How to use the ACoS calculator
- Enter your ad spend and the sales attributed to your ads for the same period, taken from your Amazon Advertising campaign report.
- Optionally enter your total sales (organic plus advertised) to calculate TACoS.
- Enter your selling price and your profit per unit before advertising to find your break-even ACoS. You can get the profit figure from our Amazon FBA Calculator with ad spend set to zero.
- The verdict tells you whether your campaigns are profitable, breaking even or losing money on each ad sale.
The key advertising metrics
| Metric | Formula | What it tells you |
|---|---|---|
| ACoS (Advertising Cost of Sale) | Ad spend ÷ Ad sales × 100 | What share of ad-driven revenue went on ads |
| ROAS (Return on Ad Spend) | Ad sales ÷ Ad spend | Revenue per $1 of ads — the inverse of ACoS |
| TACoS (Total ACoS) | Ad spend ÷ Total sales × 100 | How dependent the whole business is on advertising |
| Break-even ACoS | Profit before ads ÷ Price × 100 | The highest ACoS you can afford before ads make a loss |
Example: $450 of ad spend producing $1,800 in sales is an ACoS of 25% and a ROAS of 4.0. If your product earns $9.50 profit before ads on a $29.99 price, your break-even ACoS is 31.7% — so a 25% ACoS is profitable.
What is a good ACoS?
There is no universal number. A “good” ACoS is any ACoS below your break-even ACoS, and how far below depends on your goal:
- Product launch / ranking: spending at or even above break-even can make sense for a short period to build sales history, reviews and organic rank.
- Profit focus: aim for an ACoS well below break-even, often 10–15 percentage points lower.
- Brand defence: campaigns on your own brand terms usually achieve very low ACoS.
Why TACoS matters
ACoS only looks at ad-attributed sales. TACoS compares ad spend with all sales. If your TACoS is falling over time while sales grow, advertising is successfully boosting organic sales — the long-term goal. A rising TACoS means you are buying more of your sales with ads.
Ways to lower ACoS
- Add irrelevant and non-converting search terms as negative keywords.
- Move proven search terms into exact-match campaigns with controlled bids.
- Improve the listing — main image, title, price and reviews drive conversion rate, which lowers ACoS directly.
- Lower bids on placements and keywords whose ACoS is above break-even.
Frequently asked questions
How is ACoS calculated?
ACoS = ad spend ÷ ad-attributed sales × 100. For example, $450 spend and $1,800 sales gives 25% ACoS.
What is break-even ACoS?
It is your profit margin before advertising. If you keep $9.50 of a $29.99 price before ads, your break-even ACoS is 31.7%. Above that, each ad sale loses money.
What is the difference between ACoS and ROAS?
They show the same thing inversely. ROAS = 1 ÷ ACoS. A 25% ACoS equals a ROAS of 4.
What is TACoS?
Total Advertising Cost of Sale: ad spend divided by total sales including organic. It shows how dependent your business is on ads.