Three metrics, three different questions.
- ACoS = (ad spend ÷ ad sales) × 100. How efficiently your ads convert. Lower is better.
- ROAS = ad sales ÷ ad spend. The same relationship expressed as a return. Higher is better.
- TACoS = (ad spend ÷ total revenue) × 100. What your advertising costs relative to the whole business, organic sales included. Lower is better.
Here is the fact I’ve found most explanations skip entirely: ACoS and ROAS are mathematically the same measurement. ROAS is 1 ÷ ACoS. A 25% ACoS is a 4:1 ROAS. A 50% ACoS is a 2:1 ROAS. They contain identical information, expressed for different audiences.
So there are really only two metrics in play, and in my view the one telling you something genuinely different is TACoS. That distinction is what this article is actually about.
We manage advertising for client accounts as a verified Amazon Ads partner. We tested our reporting both ways over time, and now TACoS is the figure we show owners while ACoS stays the figure we work with daily.
The formulas, side by side
| TACoS | ACoS | ROAS | |
|---|---|---|---|
| Full name | Total Advertising Cost of Sales | Advertising Cost of Sales | Return on Ad Spend |
| Formula | (ad spend ÷ total revenue) × 100 | (ad spend ÷ ad sales) × 100 | ad sales ÷ ad spend |
| Sales counted | All sales, organic and ad | Ad-attributed only | Ad-attributed only |
| Typical target | 5% to 15% | 15% to 30% | 3:1 or higher |
| Direction | Lower is better | Lower is better | Higher is better |
| Answers | Is the business healthy? | Is this campaign efficient? | What is my return? |
Treat those target ranges as orientation, never rules. A launch justifies dreadful efficiency deliberately. A mature product defending rank runs far tighter. Category economics differ enormously. Anyone quoting you one universal target has not looked at your margins, and I’d distrust them accordingly.
A worked example
One month, one product. Say you spend $2,000 on ads, those ads generate $8,000 in attributed sales, and your total revenue across ads and organic is $20,000.
- ACoS = 2,000 ÷ 8,000 × 100 = 25%
- ROAS = 8,000 ÷ 2,000 = 4:1
- TACoS = 2,000 ÷ 20,000 × 100 = 10%
Notice the first two describe the same thing from opposite ends. The third tells you something neither can: your ads represent a tenth of the business, and organic is carrying $12,000 of the $20,000.
Now run the following month. Spend rises to $2,500, ad sales rise to $9,000, total revenue rises to $30,000.
- ACoS = 27.8% (worse)
- ROAS = 3.6:1 (worse)
- TACoS = 8.3% (better)
Read that carefully, because I’d call it the crux of the whole topic. By one measure you had a poor month. By the other you had an excellent one: spending rose, efficiency dipped slightly, and organic sales climbed faster than the budget. That is precisely what a healthy scaling account looks like. An efficiency-only view would have you cutting spend at the exact moment it was working.
What each metric is genuinely for
ACoS: the working number
This is what I optimize campaigns with, day to day, because it answers directly to the levers you actually control: bids, keywords, negatives, placements. Campaign-level ACoS tells you which targets to raise, cut, or harvest, and it is the metric behind the search-term loop we describe in our search term optimization guide.
Its weakness is scope. This figure knows nothing about organic revenue, so it cannot tell you whether advertising is building a business or merely renting sales. Important difference.
ROAS: the communication number
Identical mathematics, friendlier framing. “Four dollars back for every dollar in” lands with people who find percentages abstract, and it matches how advertising gets discussed beyond Amazon. I reach for it with investors, partners, and anyone weighing Amazon against other channels.
TACoS: the diagnostic number
TACoS answers the question that actually matters: is advertising building organic strength, or substituting for it?
- TACoS falling while revenue grows: organic is compounding. Ads are doing their job, seeding velocity that rank then sustains. Keep going.
- TACoS flat while revenue grows: you are buying growth proportionally. Sustainable, not compounding.
- TACoS rising while revenue is flat: the warning sign. You are spending more to stand still, which usually means a listing or competitive problem rather than a bidding one.
- TACoS very low with flat revenue: possibly underinvesting. There may be profitable demand you are not buying.
That third pattern deserves dwelling on, because merchants reliably respond by fiddling with bids. In our experience the cause sits elsewhere nearly every time: a rival’s stronger main image, a price undercut, a review dip, a page that quietly stopped converting. More budget cannot repair a conversion problem. Our product detail page guide covers where I’d look instead.
Which to watch, and when
Daily and weekly, at campaign level: ACoS. It is the steering wheel.
Monthly, at account level: TACoS. It is the dashboard warning light.
When reporting outward: ROAS, because it communicates.
When deciding whether to scale: the TACoS trend across three months, never one. Single-month movements are noise, and scaling decisions built on noise are exactly how accounts oscillate pointlessly.
One addition none of the three includes: profit. All three metrics ignore your cost of goods, referral fees, and fulfillment costs. A 20% ACoS is excellent on a 60% margin product and ruinous on a 25% margin one. Build your target ACoS from your actual unit economics, factoring in FBA fees and landed cost, rather than adopting a number from an article. Including this one.
If you want these tracked and acted on rather than merely reported, that is what our advertising management service does, and we set out honest market pricing in our PPC management cost guide.
FAQ
What is the difference between TACoS, ACoS, and ROAS?
ACoS measures ad spend against ad-attributed sales. ROAS expresses the identical relationship as a return ratio (ROAS = 1 ÷ ACoS). TACoS measures ad spend against total revenue including organic sales, which is why only TACoS reveals whether advertising is building organic strength.
How do you calculate TACoS?
TACoS = (ad spend ÷ total revenue) × 100. If you spend $2,000 on ads and your total sales across organic and paid are $20,000, your TACoS is 10%.
What is a good ACoS on Amazon?
Commonly 15% to 30%, but the honest answer depends on your margins and objective. Launches deliberately accept high ACoS to build velocity; mature products defending rank run tighter. Calculate your break-even ACoS from unit economics rather than adopting a benchmark.
Is ROAS the same as ACoS?
Mathematically yes, inverted: ROAS = 1 ÷ ACoS. A 25% ACoS equals a 4:1 ROAS. They carry identical information, so use whichever your audience understands better.
Why is my ACoS rising but TACoS falling?
Because organic sales are growing faster than your ad spend. That is the signature of a healthy scaling account: advertising seeds velocity, rank improves, and organic carries more of the total. Judging that month by ACoS alone would wrongly suggest cutting budget.
Which metric should I optimize for?
Optimize campaigns with ACoS, monitor account health with TACoS, and report outward with ROAS. Set your ACoS target from your real profit margin, since none of the three metrics accounts for cost of goods or Amazon’s fees.
Last updated: August 27, 2026. Target ranges reflect what we see across accounts in 2026; your own margins should set your targets rather than any published benchmark.
