Readability Score Calculator

How to Use This Tool

1. 1

   Paste your text

   An article, a landing page, an email. Two hundred words or more gives a stable reading; a paragraph does not.

2. 2

   Read the headline score

   Flesch Reading Ease is the one most people mean by a readability score. Above 60 is comfortable for a general audience; below 30 is heavy going.

3. 3

   Compare the six

   When they agree the reading is solid. When one is far from the others, the counts underneath usually explain why.

4. 4

   Look at what is driving it

   The tool names the specific cause — long sentences, a high proportion of three-syllable words, oversized paragraphs — rather than only handing you a number.

What These Formulas Actually Measure

Every formula here works from two things: how long your sentences are, and how long or complex your words are. That is the entire input. None of them reads your text in any meaningful sense.

This matters because it sets the limit on what a score can tell you. A passage of short sentences made of short words scores as highly readable whether it is lucid or nonsense. "The cat sat on the mat. The dog ran fast." scores near the top of the scale, and so would the same sentence structure containing complete gibberish.

So the number is a proxy. Long sentences and long words genuinely do make text harder to read, and reducing both genuinely does help — but a good score is evidence of nothing except that the text is structurally light. Clarity is not measurable this way, and a tool claiming otherwise is overselling itself.

The Six Formulas and When Each Is Useful

• Flesch Reading Ease — 0 to 100, higher is easier. The best known, and the one most content guidance means by "readability". Above 60 suits a general audience.
• Flesch-Kincaid Grade Level — the same inputs expressed as US school years, which is often easier to act on than a 0-100 scale.
• Gunning Fog — weighs words of three or more syllables heavily. Built for business writing, and the formula most sensitive to jargon.
• Coleman-Liau — counts characters rather than syllables, so it never has to guess at pronunciation. Useful as a check when a text has unusual names or technical terms that trip up syllable counting.
• SMOG — designed for health material, where being misunderstood has consequences. Tends to read a little stricter than the others.
• Automated Readability Index — character-based like Coleman-Liau, originally built for real-time output on teleprinters.

Why the Scores Disagree

Two of the six count characters and four count syllables, which is the main source of divergence. A text full of long but familiar words — "international", "opportunity" — looks hard to a syllable-based formula and less so to a character-based one.

Technical vocabulary widens the gap further. Gunning Fog counts every three-syllable word as complex regardless of how familiar it is to your audience, so a page written for developers scores as difficult even when its readers find it easy.

That is the useful reading of a spread: it usually means your text has long words that your audience already knows. The formulas cannot tell the difference between an unfamiliar word and a long one, but you can.

This tool averages only the five grade-level formulas into its headline grade, and deliberately leaves Reading Ease out. It runs 0-100 in the opposite direction, so folding it into an average with school-year numbers would produce something that looks like a figure and means nothing.

What Score to Aim For

It depends entirely on who is reading. Aiming for a fixed number regardless of audience is how technical writing ends up patronising and consumer writing ends up impenetrable.

For general web content, Flesch Reading Ease around 60 to 70 — roughly a 13 to 15 year old reading level — is a sensible target. That sounds low and is not an insult to the reader: people skim on screens, often on a phone, often distracted, and simpler prose survives that better.

For technical documentation aimed at practitioners, 40 to 50 is normal and fine. The vocabulary is doing necessary work and simplifying it would cost precision.

For anything health, legal or financial where being misunderstood has real consequences, aim higher than feels necessary. This is what SMOG was built for.

How to Actually Improve a Score

The single most effective change is splitting long sentences. Sentence length is weighted heavily in every one of these formulas, and it is also the thing that genuinely makes prose hard to follow. A sentence carrying three ideas usually wants to be two or three sentences.

The second is cutting unnecessary long words where a short one is exactly as precise. "Use" instead of "utilise", "about" instead of "approximately". Where the long word is more precise, keep it — the score is not worth the accuracy.

What does not work is the thing the score tempts you into: replacing accurate technical terms with vague simple ones to move a number. That improves the measurement and damages the writing, which is the wrong trade.

Worth knowing too: paragraph length affects perceived readability enormously and appears in none of these formulas. A wall of text scores identically to the same words broken into five paragraphs, and reads far worse. Our Paragraph Counter will show you the shape of what you have written.

Readability and SEO

Readability is not a Google ranking factor. There is no readability score in the algorithm, and no threshold to clear.

It matters indirectly, and the indirect route is real. Content people can read gets read; content that gets read earns time on page, return visits and links. Those are the things that do influence rankings, and readability is upstream of all of them.

The practical version: write for the person, check the score afterwards to catch prose that drifted heavier than you intended, and never rewrite good sentences to move a number. Our Word Counter and Keyword Density Checker cover the other half of the same check, and the Reading Time Calculator estimates how long the finished piece asks for.

Where These Formulas Fall Down

• Very short texts. Under 100 words one long sentence can move the score by ten points, and the tool warns you when you are in that territory.
• Lists and tables. The formulas assume prose, and a page of bullet points produces a reading that means little.
• Names and technical terms. Multi-syllable proper nouns inflate difficulty scores without making the text harder for anyone who knows the subject.
• Languages other than English. All six were built and calibrated on English, and the syllable heuristics do not transfer.
• Code samples and numbers. Both confuse the counts, so score the prose around them rather than the whole document.

Frequently Asked Questions

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