Amazon ACOS Calculator

Calculate ACOS, break-even ACOS and the target ACOS you should actually be running. Your break-even ACOS is your contribution margin percentage, so it is different for every product you sell, and no generic "good ACOS" number can tell you what yours is. It also works out the max CPC that hits your target. Nothing uploads. Nothing is stored. Think in ROAS instead? The ROAS Calculator runs the same math as sales per ad dollar.

The short version: break-even ACOS equals your margin percentage. If 45 cents of every sale dollar is left after landed cost and Amazon's fees, you break even at 45% ACOS. Below that you keep the difference. Above it you pay for the privilege of making a sale.

Your product

Manufacture, freight and duty. Not fees.

Returns allowance, storage, prep, anything else that comes out of every unit.

Selling price–
Landed cost–
Referral fee–
FBA fee–
Contribution margin–
Break-even ACOS
–
Spend more than this and the sale costs you money.
Contribution margin
–
Share of the price left before any ad spend.
Break-even ROAS
–
The same number said the other way round.

What you are running now

Optional

Sales Amazon attributed to an ad click.

Ad plus organic. Unlocks TACOS.

ACOS
–
Grades the campaign.
ROAS
–
Reciprocal of ACOS.
TACOS
–
Grades the business.
Organic share
–
Revenue no ad click touched.

What you should be targeting

There is no single correct ACOS. It depends entirely on what the campaign is for.

As a share of the selling price.

Target ACOS
–
Set your goal and margin above.
Break-even ACOS
–
The ceiling you are staying under.

Max CPC calculator: what to bid, by placement

Each placement converts differently, so each affords a different click price. Amazon lets you adjust every placement up from the base bid, Rest of Search included, but never down, so the base has to anchor on the cheapest placement and the others climb to their own ceiling. Fill in what you have. One placement still gives you a number.

Where to get these: Amazon Ads > Bulk Operations, with Placement Data for Campaigns included, or the placement report. The Placement Bid Optimizer reads them straight out of your bulk file. Do not substitute Unit Session Percentage from Business Reports: it blends branded traffic in and will tell you that you can afford more than you can.

The keyword's own conversion rate. Gives one flat ceiling, not a placement split.

Base bid
–
Set on the keyword itself.
Placement CVR Max CPC Placement adjustment Bid becomes
How to use these numbers without fooling yourself
  • Break-even ACOS is your margin percentage, not 100%. The 100% figure people quote is revenue break-even, which ignores the fact that the product cost you something to make and Amazon took a cut.
  • ACOS is per product, not per account. A 25% target that is comfortable on one ASIN can be underwater on the one next to it. Averaging across a catalogue hides both.
  • Judge ranking campaigns on TACOS, not ACOS. A rank push is supposed to look bad on ACOS. If TACOS is falling while ACOS is high, it is working.
  • Do not use Unit Session Percentage from Business Reports as your conversion rate. It blends branded and non-branded traffic, so it overstates CVR on a cold keyword and hands you a max bid you cannot actually afford.
  • Amazon attribution lags. Sales land against the click date days later, so a fresh ACOS always looks worse than the settled number. Read a window that has had time to fill in.
  • The referral fee is not 15% everywhere. Several categories differ and a few are tiered by price. Check yours rather than taking the default.
  • A target ACOS is not a bid. It becomes actionable only once you convert it into a max CPC, which is what the max CPC card does.

Questions

How do you calculate ACOS?

ACOS is ad spend divided by ad sales, multiplied by 100. Spend $300 and get $1,200 of ad-attributed sales and your ACOS is 25%. It only counts sales Amazon credits to an ad click, which is why it reads worse than reality whenever your ads are also lifting organic rank.

What is a good ACOS on Amazon?

There is no universal number, and anyone quoting one is guessing at your margin. A good ACOS is below your break-even ACOS, and your break-even ACOS is your contribution margin percentage. On a product with 45% margin, 30% is healthy. On a product with 20% margin, that same 30% loses money on every sale.

How do I calculate break-even ACOS?

Take the selling price, subtract landed product cost, the Amazon referral fee and the fulfilment fee, plus anything else that comes out of every unit. What is left is your contribution margin. Divide it by the selling price and that percentage is your break-even ACOS. A $40 product with $10 cost, a $6 referral fee and a $6 FBA fee leaves $18, which is 45% of the price, so break-even ACOS is 45%.

Is break-even ACOS really not 100%?

Not unless your product is free to make and Amazon takes nothing. At 100% ACOS your ad spend equals your ad revenue, so you have already lost the cost of goods and every fee on top. Break-even ACOS equals contribution margin percentage, and for most private-label products that lands somewhere between 25% and 50%.

What is the difference between ACOS and TACOS?

Same numerator, different denominator. ACOS divides ad spend by ad sales, so it grades the campaign. TACOS divides the same ad spend by total sales including organic, so it grades the business. Because the denominators differ they can move in opposite directions at once, and that divergence is usually the most useful thing either number tells you.

How do I calculate max CPC on Amazon?

Max CPC equals target ACOS multiplied by conversion rate multiplied by price. At a 30% target on a $40 product converting at 10%, the most you can pay per click is $1.20. Use the conversion rate for that specific keyword and placement, not the blended figure from Business Reports, which mixes branded traffic in and will tell you that you can afford more than you can.

What is break-even CPC?

Break-even CPC is the most you can pay for a click before the average ad sale loses money. It is your contribution margin per unit multiplied by your conversion rate. A product that keeps $18 per sale and converts at 10% breaks even at $1.80 a click. Your max CPC for a profit target sits below that, and the gap between the two is the margin you keep.

Should ranking campaigns have a high ACOS?

Yes, deliberately. A ranking push buys sales velocity on one keyword to move organic position, and the payoff arrives later as organic sales that carry no ad cost. Judged on ACOS alone it looks like a failure, which is how people end up killing the campaign that was working. Cap it in dollars over a fixed number of days, and watch TACOS rather than ACOS while it runs.

Why does each placement get a different bid?

Because each placement converts at a different rate, and what you can afford to pay for a click is a function of that rate. Top of Search usually converts best, so it can carry a higher click price than Rest of Search on the same target ACOS. Amazon lets you adjust every placement upward from the base bid, Rest of Search included, but never downward, so the base has to anchor on the cheapest placement and the others climb to their own ceiling with a percentage adjustment. That is why a single blended conversion rate produces a ceiling that is right for no placement in particular.

Does this calculator upload anything?

No. There is no file to send, no account to make and no email box. Every number you type stays in the page, the arithmetic runs in your own browser, and nothing is stored when you close the tab.

Knowing the target is the easy half.

A correct target ACOS does nothing if the account is spending against search terms that never convert. The free Audit Dashboard runs your bulk file through all 9 panels: search-term bleed, bid architecture, placement strategy, branded split and ASIN concentration. A 30-minute call with Alfred turns the findings into the specific changes to make first.

Run the full free audit → Book a 30-min call