Plain-English guides to the numbers behind book ads: what they mean, and what to do about them.
ACOS (advertising cost of sales) is your ad spend divided by the sales those ads brought in, as a percentage. Spend $30 to make $100 in ad sales and your ACOS is 30%. For a book, the ACOS you can afford depends on your royalty: above your break-even ACOS, every ad sale loses money unless read-through makes it back.
Plain-English guides for authors running Amazon book ads: keywords, bids, search terms, seasons and the numbers behind them.
One order is as good as three, the search term’s ACOS predicts nothing, and most keywords that sell do it within a few clicks.
8 min readDrop in your search term report: the searches to promote, the ones to negate, and a starting bid for each. Runs in your browser.
5 min readOne, two, three, four to ten, eleven or more: what each level produced as a keyword, and whether the new keyword adds sales or moves them.
10 min readYour first campaign, a budget and bid worked out from your royalty, and what to do with the results.
8 min readWhere keywords that sell come from, how they differ from KDP’s seven boxes, and when to judge one.
6 min readPromote the searches that sell to exact match, negate the ones that don’t, and stop bidding against yourself.
5 min readYour royalty per sale with 2026 print costs, plus the break-even ACOS and bid it allows.
5 min readThe exact paperback cover size for your trim, page count and paper, in inches, millimetres and pixels.
4 min readResearch tools, bid managers and seller software compared by job, price and whether they work for books.
6 min readWhen to raise budgets and bids, which keywords to switch back on, and the Q4 mistakes that cost most.
5 min readWhy a Kindle Unlimited book can look unprofitable on ACOS and still make money, with the maths.
4 min readWhy price decides whether ads can work at all, and how to advertise books people buy as gifts.
4 min readPrice, features and what it cannot do for your ads — and when KDSpy, BookBeam or your own data are enough.
4 min readWhat each report counts, the five reasons they disagree, and how to put them together into one true picture.
4 min readWhat agencies, courses and software cost, and the ad spend at which each one starts to pay for itself.
5 min readHow the auction works, what a click costs, and how to set a first bid from your royalty.
5 min readACOS and ROAS are the same fact written two ways. TACOS is a different fact entirely.
4 min readWhat each paper allows, how it changes the spine, and which books suit which — plus the new groundwood option.
3 min readGet found, turn visits into sales, and use ads for the part you can control — in that order.
4 min readWhat a sale earns, how many sales it takes to pay back your costs, and who does well on KDP.
4 min readKindle Unlimited, the promotion tools and the price of exclusivity — and how Select changes the maths of your ads.
4 min readWhat Kindle Direct Publishing is, what it costs, what it pays, and what you need to publish your first book.
4 min readFrom a KDP account to a live book: files, details, ISBN, pricing, review times and your first proof.
4 min readWhat KDP charges (nothing), what printing costs come out of each sale, and the optional costs that matter.
3 min readWhat Author Central does, how to claim your books, and why a finished author page helps every ad you run.
3 min readWhat they cost, how many you can order, what you can do with them, and why neither counts as a sale.
3 min readHow BSR is calculated, how often it updates, what it can and cannot tell you, and how ads move it.
3 min readHow many clicks book keywords took to make their first sale, and a rule for pausing that does not throw winners away.
5 min readWhy cutting bids rarely fixes a high ACOS, and the levers that move it: placements, negatives and where the budget goes.
4 min readConversion by match type and placement from 250,000 book-ad clicks, and how your own rate sets your bid.
4 min readWhat you bid on versus what shoppers typed, why they differ, and how to turn search terms into keywords.
4 min readWhen ads pay for a book and when they cannot, what the clicks of a real catalogue show, and how to run a fair test.
4 min readCampaign structure, match types, placements and a weekly routine, each step checked against 250,000 clicks of book ads.
6 min readHow pay-per-click works on Amazon, the ad types authors can use, bidding strategies, and why some ads never spend.
5 min readSign in with Amazon and see ACOS for every campaign and keyword, up to 10 periods side by side, from up to 24 months of your own history. Start free, no card needed.