Readability Checker
Paste your text to get a live readability score: Flesch Reading Ease, Flesch-Kincaid grade level, Gunning Fog, SMOG and more, plus the exact sentences making your writing hard to read. Free, private, runs in your browser.
Type or paste text to see your reading level, readability scores and the sentences to fix.
Scores stabilize after about 100 words. Short samples swing hard.
Complex words have three or more syllables. Passive detection is a simple be verb plus past participle heuristic.
Very long text: scores are computed from the first 200,000 words.
Hardest sentences to fix first
Your longest, most complex sentences ranked by difficulty. Splitting or trimming these moves your readability score faster than any other edit.
Nothing to fix yet. Sentences over 25 words or heavy with complex words will show up here.
The six readability scores, explained
Every readability score is an estimate of the same thing: how much education a reader needs to understand your text on the first pass. Each formula weighs sentence length and word length a little differently, which is why this reading level checker shows all six and averages the five grade formulas into one headline number.
| Score | Formula inputs | Scale | Aim for |
|---|---|---|---|
| Flesch Reading Ease | Words per sentence, syllables per word | 0 to 100, higher is easier | 60 to 70 for the general public |
| Flesch-Kincaid Grade | Words per sentence, syllables per word | US school grade level | Grade 7 to 8 for the general public |
| Gunning Fog Index | Words per sentence, share of 3+ syllable words | Years of formal education | Under 10 for broad reach, 10 to 12 for B2B |
| SMOG Index | 3+ syllable words per 30 sentences | US school grade level | Under 10; the standard for health content |
| Coleman-Liau Index | Letters per 100 words, sentences per 100 words | US school grade level | Grade 7 to 9 for the general public |
| Automated Readability Index | Characters per word, words per sentence | US school grade level | Grade 7 to 9 for the general public |
As a rule of thumb: write for the general public at grade 7 to 8, which is where most major news outlets land. B2B, legal and technical content can run at grade 10 to 12 because the audience expects density. If your average grade level tops 13, roughly two thirds of US adults will struggle with it, and even expert readers prefer plain writing when the substance is equal.
Readability and SEO: the honest version
A readability score is not a direct ranking factor. Google has said repeatedly that it does not score pages on reading ease, so rewriting a page purely to nudge Flesch numbers will not move rankings by itself. What readability does move is everything downstream: whether visitors read past the first paragraph, scroll, click, convert, share and come back. Clear writing at the right grade level for your audience earns the engagement that content is supposed to produce.
The catch is measuring that engagement honestly. Raw pageviews cannot tell you whether anyone read the page, and bots inflate exactly the metrics you would check. DevDome Analytics separates real human visitors from bots on every metric, so you can see which articles people actually read and which ones only look popular.
Readability checker FAQ
What is a good readability score?
For most web content, aim for a Flesch Reading Ease of 60 to 70 and an average grade level of 7 to 8. That is plain English: comfortable for the general public without feeling dumbed down. B2B and technical content can sit at grade 10 to 12, since that audience reads dense material for a living. Anything above grade 13 loses most casual readers.
How does the Flesch Reading Ease calculator work?
The formula is 206.835 minus 1.015 times the average words per sentence, minus 84.6 times the average syllables per word. Shorter sentences and shorter words push the score toward 100 (very easy), while long sentences and polysyllabic words push it toward 0 (very confusing). It is the most widely used readability score and is built into Word and most editing tools.
What is the Flesch-Kincaid grade level?
It converts the same two inputs, words per sentence and syllables per word, into a US school grade. A Flesch-Kincaid grade level of 8 means an average eighth grader can read the text on the first pass. It was developed for the US Navy in 1975 to grade training manuals and is now the default reading level checker in most writing software.
What counts as a complex word in the Gunning Fog Index?
Words with three or more syllables. The classic Gunning Fog definition excludes proper nouns, familiar jargon and compound words, but no automated tool can judge familiarity reliably, so this checker counts every word with three or more syllables. On name-heavy text the Fog Index can read slightly high as a result.
Why does my readability score differ from other tools?
Syllable counting. English syllables cannot be counted perfectly without a pronunciation dictionary, so every readability checker uses a heuristic: vowel groups, silent e rules and an exceptions list. Small differences in those rules shift the syllable count, which shifts Flesch and Flesch-Kincaid results by a point or so between tools. Sentence splitting around abbreviations causes similar drift. The direction and the trend are what matter, not the second decimal.
How does the passive voice detection work?
It is a simple heuristic: a be verb (is, are, was, were, be, been, being) followed by a past participle, like "was written" or "is being reviewed". It catches most passive constructions but can flag descriptive phrases like "was tired", so treat the percentage as a pointer, not a verdict. Under 10 percent passive is a good target for web copy.
Is my text uploaded or stored anywhere?
No. The readability checker runs entirely in your browser and your text never leaves your device. Your draft is saved to your browser's local storage so a reload does not lose it, and pressing Clear removes it completely.
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