What are ACOS and TACOS?
Amazon advertising cost of sales, or ACOS, is ad spend divided by attributed ad revenue, expressed as a percentage. TACOS is commonly used by sellers to compare ad spend with total revenue, including both attributed and organic sales. ACOS describes advertising efficiency within attributed sales; TACOS adds a wider view of how advertising relates to total account sales.
How ACOS and ROAS relate
Amazon defines ACOS as ad spend divided by ad revenue. ROAS uses the inverse relationship: ad revenue divided by ad spend. Both describe the same spend and attributed-revenue relationship from different directions.
Neither metric is profit. They do not automatically subtract product cost, Amazon fees, fulfillment, returns, discounts, storage or business overhead.
- ACOS = ad spend divided by attributed ad revenue.
- ROAS = attributed ad revenue divided by ad spend.
- Lower ACOS is not always the correct objective.
- Attribution windows and campaign reports should be read consistently.
Estimate break-even ACOS from contribution margin
A simplified break-even ACOS can begin with the contribution margin available before advertising. If a product has little room after product cost, referral fees, fulfillment, shipping and expected returns, it cannot support aggressive ad spend without another strategic reason.
The calculation must use current per-unit economics. A percentage copied from another seller, category or product does not reveal whether your own campaign is sustainable.
Why campaign intent matters
A branded defense campaign, mature exact-match campaign, product launch, competitor campaign and discovery campaign can reasonably have different goals. Combining them into one target may hide useful search terms or protect inefficient spend.
Evaluate placement, targeting type, match type, search-term relevance, conversion evidence, inventory position and listing readiness before changing bids.
Use TACOS as a trend, not a promise
TACOS can help monitor the relationship between ad spend and total sales over time. A falling TACOS may accompany stronger organic sales, but it does not prove that advertising caused the change.
Compare consistent periods and account for seasonality, promotions, stockouts, price changes and catalog events. Short-term movements should not be treated as guaranteed ranking evidence.
Amazon PPC review checklist
- Calculate current contribution margin before advertising.
- Separate campaign objectives and product lifecycle stages.
- Review search terms, not only campaign averages.
- Check listing readiness, price, reviews and inventory context.
- Compare ACOS with break-even economics.
- Monitor TACOS across consistent periods.
- Document bid, budget and placement changes.
- Avoid judging a campaign before meaningful data is available.
Amazon PPC Management
Get structured campaign, search-term, bid and budget support aligned with listing readiness and product economics.
Vezon Digital Calculators
Model marketplace fees, margin, profit, ROI and break-even assumptions using editable inputs.
Official sources and further reading
Platform rules, fees and government requirements can change. Verify current information before acting.
Amazon ACOS and TACOS FAQs
What is a good Amazon ACOS?
A useful ACOS depends on contribution margin, campaign objective, product stage and growth strategy. There is no universal percentage that fits every product.
How is break-even ACOS calculated?
A simplified starting point is the contribution margin available before advertising divided by revenue. All included costs and tax assumptions should be documented.
Is TACOS an official Amazon Ads metric?
TACOS is widely used by sellers and service providers to compare ad spend with total sales. Confirm the exact data sources and time periods used in your calculation.
Does lower ACOS always mean better advertising?
No. Lower ACOS may reflect branded demand, conservative bids or limited reach. Profit, incrementality, inventory and campaign intent also matter.