Routes
KDP keywords: how to choose your seven
How Amazon's seven backend slots actually work, what belongs in them, and the wasted-slot mistakes almost every new publisher makes.
8 min read · Updated 24 July 2026
When you publish on Amazon KDP you get seven keyword slots, fifty characters each, hidden in the back end of your book's listing. They are one of the few levers you fully control over whether readers find your book — and most authors fill them badly, repeating their own title, stuffing single words, or leaving slots empty. This guide explains how KDP keywords actually behave, what to put in each slot, and how to research them without paying for a tool.
Keywords decide whether you are found; your royalty rate decides what each found reader is worth. The KDP royalty calculator below shows what a sale actually pays at your price and page count, so you can judge what better discoverability is worth to you. And because keywords can be edited at any time, nothing on this page is a one-shot decision — treat your seven as a setting to tune, not a form to survive.
KDP Royalty Calculator
Note ⊕Uses Amazon's published KDP paperback printing costs for the marketplace you pick (60% royalty on list price, minus print cost). Standard colour needs 72+ pages; shorter books are charged KDP's minimum for that ink. Comparing a print run? Try the KDP vs Short-Run Calculator.
Want the full tool? Open the KDP Royalty Calculator.
How the seven slots actually work
Each of the seven fields takes up to fifty characters, and Amazon indexes the words in them individually and in combination — a slot containing 'cozy small town mystery series' can help you surface for 'cozy mystery', 'small town mystery' and 'mystery series' alike. You do not need commas, and you should not waste characters on them: write natural phrases and let the combinations work.
Two behaviours follow from this. First, phrases beat single words: 'dragons' competes with every fantasy novel on Earth, while 'dragon rider academy romance' matches a reader who knows what they want. Second, order within a slot barely matters, but coverage across slots does — seven slots that each attack a different reader search beat seven variations of the same one.
What belongs in a keyword slot
Think in reader searches, not book descriptions. Readers search by trope ('enemies to lovers', 'found family'), by setting ('victorian london', 'small town montana'), by character type ('strong female lead', 'grumpy detective'), by mood ('feel good', 'dark'), by occasion ('beach read', 'book club'), and by audience ('teen', 'clean'). Your seven slots are seven chances to intercept a different one of those searches.
A useful drafting method: write down the ten phrases a stranger would type if your exact book was what they wanted but they did not know it existed. Keep the seven with real search behaviour behind them (the research method below), and spread them so no two slots chase the same query. Amazon's own guidance adds combinable extras like setting, character role and story tone — the categories of thought are public; the craft is in choosing specifics.
What is banned — and what is wasted
Amazon's rules prohibit: other authors' names or book titles (riding a competitor's brand can get a listing pulled), subjective quality claims ('best', 'great read'), temporary statements ('new', 'on sale'), anything misleading, and terms like 'free' or 'bestseller'. Violations risk more than the keyword — repeated abuse risks the listing itself, so the aggressive tricks in old KDP forums age badly.
Separate from the rules is the waste. Words in your title, subtitle and categories are already indexed, so spending slot characters on them buys nothing: a book called 'The Lighthouse Keeper's Daughter' gains nothing from the keyword 'lighthouse'. The same goes for irrelevant-but-popular terms — Amazon's algorithm optimises for purchases, so a keyword that attracts clicks which do not convert quietly stops helping you. Relevance is not just compliance; it is the mechanism.
A worked example: romance keywords
Romance is the clearest illustration because its readers search by trope more than any other genre's. Suppose you have written a small-town romance with a single-dad hero and a second-chance storyline. A weak keyword set repeats itself: 'romance novel', 'love story', 'romantic book' — three slots, one query, already covered by your category. A strong set intercepts distinct searches: 'small town romance', 'single dad romance', 'second chance love story', 'sweet clean romance', 'contemporary western romance', 'enemies to lovers', 'beach read for women'.
The same trope-first logic maps to every genre — fantasy readers search 'slow burn romantasy' and 'dragon shifter', thriller readers 'serial killer psychological thriller', cozy readers 'cat cozy mystery with recipes'. Genre vocabularies are living things: the search bar (next section) tells you which trope words readers use this year, not the ones from a five-year-old blog post.
Research keywords free with the search bar
Amazon's own search bar is a live keyword-research tool: it autocompletes with what real customers actually type, roughly ordered by popularity. Open an incognito window (so your own history does not colour it), set the department to Kindle Store or Books, and type your candidate phrases slowly — the suggestions that appear are demand, spelled out. Work the alphabet ('small town romance a…', 'b…') to widen a vein.
Then validate: search the phrase and look at the results. A good keyword shows books like yours, selling (check a few ranks), without a wall of thousand-review titans in the top rows. No results means no demand; wall-to-wall bestsellers means you will not be seen. Paid tools automate this loop, but the manual version costs an evening and teaches you your niche's vocabulary — which pays again when you write the blurb.
Keywords vs categories — and iterating after launch
Keywords and categories are different systems. Categories are the browse tree — you pick up to three in KDP, and they decide which bestseller lists you can chart on. Choosing a specific, less-crowded category ('Romance > Clean & Wholesome > Western') gives a new book a realistic path to an orange bestseller tag; parking in 'Romance' gives it none. Keywords, by contrast, decide search; the two work together but do not overlap.
Both are editable forever, so treat launch as the first experiment: check which searches you surface for, watch whether impressions convert, and swap your weakest slot monthly rather than annually. Keywords put eyes on the listing — what converts those eyes is the package around it, which is why the cover, blurb and route decision are the other half of every keyword strategy.
Common questions
- What are KDP keywords?
- Seven backend fields, up to fifty characters each, that you set when publishing on Amazon KDP. Amazon indexes their words individually and in combination to decide which customer searches your book appears in. Readers never see them — they are targeting, not copy.
- How many keywords does Amazon KDP allow?
- Seven slots of up to fifty characters. Because Amazon combines the words within a slot, each slot holds a phrase-cluster rather than one keyword — seven well-chosen phrases can cover dozens of distinct reader searches.
- Should I use single words or phrases as KDP keywords?
- Phrases. Single words are both too competitive and usually already covered by your title and category. A phrase like 'second chance small town romance' intercepts a specific reader intent and combines internally into several searches at once.
- What keywords are not allowed on KDP?
- Other authors' names or book titles, subjective claims like 'best', temporary statements like 'new' or 'on sale', 'free', 'bestseller', and anything misleading about the book's content. Beyond breaking rules, irrelevant keywords also backfire naturally — clicks that don't convert teach the algorithm to stop showing you.
- Can I change my KDP keywords after publishing?
- Yes, at any time, from your KDP bookshelf, with no penalty — changes take effect within a day or so. Treat them as a dial: review which searches you appear in, replace the weakest slot, and iterate monthly in the early months.
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