Paste your text to see how easy it is to read. You get the Flesch Reading Ease score, the US grade level from five formulas, and the sentences and words that make it harder than it needs to be.
| Formula | Score | What it means |
|---|
The longest and hardest sentences, with their words of three syllables or more in bold. Splitting one of these in two does more for the score than anything else.
Words of three syllables or more, most used first, with the number of syllables counted. A shorter word with the same meaning lowers the grade.
Flesch Reading Ease runs from 0 to 100, and higher is easier. Most adults read a text scoring 60 to 70 without effort, and that is a good target for anything written for the public. Below 50 it starts to feel like a contract or an academic paper.
The other five formulas give a US school grade: 8 means a 13 or 14-year-old could follow it. Advice for the public, such as patient information and letters from councils, is usually written for grade 6 to 8. The reading level at the top is the middle of the five, so one formula that runs high cannot pull it off on its own.
Every formula here comes down to two things: how long the sentences are and how long the words are. So the list under the scores shows the sentences that score worst, and the long words you use most. Split a long sentence where it says "and", "which" or "because", and swap a long word for a short one where one exists: use for utilize, help for facilitate, about for approximately.
The score follows as you type, so you can see each change make a difference.
For a web page, an email or a letter, look at Flesch Reading Ease and aim for 60 or more. For schoolwork and anything that has to fit a grade, use Flesch-Kincaid. For health information, use SMOG and aim for grade 8 or below.
All six were made in the United States between 1948 and 1975, to check that school books, newspapers, manuals and leaflets matched the people who had to read them. They count different things, so they rarely agree to the decimal, but they almost always agree on whether a text is easy or hard.
Flesch Reading Ease (Rudolf Flesch, 1948): 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). The best known score, and the one Microsoft Word shows in its readability statistics.
Flesch-Kincaid Grade Level (J. Peter Kincaid and colleagues for the US Navy, 1975): 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. The same two measures as Flesch, turned into a school grade.
Gunning Fog Index (Robert Gunning, 1952): 0.4 × (words ÷ sentences + 100 × complex words ÷ words). A complex word has three syllables or more, but names, compound words with a hyphen, and words that only reach three syllables with -es, -ed or -ing do not count.
SMOG (G. Harry McLaughlin, 1969): 1.043 × √(words of 3+ syllables × 30 ÷ sentences) + 3.1291. Made for samples of 30 sentences, and widely used for health information because it predicts full understanding rather than half.
Coleman-Liau Index (Meri Coleman and T. L. Liau, 1975): 0.0588 × letters per 100 words − 0.296 × sentences per 100 words − 15.8. It counts letters instead of syllables, so it does not depend on how syllables are counted.
Automated Readability Index (E. A. Smith and R. J. Senter, 1967): 4.71 × (characters ÷ words) + 0.5 × (words ÷ sentences) − 21.43. Also built on characters, originally so a typewriter could count them as you typed.
Syllables are counted from the spelling, as every readability tool does: vowel groups, with rules for silent endings such as the e in "make", the -ed in "walked" and the -es in "times", and a list of common words English spells one way and says another. On ordinary English it gets about 96 words in 100 right, and the errors go both ways, so the scores land where a hand count would. The long-word list shows each word's count, so you can see what was counted.
60 to 70 is plain English that most adults read without effort, and a good aim for websites, emails and letters. 70 and above is easy, the level of a novel for teenagers. Below 50 the text is hard going for most readers, and below 30 it reads like a legal or academic paper. A score is not good or bad on its own: a research paper for specialists may score 30 and be just right.
0.39 × the average words per sentence, plus 11.8 × the average syllables per word, minus 15.59. The result is a US school grade, so 8.0 means a 13 or 14-year-old could read the text. It uses the same two measures as Flesch Reading Ease, which is why the two scores always move together: when one goes up, the other goes down.
They measure the same thing on different scales. Flesch Reading Ease gives a score from 0 to 100 where higher is easier. Flesch-Kincaid Grade Level turns the same sentence and word length into a US school grade, where lower is easier. A Reading Ease of 60 to 70 is about grade 8 to 9.
Each one counts something slightly different. Flesch-Kincaid and SMOG count syllables, Gunning Fog counts words of three syllables or more, and Coleman-Liau and ARI count letters. A text with short sentences but long technical words scores higher on SMOG and Fog than on Coleman-Liau. That is why the reading level at the top is the middle of the five, not any single one of them.
Health organizations in the US usually advise a 6th to 8th grade reading level for information meant for patients and the public, and the SMOG index is the formula most often used to check it. Many adults read below the level of their schooling, and fewer still at their best when they are ill or worried.
From the spelling, as in every readability tool. Groups of vowels count as one syllable each, with rules for endings that are not said, like the e in make and the -ed in walked, and a list of common words that break the rules. It gets about 96 words in 100 right, and the mistakes go both ways, so the scores come out close to a hand count. The list of long words shows the count for each word, so you can check it.
The formulas were made for English, and the syllable counting follows English spelling, so the scores for other languages are not reliable. German, Spanish, French and other languages have their own versions of the Flesch formula, with different numbers in them, and those are not used here.
No. The checker runs in your browser, and the text you paste never leaves your computer. Nothing is stored either, so a reload or closing the tab is the end of it.