You’re looking at ACOS the wrong way

ACOS vs TACOS: Which Amazon Metric Actually Matters

Brands ask us about ACOS on almost every call, and half the time we're thinking the same thing: ACOS doesn't matter, at least not the way most sellers use it. In this episode, we explain why a lower ACOS isn't automatically a win, and why TACOS is the number that actually tells you whether your advertising is working.

In this episode: Ali and Zamir define ACOS and TACOS from scratch, then break down why ACOS gets misused as a whole-account health check when it was only ever built to judge individual keywords.

Key takeaways

• ACOS = ad spend ÷ attributed revenue. Spend £1,000, generate £2,000 in ad-attributed revenue, that's a 50% ACOS.

• TACOS = ad spend ÷ total revenue (organic and paid combined). Same £1,000 spend, but £10,000 in total revenue with only £2,000 of it ad-attributed, and TACOS comes out at 10%.

• ACOS is a tactical metric, not a strategic one. It should be judged at keyword or ad group level. Above that, at campaign or whole-account level, it stops giving you useful information.

• There's no universal "good" ACOS. Branded campaigns should sit around 10% or lower, since anyone searching your brand name should convert; above that, something's wrong. Competitor campaigns can run 30–40% ACOS quite comfortably, since you're poaching sales from someone else and that costs more.

• Generic, high-volume terms depend on your market share ambitions. How much of that keyword's market you already own versus how much you want to grow into it decides what ACOS is tolerable, and a higher one is fine short-term if you expect it to come down as you build rank.

• Chasing a lower ACOS can cost you growth. Optimising purely for margin instead of market share means leaving money on the table.

• TACOS is the strategic metric because paid advertising on Amazon feeds organic ranking, so it captures the compounding effect that ACOS alone misses entirely.

  Timestamps

  • 00:00 — Cold open: why "lower ACOS is better" isn't always true

  • 00:35 — Why brands challenge us on ACOS on every BD call

  • 01:11 — ACOS defined: ad spend ÷ attributed revenue

  • 01:32 — TACOS defined: ad spend ÷ total revenue

  • 02:01 — Why ACOS is tactical, not a macro metric

  • 03:06 — Target ACOS by campaign type: branded vs competitor vs generic

  • 04:20 — Budget split across campaigns sets your blended ACOS

  • 04:37 — The confession: chasing a lower ACOS can cost you growth

  • 05:28 — Why TACOS is the strategic metric to build around‍ ‍

  The detail

  Defining ACOS and TACOS

  ACOS is your advertising spend divided by the revenue that advertising directly generated, shown as a percentage. Spend £1,000 and get £2,000 in ad-attributed revenue back, and that's a 50% ACOS. TACOS uses the same spend figure but divides it by total revenue, organic and paid together. So if that same £1,000 spend sits inside £10,000 of total revenue, and only £2,000 of that came from ads, TACOS is 10%. The difference matters because ACOS only ever sees the slice of revenue advertising directly touched, while TACOS sees the whole picture, including the organic sales your ads may be quietly supporting. We break down what a healthy number actually looks like in What's Actually a Good TACOS?, if you want the benchmarks by category.

  ACOS is tactical, TACOS is strategic

  The core mistake sellers make is judging the whole business on ACOS. It was built to evaluate a keyword or an ad group, not a campaign and definitely not a whole account. Zoom out past ad group level and ACOS blends together so many different keyword intents that the number stops meaning anything useful.

  "ACOS is not a macro metric. It should be utilised tactically at keyword level, ideally."

  What target ACOS actually looks like

  Target ACOS depends entirely on what the keyword is doing for you. A branded campaign, where people are already searching your name, should convert hard: expect ACOS around 10% or lower, and treat anything higher as a signal something's wrong. A competitor campaign is different math: you're poaching someone else's customer, so a 30–40% ACOS is a fair price to pay for that sale. Generic, high-volume terms sit in between, and the right number there depends on how much of that market you already hold versus how much you're trying to win. Going after new share can justify a temporarily higher ACOS, on the expectation it comes down as rank builds.

  "How much of that market do you already own, and how much more do you want to grow into it?"

  Budget split sets your blended number, and TACOS is the real target

  Your overall ACOS is really just the sum of how you've split budget across branded, generic and competitor terms, and how well each of those is already performing. Optimise purely to bring that blended number down, and the risk is you're trading growth for margin, the same trap we cover in Advertising on Amazon: 5 Profit Killers You Must Avoid. TACOS is the metric to actually build strategy around, since Amazon's paid advertising feeds organic ranking over time, and TACOS is what captures that compounding relationship between the two.

  “You may be leaving money on the table... you're focusing on margin and sacrificing growth.”

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