ACoS and TACoS are the two ratios brand owners hear about most in Amazon advertising, and they are often confused. They answer different questions. ACoS tells you how efficient your ads are. TACoS tells you how dependent your whole business is on ads. Managing to only one of them is one of the most common reasons Amazon accounts stall.
What is ACoS?
ACoS stands for advertising cost of sales. It is your ad spend divided by the sales attributed to those ads, shown as a percentage.
ACoS = ad spend ÷ ad-attributed sales × 100
If you spend $1,000 on ads and Amazon attributes $4,000 of sales to them, your ACoS is 25%. ROAS, return on ad spend, is the inverse: $4,000 ÷ $1,000 = 4.0. An ACoS of 25% and a ROAS of 4.0 describe the same thing.
What is TACoS?
TACoS stands for total advertising cost of sales. It is your ad spend divided by your total sales, including organic sales that ads did not directly drive.
TACoS = ad spend ÷ total sales × 100
If you spend $1,000 on ads and your total sales are $10,000, your TACoS is 10%.
Why you need both
ACoS looks only at ad-attributed sales. It cannot see whether advertising is lifting your organic rank, or whether you are paying for sales you would have made anyway. TACoS adds that context. Together they tell a much fuller story:
- ACoS falling, TACoS falling: ads are getting more efficient and the business is less dependent on them. Usually healthy.
- ACoS rising, TACoS falling: you may be investing in ranking. Ads cost more per sale, but total sales grow faster. Often fine during launches.
- ACoS falling, TACoS rising: ads look efficient but organic sales are not growing. You may be harvesting branded searches you would have won anyway.
- ACoS rising, TACoS rising: spend is growing faster than the business. Time to investigate.
Break-even ACoS: the number that ties it to profit
Neither ratio means much without your margin. Break-even ACoS is your profit margin before advertising. If a product sells for $40 and your costs before ads (product cost, Amazon fees, shipping) are $26, your pre-ad profit is $14, or 35%. Any ACoS below 35% is profitable on ad-attributed sales; above it, each ad sale loses money.
You can calculate this with our free ACoS, TACoS and break-even ACoS calculator.
What is a good ACoS or TACoS?
There is no universal good number. It depends on margin, category competition, product lifecycle and goals. A launch product may run an ACoS above break-even on purpose to build rank. A mature product with strong organic sales might hold a low TACoS. What matters is that targets are set per product, based on margin and goal, and reviewed regularly.
Common mistakes
- Setting one ACoS target for the whole account regardless of margin.
- Cutting spend whenever ACoS rises, even during a deliberate ranking push.
- Celebrating low ACoS that comes mostly from branded searches.
- Ignoring TACoS entirely, so nobody notices organic sales slipping.
- Comparing ACoS across products with very different margins.
How we use them at CommerceKind
For every product we set a target based on margin and goal: launch, rank, profit or defense. We report ACoS, TACoS and ROAS weekly and explain changes in plain English. In one account on our Amazon PPC page, ACoS fell from 25.08% to 11.79% while ad sales grew from $14,304.05 to $28,911.90. That is efficiency and growth at the same time, which is the goal.
A simple monthly review
- Check break-even ACoS for each major product.
- Compare each product's ACoS to its break-even and goal.
- Check account TACoS trend over three months.
- Look at branded vs non-branded spend share.
- Decide where to push, hold or pull back.
Advanced: segmenting ACoS by campaign purpose
An account-level ACoS mixes very different activities. Branded campaigns usually show very low ACoS because shoppers were already looking for you. Competitor-targeting campaigns usually run higher because you are winning shoppers from someone else. Launch campaigns may run above break-even deliberately. If you report one blended number, the efficient branded campaigns hide the expensive ones, and you cannot tell which activity is actually working. Split reporting by campaign purpose and judge each against its own target.
Where TACoS can mislead
TACoS is not perfect either. If total sales rise because of a price cut, a viral TikTok video or a competitor stocking out, TACoS falls even though nothing changed in your ads. If you raise prices, TACoS may rise. Always read TACoS next to what else happened in the business that month.
Want a second opinion on your targets? Our free audit reviews ACoS, TACoS and break-even by product. See also our guide to choosing an Amazon PPC agency.
Worked example: two products, one account
Imagine an account with two products. Product A sells for $30 with $18 in costs before ads, so its break-even ACoS is 40%. Product B sells for $50 with $40 in costs, so its break-even ACoS is 20%. An account-wide target of 30% ACoS would leave money on the table for Product A, where you could afford to bid harder, and would lose money on Product B, where 30% is well above break-even. Per-product targets fix this immediately.
How ACoS and TACoS change through a product's life
- Launch: ACoS often runs above break-even on purpose to build rank and reviews. TACoS is high because organic sales are still small.
- Growth: as rank improves, organic sales grow and TACoS starts to fall, even if ACoS holds steady.
- Maturity: ACoS should sit comfortably below break-even, and TACoS should be stable. Ads defend rank and capture incremental demand.
- Decline or heavy competition: watch for TACoS creeping up as organic sales slip; it is an early warning.
Questions to ask your agency about these metrics
- What is the break-even ACoS for each of our main products?
- What target have you set for each product, and why?
- How has TACoS trended over the last three months?
- How much of our ad spend goes to branded searches?
- What would you change if TACoS rose next month?
A good agency answers these quickly and specifically. If the answers are vague, the targets probably are too.
Key takeaways
- ACoS tells you if ad sales are profitable; TACoS tells you if ads are growing the whole business.
- Set ACoS targets per product from real margins, never one account-wide number.
- A falling TACoS with steady sales usually means organic growth is working.
- Separate branded and non-branded spend before judging efficiency.
- Review both metrics monthly, alongside rank and conversion rate.
Frequently asked questions
Is a lower ACoS always better?
No. A very low ACoS can mean you are bidding too cautiously and missing profitable sales. The right ACoS is the one that meets your profit and growth goals for each product.
How often should targets change?
Review them monthly, and whenever costs, prices or fees change, since each of those moves break-even.