Last checked by the TextEditor.com team
How each readability formula works
Every readability formula counts the same few things: sentences, words, and either syllables or letters. Long sentences and long words push the grade up. No formula reads for meaning, so a score is a quick check of length and nothing more.
Edit the sentence below. Split it, swap a long word for a short one, and watch every grade move.
| Formula | Score | Bar |
|---|---|---|
| Flesch Reading Ease | 21.6 | |
| Flesch-Kincaid Grade | 15.2 | |
| Gunning Fog | 20 | |
| SMOG | 17.1 | |
| Coleman-Liau | 15.6 | |
| Automated Readability Index | 14.9 |
20 words in 1 sentence, 39 syllables, 6 hard words. Combined grade: 16.6, college graduate.
| Formula | Made by | What it counts | Weak spot |
|---|---|---|---|
| Flesch Reading Ease | Rudolf Flesch, 1948 | Words per sentence and syllables per word. Gives 0 to 100, and higher is easier. | It is not a grade, so it is harder to explain to others. |
| Flesch-Kincaid Grade | J. Peter Kincaid for the US Navy, 1975 | The same two numbers, turned into a US school grade. | Very short sentences push it below zero: "Go. Run. Stop." scores −3.4. |
| Gunning Fog | Robert Gunning, 1952 | Words per sentence and the share of words with 3 or more syllables. Names and words made long by -ed, -es or -ing do not count. | Long words everyone knows, like "interesting", still count as hard. |
| SMOG | G. Harry McLaughlin, 1969 | Only the words with 3 or more syllables, scaled to 30 sentences. | Made for 30 sentences or more. A short text gives a rough guess. |
| Coleman-Liau | Meri Coleman and T. L. Liau, 1975 | Letters per 100 words and sentences per 100 words. No syllables. | A short word with many letters, like "strength", counts as long. |
| Automated Readability Index (ARI) | E. A. Smith and R. J. Senter for the US Air Force, 1967 | Characters per word and words per sentence. | Made for typewriters that counted key presses, so it reacts strongly to word length. |
The combined grade at the top of the tool is the average of the five grade formulas. Reading Ease is left out because it uses a different scale.
What a US reading grade means
A grade level is the US school year of a reader who could follow the text. Grade 8 fits a student of about 13 to 14 years old. Grades 13 to 16 are the four years of college.
A low grade does not make a text childish. It means more people can read it the first time through. This site writes all its pages for grade 7 to 8. The Hemingway Editor aims for grade 9 by default (checked November 2026).
| Grade | Usual age | Who reads at this level |
|---|---|---|
| 1 to 3 | 6 to 9 | Early readers, picture books |
| 4 to 5 | 9 to 11 | Children's books. The Children target in the tool. |
| 6 | 11 to 12 | Middle school start |
| 7 to 8 | 12 to 14 | Most adults read this with ease. The General public target and this site's own rule. |
| 9 to 10 | 14 to 16 | High school. Many news articles. |
| 11 to 12 | 16 to 18 | End of high school |
| 13 to 14 | 18 to 20 | College. The Academic target in the tool. |
| 15 to 16 | 20 to 22 | Late college, many science papers |
| 17 and up | 22 and up | Graduate school, legal text |
How syllables are counted
Most formulas need syllables, and a computer cannot hear words. The checker uses spelling rules. It counts the groups of vowels, drops a silent e at the end, adds one for pairs that split, like the "i-a" in "media", and handles endings like -ed, -es and -ly on their own.
Rules still miss some words, so a list of exceptions fixes words like "business" and "people". Some words have two right answers. "Every" has two syllables for most speakers and three for some, and dictionaries list both.
We tested the counter on a list of 353 everyday and academic words that we did not use while writing the rules. It got 345 of them right, about 98 percent. A plain count of vowel groups got 317 right. We then fixed some of the words it missed, like "soldier". Rules will always miss a few, like "hierarchy".
people2 business2 every2 created3 table2 idea3 quietly3
Words with 3 or more syllables are marked as hard in the tool.
Where one sentence ends and the next begins
A period does not always end a sentence. "Dr." and "e.g." have one, so does 3.14, and a web address can have several. A checker that splits at every period sees many short sentences, and the grade drops for no reason.
This checker keeps a list of common abbreviations, skips dots inside numbers and links, and looks at the next word. A small letter after the dot means the sentence goes on. A line break ends a sentence too, so headings and list items count on their own. Text pasted from a PDF often has a break at the end of every line, so fix those first in the text cleaner.
- Dr. Lee met us at 5 p.m. in the U.S. office.
- She paid $3.50 for tea, e.g. a small cup.
- See www.example.com/menu.html for prices.
- Was it good?
- Yes!
5 sentences. Splitting at every period, question mark and exclamation mark would give 16 pieces.
What the highlights mean and how to fix them
| Highlight | Example | How to fix it |
|---|---|---|
| Long sentence | Over 20 words, for the general public | Split it at "and", "but" or "which". Keep one idea in each sentence. |
| Hard word | "approximately" | Use a shorter word if there is one, here "about". Keep a long word when it is the right term. |
| Passive voice | "The form was signed by the manager." | Put the doer first: "The manager signed the form." |
| Adverb | "She walked very slowly." | Cut it, or pick a stronger verb: "She crept." |
| Wordy phrase | "due to the fact that" | Use the shorter choice: "because". |
| Repeated word | "the the", or "report" three times in two sentences | Delete the typo, or use "it" or another word. |
Passive voice is not wrong. It fits when the doer is unknown or does not matter: "The bridge was built in 1932." The checker finds it by a form of "be" followed by a past participle, so it also marks some adjectives, like "the shop is closed".
The wordy phrase list has 165 entries, such as "in order to" (use "to"), "prior to" (use "before") and "utilize" (use "use"). Click a purple phrase in your text and the line under the box shows the shorter choice, with a button to swap it in. To change one phrase all through a long document, use find and replace.
What readability scores cannot tell you
The formulas count length, not sense. Shuffle the words of a sentence and every score stays the same, even though the sentence no longer means anything.
The dog ran to the park and played with a red ball until the sun went down.
Flesch-Kincaid grade 3.5, Reading Ease 100. The score does not change when you shuffle.
Short words can still be hard. "The writ was void ab initio" scores at grade 2.5 on Flesch-Kincaid, yet few readers know what it means. Long words can be easy. "Interesting" and "television" both count as hard words in Gunning Fog.
A grade also ignores layout. Headings, short paragraphs and lists help readers, and none of that shows in a score. The formulas were made for English, and other languages have their own, such as the Fernández Huerta formula for Spanish. With only a few sentences the scores jump around, so check 100 words or more.
Plain language and the grade 7 to 8 rule
In the US, the Plain Writing Act of 2010 tells federal agencies to write documents for the public in clear language. The government's plain language guide on digital.gov says to express only one idea in each sentence. It suggests paragraphs of no more than 150 words, and never more than 250 (checked November 2026).
A grade covers only part of plain language. The rest is up to you: use the words your readers use, and put the main point first. The checker helps with what a computer can count. To see how much a rewrite changed, paste both versions into text compare.
Other tools for writers
- Count words and charactersHello world → 2 wordsThe word counter also checks the limits of social media.
- Compare two textsthe
oldnew catText compare marks what was added and what was removed. - Replace a word everywherecolour → colorFind and replace, with match case and regex patterns.
- Clean up pasted texta b → a bThe text cleaner removes extra spaces and hidden characters.