Enter what you spent on Amazon ads and the sales they produced for your ACoS and ROAS. Add total sales for TACoS, and your margin for the break-even ACoS.
How it works
ACoS (advertising cost of sales) is ad spend divided by the sales attributed to those ads: $500 of spend that produced $2,000 of sales is a 25% ACoS. It is the inverse of ROAS (4x here). TACoS (total ACoS) divides the same spend by ALL sales, ads plus organic, and shows how much of the whole business is riding on paid traffic; a falling TACoS while sales grow means ads are lifting organic rank.
Formulas: ACoS = Ad spend / Ad sales x 100; ROAS = Ad sales / Ad spend; TACoS = Ad spend / Total sales x 100; Break-even ACoS = your profit margin before ads; Target ACoS = margin before ads - the margin you want to keep.
Break-even is the number that matters. If a unit leaves 30% after Amazon fees and product cost, an ACoS of 30% means the ad ate the whole profit; anything above it loses money on those sales. The Amazon FBA Revenue Calculator gives you the margin before ads.
Advanced options add your profit margin before ads and the margin you want to keep, unlocking the break-even ACoS, the target ACoS, the profit on ad sales after spend, and a verdict.
Everything runs in your browser. Your numbers are never sent to a server, and there is no signup or limit. Your last entries are remembered locally so the calculator is ready next time.
Frequently asked questions
What is a good ACoS on Amazon?
Lower than your break-even ACoS, which is your profit margin before ads. Most sellers land between 15% and 30% on established products; a launch campaign can run at or above break-even on purpose to win reviews and rank, as long as it is a decision and not a surprise. Compare against your own margin, not an industry average.
What is the difference between ACoS and TACoS?
ACoS measures the ads alone: spend divided by the sales Amazon attributes to the ads. TACoS measures the ads against the whole business: the same spend divided by total sales, organic included. A product with a 40% ACoS but a 8% TACoS is mostly selling organically; the ads are a small tax on a healthy listing. Watch TACoS over months to see whether ads are building organic sales or replacing them.
How do I work out my break-even ACoS?
Take one unit's selling price, subtract Amazon's referral and FBA fees and your landed cost, and divide what is left by the price. That percentage is the most you can spend on ads per dollar of sales before the sale loses money. Turn on Advanced options, enter it as the margin before ads, and the calculator marks whether your current ACoS is above or below it.
What is the target ACoS?
The break-even ACoS minus the margin you want to keep. With a 30% margin before ads and a 10% profit goal, the target ACoS is 20%: at that level each ad sale still leaves 10% of its price as profit. Use it as the bid ceiling when you set campaign targets.
Is ACoS the same as ROAS?
They describe the same ratio from opposite ends. ACoS is spend over sales; ROAS is sales over spend. A 25% ACoS is a 4x ROAS, a 50% ACoS is a 2x ROAS. Amazon reports ACoS; most other ad platforms report ROAS, which is why the ROAS Calculator exists beside this one.
Does this connect to my Amazon Ads account?
No. Nothing connects to Amazon or your Ads console; type the figures from your campaign report and the maths runs in your browser. The calculator remembers your last entries on this device only.