How to check the readability of your text
- Paste the text. Copy it from the page, document or email and paste it in the box. Leave out navigation, footers and code: they are not sentences and they skew the counts.
- Read the two scores. Flesch Reading Ease runs from about 0 to 100, where higher is easier. The Flesch-Kincaid grade level turns the same counts into a US school grade, where lower is easier.
- Fix the longest sentences first. The list under the scores ranks your sentences by length. Splitting the two or three longest usually moves both scores more than any other edit.
What the Flesch Reading Ease score means
Rudolf Flesch published the Reading Ease formula in 1948. It uses only two measures of a text: how long its sentences are and how many syllables its words have. Long sentences and long words make a text harder, so they lower the score.
Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
Flesch gave a table to read the result, with the school grade a reader would typically need:
| Score | Flesch's description | Typical reader |
|---|---|---|
| 90 to 100 | Very easy | 5th grade |
| 80 to 90 | Easy | 6th grade |
| 70 to 80 | Fairly easy | 7th grade |
| 60 to 70 | Standard | 8th and 9th grade |
| 50 to 60 | Fairly difficult | 10th to 12th grade (high school) |
| 30 to 50 | Difficult | College |
| 0 to 30 | Very difficult | College graduate |
Very short words and sentences can push the score above 100, and dense technical text can push it below 0. Both are valid results of the formula.
The Flesch-Kincaid grade level
In 1975, J. Peter Kincaid and colleagues recalculated Flesch's measures for the US Navy, testing them on enlisted personnel reading training manuals, and expressed the result as a school grade:
Grade level = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59
A grade of 8 means a text an average US eighth grader, around 13 or 14 years old, should be able to follow. Grades above 12 point to college-level reading. The grade is easier to explain to a team than the 0 to 100 scale, but it uses the same two inputs, so both scores always move together.
What score should you aim for
There is no single right score: it depends on the readers and what the text has to do. Some practical anchors:
- Websites, product pages and marketing emails are read quickly by people who are skimming. Text that scores in the standard band or easier (60 or more, about grade 8 to 9 or lower) asks the least of them.
- Instructions, forms and public information are read by everyone, including people reading in a second language or under stress. Plain, short sentences matter most here.
- Specialist content for professionals can score lower without a problem, as long as each sentence carries one idea. Technical terms lower the score but are often the clearest word for that reader.
A formula counts, it does not read. It cannot tell whether a sentence is clear, true or in the right order, and a text of short, vague words can score well and say nothing. Use the score to find the heavy passages, then judge them as a reader.
How to improve your score
- Split long sentences. A sentence that joins two ideas with “and”, “which” or a semicolon can usually become two sentences.
- Prefer the shorter word when it means the same: use for utilize, help for facilitate, start for commence, about for approximately.
- Turn nouns back into verbs. “We will carry out an evaluation of” becomes “We will evaluate”.
- Use lists for steps and options instead of a long sentence full of commas. Each item counts as its own sentence here when it is on its own line.
- Read it aloud. Where you run out of breath, the reader runs out of attention.
Why different tools give different scores
Every readability tool uses the same formulas, but each counts syllables and sentences its own way. English syllables cannot be counted perfectly by rules (compare “fire”, “hire” and “higher”), and tools disagree on whether a heading, a bullet or an abbreviation ends a sentence. The same text can differ by a few points between this page, Microsoft Word and other checkers. Compare scores from the same tool, before and after an edit, rather than across tools.
Methodology and limits
- Formulas
- Flesch Reading Ease (Flesch, 1948) and Flesch-Kincaid Grade Level (Kincaid et al., 1975), exactly as published, with the coefficients shown above. Scores are rounded to one decimal place.
- Sentences
- A sentence ends at a period, question mark or exclamation mark followed by a space or a line break, and at every line break. Common abbreviations (Mr., Dr., e.g., i.e., etc., vs.) and decimal numbers do not end a sentence.
- Words
- A word is a run of letters, which may include apostrophes and hyphens. Numbers and symbols are not counted as words.
- Syllables
- Counted by rule: groups of vowels (a, e, i, o, u and y) in each word, with corrections for a silent final e, the endings -es and -ed, and a final -le after a consonant, and a minimum of one per word. The count is right for most common English words and close for the rest.
- Reading time
- Words divided by 238 words per minute, the average silent reading rate for non-fiction in Brysbaert's 2019 review of 190 studies.
- Limits
- English only. Very short texts (under about 100 words) give unstable scores. The formulas say nothing about meaning, order, tone or accuracy.
Sources
- Flesch, R. (1948). A new readability yardstick, Journal of Applied Psychology, 32(3), 221 to 233, the Reading Ease formula and its interpretation table
- Kincaid, J. P., Fishburne, R. P., Rogers, R. L. and Chissom, B. S. (1975). Derivation of new readability formulas for Navy enlisted personnel, Research Branch Report 8-75, Naval Technical Training Command, the Flesch-Kincaid grade level formula
- Brysbaert, M. (2019). How many words do we read per minute? A review and meta-analysis of reading rate, Journal of Memory and Language, 109, the 238 words per minute reading rate