenue counted | Purchases the platform attributes to its own ads | Every order in your store |
| Spend counted | That platform's spend | All marketing spend |
| Can double-count | Yes, two platforms can claim the same order | No |
| Best for | Choosing between campaigns and ads inside Meta | Deciding whether total spend is growing the business |
When you scale, watch both. If you raise spend by 30% and Meta's ROAS holds while MER falls, the extra spend may be getting credit for sales that would have happened anyway. That's an incrementality question, and MER is the simplest early warning. Scaling Meta ads without killing ROAS covers what to do next.
Some brands also track new-customer MER: revenue from first-time customers ÷ marketing spend. It strips out repeat buyers who would have come back anyway. The glossary explains the related idea of NC-ROAS.
What counts as marketing spend?
| Include | Usually include | Decide once and keep it |
|---|---|---|
| Ad spend on every platform | Influencer fees and product seeding | Agency fees |
| Affiliate commissions | Creative production | Marketing software and tools |
Revenue needs the same discipline. Decide whether you use revenue before or after returns, and before or after tax such as GST or VAT, then keep that definition every month. A change of definition can move MER more than a change of strategy.
What is a good MER?
A good MER is one above your break-even MER with enough left over to cover fixed costs. To find the MER that covers them:
MER needed = (1 + fixed costs ÷ marketing spend) ÷ margin %
Example: at a 45% margin, ₹4,00,000 of marketing spend and ₹1,00,000 of fixed costs, you need an MER of (1 + 0.25) ÷ 0.45 = 2.78. The store above, at 3.0, clears it. A figure from another brand tells you little, because margins, repeat rates and channel mix differ.
How to use MER week to week
- Track it weekly or monthly with the same definitions every time.
- Compare it with the spend you added. A falling MER as spend rises means each extra rupee or dollar is buying less.
- Use platform ROAS to allocate budget inside Meta, and MER to decide the total budget.
- When the two drift apart, check tracking and your attribution window before you move budgets. Meta ads attribution settings explains the options.
For profit on the orders your ads drove, use the POAS calculator. For a single campaign's return, use the ROAS calculator.
Frequently asked questions
What is MER in marketing?
MER (marketing efficiency ratio) is total store revenue divided by total marketing spend across every channel. ₹12,00,000 of revenue on ₹4,00,000 of marketing is an MER of 3.0. It's sometimes called blended ROAS, and it doesn't rely on any platform's attribution.
How do you calculate MER?
Add up all marketing spend for a period, including every ad platform, influencers and affiliates, and divide total store revenue for the same period by it. Keep the definitions the same every month, including whether revenue is before or after returns and tax.
What is a good MER?
A good MER clears your break-even MER, which is 1 ÷ your contribution margin, with room to cover fixed costs. At a 45% margin, break-even is 2.22. The MER that also covers fixed costs is (1 + fixed costs ÷ marketing spend) ÷ margin. Other brands' figures tell you little because margins differ.
What is the difference between MER and ROAS?
ROAS divides the revenue one platform attributes to its ads by that platform's spend. MER divides all store revenue by all marketing spend. Platforms can claim the same order twice, so their ROAS figures can add up to more than you sold. MER can't be inflated that way, but it can't tell you which channel caused what.
Should MER include agency fees and software?
It's a choice, as long as you make it once and keep it. Ad spend, influencer fees and affiliate commissions are almost always included. Agency fees, creative production and tools give a stricter view. Changing the definition from month to month makes trends meaningless.
