ACoS, TACoS & ROAS Explained for Amazon Sellers
If Amazon advertising has an alphabet soup problem, this is it. ACoS, TACoS, and ROAS get thrown around as if they mean the same thing, but each answers a distinct question about your business. Confuse them and you'll make the wrong call on your budget. Here's what each one actually measures and the targets to aim for.
Try Helium 10 free — then save with our link
Start on the free plan and unlock member savings on Platinum & Diamond. Cancel anytime.
ACoS: the efficiency of your ads
ACoS — Advertising Cost of Sale — is ad spend divided by the sales those ads generated, shown as a percentage. Spend $15 to make $75 in ad sales and your ACoS is 20%. It answers one narrow question: how much of your ad revenue did you spend to earn it? Lower is more efficient, but lower isn't automatically better — a low ACoS with tiny sales volume may be leaving growth on the table.
ROAS: the same story, flipped
ROAS — Return on Ad Spend — is just ACoS turned upside down: ad revenue divided by ad spend, expressed as a ratio. That same campaign has a ROAS of 5, meaning $5 back for every $1 in. ACoS and ROAS describe the identical relationship; some sellers simply prefer thinking in a "return multiple" rather than a cost percentage.
TACoS: the whole-business view
TACoS — Total Advertising Cost of Sale — divides ad spend by total sales, both ad-driven and organic. This is the metric that reveals whether advertising is building a healthy business or propping up a dependent one. A falling TACoS over time means your organic sales are growing faster than your ad spend — exactly what you want. A rising TACoS means you're increasingly buying sales you used to get for free.
ACoS tells you if a campaign is efficient. TACoS tells you if your business is actually healthy.
The three metrics side by side
| Metric | Formula | Answers | Healthy signal |
|---|---|---|---|
| ACoS | Ad spend ÷ ad sales | Are my ads efficient? | Below your break-even margin |
| ROAS | Ad sales ÷ ad spend | What's my return multiple? | Above your break-even ratio |
| TACoS | Ad spend ÷ total sales | Is the business healthy? | Flat or trending down over time |
What targets should you aim for?
There's no universal number — your break-even ACoS is simply your profit margin before ads. If you net 30% margin, an ACoS above 30% loses money on that ad-driven sale, while anything below it is profit. For TACoS, many established sellers sit comfortably in the 8–15% range, but the direction matters more than the absolute figure.
Quick tip
During a launch, accept a high ACoS — even above break-even — to buy rank and reviews. Once you're ranking organically, tighten ACoS and watch TACoS fall as free sales take over.
A worked example
Say you sell a product for $40 with a 35% margin before advertising — that's your break-even ACoS. In a given month you spend $500 on ads and generate $2,000 in ad-attributed sales, for an ACoS of 25% (and a ROAS of 4). Because 25% sits comfortably under your 35% break-even, those ad sales are profitable. Now suppose your total sales that month, ads plus organic, were $5,000. Your TACoS is $500 ÷ $5,000, or 10%. Track that same 10% over several months: if it drifts down while sales climb, your organic engine is strengthening; if it creeps up, you're becoming more dependent on paid traffic.
Common mistakes with these metrics
- Chasing a zero ACoS: the lowest ACoS often comes from barely advertising at all, which stunts growth. Aim for profitable volume, not minimal spend.
- Ignoring TACoS entirely: a great ACoS can mask a business that's slowly losing organic rank — TACoS is what reveals it.
- Using list margin instead of true margin: if your break-even ACoS is based on a margin that ignores storage, returns, and PPC itself, every target you set will be wrong.
- Judging too soon: a few days of data is noise. Give campaigns enough conversions before reading their ACoS as truth.
Tracking them without spreadsheets
Amazon's console shows ACoS and ROAS but doesn't calculate TACoS for you, since it requires blending ad data with total sales. Helium 10's Adtomic surfaces all three together and trends them over time, while Profits ties your true net margin into the picture so you know your real break-even ACoS rather than guessing. Seeing the metrics side by side is what turns them from trivia into decisions.
How the metrics change as you grow
These numbers aren't static targets — they should evolve with your product's maturity. A brand-new listing will run a high ACoS and a high TACoS because you're buying almost every sale. As reviews accumulate and organic rank builds, both should trend down: your ACoS improves as your listing converts better, and your TACoS falls as free organic sales take a larger share of the total. Watching that downward drift over months is the clearest signal that your advertising is doing its real job — building a business that increasingly sells without paid help rather than one permanently dependent on it.
The bottom line
Use ACoS or ROAS to judge individual campaigns, and use TACoS to judge the business. Efficient ads that leave TACoS climbing quarter after quarter mean you're renting your sales; efficient ads with a falling TACoS mean you're building something that lasts.
Ready to put this into action?
Helium 10 gives you the tools in this guide in one dashboard. Start free through our link.