ACoS (Advertising Cost of Sales) is ad spend divided by ad-attributed revenue — it measures how efficient a campaign or keyword is. TACoS (Total Advertising Cost of Sales) is ad spend divided by total revenue, organic included — it measures how your ad investment relates to the whole business. Use ACoS to tune campaigns; use TACoS to judge whether the brand is actually growing.
Two acronyms, one very expensive misunderstanding. Sellers obsess over ACoS because Amazon puts it front and centre — but optimising for a low ACoS is one of the most common ways to quietly cap a brand's growth. Here's what each number really tells you, and which one to manage to.
- ACoS = ad spend ÷ ad revenue. A campaign-level efficiency metric.
- TACoS = ad spend ÷ total revenue. A business-level health metric.
- A falling TACoS means ads are building organic rank. That's the goal.
- Chasing the lowest possible ACoS often means starving the campaigns that build rank.
What ACoS actually measures
- ACoS (Advertising Cost of Sales)
- Ad spend divided by the revenue those ads directly generated, shown as a percentage. £250 of spend producing £1,000 of ad sales is a 25% ACoS. It tells you how efficient a specific campaign, ad group or keyword is — nothing more.
ACoS is the right tool for a narrow job: comparing keywords and campaigns against each other and against your break-even point. Your break-even ACoS is your profit margin — the ACoS at which an ad-driven sale makes zero profit. Below it, ads are profitable in isolation; above it, that sale loses money on paper.
The trap is treating "below break-even ACoS" as the only definition of success. It ignores everything ads do beyond the click they're credited for.
What TACoS measures, and why it matters more
- TACoS (Total Advertising Cost of Sales)
- Ad spend divided by total revenue — organic plus advertising — as a percentage. £250 of spend against £2,500 of total sales is a 10% TACoS. It shows how dependent your revenue is on ads, and which direction that dependence is heading.
TACoS is the number that reveals the flywheel. When your ads drive sales velocity, Amazon lifts your organic rank, which brings free sales. If that's working, total revenue grows faster than ad spend — so TACoS falls over time even while you spend the same or more.
- TACoS falling: organic is compounding. Ads are building an asset. Healthy.
- TACoS flat: you're buying sales but not building rank. Sustainable, not scaling.
- TACoS rising: you're increasingly dependent on ads to hold revenue. Investigate.
Why chasing a low ACoS backfires
Cut spend on every keyword above break-even ACoS and your reported ACoS drops beautifully — the dashboard looks great. But you've just defunded the exact campaigns that were buying rank on high-value terms. Organic velocity fades, positions slip, and three months later total revenue is down while ACoS looks "efficient."
This is the core mistake: ACoS is a campaign metric being used as a business decision. A high-ACoS keyword that's dragging you onto page one is an investment, not a leak.
Which one to optimise for, by stage
- Launch: ignore ACoS almost entirely. Accept a high, even above-break-even ACoS to buy rank and reviews. Watch rank, not efficiency.
- Growth: manage individual campaigns by ACoS, but judge the account by TACoS trending down. That combination — efficient campaigns plus falling total dependence — is exactly what scaling looks like.
- Maturity: hold a stable, low TACoS and use ACoS to trim genuine waste.
If you only track one number on a wall, make it TACoS. It's the one that knows whether the business is growing. For the campaign structure that moves it in the right direction, see our Amazon PPC management guide.
Frequently asked questions
Is a lower ACoS always better?
No. A lower ACoS only means a campaign is more efficient in isolation — it says nothing about whether you're building organic rank or growing total revenue. Cutting every above-break-even keyword to lower ACoS often reduces the sales velocity that drives organic position, shrinking the business while the metric improves.
What is a good TACoS on Amazon?
It depends on category and stage, but many established brands sit in the 8–15% range, with the key signal being the trend. A TACoS that falls quarter over quarter means advertising is successfully building organic sales. A rising TACoS means growing reliance on ads and is worth diagnosing.
Should I use ACoS or TACoS to manage my ads?
Both, for different jobs. Use ACoS to optimise within the account — comparing keywords, setting bids, cutting genuine waste. Use TACoS to judge whether the overall advertising strategy is growing the brand. Managing only to ACoS is the classic way to stall.
Not sure which number to manage to?
We set ACoS and TACoS targets by stage and manage the ads to hit them. Get a free audit or book a call.