Advertising cost of sale (ACoS) and TACoS calculator
This ACoS calculator works out the advertising cost of sale for your campaigns: how much you spend on ads for each dollar of sales those ads bring in. It also gives TACoS (total advertising cost of sale), which compares the same spend with all your sales including organic ones, and your break-even ACoS from your margin.
It is built for Amazon sellers running sponsored ads and for authors using KDP ads, but the formula is the same wherever a platform reports ad sales. Nothing leaves your browser.
How to use the ACoS Calculator
- Enter your advertising spend and the ad sales the campaign report attributes to it.
- Enter total sales for the same period to get TACoS and the organic share.
- Enter your profit margin before ads. For KDP, use the royalty you earn divided by the list price.
- Set a target profit margin to see the highest ACoS you can run and still reach it.
ACoS Calculator features
ACoS and TACoS together
Ad-only efficiency next to the whole-business view, so rising organic sales show up.
Break-even ACoS
Equal to your margin before ads: above it each ad sale loses money.
Target ACoS
Margin minus the profit margin you want, to set bids and budgets.
ROAS equivalent
1 ÷ ACoS, handy when you compare with other ad channels.
The ACoS and TACoS formulas
ACoS = ad spend ÷ ad sales × 100. Spending $500 to get $2,000 of ad sales is an ACoS of 25%.
TACoS = ad spend ÷ total sales × 100. If total sales were $6,000, TACoS is 8.33%. When ads lift organic rank, TACoS falls even if ACoS stays flat.
Break-even ACoS = profit margin before ads. At a 35% margin, 35% is the most you can spend per sales dollar before the ad sale loses money. The target ACoS for a 15% profit is 35% − 15% = 20%.
Reading the numbers
A worked example: a book sells for $20 and earns a $7 royalty, a 35% margin. Ads cost $500 and bring $2,000 of sales, so ACoS is 25%, ten points under break-even, and the ad sales earn $200 after ads. If ACoS climbs to 45% the same campaign loses $200 on those sales. Compare with the ROAS calculator if you think in multiples, and find your margin with the marketplace seller profit calculator.
| Situation | What it usually means |
|---|---|
| ACoS under break-even | Ad sales are profitable on their own |
| ACoS over break-even, low TACoS | May be a launch or ranking investment if organic sales grow |
| ACoS over break-even, TACoS rising | Ads are losing money without lifting organic sales |
| ACoS very low | Likely room to raise bids and win more traffic |
Limits to keep in mind
- Ad sales are the platform’s attribution (often a 7- or 14-day window), so ACoS for a recent period can look better or worse than it finally is.
- Margin here is a single percentage; refunds, storage fees and overheads are not subtracted.
- KDP royalties differ by price, format and marketplace, so work out your royalty share per book first.
- The calculator is a planning aid, not advice.
ACoS Calculator FAQ
What does ACoS stand for?
Advertising cost of sale: advertising spend divided by the sales those ads generated, as a percentage. It has nothing to do with arccos, the inverse cosine on a scientific calculator.
What is a good ACoS on Amazon?
One at or below your break-even ACoS, which equals your margin before ads. A product with a 40% margin can run a 30% ACoS and still profit; one with a 20% margin cannot.
What is the difference between ACoS and TACoS?
ACoS divides ad spend by ad sales only; TACoS divides it by total sales, organic and paid. TACoS shows whether ads are building a business that sells without them.
How do I calculate ACoS for KDP?
Divide your KDP ad spend by the book sales revenue the ads produced. For break-even, your margin is the royalty per sale divided by the list price.
How is ACoS related to ROAS?
They are inverses: ROAS = 1 ÷ ACoS. An ACoS of 25% equals a ROAS of 4.
How do I lower my ACoS?
Raise conversion rate with better listings and prices, cut keywords that spend without selling, and lower bids on weak placements. Each step improves sales per click.