TACoS vs ACoS: Which Amazon Ad Metric Actually Matters | Inventory Hero
·5 min readProfitability
TACoS vs ACoS: Which Amazon Ad Metric Actually Matters
TACoS vs ACoS: ACoS measures campaign efficiency, TACoS measures ad reliance against total sales. The formulas, a worked example, and when to use each.
ACoS (advertising cost of sales) is ad spend divided by the sales those ads directly generated, so it measures campaign efficiency. TACoS (total advertising cost of sales) is ad spend divided by your total sales, both advertised and organic, so it measures how reliant your entire business is on advertising. ACoS tunes campaigns; TACoS judges the health of the whole account.
What is a good TACoS for Amazon FBA?
It depends on your stage and margins, but many established sellers aim for a TACoS in the low teens or single digits, because a low TACoS means most of your sales come organically rather than from paid ads. A new product launch will run a much higher TACoS on purpose. The most useful signal is the trend: a TACoS falling while sales rise means your organic rank is strengthening.
T. Brian Jones is co-founder and CTO of Inventory Hero. He leads the engineering behind its Amazon data pipeline, demand forecasting, and the AI platform that lets sellers talk to their live inventory, sales, and supplier data in plain language.
Use both, for different jobs. ACoS is the right tool for tuning individual campaigns and keywords, where you want to know if the ad spend paid for itself. TACoS is the right tool for judging overall profitability and whether your ads are building durable organic sales or just renting them. TACoS is the one that connects to your net margin.
Read article
The difference between TACoS vs ACoS comes down to the denominator: both measure advertising cost as a percentage of sales, but they answer different questions. ACoS is your ad spend divided by the sales those ads directly drove, so it measures campaign efficiency. TACoS is your ad spend divided by total sales, advertised and organic together, so it measures how reliant your whole business is on ads. The short version: use ACoS to tune campaigns and TACoS to judge the health of the business, and TACoS is the one that actually connects to profit. Below are the formulas, a worked example, and when to reach for each.
They share a numerator (ad spend) and differ in the denominator:
ACoS = ad spend / ad-attributed sales
TACoS = ad spend / total sales (ad + organic)
Because total sales are larger than ad-attributed sales, your TACoS is always lower than your ACoS (they are equal only in the degenerate case where you have no organic sales at all). The gap between them is the story: a big gap means a healthy share of your sales are organic; a small gap means almost all your sales are coming from ads.
The 25 percent ACoS says the campaigns are reasonably efficient. The 10 percent TACoS says ads are 10 percent of total revenue, and the gap between 4,000 dollars of ad sales and 10,000 dollars total says 6,000 dollars came in organically. That is a healthy picture.
TACoS is the right tool at the business level, where the question is "how dependent am I on advertising, and is that improving?"
Judging overall health. A low, stable TACoS means most sales come organically; a high one means ads are propping up revenue. Many established sellers aim for a TACoS in the low teens or single digits, while a new launch runs much higher on purpose to buy rank.1
Watching the trend. A TACoS falling while sales rise is the signal you want: your organic rank is strengthening, so each sales dollar costs less in ads over time.
Connecting to profit. Because TACoS counts ad spend against every dollar you earn, it flows straight into net profit margin. A rising TACoS with flat sales is margin leaking out. The FBA profit calculator lets you model what a two-point TACoS reduction is worth in net margin before you cut spend.
TACoS is the strategic number. It is the one to put on your monthly dashboard next to net margin.
The real insight comes from watching both at once:
ACoS
TACoS
What it signals
Low
Low
Efficient ads and strong organic. The healthy state.
Low
High
Campaigns are efficient but you depend heavily on ads; organic is weak.
High
Low
Ads are inefficient but a small part of the business; worth tuning, not urgent.
High
High
Inefficient ads carrying most of your sales. The danger zone, and a drain on cash and margin.
A rising TACoS is also a cash-flow signal: ad spend is a cost you pay now for sales that pay back later, so it belongs in your FBA cash flow planning, and ads on a SKU you cannot keep in stock are pure waste. See PPC inventory planning for aligning spend with stock.
A falling TACoS is the goal, and you lower it by growing the organic share of your sales rather than by simply cutting ads:
Strengthen organic rank. Better listings, images, and reviews convert more of the traffic your ads buy into organic momentum, so ranking holds when you ease off spend.
Prune wasteful keywords. Use ACoS at the keyword level to cut spend on terms that never convert, which lowers total ad spend without losing sales.
Let winners ride on organic. Once a SKU ranks well organically, you can often pull back paid spend on its main keywords and let organic carry it, which drops TACoS directly.
Do not starve a launch. A new product needs a high TACoS to build rank; cutting too early strands it. Lower TACoS is a goal for established SKUs, not new ones.
The trap is cutting ads across the board to force TACoS down. That can tank sales and rank together. The durable way down is more organic sales, not less advertising.
TACoS and ACoS are the same idea with different denominators: ACoS measures campaign efficiency against ad sales, TACoS measures ad reliance against total sales. Tune campaigns with ACoS, judge the business with TACoS, and watch the two together to see whether your ads are building organic rank or renting it. If you track only one ad metric on your monthly dashboard, make it TACoS: it is the one tied to your actual P&L. It connects straight to net margin and belongs beside the inventory KPIs.
The low-teens-or-single-digits TACoS target is a common operator rule of thumb, not a measured or Amazon-published figure. The right target depends on your margins, category, and product stage (a launch runs far higher on purpose); use it as orientation and track your own trend. ↩