Amazon KDP ACoS Calculator

How to calculate ACoS?

Advertising Cost of Sales (ACoS) is a key metric used by KDP authors to measure the performance of their Amazon Advertising campaigns. It represents the ratio of ad spend to target sales, expressed as a percentage.

ACoS = (Ad Spend / Sales) x 100

Using the ACoS calculator: an example

Suppose you are running a Sponsored Products campaign for your paperback. Over the last 30 days, you spent $40 on clicks. Those clicks resulted in 20 book sales totaling $200 in revenue.

Step-by-step calculation

1. Identify the Spend: Total ad spend is $40.
2. Identify the Sales: Total sales from ads is $200.
3. Divide Spend by Sales: $40 / $200 = 0.20.
4. Calculate Percentage: 0.20 x 100 = 20%.

Frequently Asked Questions

What is a good ACoS for KDP?

A good ACoS is one that is lower than your net profit margin. If your royalty rate is 70% (after print/delivery costs), any ACoS under 70% means you are technically profitable on those ad-attributed sales.

How does royalty affect break-even ACoS?

Your royalty percentage directly defines your break-even point. If you earn $3.50 on a $5.00 ebook, your margin is 70%. Your break-even ACoS is therefore 70%. If your ACoS is 75%, you are losing money on each sale.

Should I focus only on ACoS?

No. While ACoS measures ad efficiency, you should also track Total ACoS (TACoS), which compares ad spend to total sales (organic + ads). A rising organic rank can justify a higher ACoS in the short term.