Hi Burty, I would imagine it’s up to the author and the type of project they’re working on. Â I work on a 24 chapter format (historical fiction) for which there are various templates and so on. Â There are 27 chapter templates available as well. Â I quite like formulaic though as it means I’ve got a rough chance of hitting beats and so on – not for everyone of course. For this I would expect to write approx 80k words.
If you take author Bernard Cornwell (who will probably write to something approaching a formula) his early Last Kingdom books average about 13 chapters, but as the series goes on I think he nearly doubles this – although probably not the word count.
Just as a fun comparison – War and Peace has 350ish chapters and is about 500k words.