top of page

The Maths of Better English

Making writing readable

Maths formulae

Your vocabulary is vast. Your spelling, superb. You’re a genius of grammar.

The writing you do for your business is wonderful.

But is reading it enjoyable?

It doesn’t matter how complicated or drab the subject matter. Or how intelligent the audience. If people must work hard to read what you’ve written, they…well, they won’t bother.

It’s difficult to be objective about enjoyability. After all, one person’s poetry is another’s polemic. But there is a proxy you can use to help.

Readability can be measured by using a bit of maths.

The Maths of Words

The idea of using a formula for readability is not without its detractors.

It is true that an equation can’t know the meaning of your words. It won’t consider creativity. Using a readability formula as your only QC barometer can result in copy that is bland and purely functional.

But adding readability to your armoury – like running a spellcheck program or a plagiarism scan – can help you make your writing better.

Readability formulae look at writing complexity. They highlight problems you may have overlooked when writing. They can draw attention to “bullshit bingo” words that slip in occasionally. What you decide to change is up to you.

There are several tests you can use to evaluate readability. This site allows you to choose a selection if you wish.

We will use Flesch-Kincaid to illustrate how readability scores work.


Originally created in the 1940s, Flesch / Flesch-Kincaid is the readability test most widely used. It is referenced in the Style Guide given to those writing for the UK Government. It is the maths behind Microsoft Word’s Editor tool. (You can enable readability in Word by following the steps here.)

F-K calculates complexity by the number of syllables per word and the number of words per sentence. It counts both these averages and applies a multiplier. A bit of addition and subtraction, and you get a score.

Flesh Reading Ease Formula

The higher the score given, the more accessible it is likely to be to more people.

Flesch-KIncaid Grade Level Formula

The score here equates to an American High School grade. It’s the reverse of the above, with a lower score (or school grade) meaning higher accessibility.

How to Write Your Copy Readable

We took this copy from the home page of a marketing agency.

This style of copy may be recognisable to many. So it might not seem that complicated.

But it gets a Flesch score of only 43.6/100.

We know the main detractors to the readability score so let’s focus there. We can then decide where we can, or should, make changes.

There are 53 words in only 3 sentences. The second contains 24 words. The copy has a whopping 95 syllables.

Jeez! Take a breath.

As well as that marathon of a sentence, there are many “wallpaper words.” Words we commonly use even though they add little. Could these words be replaced?

  • Do ‘strategise’ and ‘implement’ sound more intelligent than ‘think’ and ‘do’?

  • Are ‘creative visions’ better than ‘ideas?

  • Do the adjectives add clarity? The thinkers (people) who are ‘passionate’ as opposed to what? Nonchalant? Or the results that are ‘unparalleled’, a literal lie.

This gives us two tasks. To break up sentences. And to simplify word choice.

How about...

We can only work with what we have here.

We have tried not to add or remove anything. And we have stuck to the same word count.

Ultimately, we have only been able to apply lipstick to a pig.

But this has increased readability from 42.6 to 79.4

And decreased the grade level from 11.5 to 4.0.

The revised copy is not going to win any awards. But by focussing on just the sentence length and syllables, we have been able to retain the sentiment but make the copy much more readable.

And enjoyable.

Some Last (Readable) Words

A good readability score doesn’t mean great copy so don’t aim for a high/low (depending on your preferred formula) score. It’s important to retain the personality of your own business if you want to stand out.

And don’t think your subject matter or audience means your copy will always score poorly for readability.

Research shows that the more educated the person, the greater their preference for plain English. It’s the same when knowledge is specialist. Technical terms – which you wouldn’t expect your average child to understand – are fine. Using them unnecessarily, or surrounding them with wordy description, is not.

As a rule, a score of around 70 is fine for most audiences.

A score less than 50, means it’s likely you’re being overcomplicated.

Less than 40 and you should really consider rewriting or revising.

PS If you’re curious, this article scores 60.1, which is lower than I would like. This is impacted by two things out of my control. I could not write about this subject without using the five-syllable word ‘readability’ many times. And the inclusion of the poorly scoring website copy does me no favours either.

Remove both elements and it scores a perfectly acceptable 69.7.

Whatever your views on using maths to evaluate English, readability scoring is a useful and subjective way to check your writing will be both read and enjoyed.

24 views0 comments

Recent Posts

See All


bottom of page