Key takeaways
- **What Is ACoS:** Use this guide to decide what to fix first, what can wait, and how the work should support measurable growth.
ACoS, or Advertising Cost of Sales, is the percentage of ad-driven revenue you spent on advertising. Divide ad spend by ad sales and multiply by 100. Spend 200 dollars to generate 1,000 dollars in ad sales and your ACoS is 20 percent. It is the metric Amazon sellers use to judge whether a campaign pays for itself.
ACoS is the inverse of return on ad spend. A 20 percent ACoS equals a 5.0 ROAS, because 1,000 divided by 200 is 5. Sellers use ACoS because it maps directly onto margin: if a product earns 35 percent gross margin, you can see at a glance whether a 25 percent ACoS leaves profit or a 40 percent ACoS eats it. To keep ACoS in line as sales grow, our Amazon PPC agency manages it alongside the rest of your account.
The formula, worked out
The calculation has two inputs and one output.
- Ad spend: total dollars Amazon charged you for clicks in the period.
- Ad sales: revenue attributed to those ads within Amazon's attribution window, usually 7 days for Sponsored Products.
- ACoS equals ad spend divided by ad sales, times 100.
A concrete example:
| Input | Value |
|---|---|
| Ad spend | 150 |
| Ad sales | 600 |
| ACoS | 25% |
| Equivalent ROAS | 4.0 |
The one trap to avoid: ad sales counts only sales attributed to the ad, not your total store revenue. That distinction is exactly why TACoS exists.
Two more details change how you read the number. The attribution window matters. Sponsored Products reports on a 7 day window, so a click today can log a sale six days from now. That means a campaign you judge on Monday may look worse than it will by Friday. Wait for the window to close before you react. The second detail is ad type. Sponsored Products, Sponsored Brands, and Sponsored Display each report ACoS separately, and they do different jobs. A Sponsored Display retargeting campaign at 30 percent is not directly comparable to a Sponsored Products exact campaign at 18 percent. Compare like with like.
ACoS versus TACoS
ACoS measures ad efficiency in isolation. TACoS, Total Advertising Cost of Sales, measures ad spend against your total revenue, both ad-driven and organic.
- ACoS equals ad spend divided by ad sales.
- TACoS equals ad spend divided by total sales.
Why the second one matters: healthy advertising lifts organic sales, because ad-driven purchases improve your best-seller rank and organic ranking. If your ACoS holds at 25 percent but your TACoS falls from 12 percent to 8 percent over three months, your ads are doing their real job. They are pulling in organic sales you no longer pay for directly.
Watch both. ACoS tells you if a campaign is efficient. TACoS tells you if advertising is building the brand or just renting sales.
| Metric | Numerator | Denominator | Answers |
|---|---|---|---|
| ACoS | Ad spend | Ad sales | Is this campaign efficient? |
| TACoS | Ad spend | Total sales | Is advertising growing the business? |
A rising TACoS is not always bad. During a launch you expect it to climb, because you are spending hard to buy rank before organic sales catch up. What you want to see is TACoS peak and then fall as organic orders take over. A TACoS that keeps climbing month after month on a mature product is the warning sign. It means you are buying sales that used to come for free, often because a competitor moved on your keywords or your organic rank slipped.
Break-even ACoS sets your ceiling
Your break-even ACoS equals your gross profit margin before ad spend. If a product sells for 30 dollars and costs 18 dollars to make, land, and fulfill, your gross margin is 40 percent. That 40 percent is your break-even ACoS. Run at exactly 40 percent and advertising eats all your product profit. Run above it and you lose money on every ad sale.
- Product price: 30
- Cost of goods, fees, shipping: 18
- Gross margin: 40 percent
- Break-even ACoS: 40 percent
Every target you set lives below that ceiling. How far below depends on your goal.
Calculate this per product, not per account. A catalog with a 55 percent margin hero product and a 22 percent margin accessory has two very different ceilings, and a single account-wide target will overspend on one and starve the other. Include every cost that scales with the sale: referral fee, FBA fulfillment, inbound shipping, returns provision, and the landed cost of goods. Sellers who leave returns out of the math routinely set a break-even that is three or four points too high, then wonder why a campaign that reports profit still loses money at the bank.
What a good ACoS target looks like by goal
There is no single good ACoS. The right number depends on what a campaign is supposed to do.
- Launch or ranking goal: run at or slightly above break-even, sometimes 40 to 60 percent, on purpose. Early sales buy organic rank that pays back later. Losing a few points now to reach page one is a deliberate trade.
- Growth goal: run below break-even but not tight, often 25 to 35 percent, to capture market share while staying profitable on each sale.
- Profit goal: run well below break-even, often 10 to 20 percent, on mature keywords where you already hold organic rank and just want efficient incremental sales.
- Defensive branded goal: single digits, often 5 to 10 percent, because shoppers searching your brand name convert cheaply and you are mostly blocking competitors.
A mature account blends these. A branded keyword at 8 percent and a discovery keyword at 45 percent can average to a healthy 22 percent across the account.
Why your ACoS moves
ACoS is not one lever, it is the product of several. Understanding the drivers tells you where to act.
- Conversion rate: a listing that converts 12 percent of clicks earns twice the sales per click of one at 6 percent, cutting ACoS in half at the same bid. Listing quality is an ACoS lever.
- Cost per click: rising competition pushes CPC up and ACoS with it. Lower bids or better relevance pull it back.
- Average order value: bundles and higher-priced items spread the same click cost across more revenue.
- Keyword relevance: broad terms with weak intent convert poorly and inflate ACoS. Tight, intent-matched keywords do the opposite.
Because conversion rate sits inside the formula, fixing a product listing often lowers ACoS more than any bid change. Deciding your targets is the first step of any Amazon PPC strategy, and understanding the full cost picture helps too. See Amazon advertising cost for how CPC and spend build up.
How to lower ACoS without cutting sales
The instinct when ACoS climbs is to cut bids. That works, but it usually cuts sales at the same rate, so your ACoS holds and your revenue drops. Better moves attack the formula from the numerator and denominator at once.
- Add negative keywords. Terms that spend and never convert drag the whole campaign average up. Pull the search term report and negate the dead ones. This removes cost without removing a single sale.
- Fix the listing before the bid. Better main image, clearer title, more review volume, and a sharper price all lift conversion rate, which lowers ACoS at the same bid.
- Raise average order value. Add a bundle or a larger pack size so one click can produce a bigger sale.
- Move budget to placements that convert. If top of search converts at twice the rate of product pages, a placement modifier concentrates spend where sales happen.
Work these in order and you often pull ACoS down five to ten points while sales stay flat or grow. Blunt bid cuts almost never do that.
Reading ACoS in context
A number on its own means little. A 35 percent ACoS is excellent for a launch and alarming for a mature profit campaign. Always ask three questions before reacting: what is this campaign's goal, where does it sit against break-even, and which way is the trend moving over 30 days. A rising ACoS on a stable campaign signals a listing or competition problem worth investigating. A high ACoS on a two-week-old launch is simply the cost of gathering data.
If you are unsure how to set targets for your own margins, our Amazon PPC agency can map ACoS goals to your catalog with you.
Related terms
You may see this topic described with related searches like acos formula, acos marketing, acos vs roas, and tacos amazon. Those phrases are useful when they clarify what the reader needs next, but they should still point back to one clear plan.
How to lower ACoS without cutting sales
The reflex when ACoS climbs is to cut bids, but that often just trims sales and leaves efficiency flat. The durable moves work on the drivers inside the formula.
- Fix the listing first. Better main images, a clearer title, and stronger bullets raise conversion rate, and a higher conversion rate lowers ACoS at the same bid.
- Harvest and isolate winning search terms. Move proven converters out of broad and auto campaigns into exact-match ad groups where you can bid them precisely.
- Add negatives for terms that spend without selling. A weekly pass through the search term report keeps wasted clicks from dragging the average up.
- Trim placement bids where top of search converts no better than product pages, so you stop overpaying for a spot that does not earn it.
- Raise average order value with bundles or multipacks, which spreads the same click cost across more revenue.
Cutting bids is a last resort, used on keywords that convert poorly even after the listing and targeting are clean. On everything else, lifting conversion rate does more for ACoS than any bid change.
A worked example across a small catalog
Numbers make the targets concrete. Picture a seller with three products at different stages.
| Product | Stage | Break-even ACoS | Target ACoS | Why |
|---|---|---|---|---|
| Product A | Launch | 42% | 50% | Buying rank on purpose |
| Product B | Growth | 40% | 30% | Share while staying profitable |
| Product C | Mature | 38% | 15% | Efficient, holds organic rank |
Blend the three and the account might land near 28 percent even though one product runs above break-even. That blended number is the one to judge, not any single campaign in isolation. When Product A reaches page one, its target drops toward the growth band, and the account average falls with it without any product losing volume.
Frequently asked questions
What is a good ACoS on Amazon?
There is no universal number. A good ACoS is one that fits your margin and your goal. For a profit-focused campaign on a mature product, 10 to 20 percent is strong. For a launch buying organic rank, 40 to 60 percent can be correct. Always compare your ACoS to your break-even, which equals your gross margin.
Is a lower ACoS always better?
No. A very low ACoS often means you are underspending and leaving sales on the table. Pushing ACoS to single digits on a growth product can starve it of the volume that builds organic rank. The goal is the ACoS that maximizes profit dollars, not the lowest percentage.
How is ACoS different from ROAS?
They are two views of the same relationship. ACoS is ad spend divided by ad sales, expressed as a percentage. ROAS is ad sales divided by ad spend, expressed as a ratio. A 20 percent ACoS equals a 5.0 ROAS. Amazon sellers favor ACoS because it compares directly to profit margin.
Why is my ACoS going up?
Usually one of three things: cost per click rose because of more competition, your conversion rate fell because of a listing or pricing change, or you added broad keywords with weak intent. Check your search term report and placement report to see which driver moved, then act on that specific cause rather than cutting bids across the board.
What is the difference between ACoS and break-even ACoS?
ACoS is what a campaign actually spent as a share of its sales. Break-even ACoS is the ceiling, equal to your gross margin, where advertising exactly consumes your product profit. You compare the two to judge health. An ACoS of 25 percent is profitable against a 40 percent break-even and a loss against a 20 percent break-even. The number only means something next to your margin.
Does ACoS include organic sales?
No. ACoS uses ad sales only, meaning revenue Amazon attributes to a click within the reporting window. Organic sales that your ads may have helped create do not appear in ACoS. To see advertising's effect on total revenue, watch TACoS, which divides ad spend by all sales, ad-driven and organic together.
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In this guide, what is amazon ppc and how does it work points back to the practical work behind what is acos: what matters, what changes first, and how the result should be measured.
What is T-ACOs?
In this guide, what is t-acos points back to the practical work behind what is acos: what matters, what changes first, and how the result should be measured.