01 The setup
Picture your third month in marketing. Your manager is pleased: online revenue is up for the fourth month running, and the ad dashboard shows a ROAS of 1.5 — every dollar spent on ads brings back a dollar fifty.
Then finance sends a note. The business made less money this quarter than last, and paid media is the biggest line item that grew. Both things are true at once. This lesson is about how.
02 Money in, money out
ROAS compares revenue with ad spend. But revenue isn’t yours to keep. First you pay for the product itself. What’s left after that is your gross margin — and the ads have to be paid out of that, not out of revenue.
Move the sliders. Watch what happens to the gap between the two bars.
Simulator · Revenue vs. profit
Illustrative numbers, one month ·
Orders
250
ROAS
1.50
Break-even ROAS
2.86
Profit after product cost and ads
−$4,750
ROAS is 1.50 — “positive” on a dashboard — but below the 2.86 this margin needs. Revenue grows; the business loses money on every ad-driven order.
03 The one-line formula
If you only keep 35 cents of every dollar of revenue, each ad dollar has to bring back enough revenue to leave a dollar behind after product costs. That gives you the line worth memorising:
Break-even ROAS = 1 ÷ gross margin
| Gross margin | Break-even ROAS | Typical Of |
| 20% | 5.00 | Electronics, appliances |
| 35% | 2.86 | Many consumer goods |
| 50% | 2.00 | Own-brand apparel |
| 70% | 1.43 | Cosmetics, digital products |
Quick check · optional
04 Same month, two dashboards
The campaign from the setup, reported two ways. The numbers on the left are all true. They just don’t answer the question your manager actually has.
Impressions
1.2M
Clicks
12,500
Revenue
$15,000
ROAS
1.5
1Every number is up. None of them say whether the business made money — and there’s no target to compare ROAS against.
2Leads with the number the business cares about.
3Gives ROAS a target, so “1.5” finally means something.
05 Your call
A campaign spends $10,000 a month. Revenue keeps growing, but profitability is falling. What do you investigate first?
Pick one. Every option gets an explanation — there’s more than one reasonable answer, but one is the best place to start.
Treats a symptom
Cheaper clicks can help, but nothing here says click costs rose. Cutting bids blind often cuts your best-converting traffic first.
Strongest first move
Revenue up + profit down usually means each sale is worth less. If growth comes from discounted or low-margin items, your break-even ROAS has risen while reported ROAS looks fine. This check takes an hour and changes every decision after it.
Makes it worse
If each sale is losing money, more spend buys more losses. Growth in revenue is not evidence of profit.
Good second question
If ads increasingly reach people who would have bought anyway, you pay for sales you already had. Worth checking right after the margin mix.
The habit to build: before you change the campaign, check what changed in what you’re selling.
06 Take it to work
Principles
- 1ROAS measures revenue. Profit needs margin.
- 2Every product has its own break-even ROAS: 1 ÷ margin.
- 3A ROAS number without a target is decoration.
- 4When profit falls, check the product mix and discounts before the bids.
Questions to ask on Monday
- What’s the gross margin on the products we advertise most?
- Is our ROAS target set from margin, or from habit?
- Does the ROAS we report include returns and discounts?
- What share of ad-driven sales are new customers?
Free with the newsletter
Break-even ROAS sheet
A Google Sheet: list your products and margins, get a ROAS target for each. Plus the Monday lesson every week.
Where to next?
Back to the libraryMore lessons are on the way — check back soon.