The Innovative Marketer's Blog

The Mathematical Equation That Will Make You a Better Blog Writer

Posted by Matthew Cook


OnContent_by_MC_border.pngCan you measure in numbers whether a blog article is good or bad?

I’ve always resisted any claim that good writing could be quantified by a computer. Surely no app can beat my brain at crafting perfect sentences and choosing the right words.

Je suis une artiste!

My own rage against the machine aside, the rise of inbound marketing has caused the creation of an army of reluctant writers. These are executives, sales professionals, marketers, and rank-and-file team members asked to contribute to their company’s blog. Perhaps you’re one of them.

Most of these people have fewer artistic pretensions than me and would be more than happy for some objective way to measure — and improve — the quality of their writing.

So I’m going to hold my nose and take a look at the most well-known tools for improving your writing, the Flesch-Kincaid readability tests.

‘Can the Flesch-Kincaid Tests Really Help Me Blog Better?’

For a while, I’ve been vaguely aware Flesch-Kincaid scores are included when you run a spelling and grammar check in Microsoft Word. But I never gave these two numbers much thought until I stumbled across chapter 25 of Ann Handley’s excellent guide for new content writers, “Everybody Writes.”

(This, by the way, is the first book you should buy for your blogging team’s bookclub.)

Like me, Handley is a skeptic about mathematical writing tools:

“I have a bit of love-hate for readability scoring methodologies, in part because I think writers should rely on their own sensibilities to determine whether their writing is on target for their audiences. In other words, relying on a formula to spit out a score seems like you’re selling yourself short.”

But, Handley concedes, “...Readability scores can be useful if you’re facing a steep learning curve in getting to know a new audience. And I get that you sometimes might need a little extra data to convince a boss or client that something is on target.”

With that grudging endorsement from a content writing guru, how do the Flesch-Kincaid tests work?

‘How Do the Flesch-Kincaid Tests Work?’

equation.jpgThe original Flesch-Kincaid readability test is a simple formula. In theory, you could work out the Flesch-Kincaid readability score of any piece of text without a computer — if you like to count.

In his 1979 book, “How to Write Plain English,” reading expert Rudolf Flesch explained his eponymous formula in refreshingly plain English:

“It measures the average sentence length in words and the average word length in syllables. You put these two numbers into an equation and get a number between 0 and 100 that shows you the difficulty of your piece of writing. If it's too hard to read for your audience, you shorten the words and sentences until you get the score you want.”

That equation, for the math-inclined among you, is:

206.835 - 1.015 (total words / total sentences) - 84.6 (total syllables / total words)

The thinking is, Flesch explains, “Longer sentences are more likely to be complex — more subordinate clauses, more prepositional phrases and so on. That means more mental work for the reader. So the longer a sentence, the harder it is to read.”

The same thing goes for words, he says.

In even more plain English: The Flesch-Kincaid score uses the length of sentences and the length of words to figure out the readability of any text on a 100-point scale. The lower the number, the less readable the piece.

Flesch sampled a few of the publications of his day. Here are some of his results. Remember, the higher the score, the more readable.


Flesch-Kincaid Readability Score



Consumer ads in magazines




Reader's Digest


Sports Illustrated


New York Daily News


Atlantic Monthly




Wall Street Journal


New York Review of Books


Harvard Law Review


Standard auto insurance policy


Internal Revenue Code



Pretty much what you’d expect, right?

It seems that, to Flesch (and co-creator J. Peter Kincaid), a piece is more readable when more people can understand it. The more education you need to understand a piece, the less readable it is.

Indeed, Flesch published a helpful chart placing American grade levels along his 100-point scale:


School Level

90 to 100

5th grade

80 to 90

6th grade

70 to 80

7th grade

60 to 70

8th and 9th grade

50 to 60

10th to 12th grade (high school)

30 to 50


0 to 30

college graduate


To make it even easier, Flesch and Kincaid created a version of their formula that outputs the result as a grade level. This is the second readability number you’ll see when you run a spelling and grammar check in Word.

‘Isn’t This a Bit Too Simplistic?’

Yes, it is.

Clearly, there is more to making writing readable than, as Flesch says, sprinkling periods over it. But if you’re new to writing and don’t have an editor to help you, it’s a start.

I wrote a few months ago about how the human mind seeks rewards and tries to avoid punishment. When content is difficult to read, that’s a punishment.

Any writer should strive for readability. After all, why wouldn’t you want to be understood? But as an online writer, you should make it your top goal.

Report after report after report tells us that online readers are rarely readers at all. They don’t read. They scan. Content with high Flesch-Kincaid scores is easier to scan. Frequent pauses and short words makes its more digestible at a glance.

Given the choice of finding their answers somewhere else or slogging through your dense prose your readers will go elsewhere. “More mental work for the reader,” Flesch says.

‘Doesn’t This Insult My Readers’ Intelligence?’

wordmadeflesch.pngThis blog article scores a 69.1 on the Flesch-Kincaid scale. That’s a seventh-grade reading level, somewhere around Seventeen magazine territory. Do you feel insulted?

The truth is, no one ever complained about content being too easy to understand.

Very few of your readers are reading your marketing content for fun. They’re looking for answers. When your content is readable, your readers will get their answers faster, which makes them happy.

Of course, you know your audience best — or you should. If you feel they need multisyllabic jargon (I hope that doesn’t kill my readability score) to understand your point, then by all means, use it. But if they don’t need it, don’t use it.

‘What Flesch-Kincaid Score Should I Aim For?’

For a general audience, aim for a Flesch-Kincaid score of about 60 or above or a grade level of 8 or 9 or lower. This is what Flesch recommended and Ann Handley agrees.

If your score is below 60 (or above grade 9), replace longer words with shorter ones that mean the same thing. Look for long sentences and break them into smaller ones. Anywhere you see a comma is usually a good place to make one sentence into two.

Here is how to check your Flesch-Kincaid score in Microsoft Word.

Here is where you can do it for any piece of writing.

How Else Can I Improve My Blog Writing?’

When it comes down to it, though, the Flesch-Kincaid score is just a number and there's only so much you can learn from it. Here are a few articles with practical blog writing tips that will help you go farther:

Inbound Marketing: Get The Truth

Topics: Blogging