Amazon Ads glossary for authors
The terms you'll meet in the Amazon Ads console and KDP reports, in plain English.
- ACoS (advertising cost of sales)
- Ad spend divided by attributed sales. $30 of spend for $60 of sales is 50% ACoS. It ignores Kindle Unlimited page reads and later books in a series. Learn more
- ACoR (advertising cost of royalties)
- Ad spend divided by the royalties you keep from attributed sales. For a 70% royalty book, ACoR is about 1.43 × ACoS. Learn more
- True ACoS
- Ad spend divided by every royalty the ads earned: sale royalties, KU page reads and later-book royalties from read-through. Under 100% means the ads pay for themselves. Try the analyzer
- ROAS (return on ad spend)
- Attributed sales divided by ad spend. The inverse of ACoS: 50% ACoS is 2.0x ROAS. Learn more
- Break-even ACoS
- The ACoS at which ads earn back exactly what they cost. For a single book it's the royalty rate; for a KU series it's much higher once page reads and read-through count. Learn more
- KENP (Kindle Edition Normalized Pages)
- Amazon's standard page count for Kindle Unlimited reads. Authors are paid per KENP page read. Learn more
- KENPC
- The KENP page count of a whole book. A full read pays KENPC × the month's KENP rate. Shown on the book's Promote and Advertise page in KDP. Learn more
- KENP rate
- What Kindle Unlimited pays per page read in a month: the KDP Select Global Fund divided by all pages read. It changes monthly. Learn more
- KDP Select Global Fund
- The monthly pool Amazon pays Kindle Unlimited authors from, divided across all pages read. Learn more
- Read-through
- The share of readers of one book who go on to read the next. 45% read-through to book 2 means 45 of every 100 book 1 readers read book 2. Learn more
- Search term (customer search term)
- What a shopper actually typed before clicking your ad. One keyword can match many search terms. Learn more
- Targeting
- What you bid on: a keyword, a product (ASIN) or an auto-campaign group. Bids are set on targets, not search terms. Learn more
- Match type
- How closely a search must match a keyword: broad (loosest), phrase (contains the phrase in order) or exact (the same words, allowing close variants). Learn more
- Negative keyword
- A word or phrase that stops your ad showing for searches containing it. Negative exact blocks one search; negative phrase blocks any search containing the phrase. Learn more
- Product targeting (ASIN targeting)
- Showing your ad on specific book pages. Search terms that look like B0XXXXXXXX in your report come from product pages. Learn more
- Auto campaign
- A campaign where Amazon picks the searches and pages, grouped as close match, loose match, substitutes and complements. Good for finding new search terms. Learn more
- Harvesting
- Moving a search term that converts in an auto, broad or phrase campaign into its own exact keyword so you control its bid. Try the analyzer
- CPC (cost per click)
- What you paid for a click. You set a maximum (your bid); Amazon's auction decides the actual price. Learn more
- Attribution window
- How long after a click a sale or page read counts toward the ad: shown as 7 day or 14 day in report column names. Learn more