TACoS is total advertising cost of sale: ad spend divided by total Amazon sales, paid and organic. Contribution margin is what is left after landed COGS, Amazon fees and ad spend. Together they tell you whether advertising is growing the business you keep, which ACoS on its own cannot.
ACoS is the number most ad consoles lead with, and it is useful for one thing: judging whether a campaign’s attributed sales are efficient. It says nothing about whether those sales grew the business, whether they pulled organic sales along with them, or whether there was any money left after fees and product cost. That is why we grade every account on TACoS and contribution margin first.
The three formulas
| Metric | Formula | What it tells you |
|---|---|---|
| ACoS | Ad spend ÷ ad-attributed sales | How efficient the ads are at generating the sales they are credited with |
| TACoS | Ad spend ÷ total Amazon sales | How dependent the whole business is on advertising |
| Contribution margin | Revenue − landed COGS − Amazon fees − ad spend | The part you deposit |
A falling TACoS while total sales grow is the signature of a healthy account: advertising is pulling organic sales along with it, so each ad dollar supports more total revenue. A rising TACoS with flat total sales means the brand is renting its revenue.
A worked example
Take a month with $100,000 in Amazon revenue, landed COGS at 30% of revenue, Amazon fees, storage and returns at 32%, and $18,000 in ad spend.
| Line | Amount | % of revenue |
|---|---|---|
| Revenue | $100,000 | 100% |
| Landed COGS | −$30,000 | 30% |
| Fees, storage, returns | −$32,000 | 32% |
| Ad spend | −$18,000 | 18% (this is the TACoS) |
| Contribution margin | $20,000 | 20% |
If ad-attributed sales were $45,000, the ACoS would be 40%, which looks alarming in isolation. But the TACoS is 18% and the business keeps 20% of revenue. Now change one input: push ad spend to $30,000 for the same $100,000. ACoS gets worse, TACoS rises to 30%, and contribution margin falls to 8%. Revenue did not move at all. You can try your own numbers in the margin calculator on our homepage.
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Why ACoS alone misleads
- It ignores organic lift. Ads on target terms support organic rank on those terms. A campaign with a mediocre ACoS can be the reason organic sales grew.
- It ignores product economics. A 30% ACoS is profitable on a high-margin SKU and a loss on a low-margin one. Targets have to be set per SKU.
- It rewards shrinking. The easiest way to lower ACoS is to stop bidding on anything competitive. Efficiency goes up while the business gets smaller.
What good looks like in practice
There is no universal “right” TACoS. It depends on margins, category and stage. These are real figures from accounts we run:
- Save Trees reached a 9.6% TACoS by month 31, at more than $450K a month in sales, with organic sales up 9.3x.
- Bird Darts ran a 15% TACoS in its biggest month ever, a $94K December, because the rank was already owned before the season started.
- Olive My Pickle went the other way on purpose: ad investment scaled roughly 5x into a managed TACoS band, trading a starved 10% for rank, volume and owned demand. Sales grew 4x in 18 months.
The last example matters. A lower TACoS is not always better. A brand that is under-investing can have a beautiful TACoS and a shrinking share of the shelf. The goal is the TACoS your contribution margin can afford while the business grows.
How to set ad targets from your unit economics
- Start with landed COGS and Amazon fees per SKU. That gives you the margin before advertising.
- Decide the contribution margin you need to keep. This is a business decision, not a marketing one.
- The difference is your affordable TACoS. If margin before ads is 38% and you need to keep 20%, you can afford roughly 18% of revenue in ad spend.
- Set SKU-level ACoS targets inside that envelope, higher for SKUs where ads clearly lift organic rank or repeat purchase, lower for SKUs that don’t.
- Review weekly against cash flow and inventory, so spend never outruns supply.
Where Subscribe & Save fits
For consumable products the math changes again, because a first order that barely breaks even can be very profitable if the customer subscribes. That is why we price acquisition on lifetime value for repeat-purchase brands. Our Subscribe & Save guide covers how to build that engine.
Frequently asked questions
What is a good TACoS on Amazon?
It depends on your margins, category and growth stage. The right TACoS is the one your contribution margin can afford while total sales grow. Accounts we run range from under 10% at scale to deliberately higher during growth pushes.
What is the difference between ACoS and TACoS?
ACoS divides ad spend by ad-attributed sales. TACoS divides ad spend by total Amazon sales, including organic. TACoS shows how dependent the whole business is on advertising.
How do I calculate contribution margin on Amazon?
Revenue minus landed COGS, minus Amazon fees, storage and returns, minus ad spend. It is the part of revenue you actually keep.