In short: A good blurb is not a summary. It is a sales text with one job: getting someone to open the first page. For a novel it almost always follows the same structure – a hook, the protagonist in their starting situation, the conflict and what is at stake, and an open question where the text stops. As a rule of thumb, 100 to 200 words are enough for the back cover. Never give away the ending, and leave out self-praise like "gripping" or "moving". Below you will find a fill-in template, a weak and a strong example side by side, and the lengths BoD and Amazon KDP allow.
The blurb is the text most people read first about your book – often the only one. In a bookshop they turn the book over; on Amazon they scroll down below the cover. A few seconds later the decision has been made. That is why these few lines deserve almost as much care as your first chapter.
What a blurb has to do
A blurb answers three questions, in this order:
- Who is this about? One character the reader can follow – not five.
- What is at stake? A problem this character cannot simply ignore.
- Why should I keep reading? A question whose answer is only in the book.
What it does not have to do: retell the whole plot, introduce every side character, explain the world or interpret the theme. You need the full synopsis for a submission to a publisher or agent, not for readers.
The structure in four parts
1. The hook (one sentence). A situation, a contradiction or a claim that only exists in your book. Not a general statement about life ("Sometimes everything changes in an instant"), but something concrete.
2. Character and starting situation (two or three sentences). Who is the protagonist, what does their everyday life look like – and what disrupts it? The disruption is the moment your story begins.
3. Conflict and stakes (two or three sentences). What does the character have to decide or achieve, and what do they lose if it goes wrong? The more concrete the stakes, the stronger the text.
4. The open question (one sentence). This is where the blurb stops – before the answer. Often it is a choice between two things that both cost something.
Optionally, add a positioning line: one sentence naming the genre or theme ("A novel about …"). It helps booksellers and readers looking for a particular kind of book.
Fill-in template
Copy this template and fill it in for your book. Then cut everything that repeats itself or does not help answer "Do I want to keep reading?".
Hook: [One concrete sentence that only fits your book.]
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Character and starting situation: [Name, one defining trait, their everyday life.] [What disrupts it.]
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Conflict and stakes: [What the character now has to do.] [What they lose if they fail.]
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Open question: [The decision or danger the text ends on.]
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Positioning (optional): A [genre] about [theme].
Example: weak and strong
To make the rules tangible, here are two versions for an invented novel, "The Ferrywoman".
The weak version
Imke Hansen is 52 years old and has worked as a ferry operator for thirty years. She lives alone with her dog Bosse in a small house by the dyke. One day her brother Jens turns up, whom she has not seen in twenty years. He tells her that their father did not drown back then, but was betrayed by a neighbour. Together they uncover the truth, reconcile, and in the end Imke sells the ferry. A gripping, moving and profound novel about family, guilt and forgiveness.
What goes wrong here:
- A CV instead of a hook. The first sentence reads like a personnel file. Nothing in it is unique to this book.
- Irrelevant details. The dog and the house by the dyke take up space and add no tension.
- Spoilers. The solution (betrayal), the reconciliation and even the ending (the ferry is sold) are all in the blurb. No question is left open.
- Self-praise. "Gripping, moving and profound" claims what the text should show. Readers do not believe such adjectives.
The strong version
For thirty years Imke Hansen has taken everyone across the river who asked. Everyone except her brother.
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Ever since her father vanished with his boat one November night, Imke has kept the little ferry to Kranensand running – fourteen crossings a day, in any weather. Then Jens is standing on the landing stage, after twenty years of silence, asking to come aboard. In his jacket pocket is a letter proving that someone on the island saw more that night than they admit to this day.
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Imke has to decide what weighs more: the truth about her father – or her peace with the people she ferries across the water every morning.
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A novel about what families keep from each other.
What this version does differently:
- The hook is a contradiction ("everyone … except her brother") that immediately raises a question.
- The starting situation shows Imke's everyday life in one detail (fourteen crossings, any weather) instead of a list.
- The disruption is concrete: a person, a place, a letter.
- The stakes are a choice between two things that both cost something. How it turns out stays open.
- The positioning line names the theme in one sentence, without adjectives.
At around 110 words it fits comfortably on the back of a paperback, next to the barcode and the price.
A blurb for non-fiction
Non-fiction uses the same idea with different building blocks. The reader takes the place of the character, and their problem takes the place of the conflict:
- The problem, as a scene from the target reader's everyday life – not as a statistic.
- Who is writing and why this person would know.
- What the book concretely delivers: methods, templates, answers – as precisely as possible.
- Who it is for.
An example for an invented guide:
Monday, 9 a.m.: alignment meeting. 10 a.m.: meeting to align on the alignment. Anyone who works in an office knows the weeks when the actual work only starts after hours.
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Organisational consultant Maren Albers has spent twelve years working with more than a hundred teams that failed at exactly this – and a few that solved it. She shows which meetings can be replaced, how decisions get made without a calendar slot, and how to decline a meeting without offending anyone. With templates for minutes people actually read.
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For team leads, project managers and everyone whose calendar no longer belongs to them.
The most common mistakes
- Too many names. More than two named characters is overwhelming. Side characters become "her brother" or "a stranger".
- Giving away the ending. Even hints like "until she finally realises that …" kill the tension.
- Adjective chains. "A gripping, emotional and surprising thriller" – everyone writes that about every book.
- Question cascades. One question at the end works. Five in a row ("Who is the stranger? What does he want? And can she trust him?") sound helpless.
- Clichés. "Nothing is what it seems", "a journey of self-discovery", "a race against time" – these lines appear on hundreds of books.
- Comparisons with bestsellers. "For fans of …" can help in an online shop; on the back cover it easily sounds presumptuous.
- The wrong tone. A cosy crime needs a different voice than a psychological thriller. The blurb is the first sample of your book's style.
How long can a blurb be?
There is no standard, but there are practical limits:
- Back cover: As a rule of thumb, 100 to 200 words. On a paperback the text shares the space with the barcode, the price and maybe a quote – and it has to be set in a size people can still read in the shop.
- BoD: The "Information about the title" field in the book project accepts 50 to 2,500 characters. The text appears in shops and the book trade catalogue.
- Amazon KDP: The book description can be up to 4,000 characters. There is room for a longer version here: the blurb at the top, followed by a line about the series or the genre.
Write the short version first. A long version grows out of it easily – the other way round almost never works.
Writing a blurb with AI
AI is a good sparring partner for a blurb, but rarely the last step. It produces a rough draft in seconds that shows what stands out about your story from the outside. The typical weaknesses of such drafts are exactly the mistakes listed above: adjective chains, clichés and too much plot.
The best way to work with it:
- Generate two or three drafts.
- Take the strongest sentence from each and build your own version using the template.
- Cut every adjective that claims an effect ("thrilling", "moving").
- Read the result out loud. What stumbles when spoken also stumbles when read.
In Hermes 3000 you will find the blurb in the left column under "Optional", in the "Blurb" field. The "Auto-generate" button writes a draft from your plot, characters, chapter overview and the beginning of your manuscript – you revise it right there in the field. The finished text is then reused: on your book's landing page, on the back of the cover PDF for print, and pre-filled in the "Publish with BoD" assistant. For Amazon, the KDP assistant prepares its own, longer description.
Checklist
- The first sentence only fits this book.
- There is one protagonist (fiction) or one clear problem (non-fiction).
- Two names at most.
- The stakes are concrete: what is lost if it goes wrong?
- The text ends before the answer.
- No adjective claims an effect.
- Reads aloud without stumbling, under 200 words.
Frequently asked questions
How long should a blurb be?
For the back cover, 100 to 200 words is a good rule of thumb. Online it can be longer: Amazon KDP allows up to 4,000 characters, BoD up to 2,500 characters in the "Information about the title" field.
Can a blurb give away the ending?
No. A blurb ends before the resolution, ideally on an open question or a decision the protagonist has to make. Even hinting at the ending takes away tension.
Which tense is a blurb written in?
Usually the present tense, even if the novel is narrated in the past tense. The present tense brings the starting situation into the reader's here and now. More important than the tense itself is keeping it consistent throughout.
What is the difference between a blurb and a synopsis?
The blurb sells the book to readers and does not reveal the ending. The synopsis is written for publishers or literary agents and summarises the entire plot, including the ending.
Can AI write a blurb?
It can produce a usable rough draft that shows what stands out about the story. The final polish should be yours: AI drafts tend towards adjective chains, clichés and too much plot.