ACoS, ROAS and break-even ACoS
ACoS and ROAS are the two numbers every marketplace advertiser watches, and they measure the same thing from opposite directions. Both come from just two inputs — ad spend and the revenue those ads brought in:
- ACoS = ad spend / ad revenue × 100. The share of ad revenue eaten by ad cost. Lower is better.
- ROAS = ad revenue / ad spend. How many liras of revenue each lira of spend returns. Higher is better. ROAS = 1 / ACoS.
A concrete example: you spend 500 TL and the ads bring in 2.500 TL. From this:
| Measure | Formula | Result |
|---|---|---|
| ACoS | 500 / 2.500 | %20 |
| ROAS | 2.500 / 500 | 5x |
A %20 ACoS and a 5x ROAS describe the exact same campaign. Neither number alone tells you whether the campaign makes money — for that you need the break-even ACoS.
Break-even ACoS: the line between profit and loss
Break-even ACoS is the ACoS at which the profit from advertising is exactly zero, and it equals your profit margin. If your net margin before ads is %25, then any campaign running at %25 ACoS breaks even. Below that line the ads add profit; above it they eat into the margin and each sale loses money.
The net effect of ads makes this concrete: revenue × margin − spend. With 2.500 TL of ad revenue at a %25 margin and 500 TL of spend, the net effect is 2.500 × 0,25 − 500 = +125 TL. Since the %20 ACoS is below the %25 break-even, the campaign is profitable. Push spend until ACoS climbs past %25 and the same maths turns negative.
Getting the margin right
The whole result hinges on the margin you enter, so use the net margin before ads — what is left after commission, shipping/desi, service fee and VAT, but before the ad cost. Entering a gross margin (only product cost removed) inflates the break-even ACoS and makes a loss-making campaign look profitable. The exact rates and deductions vary by marketplace and category, so verify your true margin from the actual figures in your own panel.
To find that net margin per sale, use the Trendyol profit calculator, and to separate margin from markup take a look at the profit margin calculator.