ACoS Calculator

Is my Amazon ad spend profitable, and what is my break-even ACoS?

Your numbers

Result

ACoS

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How this is calculated

ACoS is ad spend divided by ad-attributed sales. On its own it says nothing about profit — the comparison that matters is against your break-even ACoS, which is the unit margin you have available before advertising.

Real example: Launch-phase advertising

Spend $1,800 on ads, $7,200 in ad-attributed sales, $15,400 total sales. Price $29.99, COGS $7.50, fees $10.50, shipping $1.20.

Result: ACoS 25%, break-even ACoS 43%. Ads are profitable — each unit earns $8.49 before ads, leaving room for ad spend up to $12.90.

ACoS = ad spend ÷ ad-attributed sales
TACoS = ad spend ÷ total sales (paid plus organic)
Pre-ad margin per unit = price − COGS − Amazon fees − other costs
Break-even ACoS = pre-ad margin per unit ÷ selling price
Profit per unit after ads = pre-ad margin − ad cost per unit

What to make of the number

Break-even ACoS is simply your pre-ad margin as a percentage of price. If you keep $13 on a $30 product, break-even ACoS is 43% — a figure far higher than most sellers assume, which is why aggressive launch-phase ACoS is sometimes genuinely rational rather than reckless.

Frequently asked questions

What is the difference between ACoS and TACoS?

ACoS compares ad spend to ad-attributed sales only. TACoS compares ad spend to total sales including organic. TACoS is the better health indicator, because as organic ranking improves, TACoS should fall even if ad spend stays flat.

What is a good ACoS?

Anything below your break-even ACoS is profitable. There is no universal good number — a 40% ACoS can be profitable on a high-margin product and disastrous on a thin one.

Why run ads above break-even ACoS at launch?

Because advertising drives rank, and rank drives organic sales that carry no ad cost. This is a deliberate investment, but it should have a defined budget and a point at which spend is reduced and organic is expected to carry the volume.

How do I lower ACoS?

Improve conversion rate on the listing first, since the same clicks then produce more sales. Then cut spend on search terms that convert poorly rather than lowering bids across the board, which usually just reduces volume.

Should ACoS be measured per product or across the account?

Per product. Blended account ACoS hides products where advertising is quietly destroying margin, and hides products where more spend would be profitable.

What is the break-even ACoS formula?

Break-even ACoS equals your pre-ad profit per unit divided by the selling price. It is the maximum ACoS you can sustain and still make money on each sale.

How do negative keywords affect my ACoS?

Negative keywords block irrelevant searches, reducing wasted spend. Adding well-chosen negatives is one of the fastest ways to drop ACoS without cutting budget.

When should I kill an ad campaign?

Kill campaigns that have spent 2–3x your target ACoS without generating a sale, or campaigns where the search term report shows consistently irrelevant matches.

Do the research before you commit inventory

SkuMath shows you the math. Helium 10 supplies the live Amazon data those calculations need as inputs — product demand, keyword volume, competitor reviews and profit tracking.

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