An interesting question, and one you hear all the time from people who want to get into writing. Nor is there a straightforward answer except for the infuriating… it depends.

What you’re aiming at for one thing. Today in mainstream commercial publishing you’ll find most books fit between 80k and 100k. If you self-publish, however, the length of a book is entirely up to you. I’ve seen people uploading ‘novels’ on Kindle which amount to nothing more than a short story, which is why canny buyers always check the page count first.

But let’s stick to commercial publishing which is really the only area I know.

When I started out in this game thirty years ago books were much, much longer than they are now. This was what I came to think of as the Stephen King effect. In the 1990s King was turning out some huge books. They sprawled and sprawled, brilliantly for the most part. But works like The Stand were still massive chunks of reading. And, from a publisher’s point of view, expensive to print too with all that excess paper.

My first novels came in around the 130,000 to 150,000 word mark, standard for mainstream fiction of the time. The exception was my adaptation of The Killing TV series set in Copenhagen. This involved turning twenty hours of television into a book, with some crucial changes and new narrative twists along the way. The contract asked for the book to be 100,000 words long.

Think about that. Twenty one-hour episodes, each reduced to a mere five thousand words of story. It was never going to happen. My first draft included every scene in the book and ran to nearly 300,000 words. With some ruthless editing and removal of what I felt were unnecessary story strands I managed to get that down to around 220,000 words, and the book, it has to be said, did very well at that length, still bringing me a trickle of royalties to this day. Taking a scythe to the story did it a favour too. One thread I excised altogether was a dead-end clue to do with something stuffed down a toilet, which occupied the best part of a one-hour episode and was a cinch to drop.

But I never want to write anything that long ever again, for my sake and for the reader.

I’d feel decidedly wary of submitting anything way outside the 80k to 100k figures. Higher than that and editors will be thinking about what could be cut (toilet threads for example). Much lower than that and they’ll be asking themselves if it’s a novella instead, and that’s a tricky beast to sell commercially, for unknown writers anyway.

The real answer to the question ‘how long should a book be?’ is the story should be telling you that itself. Narratives should have a discernible rhythm, a start, a central section that keeps the reader’s interest, and then the final trajectory on its close. I can always feel when I’m edging towards that part. It’s like a plane manoeuvring to get on the final approach.

At that point I’m not thinking about an exact word count between those 80k to 100k figures. I’m just focused on the story, trying to land it and make it work before the inevitable revise. If you’re too long when you’re down on the ground you look to cut. If you’ve fallen short of the length you think you need, you face a bigger problem.

Padding writing to fit a certain length is always obvious to any seasoned editor, and many readers too. They know when it’s happening and they really don’t like it. Scenes that are expendable should be cut, not used as filling. If the story still feels too short you need to look at its overall structure and see if there’s some way round the length issue that keeps it as a believable, readable piece from beginning to end.

You need to listen to your story and your characters and let them tell you when to make that turn onto a final approach to landing. Inventing scenes and side threads just to make weight won’t work.

Better that than having a fixed word count target in your head from the beginning. My work in progress I assumed would come in around the 95,000 word mark, which is standard for the Venice stories of Arnold Clover. But approaching its end I realised this one’s a bit different. A whole chapter I envisaged between two key moments in the story was, I came to see, unnecessary. The tale needs to go from one place to the other more quickly.

In the end I suspect this book will come in around the 90,000 word mark, perhaps even a little less than that. ( Update. I finished the first draft yesterday and it came in at 93k.) None of this matters so long as the story works. I’m in the sweet spot I have in my own head of between 80k and 100k and that’s just fine.

In short… focus on writing the best work you can and try to make the rhythm of it land the finished whole between those two figures. By all means monitor your progress — I do all the time — but the final extent of the book should be determined by the story itself, not a precise number you think you must chase. The work should have a better idea of how long it should be than you.