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Blended ROAS & MER Calculator

Combine all your ad spend and revenue to see true marketing efficiency.

Your numbers

Total revenue and every channel’s ad spend — results update instantly.

$

All channels, this period

×

Revenue ÷ spend goal

$
$
$
$
$
MER · blended ROAS
4.14×
+0.14× vs target
Total ad spend
$29,000.00
Spend % of revenue
24.2%
Marketing cost ratio

See your real MER, updated daily

Connect Meta, Google, Amazon and your store and the Captain calculates blended ROAS automatically — and flags the day it drops below target.

Get early access

How it’s calculated

MER (blended ROAS) = Total revenue ÷ Total ad spend

Total ad spend is every channel added together (Meta + Google + Amazon + TikTok + other). Spend as a % of revenue is the inverse: Total ad spend ÷ Total revenue.

Worked example

Total revenue
$120,000
Total ad spend
$29,000
Result
MER = 120,000 ÷ 29,000 = 4.14×

Every $1 of ad spend returned $4.14 of revenue, and ads were 24.2% of revenue.

What your result means

MER measures whether your whole marketing engine pays off — not one campaign. A single channel can report a 6× ROAS while the blend limps at 2× because of overlap, brand spend and discounts. A ‘good’ MER depends on your margins: a 60%-margin brand can thrive at 2.5×, a 25%-margin brand may need 4×+. Watch the trend, not one week.

Common mistakes

  • Judging channels on in-platform ROAS alone — every ad platform claims the same sale, so those numbers double-count.
  • Ignoring organic revenue — MER uses total revenue, so strong organic can flatter paid efficiency.
  • Comparing MER across brands with different margins — the right target depends on your contribution margin, not a universal benchmark.

Learn how it works

5 min guide
How to Calculate Blended ROAS (and Why It Beats Channel ROAS)

Blended ROAS — also called MER — divides total revenue by total ad spend across every channel. Learn the formula, why it's lower (and more honest) than per-platform ROAS, and what a good number is.

8 min guide
The E-commerce Guide to ROAS, MER, CPA and Profit

ROAS, blended ROAS, MER, CPA, break-even — the advertising metrics that decide whether your marketing makes money. This guide connects them, shows which to trust, and turns them into a daily decision rule.

Related Marketing tools

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Break-even CPA Calculator

Find the most you can spend to win a customer and still break even.

Ad Spend Pulse

Live cost, clicks, conversions, and ROAS from Google Ads.

Frequently asked questions

What is a good MER?

It depends on margin. Many e-commerce brands aim for roughly 3–4×; higher-margin brands can profit lower and thin-margin brands need more. Compare against your break-even ROAS, not a fixed number.

Is MER the same as blended ROAS?

Yes — both divide total revenue by total ad spend across all channels. ‘MER’ (marketing efficiency ratio) is the common e-commerce term; ‘blended ROAS’ is the same figure, as opposed to per-platform ROAS.

Why is my blended ROAS lower than each platform's ROAS?

Because the platforms each take credit for overlapping conversions. Blended ROAS counts every sale once, so it's the honest — and more useful — lower number.

Last reviewed 31 Jul 2026 · reviewed by the Dash Captain team.