Readability Score Checker
Five Formulas, One Paste

What Readability Scores Really Count

Every readability formula counts the same three things: how many words you use, how long your sentences run, and how many syllables sit inside each word. None of them reads meaning, and none of them can.

That sounds like a weakness, yet it is exactly why the numbers are useful. Long sentences and long words genuinely do slow a reader down, whatever the subject happens to be.

So treat a score the way a doctor treats a temperature. It flags a passage that deserves a second look. However, it cannot suggest the better wording for you.

Researchers built these formulas many decades ago. Flesch argued for shorter sentences in 1948, and usability research has kept finding the same thing since. The Nielsen Norman Group's work on legibility, readability and comprehension puts a broad audience at about an eighth-grade level, which is roughly where a Flesch score of 60 to 70 lands.

Flesch Reading Ease, And What 60 Means

Rudolf Flesch published his formula in 1948, and it still runs inside Word, Google Docs and most SEO plugins. Flesch Reading Ease runs roughly 0 to 100, higher meaning easier.

Most style guides call anything above 60 plain English. Most readers can follow text at that level. Between 50 and 60 the text turns specialist. Below 30 you are writing for people whose job is to read it.

Used this way, the page doubles as a flesch reading ease calculator and a grade-level checker. Because the formula rewards short words, though, it treats a technical term as difficulty. For instance, a page for pharmacists scores badly and reads perfectly.

The Reason Denwix Runs Five Readability Formulas

The other four were built for other jobs. Flesch-Kincaid converts the reading ease into a US school grade, SMOG counts only the long words, and the Automated Readability Index ignores syllables and counts characters instead.

Consequently they disagree, sometimes by three grades on the same paragraph. That gap is information: a text that scores well on all five is genuinely plain, while one that scores well on ARI alone simply has short words in very long sentences.

Matching Each Formula to the Right Page

Choose a formula for your readers, not out of habit. Flesch Reading Ease suits marketing pages and help articles, because the scale is easy to explain to a client.

Flesch-Kincaid and SMOG both report a school grade, so they suit teaching material, health leaflets and public notices. SMOG is the stricter of the two. It was built for health writing, and it counts only the long words.

The Automated Readability Index ignores syllables and counts characters. That makes it the steadiest choice for text full of names, codes or abbreviations, where a syllable counter guesses badly.

Gunning fog sits between the two camps. It punishes long sentences and long words together, which is why business writing courses have leaned on it for seventy years. The published formulas are short enough to check by hand if you ever want to.

The Minimum Text for a Fair Score

Two hundred words give a steady reading. Below fifty, a single long sentence can move the score by fifteen points, so treat a short sample as a hint rather than a verdict.

For a long page, score it in parts. An introduction that reads easily and a specification that does not will average out to a number that describes neither.

Using the Readability Score as a Signal

You can move any of these numbers without improving a word. Cut every sentence in half at the nearest comma and the score jumps. Yet the writing now reads like a list of alarms. So use this readability score checker to find weak spots, not to chase a figure.