A number circulates among new Amazon sellers: 10% ACOS. It gets repeated until it sounds like a standard, and every seller reporting 45% or 70% concludes they are failing an exam.
ACOS is not a grade. It is a cost, and a cost can only be judged against what you have to spend it from. The same 45% is comfortable for one product and ruinous for another, and the difference is not skill at advertising. It is arithmetic about fees and product costs, settled before any ad runs.
01What do ACOS and TACOS actually measure?
ACOS is ad spend divided by ad-attributed sales, as a percentage. Ad-attributed sales are the sales Amazon credits to a click on one of your ads, within Amazon’s attribution window. Spend $600, get $2,000 credited to those ads, and ACOS is 30%.
TACOS is ad spend divided by total sales — ad-attributed and organic together. Organic sales are the ones Amazon does not credit to an ad click. Keep that same $600 and that same $2,000, add $500 of organic sales, and total sales are $2,500. TACOS is $600 divided by $2,500, which is 24%.
Both share the same top number and differ only in the bottom one. That single change of denominator is what separates them: ACOS asks how expensive your advertising is, TACOS asks how much of your whole business it is paying for.
02Is there a right ACOS number to aim for?
No, because ACOS compares ad spend to a selling price, and how much of that price you keep differs for every product. Two sellers both report 35% ACOS on a $30 item. Each pays $10.50 per unit for advertising. If the first keeps $12 per unit after fees and costs, that is profitable. If the second keeps $8, every unit loses money. Same percentage, opposite outcome.
A target borrowed from someone else was calculated from someone else’s costs. Chasing it can push you to cut bids on advertising that was profitable, or to relax about advertising that was not. That is a random choice, not a cautious one.
03How do I work out my own break-even ACOS?
Break-even ACOS is the ACOS at which a unit sold through advertising leaves exactly zero: the contribution left per unit before advertising, as a percentage of the selling price. Contribution before advertising is what remains after Amazon’s fees and all product costs. Every figure below is illustrative; replace each line with your own.
Selling price | $29.99 Amazon referral fee, 15% in this example’s category | $4.50 FBA fulfillment fee, this example’s size and weight | $5.60 Landed cost per unit, imported: factory price, freight, duty, inland transport | $7.20 Storage and refund allowance per unit | $0.70 Total cost before advertising | $18.00 Contribution before advertising, $29.99 minus $18.00 | $11.99 Break-even ACOS, $11.99 divided by $29.99 | 39.98%
The referral fee line is 15% of $29.99, which is $4.4985, rounded to $4.50. Every figure in the stack is rounded to the nearest cent.
This product breaks even at 39.98%, not at 10%. A seller running it at 30% ACOS and worrying is making money and worrying anyway.
Every cost you leave out raises your break-even ACOS, and refunds are the line beginners most often omit. That errs in the dangerous direction: it makes break-even look higher than it is, which makes more spending look safe. Until you can calculate your own refund rate, put a deliberately cautious allowance in rather than nothing.
04What does an ACOS above or below my break-even mean in money?
Ad cost per ad-attributed unit is the ACOS multiplied by the selling price; profit on that unit is the contribution minus that ad cost. The same illustrative product, at four ACOS figures:
| ACOS | Ad cost per ad-attributed unit | Contribution before advertising | Profit per ad-attributed unit |
|---|---|---|---|
| 10% | $3.00 | $11.99 | $8.99 |
| 20% | $6.00 | $11.99 | $5.99 |
| 39.98% (break-even) | $11.99 | $11.99 | $0.00 |
| 55% | $16.49 | $11.99 | -$4.50 |
At 55% ACOS this product loses $4.50 on every unit advertising sells, and selling more units makes the loss larger, not smaller. That is the situation behind every seller reporting good sales and no money.
05Should I ever spend above my break-even ACOS?
Yes, deliberately and for a stated period. Advertising sells a unit now, and that sale also lifts your organic ranking for the search term behind it. Better ranking produces later sales that carry no ad cost.
Spending above break-even during a launch is an investment with a payback period, not a loss to be eliminated. The question is not whether the ACOS is above break-even — it will be — but how much you are investing and when organic sales return it.
Break-even ACOS | 39.98% Actual ACOS during the launch month | 70% Ad-attributed sales that month | $2,000.00 Ad spend, 70% of $2,000.00 | $1,400.00 Contribution those sales generate, 39.98% of $2,000.00 | $799.60 Amount invested that month | $600.40 Organic sales per month once ranking settles | $1,500.00 Contribution from those organic sales | $599.70 Months at that organic level to return the investment | just over 1
An ACOS above break-even with no written amount and no expected payback is not an investment. It is a loss with an optimistic name.
The payback only arrives if the ranking holds. If your organic position depends on advertising running continuously, you are renting it, not investing. Watch that position weekly, not only your ACOS.
06Why can a low ACOS still be a bad sign?
Because ACOS has no idea how big your business is. A seller who bids almost nothing, gets a few clicks and converts two of them reports a beautiful ACOS on a product selling almost nothing. The ratio looks identical at $100 of ad-attributed sales and at $100,000.
ACOS also cannot see organic sales. A product whose organic sales are collapsing and one whose organic sales are growing can report the same ACOS, because organic sales sit in neither half of it.
07What should TACOS do over time, and when is it a warning?
On a product that is working, TACOS falls. The table below holds ad spend and ad-attributed sales constant across three illustrative months, and grows only organic sales.
| Month | Ad spend | Ad-attributed sales | Organic sales | Total sales | ACOS | TACOS |
|---|---|---|---|---|---|---|
| 1 | $600 | $2,000 | $500 | $2,500 | 30.0% | 24.0% |
| 3 | $600 | $2,000 | $2,000 | $4,000 | 30.0% | 15.0% |
| 6 | $600 | $2,000 | $4,000 | $6,000 | 30.0% | 10.0% |
ACOS is 30.0% in all three months and reports that nothing changed. TACOS falls from 24.0% to 10.0% and reports that the business became far less dependent on advertising.
A rising TACOS on a mature product is a warning, even when ACOS has not moved. Take the same product three months after that month 6 row.
Month 9 — ad spend | $900 Month 9 — ad-attributed sales | $3,000 Month 9 — organic sales | $1,800 Month 9 — total sales | $4,800 Month 9 — ACOS | 30.0% Month 9 — TACOS | 18.75%
ACOS is 30.0% in month 9, exactly as in month 6. But organic sales fell from $4,000 to $1,800 and the business replaced them by buying advertising: total sales dropped from $6,000 to $4,800 while the ad bill rose from $600 to $900. TACOS is the only one of the two that shows it.
During a launch, expect a high TACOS and watch it fall month by month. On a mature product, if TACOS climbs while total sales are flat or falling, stop tuning bids and find out why organic sales are declining — a competitor’s price move, a drop in organic position, a stockout that broke your ranking, or a listing change.
08Where do these numbers come from, and do they cover the same thing?
The two halves of TACOS come from different places and do not automatically line up.
Ad spend and ad-attributed sales come from Campaign Manager, in the columns named Spend and Sales. Both cover ad traffic only, for the campaigns and date range you selected. Sales counts what Amazon credits to clicks on those ads within the attribution window — for a seller running Sponsored Products that window is 7 days from the click; for Sponsored Brands and Sponsored Display it is 14 days. Orders keep filling in after the click, so a range ending today is incomplete and will rise over the following days.
Total sales — the TACOS denominator — do not come from Campaign Manager, which cannot see sales that were not credited to an ad. That figure lives in Seller Central under Reports, then Business Reports, then Detail Page Sales and Traffic by Child Item, in the column named Ordered Product Sales. It covers every order for that child ASIN in the date range, from all traffic sources, valued at the moment the order was placed.
Ordered Product Sales is recorded when the order is placed, so an order later cancelled or refunded was still counted on the day it was placed. It is a top-line sales figure: not revenue after returns, and not a payout, because Amazon’s fees are not deducted from it either. Use it strictly as the TACOS denominator and take settled money from your payout reports.
Use the same date range on both screens, ending at least a week ago so the attribution window has finished filling in. Filter Campaign Manager to the campaigns advertising one ASIN and pull Ordered Product Sales for that same child ASIN — a TACOS mixing one product’s ad spend with the whole account’s sales means nothing. Both are order-time sales figures rather than payout figures, which is what makes dividing one by the other meaningful.
Fee figures need the same care. Referral fees vary by category and fulfillment fees vary by size and weight, so no single percentage is right for everyone, and the 15% above is only this example’s category. Both come from Amazon’s Revenue Calculator for your own ASIN and price. You reach it by clicking the estimated fee figure shown against your listing rather than through a menu, and it breaks the charges out line by line — the referral fee and the closing fees separately from the fulfilment cost — so you can read the two figures this calculation needs instead of one combined number.
Frequently asked
Is a 10% ACOS realistic?
For some mature products in some categories, yes. As a general target, no. If a product breaks even near 40%, chasing 10% has you cutting bids on advertising that was making money.
My ACOS is above break-even. Should I pause the campaigns?
Not automatically. If you are launching, with a planned amount and an expected payback, continue and watch organic position. If the product is mature and there is no plan, that spend is losing money per unit and needs cutting.
Can I calculate break-even ACOS while running a coupon?
Use the price customers actually pay, not the list price, and put the coupon cost into the stack. A break-even ACOS built on a price nobody pays is too generous, in the direction that encourages more spending.
Final thoughts
The 10% figure that circulates is someone else’s arithmetic, repeated until it sounded like a rule. Your own break-even ACOS takes ten minutes to build from your real fees, your real landed cost and a cautious refund allowance. Treat it as a reference point rather than a target: at launch you will spend above it, in a profit phase well below it.
Keep TACOS in view alongside it, because ACOS can look perfect on a product that is quietly dying. TACOS falling month after month is the clearest single sign that advertising is doing the job it is meant to do: buying its own replacement.