Advertising · chapter 05 / 06
ACoS, TACoS and campaign optimization
Daniel Pawłowski · Amazonway · 12 min czytania
Amazon advertising is managed by numbers. Without understanding ACoS, TACoS and break-even, even a large budget turns into a lottery. In this chapter of the Amazon advertising guide we explain the key metrics, show how to calculate a campaign's break-even, and give a concrete optimization process that lowers ACoS without choking sales.
What is ACoS
ACoS (Advertising Cost of Sales) is the share of ad spend in the revenue generated by that advertising. It is the core efficiency metric: it shows how many currency units of advertising each unit of ad-driven sales costs you.
ACoS = ad spend ÷ sales from ads × 100%
Example: you spend 200 on ads and generate 1000 in sales from them. ACoS = 200 ÷ 1000 × 100% = 20%. The lower the ACoS, the more efficient the campaign — but, as you will see, an ACoS that is too low can hold back growth.
ACoS vs TACoS vs ROAS
ACoS is not the only metric worth tracking. Two more show the bigger picture.
TACoS = ad spend ÷ TOTAL sales × 100%
TACoS relates ad spend to all sales (advertising and organic). It is the most important long-term indicator: when TACoS falls while sales grow, advertising is driving the flywheel and organic sales are taking over the load.
ROAS = sales from ads ÷ ad spend
ROAS is the inverse of ACoS expressed as a multiplier (ACoS 20% = ROAS 5.0). It is simply another view of the same relationship, more common outside Amazon.
Break-even ACoS — the profitability threshold
Break-even ACoS is the level at which advertising yields neither profit nor loss. It equals your margin before ad cost, expressed as a percentage of price. Above this threshold you lose money on the sale, below it you profit.
= (price − product, referral and FBA costs) ÷ price × 100%
Worked example: you sell a product for 100, and the product, Amazon referral fee and FBA logistics cost 70. Profit before advertising is 30, so break-even ACoS = 30 ÷ 100 × 100% = 30%. As long as ACoS is below 30%, every ad-driven sale is profitable; above it, you are subsidizing. This one number sets the whole campaign goal.
Target ACoS by goal
There is no single "good" ACoS — it depends on the goal. A deliberately higher ACoS at launch is an investment in ranking; a low ACoS on a mature product means focusing on profit.
| Goal | ACoS stance | Why |
|---|---|---|
| Product launch | High (even above break-even) | You are buying early sales, reviews and ranking |
| Growing share | Near break-even | Scale volume without loss |
| Maximizing profit | Low, below break-even | Mature product, margin matters |
| Defending position | Controlled | Keep visibility on a branded term |
How to optimize campaigns — the loop
Optimization is not a one-off task but a repeatable cycle. The best accounts run through it regularly, every 1–2 weeks.
The main levers each cycle: adjust bids (up on low-ACoS terms, down on expensive ones), raise the bid for the "top of search" placement, harvest and negate keywords from the search term report, and move budget to the best campaigns.
Do not optimize only for the lowest ACoS, or you will easily choke growth. Set TACoS as your main metric and watch its trend: if sales grow while TACoS falls, advertising is genuinely driving organic sales — even at a temporarily higher ACoS on individual campaigns. This is what separates scaling from cost-cutting.
A glossary of supporting metrics
ACoS and TACoS are the top-level indicators, but to know why a campaign works or not, read the metrics that make them up:
- CTR (click-through rate) — the share of clicks in impressions. A low CTR signals that the image, price or reviews do not earn the click.
- CVR (conversion rate) — the share of purchases in clicks. A low CVR with a good CTR means a problem on the listing, not the ad.
- CPC (cost per click) — the real auction price for a term; it rises with competition.
- RoAS — revenue per unit of spend (the inverse of ACoS as a multiplier).
The diagnosis is simple: a high ACoS with a low CTR is a creative/offer problem at the impression level; a high ACoS with a good CTR but low CVR is a listing problem; and a high ACoS with good CTR and CVR is usually too high a CPC, i.e. a bidding issue.
Dayparting and seasonality
Not every hour and not every week converts the same. Dayparting means adjusting bids to the times of day and days of week when your product sells best — for example raising budget in the evenings when customers buy, and cutting it in low-conversion hours. Seasonality works the same way: in shopping peaks (holidays, sales events) competition and CPC rise, so you deliberately raise budget and accept a higher ACoS to keep visibility at the most important time of year. Outside the peak you return to a profit stance. Planning budget to the rhythm of the season is one of the easiest things to miss when running campaigns yourself.
FAQ — ACoS and optimization
What ACoS is good?
The one that fits the goal. At launch you deliberately accept a high ACoS for ranking and reviews; on a mature product you target below break-even to profit. The reference is always your profitability threshold.
What is the difference between ACoS and TACoS?
ACoS measures spend against ad sales, TACoS against all sales. ACoS measures campaign efficiency, while TACoS shows whether advertising also drives organic sales.
How do I calculate the advertising break-even?
Break-even ACoS is your margin before advertising as a percentage of price: (price minus product, referral and FBA costs) divided by price. Below that ACoS you profit, above it you subsidize.
How often should I optimize campaigns?
Usually every 1–2 weeks, after fresh data comes in. Changing too often gives the algorithm no time to learn and makes results hard to judge.