Royalty Lens - Book Market Research

Rank, estimated sales, royalty maths, publisher type and problem-solving title scores, shown inline while you browse book listings.

Royalty Lens adds the numbers you actually need to judge a book market, right on the listings you are already looking at. For every book it shows: - Best Sellers Rank, read directly from the product page - Estimated sales per day, from a log-log curve fitted to published rank data - Estimated royalty per day, using KDP US maths: 60% of list price minus the real print cost for that page count and format, or the 70%/35% Kindle bands - Whether the publisher is self-published, a small press, or a major house - A 0-100 "problem-solver" score for the title and subtitle - A composite opportunity score, with a full breakdown you can inspect WHY THE PUBLISHER LABEL MATTERS Applying self-publishing royalty maths to a book from a major publishing house produces a meaningless number. Other tools show it anyway. Royalty Lens labels the publisher and shows "n/a" instead, which is also more useful, because a self-published competitor is the one whose success you could actually repeat. PROBLEM-SOLVING TITLE ANALYSIS Non-fiction that sells names a pain and promises a specific outcome to a specific person. Royalty Lens scores every title against five signal groups: instructional framing, outcome verbs, named pains, a specific audience, and numbers or timeboxes. It then shows you exactly which phrases fired and what each one was worth, so you can disagree with the score instead of trusting it. Fiction, memoir, poetry and journals are detected and scored down, because none of that framing applies to them. FIND NICHES, NOT JUST BOOKS You do not have to know what to search for. Open a Best Sellers in Books page and Royalty Lens reads the subcategory list, then crawls each one and ranks whole categories by how much money is realistically reachable in them. It measures earnings at list position 20, not position 1. You are unlikely to beat a category champion; position 20 is roughly where a competent new book lands, so that is the honest answer to what a category is worth to you. EVERYTHING STAYS ON YOUR MACHINE No account. No sign-up. No server. Royalty Lens has no backend at all. Every figure is computed in your browser and stored in local extension storage. Nothing is collected, transmitted, sold or shared. Export your results to CSV whenever you want them elsewhere. BUILT TO BE POLITE Rank lookups are lazy, so a listing is only looked up once you actually scroll to it. They are throttled to two at a time with random delays, capped per page, cached for 12 hours, and stopped automatically if the site asks for a robot check. HONEST ABOUT WHAT IT KNOWS Sales and royalty figures are estimates derived from public rank data. No retailer publishes per-book sales, so every tool in this category, including this one, is inferring. Royalty Lens shows its working, widens its uncertainty band at deeper ranks where the data is noisier, and tells you when it does not know something instead of filling the gap with a confident-looking number. Royalty Lens is an independent tool. It is not affiliated with, endorsed by, or sponsored by Amazon.com, Inc.