Ad spend calculator: ROAS, ACOS and break-even

Ads bring orders but cost money. This shows if each ad sale leaves you with profit or a loss.

The terms

ROAS (return on ad spend) = sales from ads divided by ad spend.
ACOS (advertising cost of sales) = ad spend divided by sales from ads. It is the inverse of ROAS, as a percentage.
Break-even ACOS = profit before ads divided by price. Above it, each ad sale loses money.

Example

A product sells at 599 and earns 140 before ads, so the break-even ACOS is 23 percent. If 55 ad orders cost 6,000, the ACOS is 18 percent: below break-even, so ads add profit. If the same ads gave only 30 orders, the ACOS would be 33 percent and the ads would lose money on every sale.

Habits of careful advertisers

Set a daily budget and a stop rule before you begin.
Review every search term or placement that spends money without orders.
Raise bids only on the products that pass the break-even test.
Include the ad cost in the product price when you can.

Common questions

What is a good ACOS?

There is no universal figure. It is good if it is below the break-even ACOS of your product, which depends on your margin before ads. The calculator shows that number.

Are ads ever worth a loss?

They can be, if they bring buyers who come back, or if they raise the sales rank so that unpaid orders increase. Decide the limit in advance and review it, instead of letting spend drift.

Keep going

Fee percentages, GST rates and other figures in the examples on this site are made up to show the working. They are not the fees or rates of any marketplace or country: type the numbers from your own seller account and from the tax authority. Checked 14 November 2026.