KDP Keyword Byte Counter
Amazon measures each of your 7 keyword slots in bytes, not characters — and an over-long box may be ignored entirely. Paste your keywords to count them the way Amazon does and catch the problems that quietly cost you rank. Free, no signup.
50 bytes is not 50 characters
Each of KDP's seven keyword boxes accepts up to 50 bytes. For plain English letters a byte and a character are the same thing — but the moment a keyword contains an accented letter, a curly apostrophe, or any non-Latin script, characters start costing two or more bytes each. "café noir mystère" is 17 characters and 19 bytes. Paste from a word processor and a single smart quote can silently push a box over.
Going over doesn't truncate gracefully: an over-limit box may simply be ignored, taking every keyword in it out of the index. This checker also flags things Amazon's own guidelines tell you not to spend bytes on — subjective claims like "bestseller", words already indexed from your title and author name, the same word repeated across slots (the seven boxes are indexed as one pool), and punctuation, which Amazon treats as a space anyway.
Keyword questions, answered.
How long can Amazon KDP keywords be?
Each of the 7 keyword slots holds up to 50 bytes. For plain English text that is 50 characters, but accented letters and non-Latin scripts use 2 or more bytes per character, so "50 characters" is only true for ASCII. This counter measures your keywords in bytes, exactly as Amazon does.
What happens if a KDP keyword slot is over 50 bytes?
Amazon may ignore the whole box rather than truncating it, which silently removes every keyword in that slot from the search index. Trim the slot below 50 bytes and republish.
Should I use commas between KDP keywords?
No. Amazon separates keywords on spaces, so commas, semicolons, and quotes just burn bytes without adding anything. Write a natural string of search words, separated by single spaces.
Can I repeat a word in two different keyword slots?
You can, but it is wasted space — the seven boxes are indexed together as one pool, so a word only needs to appear once across all of them. Every repeated word is bytes you could have spent on a new search term.
Are words like "bestseller" or "free" allowed in KDP keywords?
KDP's guidelines prohibit subjective or time-sensitive claims (bestselling, award-winning, new, free, on sale) and information that belongs elsewhere, like "ebook" or "kindle". Amazon can suppress a listing over it, and those words do not help you rank anyway.
Inside Pendrilo, keywords live next to your book — 7 tracked slots with the same byte math, verdicts on what's working, and check-in reminders so a listing never goes stale. The free tier includes a full book, no credit card needed.
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