What Is a Good ACoS on Amazon? (It Depends on One Number)

"What's a good ACoS?" is the most common question in Amazon PPC, and every generic answer — "aim for 20–30%" — is wrong for roughly half the people who hear it.

A good ACoS is any ACoS below your break-even ACoS. That's it. Everything else is context.

The one number: break-even ACoS

Break-even ACoS is your profit margin before ad spend:

(price − COGS − Amazon fees) ÷ price × 100

Say you sell at $29.99, your unit cost is $7.50, and Amazon takes $10.00 in referral + FBA fees. You keep $12.49 — a 41.6% margin. That's your break-even ACoS. Run ads at 41.6% and every ad-attributed sale nets exactly zero. (Calculate yours here.)

Now the generic advice falls apart in both directions:

Same ACoS. Three completely different businesses.

That table isn't hypothetical. I've seen all three scenarios in the same week across different accounts. A supplement brand at 55% margin can run a 35% ACoS and bank real profit on every ad-attributed sale. A household accessory at $18.99 with a 21% margin hits the wall at 21% — not a cent above it. A $29 kitchen gadget in a crowded sub-category might land at 28% after Amazon's referral and FBA fees eat into the price point. Blanket advice applies to none of them.

I manage 500+ campaigns across six brands. The first question on every account review is the same: what's your current break-even, and has it changed since we last checked? COGS creep, referral fee adjustments, and price moves all shift the number. ACoS targets need to move with them.

Why category averages mislead

Published benchmarks — "home and kitchen averages 28%", "supplements average 31%" — are calculated across accounts with wildly different margin profiles. A seller with a 55% margin in supplements pulls the average down. A seller at 22% pulls it up. The average tells you what the category spent, not what was profitable.

The only benchmark that matters is your break-even. If the industry average is 30% and your margin is 22%, the industry average is a leak disguised as a target. If your margin is 50%, running at 30% means leaving efficiency on the table in markets where lower ACoS is achievable.

Benchmarking yourself against category averages is meaningful only if your margin matches the average seller's margin. It rarely does.

Setting a target ACoS

Break-even is a ceiling, not a target. I set target ACoS around 70% of break-even so each sale keeps meaningful profit after ads. On a 41.6% break-even, that's a ~29% target.

The whole account gets managed against it: keywords below target get budget, keywords between target and break-even get optimised, keywords above break-even with real click data get cut or restructured.

The 10-click rule applies before cutting anything. No term gets paused before it has ten clicks. Before ten clicks, conversion variance is too wide to separate signal from bad luck. After ten clicks with no sale, you have data — act on it.

ACoS across the product lifecycle

The right ACoS target shifts as a product matures. Running the same settings from launch through year two is one of the more expensive mistakes I see on accounts.

Launch. Priority is velocity, not efficiency. I run at or near break-even for a defined window — four to six weeks on most products — to build keyword rank through sales volume. Running a 38% ACoS on a 38% break-even product is deliberate if the goal is rank. The plan has a close date.

Growth. Once rank stabilises on core terms, I pull ACoS back toward the 70%-of-break-even target. Budget shifts toward proven exact-match terms. Broad and auto campaigns run with tighter bid caps and serve mainly as research — generating a list of converting search terms to harvest into dedicated campaigns.

Maturity. The account has enough history to know which terms convert at margin. Those get protected and bid up. Terms with ten or more clicks and no sale get bid reductions or cuts. The focus moves from building rank to defending it efficiently.

The mistake I see most often is running growth-phase settings indefinitely on a mature product — holding ACoS at break-even and calling it normal. The number might not look alarming in a dashboard view. But month after month, it means zero profit on every ad-driven sale.

When a "bad" ACoS is the right call

The exception that matters: launch. Amazon's flywheel rewards sales velocity with organic rank. During a launch window, deliberately running at or even slightly above break-even buys rank that keeps paying after you throttle back.

The difference between strategy and a leak is that strategy has an exit date. "We run at break-even for six weeks to establish rank, then tighten to target" is a plan. "Our ACoS has been 45% for a year and we're not sure why" is a leak.

What to do when ACoS is above break-even

If you're outside a deliberate launch window and ACoS is above break-even, there are usually three causes: structure, targeting, or product economics.

Structure is the most common. A single broad campaign bleeding spend into mismatched search terms can drag an entire account's ACoS above target. Pull the search term report. Find where spend actually landed versus where you aimed it. The answer is usually obvious once you look.

Targeting comes second. Running broad or auto traffic on a product with no conversion history yet funds discovery for Amazon without capturing the sale. Tighten to exact and phrase match on terms with proven conversion data. Use broad and auto for research, with tight negative lists pulling out irrelevant traffic as it appears.

Product economics is the hard one. Some products have margins that make profitable PPC structurally impossible — not a campaign problem, a unit economics problem. A 15% margin product cannot sustain Amazon ads in most categories. Either raise the price, reduce COGS, or treat ads strictly as a temporary rank-building tool with a plan to pull back and ride organic. If the unit economics do not support a break-even ACoS, the problem is not the campaign structure.

TACoS: the number your ACoS hides

ACoS only measures ad-attributed sales. TACoS (total ACoS) divides ad spend by total revenue — ads plus organic. A healthy account shows TACoS trending down over time as ad-driven rank compounds into organic volume, even while ACoS holds steady.

Here is what it looks like in practice. One brand I managed January through August 2024 generated $234,583 in ad-attributed sales on $55,746 in spend — 23.76% ACoS, 4.21 ROAS. The break-even ACoS on the flagship product sat at 38%. Target was roughly 26%. Running at 23.76% meant every ad-attributed sale kept meaningful margin. But the more useful read was TACoS — because organic volume built consistently across those eight months, total ad spend as a share of all revenue tracked well below ACoS. That spread between ACoS and TACoS is the proof that ad spend was compounding into organic rank, not just subsidising individual clicks.

If TACoS is flat or climbing after months of spend, ads are not building anything — they are a treadmill. That is usually a structure problem, and structure is fixable.

Not sure which side of the line your account is on? The free audit answers exactly that — wasted spend, ACoS versus your real break-even, and the three highest-leverage fixes, sent as a short video.