Can ACoS be lower than TACoS?

No. ACoS is always equal to or higher than TACoS for the same listing and time period. This is because ACoS uses a smaller denominator (ad-attributed revenue only), while TACoS uses a larger denominator (total revenue including organic sales). Dividing the same ad spend by a smaller number always produces a larger percentage. If you see a figure where your calculated TACoS appears higher than your ACoS, it means you have used inconsistent data: different date ranges, different revenue definitions or different campaign sets in each calculation.

Is TACoS more important than ACoS for Amazon sellers?

TACoS provides a more complete picture of your listing's advertising health, but ACoS is the more actionable metric for day-to-day campaign management. Both are important and they serve different purposes. Use ACoS for bid and budget decisions within Campaign Manager. Use TACoS for monthly strategic reviews of whether your advertising investment is building sustainable organic growth. Relying on ACoS alone risks optimising campaigns in ways that reduce total revenue; relying on TACoS alone gives insufficient granularity for making specific campaign adjustments.

What is a healthy gap between ACoS and TACoS?

There is no universal definition of a healthy gap, but a larger gap generally indicates better listing health, because it means a higher proportion of total revenue is coming from organic search rather than paid clicks. For a mature, well-ranked listing, an ACoS of 25% with a TACoS of 8% to 10% indicates that roughly 65% to 70% of revenue is organic: this is a strong position. A gap of less than 3 to 5 percentage points between ACoS and TACoS suggests very high ad dependency, meaning most sales require a paid click, which makes revenue fragile if ad budgets are cut.

What is the difference between ACoS and TACoS?

ACoS and TACoS use the same numerator, your total ad spend, but a different denominator. ACoS uses ad-attributed revenue, the sales Amazon recorded as resulting from an ad click. TACoS uses total revenue, organic sales plus ad-attributed sales combined. This single difference in the denominator makes the two metrics tell fundamentally different stories about advertising performance. ACoS measures how efficiently your campaigns convert ad spend into ad-attributed sales. TACoS measures what advertising truly costs as a fraction of your listing's full commercial output. The distinction becomes clear when you see both formulas together. ACoS = (Ad Spend / Ad-Attributed Revenue) × 100. TACoS = (Ad Spend / Total Revenue) × 100. In both cases the numerator is identical: the total amount spent on Amazon advertising for the measurement period. The only difference is the denominator. ACoS uses ad-attributed revenue, the subset of total revenue that Amazon's attribution system linked to an ad click. TACoS uses total revenue, which includes organic sales as well. Because total revenue is always greater than or equal to ad-attributed revenue (organic sales add to the denominator without changing the numerator), TACoS will always be the same as or lower than ACoS. The difference between the two figures is directly proportional to the volume of organic sales. If ACoS is 30% and TACoS is 12%, it means that only 40% of your total revenue came through ad clicks: the remaining 60% was organic. That organic proportion is the gap that separates your ACoS from your TACoS. ACoS is the right metric for day-to-day campaign management decisions. When you are reviewing individual campaigns, ad groups or keywords to decide whether to raise or lower a bid, pause a keyword, or adjust a budget, ACoS tells you directly how efficiently that campaign is converting ad spend into attributed sales. It is a fast feedback loop: if a keyword's ACoS is far above your target, you reduce the bid or pause it. ACoS is not meaningful for understanding the health of the listing as a whole, but it is exactly the right metric for the granular decisions that make up campaign optimisation. TACoS is the right metric for strategic business decisions. It answers questions like: Is this listing becoming more or less dependent on advertising over time? Is my PPC investment actually building organic ranking and therefore organic revenue? Should I increase or decrease my overall advertising budget on this listing? These are monthly or quarterly questions, not daily ones. TACoS provides the context that ACoS lacks: a listing with a rising ACoS but a falling TACoS may actually be in excellent health, because the organic sales growth is outpacing the ad spend growth. A common error among Amazon sellers is to optimise their campaigns purely to a low ACoS target without tracking TACoS. This can lead to cutting ad spend on keywords that are actually driving organic ranking gains, even when the ACoS on those keywords looks poor in isolation. A keyword with a 50% ACoS might appear to be burning money, but if it is a keyword where your listing recently moved from page three to page one and is now generating significant organic traffic, cutting that keyword's bid could reverse the ranking gain and cost you far more in lost organic revenue than you saved in ad spend. TACoS captures this dynamic. If a keyword is generating ranking that drives organic sales, the true cost of the advertising on that keyword, measured as a proportion of total revenue including organic, is much lower than its ACoS suggests. Sellers who track only ACoS are prone to over-optimising their campaigns in ways that look efficient in Campaign Manager but reduce total revenue. Tracking TACoS alongside ACoS prevents this mistake.

ACoS measures ad spend against ad-attributed revenue only. TACoS measures ad spend against total revenue including organic sales. Learn when to use each metric.