ACoS(Advertising Cost of Sales)
Also called: Advertising Cost of Sales, ad spend ratio
Definition
ACoS (Advertising Cost of Sales) is the Amazon Ads metric showing ad spend divided by ad-attributed sales revenue, expressed as a percentage. An ACoS of 30% means the publisher spent $30 in ads for every $100 of ad-attributed sales. For an 8.5 x 11 KDP coloring book of up to 50 designs, break-even ACoS runs from about 32% at $9.99 to about 41% at $14.99, and falls to about 14% below the $9.99 royalty cliff.
What is ACoS in Amazon Ads?
ACoS is the headline efficiency metric for Amazon Sponsored Products and Sponsored Brands campaigns. The formula is total ad spend divided by total ad-attributed sales, multiplied by 100 for percentage. An ACoS of 20% means 20 cents of ad spend per dollar of sales credited to ads.
What is a good ACoS for a coloring book?
For an 8.5 x 11 KDP coloring book priced at $9.99 with a 60% royalty and a $2.84 print cost, the publisher earns about $3.15 per sale. Break-even ACoS is around 32% on that book. A "good" ACoS is anything materially under break-even with stable conversion; campaigns at 15 to 25% ACoS are profitable, while anything above about 32% loses money on every ad-driven sale.
How does ACoS relate to TACoS?
ACoS only measures ad-attributed sales. TACoS (Total ACoS) divides ad spend by total sales, including organic. A book with healthy organic sales can show high ACoS (because most sales are not ad-attributed) but a low TACoS (because the ad spend is a small share of total revenue). TACoS is the better north-star metric.
Why do new ad campaigns start at high ACoS?
Amazon's ad auction needs data to learn which keywords convert for a given book. New campaigns typically run at 60 to 100%+ ACoS for the first 7 to 14 days while Amazon explores the keyword space. The right move is to let the campaign collect 30 to 50 clicks per keyword before pruning underperformers, not to pause early on day-1 ACoS.
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Related terms
BSR
BSR (Best Sellers Rank) is Amazon's hourly-updated rank of every product against all others in its top-level store. For KDP coloring books, BSR sits in the Books store and approximates how recently a book sold. Lower number means more recent sales. BSR of 100,000 in Books equals roughly 2 to 3 sales per day.
KDP keyword
KDP gives every published title 7 keyword slots, each up to 50 characters, used by Amazon search to match queries to books. For coloring books, the slots should hold long-tail buyer queries ("coloring book for adults stress relief animals") not single words. Title, subtitle, and category placement also feed search but the 7 slots are the dedicated backend lever.
Royalty cliff
The royalty cliff is the jump in KDP paperback royalty at $9.99 on Amazon.com. Standard distribution pays 50% of the list price below $9.99 and 60% at $9.99 or above, minus print cost either way, so one cent from $9.98 to $9.99 adds about $1.00 per sale.