Free tool · Amazon advertising
Profit X-Ray
ACoS tells you whether an ad click paid. TACoS tells you how far advertising can scale. Enter your numbers, your stage and your category, and see whether you are under-investing, on plan or eating profit, in pounds. Nothing leaves your browser.
- 60 seconds
- Runs in your browser
- No sign-up
Reading your figures…
Your TACoS plan
- TACoS now
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- Your ceiling
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- Plan for this stage
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- Sales without an ad click
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Category ranges are a guide, not an Amazon figure: practitioner benchmarks published in 2026, checked against the TACoS in the accounts we manage. Stage moves them: launch runs 15 to 25 points higher, growth 4 to 8.
- Profit after advertising, per month
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- TACoS
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- ROAS
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- Margin back per £1 of ads
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- ACoS against your break-even
TACoS, not ACoS, decides how far advertising can scale: an ad-attributed sale can lose money on its own and still be right while it buys rank that organic sales then hold. Some ad-attributed sales would also have happened anyway. The Profit Audit separates the two, product by product, and tests how far spend can grow before returns fall away.
Drop your Business Report here
The CSV called Detail Page Sales and Traffic by Child Item. It is read on your device and never uploaded.
How to download it from Seller Central
- In Seller Central, open Reports, then Business Reports.
- Under By ASIN, choose Detail Page Sales and Traffic by Child Item.
- Set the dates (the last 30 days works well) and choose Download (.csv).
Bring your X-Ray to a Profit Audit.
Robert and the team will go through it with you, product by product, and show you what to change first. Your summary travels with the booking only if you choose to send it; the report file never leaves your device.
How it works
The numbers behind the X-Ray, and the TACoS plan
The X-Ray answers one question: after you pay for advertising, how much of each pound of sales do you keep? It uses the definitions Amazon itself publishes, and the same arithmetic our team uses on client accounts.
The five numbers
TACoS (total advertising cost of sales)
TACoS = ad spend ÷ total sales
All ad spend divided by all sales in the period, advertised or not.
ROAS and ACoS
ROAS = ad sales ÷ ad spend · ACoS = ad spend ÷ ad sales = 1 ÷ ROAS
Amazon defines ROAS as ad-attributed sales per £1 of ad spend. ACoS is the same ratio upside down, so a 25% ACoS is a 4.0× ROAS.
Break-even ACoS
Break-even ACoS = margin before advertising ÷ price excluding VAT
Amazon Ads reports attributed sales without VAT, so the margin is measured against the ex-VAT price. Below it, each ad-attributed sale adds profit; above it, each one loses money. The X-Ray converts for you: at 20% VAT, a 28% margin on the shopper’s price is a 33.6% break-even ACoS.
Profit after advertising
Profit after ads = total sales × (margin − TACoS)
The bridge from advertising to the P&L.
TACoS ceiling
Ceiling = margin before advertising − target profit
The most TACoS you can run and still keep the profit you want. Growth runs close to it, a mature product well below it, a launch above it only by decision.
The TACoS plan
TACoS is the number that lets advertising scale. A brand with a 28% margin that wants to keep 10% has an 18% ceiling. It sells £120,000 a month and spends £14,000 on ads, a TACoS of 11.7%. If its category typically runs 16% to 26% in growth, it is under-investing: it could spend £5,200 to £7,600 more a month and still keep its target, while rivals with more margin take the rank. The same 11.7% in a mature electricals line, where 6% to 10% is typical, is paying for sales it would mostly get anyway.
The X-Ray reads three things together: your ceiling from your margin, the range your category typically runs at your stage, and how many of your sales come without an ad click. The category ranges are a guide, not an Amazon figure: practitioner benchmarks published in 2026, checked against the TACoS in the accounts we manage.
A worked example
A brand sells £40,000 in a month, spends £6,000 on advertising and keeps 28p of every £1 before ads. TACoS is 15%, so profit after advertising is £40,000 × (28% − 15%) = £5,200, or 13p in every £1. If Amazon Ads reports £20,000 of ad-attributed sales, ROAS is 3.33× and ACoS is 30%. That looks worse than the 28% margin, but Amazon reports ad sales without VAT: with 20% VAT added back they are worth £24,000 at shop prices and carry £6,720 of margin, against £6,000 of spend. The break-even ACoS on Amazon’s basis is 33.6%, so these ads add about £720 a month. Push ACoS past 33.6% and they start to cost money even while the account as a whole stays profitable. That is the gap the X-Ray is built to show.
What it does not know
The X-Ray cannot see why a number is what it is: which search terms waste spend, which products carry the account, or whether organic rank would hold without ads. It also relies on the margin you enter. Treat it as a first read, then check the products it flags.
For the full method, with UK fees, VAT and a line-by-line example, read the guide linked alongside.
Questions
About this tool.
Is the Profit X-Ray really free, and do you see my numbers?
It is free and needs no sign-up. The calculator and the Business Report reader run as code in your own browser, so the figures you type and the file you drop are never uploaded to us or anyone else. If you book a Profit Audit, you choose what to share on the call.
Which Business Report do I need?
In Seller Central go to Reports → Business Reports → Detail Page Sales and Traffic by Child Item, choose a date range (the last 30 or 60 days works well) and download it as a CSV. Drop that file into the X-Ray. The file contains sales and traffic, not advertising spend, so the X-Ray asks for your ad spend separately.
What margin should I enter?
Your margin before advertising: what is left of each £1 the shopper pays after cost of goods, Amazon’s referral and fulfilment fees, inbound shipping and VAT, before any ad spend. Then choose the VAT rate on your products: Amazon Ads reports ad sales without VAT, so the X-Ray adds it back before comparing ACoS with your margin. If you are not sure of your margin, work it out for your best-selling product first; the method section below shows how.
Why does the X-Ray focus on TACoS rather than ACoS?
ACoS only counts the sales Amazon attributes to an ad click. TACoS divides the same spend by all your sales, so it connects straight to profit: profit after advertising = total sales × (margin − TACoS). That is why TACoS, not ACoS, decides how far advertising can scale. An ad-attributed sale can lose money on its own and still be the right call while it buys rank that organic sales then hold. ACoS still matters campaign by campaign, which is why the X-Ray shows your break-even ACoS too.
What is a good TACoS for my category?
It depends on the category and the stage. Electricals, office and DIY brands typically run lower, around 5% to 10% once established; home, garden, pet and fashion sit in the middle; beauty, supplements and gifts run higher, around 12% to 20%. A launch runs 15 to 25 points above that, and growth 4 to 8. These are guides, not Amazon figures: practitioner benchmarks published in 2026, checked against the TACoS in the accounts we manage. Your own ceiling comes from your margin.
What is a TACoS ceiling?
Your margin before advertising minus the profit you want to keep. With a 28% margin and a 10% profit target, the ceiling is 18%: spend more than that, as a share of all sales, and you keep less than your target. A growth product runs close to the ceiling, a mature one well below it. A launch can run above it, as a decision with a fixed budget and an end date.
Is the result a recommendation?
No. It is arithmetic on the numbers you enter, with a plain-English reading of the result. Running above break-even can be right for a launch or a rank defence, as a decision with a budget and an end date. A Profit Audit looks at the reasons behind the numbers.
The Profit Audit
Want a senior team to read your numbers with you?
One call with Robert Prime and the team. We go through your accounts product by product and show you the changes most likely to add net profit.