Which readability formula should I use?

For general prose, Flesch-Kincaid Grade Level is the usual default and Flesch Reading Ease is easy to read as a plain score. For health and patient material, SMOG is the common choice. When the answer matters, compare two or three; a single formula is a convention, not a measurement.

Why do the six formulas disagree with each other?

They use different inputs. The syllable-based formulas respond to word length, while Coleman-Liau and the Automated Readability Index use letters and characters. A passage with short words but long sentences therefore scores differently depending on which arithmetic is applied.

Does a reading level measure how good the writing is?

No. It measures sentence length and word length. A high score can mean dense prose or a specialist audience, and a low score can mean plain writing or a shallow one. Treat the grade as a property of the arithmetic, not a verdict.

How are syllables counted without a dictionary?

With a documented heuristic: vowel groups are counted, silent final e is dropped, -ed and -es endings are discounted unless the stem needs them, and a short exception list covers hiatus words. It is accurate most of the time and occasionally wrong, which the notes state.

Why is the grade so high on a short paragraph?

Formulas are quoted for samples of about 100 words or more. Below that, one long sentence or one polysyllabic word moves the grade several levels and a single sentence can produce any number at all. The tool flags the sample size rather than hiding it.

Readability Grade Scorer

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Reading level

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The Readability Grade Scorer runs every common published readability formula over your text at once and shows the counts each one was computed from, so a reading level you can check by hand replaces a number you have to trust.

What is Readability Grade Scorer?

A readability grade turns a passage into a number on a school scale, and this scorer computes every common published formula at once so you can see where they agree and where they do not. Nothing is estimated. Each score is a formula applied to counts the page displays beside it, in your browser and without an upload.

Six formulas are reported together. Flesch Reading Ease scores from 0 to 100, where higher means easier. Flesch-Kincaid Grade Level, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index each report a US school grade. They are not rival opinions competing for the truth. They are different arithmetic over the same handful of counts — words, sentences, syllables, words of three or more syllables and Gunning complex words — and their disagreements are informative rather than a bug. Flesch Reading Ease and the syllable-based grades rise and fall with word length, while Coleman-Liau and the Automated Readability Index use letters and characters instead. That is why the letter-based pair often lands a grade or two away from the syllable-based pair on the same passage.

A reading level is only as good as the counts behind it, so the tool prints them. You get words, sentences, paragraphs, syllables, the share of words with three or more syllables, the Gunning complex-word count and the two averages every syllable formula needs: words per sentence and syllables per word. From that table any of the six can be recomputed by hand, and a score you disagree with can be traced to the input that produced it rather than accepted on faith.

Syllables come from a documented English heuristic rather than a pronunciation dictionary. Vowel groups are counted, a silent final e is dropped after a consonant, the -ed and -es endings are discounted unless the stem genuinely needs the syllable, and a short exception list covers hiatus words such as media, theatre and aquarium. The heuristic is right most of the time and wrong occasionally, and every score built on it inherits that error. The page says so instead of implying a dictionary was consulted.

Two reliability limits matter more than the choice of formula. Readability formulas are quoted for samples of roughly 100 words or more and swing widely below that, so a single sentence can produce a grade that means nothing at all. SMOG was validated on at least 30 sentences. Both thresholds are checked against your text and reported when they are not met, which is the difference between an indicative figure and a misleading one.

What to aim for depends entirely on the audience. Plain-language guidance for public communication usually sits around a 7th to 9th grade score. Technical documentation written for specialists reads higher, and it should. Academic abstracts read higher still. A readability grade describes sentence and word arithmetic; it says nothing about argument, structure, tone or whether the writing is any good, and it cannot tell you that a short, clear sentence is condescending or that a long one is elegant.

The practical use is comparison rather than a target. Score a draft, rewrite the sentences the table flags as long or polysyllabic, then score it again. Because the formulas are deterministic and the counts are visible, the difference between the two readings is a real change in the text rather than noise. Paste the result into a submission form, keep it in the copy summary, or download it as plain text; nothing you type is stored.

How to use Readability Grade Scorer

Paste or type your text — at least a few paragraphs, since the formulas need roughly 100 words to settle.
Read the overall grade level, then the six individual scores in the table beneath it.
Check the counts panel: words, sentences, syllables and the share of long words are the inputs every formula uses.
Read the notes under the scores, which flag a short sample and the SMOG sentence threshold.
Rewrite the flagged sentences, paste back, and compare the two readings; copy or download the summary to keep it.

When to use Readability Grade Scorer vs related tools

Use the readability grade when you want one pass over every formula at once and need to see the underlying counts. When the question is narrow — the education-grade number alone — the Flesch-Kincaid Score Calculator walks through the two Flesch formulas from the same engine, and the SMOG Index Calculator covers the index health-literacy research prefers.

If the scores come out high because individual sentences are overloaded rather than because the vocabulary is difficult, the Sentence Complexity Analyzer locates the specific sentences carrying too many clauses, which is a more actionable start than the grade itself.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.