SellersCalc

Ad math

ACOS Calculator

The share of every ad-driven sale that went straight back to the ad platform — Amazon PPC's favorite scoreboard.

ACOS = ad spend ÷ attributed sales × 100. Spend $300 on Sponsored Products that generate $1,200 in attributed sales and your ACOS is 25% — a quarter of that ad-driven revenue paid for the ads themselves. ACOS and ROAS are the same fact upside down: 25% ACOS equals a 4× ROAS. The profitability test is simple: ACOS below your pre-ad profit margin means the campaign makes money, above it means the ads eat the profit. Enter spend and sales to get both numbers.

ACOS Calculator — your numbers

ACOS

25.0%

Equivalent ROAS

4.00×

Estimate only. Results reflect exactly the numbers you enter — verify against your own accounting before making pricing decisions.

Embed this calculator on your site — free →

Worked examples

Profitable Sponsored Products campaign

Ad spend $300.00
Attributed sales $1,200.00
ACOS 25.0%
Equivalent ROAS 4.00×

A 25% ACOS — profitable for any product with a pre-ad margin above 25%.

Launch-phase spending

Ad spend $450.00
Attributed sales $1,500.00
ACOS 30.0%
Equivalent ROAS 3.33×

A 30% ACOS — common while buying reviews and rank, but not sustainable forever.

Frequently asked questions

What is a good ACOS on Amazon?

Whatever sits below your break-even ACOS, which equals your pre-ad profit margin. If a product nets 30% after COGS and Amazon fees, any ACOS under 30% is profitable ad spend. Mature campaigns for established products often run 15–25%; launches deliberately run higher to buy rank and reviews. There is no universal number — only your margin.

How do ACOS and ROAS relate?

They are reciprocals: ACOS = 1 ÷ ROAS × 100, and ROAS = 100 ÷ ACOS. So 20% ACOS is a 5× ROAS, 25% is 4×, 50% is 2×. Amazon-native sellers tend to speak ACOS while Google and Meta advertisers speak ROAS; this calculator returns both so you can compare campaigns across platforms in one language.

What is break-even ACOS and how do I find mine?

Break-even ACOS is your profit margin before ad spend: (price − product cost − fulfillment − marketplace fees) ÷ price × 100. Sell at $40 with $28 in total costs and your break-even ACOS is 30% — at exactly 30% ACOS the ads consume every cent of profit. Target ACOS should sit comfortably below it, not at it.

Why is my ACOS high even though sales are growing?

Usually a mix effect: broad or auto campaigns scale spend faster than efficient exact-match terms, so growth arrives with worse averages. Check ACOS per campaign and per search term, not just the account roll-up. High ACOS is fine when it is deliberate (launches, ranking pushes) and a slow leak when it is just unpruned keywords.

Related calculators

Part of the Advertising & ROAS collection.