The Readability Checker scores English text with the Flesch Reading Ease, Flesch-Kincaid Grade Level and Gunning Fog formulas. It shows the reading level, average sentence length and share of complex words, and lists the longest sentences worth splitting. Scores update as you type, and the text stays in your browser.
Made for marketers and seo. Typical uses:
A short passage of four simple sentences scores 117.4 (very easy, grade level below zero), while a single 17-word sentence full of long words scores -173.7 with 88% complex words. Real writing sits between these, and the useful signal is how the score changes as you edit.
The formulas were designed for English and count syllables by estimate, so results are a guide rather than exact. They do not judge accuracy, tone or structure.
Accuracy: Results show what the tool can measure at the moment you run it and can differ from what search engines see. Use them as guidance.
Expert Tip
Split every sentence the tool lists as too long and swap long words for short ones, then watch the Flesch score rise. Aim for 60 or higher on web pages meant for a general audience.
The Readability Checker scores English text with three well-known formulas and updates the scores as you type. The main score is the Flesch Reading Ease, from about 0 to 100, where a higher number is easier. Alongside it you get the Flesch-Kincaid grade level, the Gunning Fog index, the average words per sentence, the percentage of complex words and the counts of words, sentences and syllables. A list of long sentences shows the ones worth splitting.
All three use sentence length and word length, and they are simple enough to check by hand.
The tool labels the Flesch score and the audience it suits: 90 and above is very easy (5th grade), 80 to 89 easy (6th grade), 70 to 79 fairly easy (7th grade), 60 to 69 plain English (8th to 9th grade), 50 to 59 fairly difficult (10th to 12th grade), 30 to 49 difficult (college) and below 30 very difficult (college graduate). The box is green from 60, amber from 40 and red below that. Web content usually works best at 60 or higher, but a legal or scientific text for experts can legitimately score lower.
A short passage of simple sentences, "The cat sat on the mat. The dog ran to the park. We like to play. It is fun.", has 19 words in 4 sentences and scores 117.4, labelled very easy, with a grade level below zero and a Fog index of 1.9. Scores can go beyond 100 for very short words and sentences. One long sentence packed with words such as "organizational" and "multidimensional", 17 words long, scores -173.7 and a grade level of 41.7, with 88 percent complex words. Real writing falls between these, and what matters is the change as you edit.
The quickest gains come from splitting sentences of more than 25 words, which the tool lists with their word counts, and from replacing long words with short ones where the meaning is the same. Use the active voice, put the main point first, and break long paragraphs. Readability is not a direct ranking factor, but clear writing keeps people on the page. Check the length of the finished piece with the Word Counter for SEO and keyword use with the Keyword Density Checker.
The formulas were designed for English and the tool estimates syllables by rules, so results are a guide, not an exact measure, and they are unreliable for other languages. They do not judge accuracy, tone, structure or whether a text is interesting. Technical terms that cannot be replaced will raise the grade level. The Meta Description Generator helps summarise a finished page. The text stays in your browser.
Typical lengths for essays, articles, meta descriptions, social posts and speeches, plus how reading time and speaking time are calculated.
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