Blurb A/B TesterFree

How it works. All checks are simple text rules run in your browser, not a sales predictor. Only real readers (or an ad or cover test) can tell you which blurb sells better. Readability uses the Flesch Reading Ease and Flesch-Kincaid grade formulas with an estimated syllable count. Passive voice, adverbs (-ly words), power words and clichés come from small built-in lists, so expect a few misses. KDP descriptions are limited to 4,000 characters, and KDP counts HTML tags too (for example, <b></b> adds 7). The count here includes any tags you paste. KDP also doesn't accept reviews or quotes, requests for reviews, contact details or links, pricing or availability, time-sensitive info, or emojis in descriptions, so the checks flag the obvious cases.