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ROAS Calculator

Calculate return on ad spend (ROAS) for your book ads, convert it to ACOS, and compare it with your break-even ROAS.

Your Inputs

$

Sales your ad report credits to ads.

$
$
$

Both are needed for break-even ROAS.

Your Results

ROAS
4.00x
$600.00 sales from $150.00 spend
Equivalent ACOS
25%
Ad spend ÷ ad revenue
Break-even ROAS
3.00x
Book price ÷ royalty per sale
Pass: Profitable

Your ROAS is above your break-even ROAS, so ad-driven sales earn more royalty than the ads cost.

About the ROAS Calculator

ROAS, return on ad spend, tells you how many dollars of sales each dollar of advertising produced. A ROAS of 4.00x means $4 of ad-attributed sales for every $1 spent. It is the same information as ACOS, just turned upside down: ACOS is spend divided by sales, ROAS is sales divided by spend.

As with ACOS, a high ROAS is not automatically profitable for a book, because Amazon reports sales at list price and you only keep your royalty. Your break-even ROAS is your book price divided by your royalty per sale. A $14.99 paperback earning $4.99 needs a ROAS of about 3.00x just to cover its ads. A $4.99 eBook earning about $3.40 needs only about 1.47x.

Enter ad revenue and ad spend for ROAS and the equivalent ACOS. Add your book price and royalty to see break-even ROAS and a clear profitable or unprofitable status.

How It Works

ROAS is ad revenue divided by ad spend, shown as a multiple such as 4.00x.

Equivalent ACOS is ad spend divided by ad revenue, the inverse of ROAS.

Break-even ROAS is your book price divided by your royalty per sale. A ROAS above that number means the royalty from ad sales covers the ad spend.

Formula

ROAS
ROAS = Ad revenue ÷ Ad spend
Equivalent ACOS
ACOS = Ad spend ÷ Ad revenue = 1 ÷ ROAS
Break-even ROAS
Break-even ROAS = Book price ÷ Royalty per sale

Example

$600 in ad sales from $150 spend, $14.99 paperback earning $4.99 per sale

  1. ROAS: $600 ÷ $150 = 4.00x.
  2. Equivalent ACOS: $150 ÷ $600 = 25.00%.
  3. Break-even ROAS: $14.99 ÷ $4.99 = 3.00x.

A 4.00x ROAS is above the 3.00x break-even, so the ads are profitable for this book.

Important Notes

  • Ad revenue is sales at list price as reported by Amazon Ads, not your royalty.
  • Kindle Unlimited page reads are not included in ad revenue.
  • Break-even ROAS assumes one price and royalty. Use blended figures if ads sell several formats.
  • Recent ROAS can rise for several days as late-attributed orders arrive.

Frequently Asked Questions

Is a ROAS of 2x good for a book?

Only if your break-even ROAS is below 2x, which happens when your royalty is more than half of your list price, typical of 70% royalty eBooks. For most paperbacks, 2x is a loss.

How do I convert ROAS to ACOS?

Divide 1 by ROAS. A 4x ROAS is a 25% ACOS, and a 2.5x ROAS is a 40% ACOS. The calculator shows both.

Why does Amazon show ACOS but other platforms show ROAS?

They are two views of the same ratio. Amazon Ads leads with ACOS, while many other ad platforms lead with ROAS. Both rely on sales, not profit, so check them against your royalty.

What is a break-even ROAS?

The lowest ROAS at which royalties from ad sales cover the ad spend. It equals your price divided by your royalty, the inverse of your break-even ACOS.

Should I include page reads in ad revenue?

Amazon Ads does not, but you can estimate KU earnings and add them to get a fuller picture for KU-enrolled books. Keep the method consistent so comparisons stay fair.

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