For authors getting a book ready to sell
Book Blurb and Amazon Description Generator
Paste your synopsis or drop your manuscript. Get a back cover blurb, an Amazon description ready for KDP, a one-line pitch and an ad hook.
Free to start. No card needed.
How to write a book blurb by hand
Read a few back covers in your genre, then build yours one sentence at a time. Morgan Lee Clasper, a copywriter who says he has written 4,000 blurbs, gives each sentence a job1 in a guest post on publishing commentator Jane Friedman's site. In order: who this person is, what changed, what trouble they face and what happens if they fail. Stop there, while the outcome is in doubt. Developmental editor Jessi Rita Hoffman says most back covers fit 150 to 200 words at best2.
Lead with what your main character wants or fears, not a list of facts. Clasper's example trades "a retired FBI agent with PTSD" for "swore he'd never carry a gun again." His test for any detail: if it needs more than a few words of explanation, cut it. Name one main character, or both leads in a romance, and say the genre outright. At a 2018 BookExpo panel, Friedman heard a publisher's marketer admit her department had avoided calling a vampire book a vampire book3, and reader response was poor.
Then adapt it for your Amazon page, where a long description folds behind a Read more link. KDP suggests a 150-word paragraph4 of easy-to-scan sentences that opens on a line to draw readers in. Bold, italics, lists and small headings work, but their tags count toward the 4,000-character limit, so a bolded word costs 7 extra characters. KDP won't accept reviews or quotes, links, contact details, prices, time-sensitive information, spoilers, emojis or keyword lists. Review quotes can go in Author Central's Editorial Reviews section on Amazon.com.
Examples
Book blurb examples
Three short blurbs in three genres, each built the way River builds yours: a hook, someone to root for, the trouble, and a stop before the ending.
| Genre | Example blurb | What it does |
|---|---|---|
| Romance | She came home to sell the bakery. He's the only one buying. Twelve years ago, Nora Quinn left Larkspur Bay with a packed car and a broken engagement. Now her grandmother's bakery is hers, and the only offer comes from Cal Bishop, the man who chose the family boatyard over her. Cal needs the building. Nora needs the money. One month side by side should be simple. | Both leads, the second-chance trope and what each one wants, then a closing line that promises the romance without spoiling it. |
| Cozy mystery | When the judge of the Halden Maple Festival is found face down in a sugaring vat, the village blames the newcomer. Retired school librarian Agnes Pike knows better. Armed with forty years of overdue-book detective work and the best gossip network in Vermont, she starts asking the questions the state police won't. But every family in Halden has a secret buried under the snow. | The crime, the sleuth and why she can solve it, in a light tone that tells cozy readers this book is for them. The culprit stays hidden. |
| Fantasy | In Carrow, every debt is paid in years of your life, and Tamsin Roe has been paying off her father's for a decade. She has nine years left when the Ledger House offers a deal: steal one contract from the Queen's archive, and the debt is cleared. No one has ever broken into the archive. The last thief who tried is still paying. | One rule of the world, tied straight to what the heroine could lose, plus a job and a reason it might be impossible. |
Written for this page to show the shape. The books and authors are invented.
How it works
How River writes your book blurb and Amazon description
Start with whatever you have, from a few lines about your book to a synopsis, some chapters or the whole manuscript. River reads for what a blurb needs: your main character, the opening trouble, the stakes and the genre. It takes the tone, point of view and heat level from your pages instead of asking, and it never copies the manuscript into the doc. You get one copy sheet with four pieces: back cover copy, an Amazon description, a one-line pitch and an ad hook.
Each piece is sized for where it runs. The back cover gets 100 to 170 words under a bold hook line, leaving room for your bio (the author bio template has examples). The Amazon description runs 150 to 250 words for fiction, or up to about 300 with a short list for nonfiction, and shows its character count, formatting included. The pitch is one sentence of 30 words or fewer, and the ad hook stays under 150 characters.
River keeps the twist, the culprit and the ending out of every piece, and it never invents praise, awards, rankings or sales figures. If your text shows no clear conflict, the doc ends by asking what your main character wants and what stops them. From there, fill your KDP keywords, build the whole listing with Publish a Book on Amazon or start a query letter from the pitch. For the launch itself, the book launch template counts trade review deadlines back from your publication date.
How it works
From your book to four pieces
Paste what you have
Paste a few lines, your synopsis or chapter one, or drop in the whole manuscript file.
River finds the hook
It picks out your main character, the trouble, the stakes and the genre promise readers expect.
Get four pieces
Back cover copy, an Amazon description with its count, a one-line pitch and an ad hook, in one doc.
Paste and use
Paste the description into KDP, send the back cover to your designer, or ask River for other hooks.
Copy sheet · a locked-island thriller
- Back coverThe ferry company's books balance. That's the problem. Forensic accountant Isla Moncrieff comes home to bury her father and finds twenty years of payments to a boat that sank the night her mother drowned.
- Amazon description · 640 of 4,000 charactersThen a storm shuts down the ferry. For a week, no one can leave the island, and the man who signed those payments is sitting in the only pub.
- One-line pitchTrapped on her home island by a storm, a forensic accountant must prove who sank the boat that killed her mother before the man who signed the payments silences her.
- Ad hookHer father's books balance perfectly. That's how she knows someone lied.72/150
What you'll get
Back cover copy, an Amazon description, a one-line pitch and an ad hook
- Back cover copy sized for a paperback
- An Amazon description ready for KDP, with its count
- A one-line pitch and a short ad hook
Before and after
Your book in. Four jobs done.
It's a locked-island thriller. Isla Moncrieff is a forensic accountant who goes home to Ardsay for her father's funeral. She agrees to spend a weekend closing out the books for his ferry company and finds twenty years of payments to the boat that sank the night her mother drowned. Then a storm shuts the ferry down for a week, nobody can leave, and the man who signed those payments is sitting in the island's only pub. He'll do anything to keep her quiet. Twist: her father wasn't the one who sank it.
Back cover The ferry company's books balance. That's the problem. Forensic accountant Isla Moncrieff comes home to Ardsay to bury her father and close his accounts. It should take a weekend. Instead she finds twenty years of payments to a boat that sank the night her mother drowned. Amazon description (640 of 4,000 characters, formatting included) ...Then a storm shuts down the ferry. For a week, no one can leave the island, and the man who signed those payments is sitting in the only pub. A tense locked-island thriller for readers who like their secrets buried deep. One-line pitch Trapped on her home island by a storm, a forensic accountant must prove who sank the boat that killed her mother before the man who signed the payments silences her. Ad hook Her father's books balance perfectly. That's how she knows someone lied about the night her mother drowned.
The twist stays out of all four pieces. That's what makes a reader open the book.
What lands in your doc
What lands in your blurb doc
- Back cover copy of 100 to 170 words, with a hook line, rising stakes and no spoilers
- An Amazon description with its character count as KDP counts it, tags included, ready to paste
- A one-line pitch of 30 words or fewer for query letters, newsletters and social bios
- An ad hook under 150 characters, with its count, avoiding what Amazon's ad guide flags
- Genre handled for you: both leads in a romance, the clock in a thriller, bullets for nonfiction
- Your real names and details in every piece, and never invented praise, awards or sales figures
Questions authors ask
Common questions
What is a book blurb?
A book blurb is the short sales copy on a book's back cover: who the story is about, what goes wrong and what is at stake, stopping before the ending. Your Amazon description does the same job with more room. Jane Friedman, who reports on publishing, notes that traditional publishing uses "blurb" to mean an endorsement1, while self-published authors mean this sales copy.
How long should a book blurb be?
For a paperback's back cover, plan on 150 to 200 words at most, which developmental editor Jessi Rita Hoffman says is all that fits attractively on most books2. For Amazon, KDP recommends a paragraph of about 150 words, even though its box takes 4,000 characters. River writes 100 to 170 words for the back cover and 150 to 250 for a fiction description.
How do you write a blurb for a nonfiction book?
Open with the reader's problem and what your book promises to do about it. Then list what they will learn: developmental editor Jessi Rita Hoffman suggests three to five bullet points2 on the back cover, each worded in the same pattern. Close with a line on why you can write it, using only credentials you hold. River follows that order and never adds a credential you didn't give.
How do I write a book blurb with River?
Paste a few lines about your book or your synopsis into the box at the top of this page, or drop in the manuscript. River reads it for your main character, the trouble and the genre. Then it writes back cover copy, an Amazon description, a one-line pitch and an ad hook into one doc in your free River workspace.
Will the book blurb generator give away my ending?
No. Every piece builds to the point where things get worst and stops there, with the outcome still open. Twists, culprits, reveals and the ending stay out, and so does any threat or death your pages don't mention. A romance can still promise its happily ever after, since readers of the genre expect that promise and it spoils nothing.
Can I use the ad hook in Amazon Ads?
Yes, though Amazon makes the final call. Amazon Ads reviews every book ad, usually within 24 hours. Its guide to ad moderation5 lists what to avoid: incorrect capitalization or grammar, false promises, customer reviews, prices and terms for specific sexual practices. River leaves all of them out of the hook. If an ad is rejected, edit the text or ask River for another hook, then resubmit.
Is the book blurb generator free?
Yes, it is free to start, with no card needed. Your blurb doc opens in a River workspace, where you can edit it, share it or ask River to change it. Paid plans add more AI use and access to the most advanced models.
Your next step