Check how easy your text is to read

The Flesch Reading Ease score measures how easy a text is to read. Rudolf Flesch published it in 1948 in the article A new readability yardstick[1]. The score usually falls between 0 and 100, and the higher it is, the less effort the text takes.

The formula uses two numbers that a program can count without understanding the text: the average sentence length in words and the average number of syllables per word. Long sentences and long words lower the score. Short sentences of one-syllable words reach 100, and a single sentence that runs for dozens of long words drops below zero.

In 1975, J. Peter Kincaid and his team turned the same two averages into a US school grade. They derived the new formula from reading tests taken by 531 Navy enlisted personnel in four technical training schools[2]. That version is known as the Flesch-Kincaid grade level. Another grade-level formula, the Gunning fog index, counts the words of three or more syllables instead of averaging syllables per word.

The calculator above shows both results, together with the level of difficulty, the syllables per word and the name of the formula it used. The versions of this page in other languages use formulas adapted to those languages, because the English numbers don't fit their longer words.

Multiply the average sentence length by 1.015 and the average number of syllables per word by 84.6, add the two results and subtract the sum from 206.835[3]. Take the sentence “The Australian platypus is seemingly a hybrid of a mammal and reptilian creature.” It has 13 words and 24 syllables. The sentence part takes away 1.015 × 13, which is 13.195. The word part takes away 84.6 × 24 ÷ 13, which is 156.18. That leaves 37.5, a Difficult text.

The Flesch-Kincaid grade level uses the same two averages with other weights[2]: 0.39 × 13 plus 11.8 × 24 ÷ 13, minus 15.59, gives 11.3, roughly the level of a US eleventh grader.

The calculator does all of this while you type. The Flesch score panel shows the Flesch score, the Level, the Flesch-Kincaid grade level, Syllables per word and the Formula used. A result appears once the text has at least three words.

Flesch gave precise counting rules[3]. Syllables are counted as the words are pronounced, and when a word has two accepted pronunciations, the one with fewer syllables counts. Figures, symbols and abbreviations count as one-syllable words, while contractions and hyphenated words count as one word each.

The calculator treats numbers and addresses the same way: a number such as 17 or 3.5 counts as one syllable, and so does a web or email address. English spelling doesn't show every syllable, so for words the calculator applies rules for silent letters and vowel pairs, listed in the table below.

We tested those rules on the 3,000 most frequent words in English film subtitles[4], comparing each word with its pronunciation in Wiktionary[5]. Before our corrections of 19 September 2026, the calculator counted 94.7% of the words correctly, and after them 99.2%.

A sentence ends at a period, a question mark, an exclamation point or a line break, so every line of a list counts as a sentence. A period after an abbreviation such as Dr. or e.g. doesn't end a sentence. Flesch also ended a sentence at a colon, semicolon or dash that closes a full unit of speech[3], which takes a human reader to judge. In the calculator, a long sentence with semicolons counts as one sentence.

Only with a formula adapted to each language. French, German, Spanish and the other languages we measured use longer words than English, so the English formula gives the same content a lower score even when it reads just as easily.

The table below shows the size of that effect on the introductions of 312 tools on this site, written separately in eight languages. An average English word has 1.41 syllables and an Italian one 1.96, so the English formula gives the English texts 73 points and the Italian ones 26.2. The adapted formulas close most of that gap, and each language version of this calculator uses its own.

Word shows both scores in its Readability Statistics window, which opens after a spelling and grammar check[12]. In Word for Microsoft 365 on the Current Channel, go to Home, then Editor, then Document stats. In older versions, such as Word 2016, go to File, then Options, then Proofing, select Check grammar with spelling and Show readability statistics, and run Spelling & Grammar. On a Mac, the same options are under Word, then Preferences, then Spelling & Grammar.

Microsoft's help page gives both formulas and recommends a score between 60 and 70 for most standard files[12]. It doesn't say how Word counts syllables, and that is where Word and this calculator part ways.

We ran four sentences through Word 2016 and through this calculator on 19 September 2026. Word gave the platypus sentence 24.4, which means it counted 26 syllables, two more than the 24 in the worked example on Wikipedia[13]. Word also showed no grade above 12, even for a sentence of long technical words for which the formula gives 39.6. Word's window also lists the number of words and sentences, and the word and character counter gives the same counts for comparison.

In English, both parts of the formula count. One syllable less per word adds 84.6 points, and one word less per sentence adds about one point. Real edits move the syllable average by only a fraction, so the two effects end up close.

The blog paragraph and the news item in the table above show the balance. The blog paragraph scores 76.5 and the news item 59.6, which is 16.8 points lower. Longer sentences account for 9.1 of those points and longer words for 7.7.

Flesch's own advice starts with sentences: break a long one into two, three or four shorter ones, even if they start with And, But or Or[3]. Then go after long words with prefixes and suffixes. He suggests replacing establishment, available and required with setting up, in stock and called for. The word and character counter shows the average sentence length while you edit.

Flesch set the minimum for Plain English at 60, which is about 20 words per sentence and 1.5 syllables per word. For conversational English aimed at consumers, he asked for at least 80[3]. Microsoft recommends 60 to 70 for most documents[12].

Flesch's tests of magazines and newspapers show what the numbers mean in print[3]: comics scored 92, Reader's Digest 65, Time 52 and The New York Times 39. This page's own prose scores 64.3 in the same calculator, at 1.48 syllables per word.

For a text that many people must read, such as a product page or instructions, aim for 70 and above. A specialist article can sit lower, because its readers came for the detail and accept a longer sentence when it carries it. To tell readers how long the text will take, use the reading time calculator. A very short text, such as a page title, gets a score that swings with every word. For titles and descriptions, length matters more, and the meta title and description checker measures it.

Only in part. Kincaid's report cites an earlier finding that readability formulas predicted schoolchildren's results in reading comprehension tests with a validity coefficient of about 0.70. That accounts for about half of the differences between texts[2].

The formula sees only the length of sentences and words. It can't tell whether your readers know the words, whether the ideas follow in a sensible order or whether the layout helps. A text of short, common words in a confusing order can score well and still be hard to follow. For text on a screen, the color contrast checker shows whether the text and background colors meet the WCAG levels.

Use the score to find the passages worth rewriting, then read them again with your readers in mind.