How to use the readability score calculator (flesch, grade level)
- Paste or type your text in the box. The scores update as you type, and the text never leaves your browser.
- Read the Flesch Reading Ease score, where a higher number means easier reading, and the Flesch-Kincaid grade level, which estimates a US school grade.
- Check the counts of sentences, words, syllables and characters. Tick the line break option if headings or list items lack end punctuation.
- Use Copy results to copy the scores and counts as plain text, without your original text.
The two formulas
Both scores come from the same three counts. Flesch Reading Ease is 206.835 - 1.015 x (words / sentences) - 84.6 x (syllables / words). The Flesch-Kincaid Grade Level is 0.39 x (words / sentences) + 11.8 x (syllables / words) - 15.59. Longer sentences and longer words lower the ease and raise the grade. These are the published formulas as listed on the Wikipedia article for the Flesch-Kincaid readability tests.
- Ease above 100 or a grade below 0 can happen with very short, simple sentences. The formulas are not limited to a range.
- Both scores are shown to one decimal, with halves rounded away from zero.
How the counts are made
The counts are estimates, because language is messy. The rules used are fixed and listed here so you can judge them.
- A word is a run of letters or digits, and it may contain apostrophes and hyphens. A hyphenated word such as well-known is one word whose syllables are added up.
- A number such as 2024 or 1,000 counts as one word of one syllable. In speech it has more syllables, so text full of numbers scores as easier than it reads aloud.
- Syllables are estimated from spelling by the same rules as the syllable counter: vowel groups, silent endings and a short list of exceptions. Words it misjudges, such as some borrowed or accented words, can be off by one.
- A sentence ends at a period, exclamation mark, question mark or ellipsis that is followed by a space or the end of the text, even when quote marks or brackets follow. Periods after Mr, Mrs, Ms, Dr, Prof, Sr, Jr, St, vs, Inc, Ltd, a single initial, or a dotted abbreviation such as U.S. or e.g. do not end a sentence. Etc. ends one only when a capital letter follows. Decimals such as 3.14 do not end one.
- Text with no ending mark is one sentence. Headings and list items without punctuation join the next sentence unless you tick the line break option.
- Only the first 200,000 characters are scored, and the page says so when your text is longer.
A small worked example
The text The cat sat. The dog ran! Did it sleep? has 3 sentences, 9 words and 9 syllables. Words per sentence is 3 and syllables per word is 1, so the ease is 206.835 - 3.045 - 84.6 = 119.19, shown as 119.2, and the grade is 1.17 + 11.8 - 15.59 = -2.62, shown as -2.6. A tiny sample like this is only a check of the arithmetic. Scores are steadier for passages of 100 words or more.
How to use the scores
Treat the numbers as a prompt for editing, not a verdict. Shorter sentences and plainer words raise the ease. The score cannot tell whether the facts are right, whether the ideas are clear, or whether your readers know the topic. Technical terms, names, lists and legal text can distort the result. Use the word counter to check length and the word count to pages converter for page estimates.
Privacy and limits
Everything runs in your browser. Nothing is uploaded, saved or sent anywhere, and the page keeps no copy of your text after you close it. The copy button copies only the scores and counts. Languages other than English are not supported, because the syllable rules are for English spelling.
Assumptions and limits
- The scores use the published Flesch Reading Ease and Flesch-Kincaid Grade Level formulas. Syllable counting and sentence splitting are approximations, so scores are estimates and other tools may give slightly different numbers.
- The score band table is reproduced as a reference from the Wikipedia article on the Flesch-Kincaid readability tests (fetched 2026-10-13). Boundaries between bands overlap in that source, so a score of exactly 10, 30, 50, 60, 70, 80 or 90 is placed in the higher band.
- Numbers count as one word of one syllable. Hyphenated words count as one word.
- English text only. Very long text is cut at 200,000 characters.
Frequently asked questions
What is a good Flesch Reading Ease score?
Higher is easier. In the published band table, 60 to 70 is described as plain English and 90 to 100 as very easy. A good score depends on your readers, so compare with similar material you know works.
Why is my grade level negative?
The grade formula has no floor. Very short sentences made of one syllable words, like a children's rhyme, push the result below zero. It means the text is easier than the formula's scale expects.
Why do two readability tools give different scores?
They count syllables and split sentences differently. Counting a number, a hyphenated word or an abbreviation another way changes the totals, so compare scores only from the same tool.
Does the copy button include my text?
No. It copies a short summary of the scores and counts only, so you can paste it into a report without sharing the original text.
Can I score a whole book?
Not at once. The tool reads the first 200,000 characters and tells you if it cut the text. Score chapters or samples separately instead.