What’s the Optimum Sentence Length?

Written by Richard Webster

Professional copywriter specialising in B2B copy and content for small businesses and solopreneurs.



Remember those wonderful days back in primary school?

Of course, you don’t. Nobody does. It was years ago. I can barely remember where I put my coffee four minutes ago.

However, if you could think back that far, you’d remember learning about sentence length at some point. You won’t have realised at the time, what with Garbage Pail Kid cards and Nintendo Game & Watches to distract you (if you’re in your mid-40s) but it was a useful lesson.

That lesson gave you the basics of sentence structure which, over the years, you’ll have forgotten. Suppose you’ve moved into the business world. In that case, you’ll now feel you have to use the longest words possible and construct the most complicated sentences you can. Because that’s what everyone else does. Right?

Allow me to take you back to that lesson. For me, it would have been about 1978, and Mr Leach was my teacher. Leach the Teach. Very square head as I remember. He had glasses which automatically darkened in the sunlight and took forever to lighten up again. As such, he had the air of a low-level hitman which I think he played to a bit. He had an under-the-jacket wallet-holster like Starsky and Hutch.

Anyway, Hitman Leach swanned into the classroom one day and introduced us to the sentence. He told us a basic sentence consisted of a subject, a noun, and a verb. For example,  ‘shot the underboss’. He then went on to explain compound sentences, made from two independent clauses. ‘I shot the underboss, and I collected a debt for Fat Tony’. Both clauses could work as independent sentences but are joined.

Sometime later, we explored complex sentences which have an independent clause then dependent clauses. ‘I shot the underboss who owed me money then went running his mouth off around town about how soft I was.’ Granted, those were dark lessons, but we learned a lot about respecting ‘the family’.

When people write in business, they tend to adopt a formal tone of voice and create long, complex sentences with multiple, dependent clauses. The problem for the reader is that they have to remember each clause in the sentence. The more clauses there are, the harder the sentence is to read. How many times have you read a passage of text which makes less sense the more times you read it? It was probably an over-long, complex sentence.


What’s the Optimum Length of a Sentence?


The best sentence length is around 15-20 words. It roughly equates to about one and a half lines of size 11 text, using normal margins. If your sentences are running on past two lines, they can usually be divided into two or more sentences. If you’re feeling really ambitious, you can also equate a good sentence to about 30-35 syllables. But let’s face it, who’s got time for that?


Is there an easy way to count words per sentence?


Finally! In the very latest version of Microsoft Word in Office 365, they have now put ‘Word Count’ as a function in the Review menu. Calculating sentence length has never been easier. Simply highlight the text then click it to see how many words are in that section. In the bottom left of the screen, it also tells you how many total words are in your document. But sometimes you only want to know how many in are a particular section.

Older versions of Word have the word count function, but it’s hidden within the spell check menu. You can ask it to show advanced statistics, and WPS (words per sentence) will be there.

The golden rule with sentences is to keep them as short as possible. Try and stick to making one point per sentence, and your text will become a joy to read.

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