What's Actually a Good TACOS?
I get asked "what's a good ACOS?" constantly. And every time, I have to resist the urge to answer with another question: good for what?
Because ACOS — advertising cost of sale, the percentage of your ad revenue you spent on ads is a genuinely useful number for exactly one job, and a dangerously misleading number for almost every other. Most sellers have it bolted into the centre of their dashboard like it's the North Star. It isn't. It's a gauge on one dial of one engine, and people are steering the whole aircraft by it.
Let me tell you what ACOS actually measures, why chasing it wrecks good businesses, and what number you should be watching instead.
ACOS measures a keyword. Your business is not a keyword.
ACOS is only really good for one job: measuring how effective a keyword is. It tells you how efficiently the spend on a given term turned into ad-attributed revenue is this keyword converting well enough to justify what I'm paying for the click? At that level, on that job, it's a genuinely useful reading.
The problem is what happens when you promote a keyword-effectiveness gauge to the top of your whole strategy. Because there's one guaranteed way to get a beautiful, low ACOS: advertise only on the terms you were basically going to win anyway. Bid on your own brand name. Bid on the dead-certain, bottom-of-funnel, someone's-already-decided terms. Your ACOS will look gorgeous. It'll be the best-looking number in the account.
And your business will quietly shrink.
Because you'll have become, as we say on The Upside Podcast, efficient at becoming irrelevant. You've optimised your advertising down to only the customers who were already coming to you. You've stopped buying new attention, stopped entering new markets, stopped acquiring customers who didn't already know your name. The dial reads perfect. The engine is winding down.
TACOS is the number that can't be gamed that way
Total advertising cost of sale, TACOS, is ad spend as a percentage of your total revenue. Not ad-attributed revenue. Total. Organic sales included.
That one change of denominator changes everything, because now you can't hide. If you pour money into ads and total sales don't move, TACOS climbs and tells you the truth: you're spending more to stand still. But, and this is the bit people miss, a rising TACOS during a growth push isn't automatically bad, and a falling TACOS is exactly what a healthy maturing product should show, because your paid spend is successfully converting into organic rank, and organic sales (which cost you nothing per click) are carrying more and more of the load.
TACOS reads the health of the whole system. ACOS reads the efficiency of one part. If you only look at one, look at TACOS.
So what's a "good" TACOS?
Annoyingly and honestly it depends, and anyone who gives you a single magic number is guessing. A brand-new product fighting for its first foothold should run a high TACOS; you're buying market entry, and that's expensive by design. A mature, well-ranked product in a category you own should run a low one, because organic is doing the heavy lifting and ads are just defending and topping up.
The mistake isn't having a high or low TACOS. The mistake is not knowing which one your product should have for where it is in its life, and then panicking at the wrong number. A launch product with a low TACOS might not be a triumph. It might mean you're under-investing and leaving the market to someone braver. A mature product with a creeping TACOS might mean your organic rank is slipping and ads are papering over it.
Read the direction, not just the level
Here's the operator's habit: don't look at TACOS as a snapshot, look at it as a trend against what you're trying to do. Launching? You expect it high and want to watch it fall over the following months as paid converts to organic. Defending a mature position? You want it low and stable, and a sudden climb is your early-warning system that something underneath has moved.
That's the whole reframe. ACOS answers "is this keyword pulling its weight?" — a fine question at the keyword bench. TACOS answers "is this business actually getting healthier?", the question you should be running the whole thing by.
Stop asking me what a good ACOS is. Start asking what your TACOS is doing, and whether that's what it should be doing for where your product is. That question will make you money. The other one just makes you feel efficient while you disappear.
FAQ
Should you panic if your TACOS climbs during a product launch?
No. If you're pushing hard on a launch, a climbing TACOS is often just what that looks like. Mature Amazon products in competitive categories usually settle somewhere around 5 to 15 percent once their organic rank stabilises, but a brand new listing can sit well above that for months and still be perfectly healthy, because it's still earning its first bit of organic footing.
Is there a version of ROAS for TACOS the way there is for ACOS?
Not really. ROAS is just ACOS looked at the other way round, revenue divided by spend instead of spend divided by revenue, and it works fine at the keyword level. TACOS doesn't have an equivalent, because organic sales don't carry any ad cost to divide against. That's really the point of TACOS, you can't optimise it the way you optimise a keyword's ROAS. It's there to tell you how healthy things are, not to be pushed up or down.
How often should you actually check your TACOS?
Once a month is plenty. Ad spend takes weeks to show up as a change in organic rank, so if you're checking TACOS week to week, you're mostly just watching noise. React to that and you end up chasing a number that hasn't even finished moving yet.
About the author
Zamir Cajee is co-founder of This Way Up, a UK business specialising in Amazon marketplace strategy, and co-host of The Upside Podcast, where he and the team break down how Amazon actually works — and how it lies to you. Zamir has built multi-million dollar businesses from scratch and has been selling into the EU since 2016.
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