Free Readability Score Checker Online
Check the readability of your text with Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog and SMOG, alongside word, sentence and syllable counts. 100% client-side — your text stays private.
What is a readability score? A readability score estimates how hard a piece of writing is to read from two measurable surface features: how long the sentences are and how long or complicated the words are. The best known is Flesch Reading Ease, which runs from 0 to 100 — 60 to 70 is plain standard English, above 80 is easy, below 30 is very difficult. Grade-level formulas such as Flesch-Kincaid convert the same inputs into a US school year instead.
How to Use the Readability Score Checker
- Paste a real, complete passage — Every score is a ratio, so a fragment gives a misleading result. Aim for at least a few hundred words of finished prose, with the sentence-ending punctuation intact — the sentence count is derived from full stops, question marks and exclamation marks.
- Watch the scores update as you type — Analysis reruns about 100 ms after the last keystroke. Editing one long sentence and seeing Flesch Reading Ease move is more useful than the absolute number on its own.
- Start with Flesch Reading Ease — The first card gives a 0-100 score and a plain-language label. Most general-audience writing aims for 60 or above; technical documentation for specialists routinely sits in the 30s and that is not automatically wrong.
- Cross-check with Flesch-Kincaid and Gunning Fog — Both report a US grade level from the same counts, Flesch-Kincaid using syllables per word and Gunning Fog using the share of three-syllable words. When the two disagree sharply, the text is usually mixing very long sentences with very plain vocabulary or the reverse.
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Read the four counters underneath the text box — Words, Sentences, Syllables and Complex Words are the raw inputs to every formula. If a score looks wrong, one of these four is usually the reason — an abbreviation such as
Dr.adds a phantom sentence. - Copy the stats into your notes — Copy Stats puts every counter, every index and both time estimates on the clipboard as plain text, which is handy for recording a before-and-after when you rewrite a page.
How the Scores Are Calculated
Readability formulas do not understand your writing. They count four things and put those counts into an equation that was fitted, decades ago, against how well real readers comprehended real passages. Everything the tool reports comes from these four numbers.
- Sentences — the text is split on runs of
.,!and?, and non-empty pieces are counted. Text with no terminal punctuation counts as one sentence. - Words — anything separated by whitespace. A hyphenated compound counts once.
- Syllables — estimated per word by counting groups of vowels (
a e i o u y), then subtracting one for a silent finale. Any word of three letters or fewer counts as one syllable. - Complex words — words longer than three letters that the syllable estimator puts at three or more syllables.
Flesch Reading Ease is the oldest of the group, published by Rudolf Flesch in 1948, and it combines average sentence length with average syllables per word:
206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words)The output is displayed on the familiar 0-100 scale, with higher meaning easier. The raw formula can go below 0 for very dense text and above 100 for very simple text; this tool clamps the display to the 0-100 range, so a score sitting exactly at 0 or 100 means the underlying value was outside it.
Flesch-Kincaid Grade Level re-weights the same two ratios so the answer reads as a US school year rather than a score:
0.39 × (words / sentences) + 11.8 × (syllables / words) − 15.59Gunning Fog, developed by Robert Gunning in 1952, swaps syllables per word for the percentage of long words:
0.4 × ((words / sentences) + 100 × (complex words / words))SMOG — Simple Measure of Gobbledygook, published by G. Harry McLaughlin in 1969 — was defined on a fixed sample of 30 sentences, and this implementation respects that. It reports 0 until your text contains at least 30 sentences, then applies the published equation to the polysyllable count scaled to a 30-sentence sample.
1.043 × √(complex words × 30 / sentences) + 3.1291Flesch Reading Ease Bands
These are the exact bands the tool uses for the label under the Flesch Reading Ease score. The grade levels are the conventional ones associated with each band rather than a separate calculation.
| Score | Label shown | Typical audience |
|---|---|---|
| 90-100 | Very Easy | Around 5th grade — children's books, simple instructions |
| 80-89 | Easy | Around 6th grade — conversational writing, consumer email |
| 70-79 | Fairly Easy | Around 7th grade — popular fiction, lifestyle content |
| 60-69 | Standard | 8th to 9th grade — general news, most web copy |
| 50-59 | Fairly Difficult | 10th to 12th grade — quality journalism, trade press |
| 30-49 | Difficult | College — academic and professional writing |
| 0-29 | Very Difficult | College graduate — legal, medical and research text |
A lower score is not a failure. Plain-language guidance for public-facing government and health information usually targets the Standard band or easier, because the audience is everyone. A specification written for engineers is meant to be precise before it is easy, and pushing it into the 70s would mean removing the vocabulary that carries the meaning.
Which Cards to Rely On
Seven indices are displayed, and they are not all implemented to the same standard. This table states plainly what each card computes, so you can weight the numbers accordingly:
| Card | Inputs used here | Status |
|---|---|---|
| Flesch Reading Ease | Words per sentence, syllables per word | Standard formula, clamped to 0-100 |
| Flesch-Kincaid Grade | Words per sentence, syllables per word | Standard formula, floored at 0 |
| Gunning Fog Index | Words per sentence, share of complex words | Standard formula, with a simplified complex-word rule |
| SMOG Index | Complex words, sentences | Standard formula; shows 0 below 30 sentences by design |
| Coleman-Liau Index | Share of complex words, sentences per 100 words | Substitutes complex words for the letters-per-100-words term the published index uses |
| Automated Readability | Share of complex words, words per sentence | Substitutes complex words for the characters-per-word term, so it reads 0 for most text |
| Dale-Chall Score | Share of non-complex words, words per sentence | Uses no familiar-word list, so it saturates at its 10.0 ceiling on ordinary prose |
Treat Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog and, on long documents, SMOG as the working numbers on this page. The Coleman-Liau, Automated Readability and Dale-Chall cards depend on inputs this tool does not measure — letters per word and a 3,000-word familiar vocabulary list — so their values are not comparable with figures produced elsewhere and should not be quoted.
The reading and speaking estimates below the indices are simple division: words divided by 200 for silent reading and by 130 for reading aloud, each rounded up to a whole minute. Both rates are common planning averages rather than measurements of you, so treat a 6-minute estimate as "roughly five to eight minutes" and use it for pacing a talk, not for a broadcast cue sheet.
What a Readability Score Cannot See
Every formula on this page is blind to meaning. It cannot tell whether the argument is coherent, whether the paragraphs are in a sensible order, whether the headings help, or whether a short sentence made of unfamiliar jargon is harder than a long sentence made of everyday words. Two passages with an identical Flesch score can differ enormously in how easy they actually are to follow, because layout, familiarity and the reader's prior knowledge do most of the work and none of them are counted.
The mechanics have limits too, and knowing them stops you chasing noise. Syllables are estimated by a vowel-group heuristic, which handles regular English well and misjudges irregular spellings, names and loanwords. Digits and accented characters are stripped before the estimate runs, so a token such as 2024 contributes one syllable instead of the four you would say aloud, and a passage full of figures ends up with a low syllables-per-word ratio and a flattering reading-ease score. Abbreviations create phantom sentences: Dr. Smith arrived at 3.30 p.m. is counted as four sentences, which shortens the average sentence length and flatters the score. Bulleted fragments without full stops merge into one very long sentence and do the opposite.
All of the formulas were also calibrated on English, so applying them to another language produces a number with no meaning behind it. Within English they are best used as a relative instrument: score a draft, edit the longest sentences and the longest words, score it again, and watch the direction of travel. A single reading in isolation says far less than the difference between two revisions of the same page.
Frequently Asked Questions
A 0-100 score where higher means easier, calculated from average sentence length and average syllables per word. 90-100 is very easy, 60-69 is standard general-audience English, 30-49 is college level and below 30 is very difficult. It is the most widely used readability measure and is built into several word processors and plain-language style guides. This page clamps the display to 0-100, so a text that computes above or below that range shows the boundary value.
It converts the same two ratios into a US school year, so 8.0 means the text should be manageable for an average eighth grader — roughly a 13 or 14 year old. It is an estimate of the reading level a text demands, not a judgement of quality. Because it uses only sentence length and syllable count, a grade of 8.0 says nothing about whether the vocabulary is familiar to your particular audience.
It averages words per sentence with the percentage of words the tool classes as complex — more than three letters and three or more syllables — then multiplies the total by 0.4. Higher means harder, and the result reads as a US grade level: around 8 for general audiences, 12 for a broadsheet newspaper, and above 17 for academic writing. Robert Gunning's original method excluded proper nouns, familiar compound words and verb endings such as -ed and -ing; this implementation does not, so its figure tends to run slightly high.
A word longer than three letters that the syllable estimator scores at three or more syllables — information, development, understanding. The estimator counts vowel groups and subtracts a silent final e, so it is a good approximation for regular English and less reliable for names, loanwords and irregular spellings. It is also purely mechanical: a familiar four-syllable word such as everybody is counted as complex, and an unfamiliar two-syllable technical term is not.
SMOG was defined on a sample of 30 sentences, and this tool returns 0 until your text reaches that length rather than reporting an unreliable extrapolation. Paste a longer passage and the card starts working. It is the one index here that deliberately refuses to answer on short input, which makes it the most trustworthy of the group on full documents such as a policy, a manual or a long article.
No. Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog and SMOG implement their published formulas. The Coleman-Liau, Automated Readability and Dale-Chall cards need inputs this tool does not collect — letters per 100 words for the first two, and the Dale-Chall list of 3,000 familiar words for the third — so they substitute the complex-word ratio instead. Their numbers move in a sensible direction as text gets harder, but they should not be compared with values from other readability checkers.
No request carries it off the page; the counting and every formula run in JavaScript in your tab. One thing to know: the tool also copies your text into the page URL so an analysis can be bookmarked or reloaded. That URL is visible in your address bar and saved in your browser history, so clear the box before sharing the link if the draft is confidential.
It depends entirely on who is reading. Plain-language guidance for public health, government and consumer information generally targets Flesch Reading Ease of 60 or above, equivalent to roughly grade 8. Marketing and blog copy tends to sit between 60 and 70. Technical documentation, contracts and academic papers routinely score in the 30s and should not be forced upwards at the cost of precision. Use the score to find the sentences that are longer than they need to be, not as a target to optimise.
Use Cases
Rewriting a Draft That Feels Heavy
Score the draft, split the three longest sentences, replace the worst of the abstract nouns, and score it again. The direction of the change tells you whether the edit did anything measurable.
Meeting a Plain-Language Requirement
Public health leaflets, benefit letters and consent forms are often held to a reading level in the region of grade 8. Check a page against Flesch-Kincaid and Gunning Fog before it goes for sign-off.
Matching Text to a Class
Teachers and course designers can check whether a handout, worksheet or extract sits near the year group it is meant for, and find the passages that will need reading aloud together.
Timing a Talk or a Voiceover
The speaking estimate divides your word count by 130 words per minute, which is close enough to plan a conference slot or a video script before you rehearse it with a stopwatch.
Auditing a Documentation Set
Run the same measurement over a dozen help articles and note which ones score far below the rest. Those outliers are usually the pages support keeps having to explain over the phone.
Settling an Argument About a Sentence
When a reviewer says a paragraph is dense and the author disagrees, paste both versions and compare the word-per-sentence figure. It moves the discussion from taste to a number both people can see.