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Flesch-Kincaid calculator: reading ease and grade level
Convertica's free Flesch-Kincaid calculator scores any English text for Flesch Reading Ease and Flesch-Kincaid Grade Level. It shows the words, sentences and syllables it counted, lists your longest sentences and longest words, and runs in your browser, so the text you paste is never sent anywhere.
Short answer
A Flesch-Kincaid calculator scores how easy English text is to read with two published formulas: Flesch Reading Ease, from about 0 to 100 with higher being easier, and Flesch-Kincaid Grade Level, a US school grade. Both use only average sentence length and average syllables per word. Convertica's runs in your browser and shows every count.
- Reading Ease = 206.835 - 1.015 × words per sentence - 84.6 × syllables per word. Grade Level = 0.39 × words per sentence + 11.8 × syllables per word - 15.59.
- Rudolf Flesch published the Reading Ease formula in 1948. The grade level version was fitted for the US Navy in 1975, from tests of 531 enlisted personnel.
- Counting syllables in English is an estimate. The calculator states its rules and shows its counts, so you can check them.
- The scores see sentence length and word length only. They cannot judge meaning, order, or whether your reader knows your terms.
- There is no score every page should reach. Compare a draft with your audience and with your own earlier version.
Score your text
Free to use, no sign-up. It runs in your browser: nothing you paste is sent anywhere. The result updates as you type.
Flesch Reading Ease
73.0
Flesch-Kincaid Grade Level: 7.3
On Flesch's table, 70 to 80 is 7th grade.
119 words, 7 sentences, 164 syllables (estimated).
Average sentence length: 17.00 words. Average syllables per word: 1.38.
Cross-check without syllables (Automated Readability Index): grade 8.9.
The working
Average sentence length = 119 words / 7 sentences = 17.00
Average syllables per word = 164 syllables / 119 words = 1.378
Reading Ease = 206.835 - 1.015 * 17.00 - 84.6 * 1.378 = 73.0
Grade Level = 0.39 * 17.00 + 11.8 * 1.378 - 15.59 = 7.3Syllables per word is shown to three decimals. The scores use the unrounded averages.
Longest sentences
Paste some text to see its longest sentences.
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Use them to find the sentences and words worth a second look, then let a reader, or a test, judge the result.
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Both formulas look at only two things: how long your sentences are, and how many syllables your words have.
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A Flesch-Kincaid calculator scores how hard a piece of English text is to read, using two published formulas.
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That makes the scores a fast check on sentence and word length, not a verdict on the writing.
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Flesch Reading Ease gives a number that usually falls between 0 and 100, where higher means easier.
Words with the most syllables
Paste some text to see its longest words.
No word in this text has 3 syllables or more.
- calculator
- interesting
- usually
- flesch-kincaid
- formulas
- sentences
- easier
- syllables
What is a Flesch-Kincaid calculator?
A Flesch-Kincaid calculator scores how hard a piece of English text is to read, using two published formulas. Flesch Reading Ease gives a number that usually falls between 0 and 100, where higher means easier. The Flesch-Kincaid Grade Level turns the same counts into a US school grade.
Both formulas look at only two things: how long your sentences are, and how many syllables your words have. They cannot tell whether the text is true, well ordered or interesting. That makes the scores a fast check on sentence and word length, not a verdict on the writing. Use them to find the sentences and words worth a second look, then let a reader, or a test, judge the result.
Those two paragraphs are the text the calculator starts with. They score 73.0 for reading ease and grade 7.3, from 119 words, 7 sentences and an estimated 164 syllables.
How to use the calculator
- Paste the running text. Body copy only. Flesch's own instruction was to test running text and to skip titles, headings, captions and the like.
- Read the two scores together. They come from the same counts and move in opposite directions: when reading ease goes up, the grade goes down.
- Check the counts. If the number of sentences looks wrong, a heading or a list has probably been counted as sentences. The rules are in the table further down.
- Go to the longest sentences first. The list shows up to 5, longest first. Splitting one of them usually moves the scores more than any other edit.
- Then look at the long words. The second list shows up to 10 words of 3 syllables or more. Keep the ones your reader expects and swap the rest.
- Score it again. Compare the new result with your last version, not with a target from someone else's page.
What are the Flesch Reading Ease and Flesch-Kincaid Grade Level formulas?
The Flesch Reading Ease formula is 206.835 minus 1.015 times the average sentence length in words, minus 84.6 times the average number of syllables per word. The Flesch-Kincaid Grade Level formula is 0.39 times the average sentence length, plus 11.8 times the average syllables per word, minus 15.59.
Flesch Reading Ease = 206.835 - 1.015 * (words / sentences) - 84.6 * (syllables / words)
Flesch-Kincaid Grade Level = 0.39 * (words / sentences) + 11.8 * (syllables / words) - 15.59Both use the same two measurements, so they nearly always agree about which of two drafts is harder. They differ in what they report. Reading Ease is a score where higher is easier. Grade Level is a US school grade, where higher is harder.
Where the formulas come from
Rudolf Flesch published the Reading Ease formula in 1948, in the Journal of Applied Psychology paper A new readability yardstick. He restated it for general readers in his 1979 book How to Write Plain English, and the constants on this page were checked against his own wording there.
The grade level version came from the US Navy. In 1975 J. Peter Kincaid, Robert P. Fishburne Jr., Richard L. Rogers and Brad S. Chissom tested 531 Navy enlisted personnel on 18 passages from Navy training manuals, and refitted Flesch's formula so that it gives a grade directly, where the original needed a conversion table (Research Branch Report 8-75). That is why the result carries both names.
A worked example
The text in the calculator has 119 words in 7 sentences and an estimated 164 syllables:
Average sentence length = 119 words / 7 sentences = 17.00
Average syllables per word = 164 syllables / 119 words = 1.378
Reading Ease = 206.835 - 1.015 * 17.00 - 84.6 * 1.378 = 73.0
Grade Level = 0.39 * 17.00 + 11.8 * 1.378 - 15.59 = 7.3Sentence length takes 17.3 points off the starting 206.835 and word length takes 116.6. Of that second figure, 84.6 is fixed, because every word has at least one syllable. What a writer can change is the rest: 32.0 points from syllables beyond the first, and the 17.3 from sentence length.
As a check on the code, Flesch scores his own example sentence, "John has a profound affection for Mary.", at 67 in that book. The calculator counts 7 words and 11 syllables and gets 66.8.
What does a Flesch Reading Ease score mean?
A Flesch Reading Ease score says how easy a text is to read, on a scale that usually runs from 0 to 100. Higher is easier. Flesch's own table ties each band to the US school level that should find the text easy: 90 to 100 is 5th grade, and 0 to 30 is college graduate.
| Reading Ease score | Easy for students at this level |
|---|---|
| 90 to 100 | 5th grade |
| 80 to 90 | 6th grade |
| 70 to 80 | 7th grade |
| 60 to 70 | 8th and 9th grade |
| 50 to 60 | 10th to 12th grade (high school) |
| 30 to 50 | College |
| 0 to 30 | College graduate |
The bands are the scale's own definition, taken from Flesch's chapter. They are not advice about your page. His ranges share their end points; the calculator puts a score that lands on a boundary, such as 70, in the easier band.
In the same chapter Flesch calls 60 the minimum score for what he named Plain English. That is his label for a point on the scale. It is not evidence about what your visitors need.
Can the score go above 100 or below 0?
Yes. The formula has no limits built in. One-syllable words in one-word sentences score 121.2, the highest possible. Long sentences of long words go below zero: Flesch himself reported a score of minus 6 for the US Internal Revenue Code. The calculator shows the score it gets and does not force it into the range 0 to 100.
What does a Flesch-Kincaid Grade Level mean?
A Flesch-Kincaid Grade Level is an estimate of the US school grade a reader needs to follow a text, worked out from sentence length and syllables alone. A grade of 8 points to 8th grade, and 12 to the last year of high school. Grades 13 to 16 are the four years of college.
Three things from the Navy report are worth knowing when you read the number:
- It was fitted to one group of readers. The grades are those of Navy personnel reading Navy training material, and the authors wrote that the recalculated formulas are specifically for Navy use.
- It was fitted to a range. The 18 test passages ran from grade 5.5 to 16.3. Outside that range the formula is extrapolating, and the calculator says so when your result falls outside it.
- It is not precise. The report itself says readability formulas are accurate only to within one grade level. A change of a few tenths between two drafts is noise.
The lowest possible result is -3.4, for one-syllable words in one-word sentences, so a negative grade is not a fault in the tool. It means the text is simpler than the scale was built for.
How the calculator counts words, sentences and syllables
The formulas are simple. The counting is where tools differ. Convertica's calculator counts words and sentences by fixed rules, taken from Flesch's and the Navy report's own instructions where they give them, and estimates syllables with the rule set written out below. Every result shows its counts, so you can check them.
| What | Rule | Where it comes from |
|---|---|---|
| Words | Anything between spaces that holds a letter or a digit. A hyphenated word, a contraction, a figure and a web address are one word each. A dash or a slash between two words splits them | Flesch (1979) and the Navy report, Appendix B |
| Sentences | A sentence ends at a period, question mark or exclamation point followed by a space, and at a line break, so a heading or a list item is its own sentence. It does not end at a period inside a number or a web address, after a listed abbreviation such as Dr. or e.g., after an initial, or at an ellipsis followed by a small letter | Convertica's rules. Flesch and the Navy report also end a sentence at a colon or semicolon when a full thought follows, which software cannot judge |
| Syllables | Vowel groups, corrected for silent endings and for vowel pairs said as two sounds, plus a list of exceptions | Convertica's rules, checked against the CMU Pronouncing Dictionary |
| Abbreviations, figures and symbols | One syllable each: SEO, U.S., 17, $15, 7% and a web address all count as one | Flesch (1979). The Navy report counts them as they are spoken, which the calculator does not attempt |
A line that was wrapped by an email program or copied from a PDF is joined to the next one when the next line starts with a small letter. Text typed mostly in capitals is read as words, not as abbreviations.
How syllables are counted
English spelling does not map cleanly to sound, so every syllable counter that works from letters is an estimate. This one works in five steps:
- Count the vowel groups in the word: a, e, i, o, u, and y where it acts as a vowel. "Reading" has two.
- Take away a silent ending: the e in "make", the es in "makes", the ed in "used". Keep it where it is sounded, as in "table", "boxes" and "wanted".
- Split vowel pairs that are said as two sounds: "create", "idea", "radio", "client". Leave the ones said as one, as in "nation", "social" and "patient".
- Find a silent e inside a word: "framework", "statement", "likely".
- Check a list of exceptions for words the rules still get wrong, such as "business", "every" and "recipe".
Convertica checked the counter against the CMU Pronouncing Dictionary, a public dictionary of American English pronunciations. On a public list of about 10,000 common English words, which was also used to tune the exception list, it agreed with the dictionary on 98.8% of the 8,607 words of four letters or more that the dictionary lists. Across all 117,493 plain entries in the dictionary, many of them surnames and place names, it agreed on 94.4%. The tool's own tests also hold a hand-counted list of more than 1,000 words that it has to get right.
It still miscounts some words. It counts "ethically" as 3 where it is said with 4, "agreeable" as 3 where it is said with 4, "acme" as 1 where it is said with 2, "Nike" as 1 where it is said with 2 and "karaoke" as 3 where it is said with 4. One miscounted word in a text of 300 words moves the reading ease by about a quarter of a point. In a text of 20 words it moves it by about four points, which is one reason to read the scores of a short text as rough.
Why your score differs from Microsoft Word or another tool
Two tools can use the same formula and report different scores, because they count differently. They may end sentences in different places, count a heading as a sentence or not, read a number as one syllable or as it is spoken, and estimate syllables with different rules. A difference of a few points in reading ease is normal. Compare drafts within one tool, not one draft across tools.
Flesch-Kincaid examples: one message, three versions
The table runs one message about a made-up payroll product through the calculator three times: as one long sentence, split in two with the same words, and rewritten in short sentences and plain words. The texts are illustrations of how the formulas respond. They are not client copy and not a benchmark.
| Version | Text | Words per sentence | Syllables per word | Reading Ease | Grade Level |
|---|---|---|---|---|---|
| One long sentence, long words | Our payroll platform automates salary calculations, tax deductions and compliance paperwork, which allows growing companies to considerably reduce the administrative work involved in paying their employees every month. | 28.00 | 2.18 | -5.9 | 21.0 |
| Split in two, same vocabulary | Our payroll platform automates salary calculations, tax deductions and compliance paperwork. It allows growing companies to considerably reduce the administrative work involved in paying their employees every month. | 14.00 | 2.18 | 8.3 | 15.6 |
| Short sentences, plain words | Run payroll for your whole team in minutes. The software works out pay and tax, then files the forms for you. You check the numbers and click approve. | 9.33 | 1.18 | 97.7 | 2.0 |
- Splitting the sentence changes only the words per sentence, from 28.00 to 14.00. Reading ease rises from -5.9 to 8.3, and the text is still hard, because the words are the same.
- Plain words do most of the work. Syllables per word falls from 2.18 to 1.18, and reading ease moves from 8.3 to 97.7.
The third version also tells the reader something the first two do not: what they will do, and how long it takes. The formula did not reward that. It rewarded short words and short sentences.
Two texts the formulas get wrong
Because the formulas see only length, a text can score as very easy and still fail the reader.
- Short and empty. "We do it all for you. It is fast and it is good. You will love what we do. Try it now and see." scores 116.1, easier than anything on Flesch's table, and says nothing about the product.
- Short and full of jargon. "Sync SKUs to your ERP via SFTP. Set the TTL, map the SSO and ship." scores 109.0, because each abbreviation counts as one short word. A reader who does not know the terms cannot follow it.
The opposite happens too. A long word everyone knows, such as "information", costs as many points as a long word nobody knows.
What is a good Flesch-Kincaid score?
There is no Flesch-Kincaid score that is good for every text. The formulas measure sentence length and word length, and whether that length suits a page depends on who reads it and what they already know. A good score is one that fits your readers and is no harder than the text needs to be.
Many pages quote a target, often with a statistic about reading levels or conversion rates beside it. Convertica does not repeat those here. The figures are rarely traced to a primary source, and a target taken from another audience says little about yours. Three comparisons are more useful:
- Against your reader. A page for specialists can carry the terms they use every day. A checkout page for the general public cannot. Decide who the page is for before you decide what the number should be.
- Against your own last version. Score the text before and after an edit. The direction of the change is more reliable than the number itself.
- Against the pages around it. If one page in a funnel scores far harder than the pages before it, look at that page first.
Use the bands in Flesch's table to describe where a text sits, not to decide whether it passes.
How to lower a Flesch-Kincaid grade level without hurting the copy
To lower a Flesch-Kincaid grade level, shorten the longest sentences and replace long words with shorter ones that mean the same. Those are the only two things the formula measures. Start with the sentences and words the calculator lists, and stop when an edit would cost the reader a fact or a term they came for.
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Split the longest sentences first
Flesch's first tip was to cut the average sentence length by breaking long sentences into two or three. He added that a sentence may start with And, But or Or, and that this has been good English for centuries.
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Swap long words where a short one says the same
His second tip was to aim first at words built from prefixes and suffixes, and to try two short words in their place: "setting up" for "establishment", "in stock" for "available", "called for" for "required".
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Keep the words your customer uses
A long word your buyer searches for and expects to see should stay. Good copy reuses the customer's own words, which is the starting point of Convertica's conversion copywriting guide.
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Cut what does not need saying
The formulas do not count total length, but your reader does. Every sentence a visitor has to read before they find the offer is work, and that work is the subject of the guide on how to reduce cognitive load.
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Do not write to the formula
Chopping every sentence to five words produces a high score and a text that reads like a telegram. The score is a check on a draft. It is not a way to write one.
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Read it aloud, then score it again
Your ear catches what the formula cannot: a sentence that is short and still confusing, or two that belong together.
Headlines are a special case. One line is too small a sample for either formula, which is why Convertica's headline analyzer reports a reading grade and does not score it.
Does a better readability score raise conversions?
A readability score cannot tell you that. It measures the text, not the visitor. Easier text may help when a page asks people to understand an offer quickly, but whether a rewrite lifts orders or leads on your page is something only your own data can show. Treat a plainer draft as a hypothesis and test it.
- Score both versions and keep the two texts, so you know what was tested.
- Work out the sample before you start. The A/B test sample size calculator turns your conversion rate and the smallest lift worth finding into visitors per variant.
- Run both versions to that sample and judge them on orders or leads, not on time on page.
- Read the result properly. The statistical significance calculator shows whether the difference is larger than chance would explain.
The A/B testing guide covers the method in full. If the page does not have the traffic for a test, ask a few people from your audience to read it once and tell you what you sell. And remember that copy sits on a page: the free landing page analyzer checks the page as a whole, and the first of the eight checks in Convertica's free CRO audit is whether a visitor can tell what you offer without scrolling.
How to get Flesch-Kincaid scores in Microsoft Word, Excel or Google Sheets
Microsoft Word reports both Flesch scores in its readability statistics. Excel and Google Sheets have no readability function and no built-in way to count syllables, so a spreadsheet can only apply the formulas to counts you already have.
In Microsoft Word
In Word for Microsoft 365, Microsoft's instructions are to open the Home tab, choose Editor, then Document stats. In older desktop versions, go to File, Options, Proofing, tick "Check grammar with spelling" and "Show readability statistics", then run Spelling & Grammar. Word shows Flesch Reading Ease and Flesch-Kincaid Grade Level, and Microsoft's help page gives the same two formulas this page uses.
In Excel or Google Sheets
Put the word count in B1, the sentence count in B2 and the syllable count in B3. The calculator on this page gives you all three.
Reading Ease: =206.835-1.015*(B1/B2)-84.6*(B3/B1)
Grade Level: =0.39*(B1/B2)+11.8*(B3/B1)-15.59To count the words of a text in cell A1, use =IF(TRIM(A1)="",0,LEN(TRIM(A1))-LEN(SUBSTITUTE(TRIM(A1)," ",""))+1). Syllables are the part a spreadsheet cannot do alone, and the part a dedicated tool does for you.
How Flesch-Kincaid compares with other readability formulas
Most readability formulas measure the same two things as Flesch's, sentence length and word length, and differ in how they decide that a word is long. The table lists three that are often shown beside the Flesch scores. The calculator reports one of them, the Automated Readability Index, as a cross-check, because it needs no syllable count.
| Formula | What it counts | Result | Published |
|---|---|---|---|
| Flesch Reading Ease | Words per sentence and syllables per word | A score, where higher is easier | Flesch, 1948 |
| Flesch-Kincaid Grade Level | Words per sentence and syllables per word | A US school grade | Kincaid, Fishburne, Rogers and Chissom, 1975 |
| Automated Readability Index | Words per sentence and characters per word, where every letter, number and punctuation mark is a character | A US school grade | Senter and Smith, 1967 |
| SMOG | Words of three or more syllables in 30 sentences: 10 from the start of the text, 10 from the middle and 10 from the end | A grade: 3 plus the square root of that count | McLaughlin, 1969 |
| Gunning Fog Index | Average sentence length, and words of more than two syllables per 100 words | A grade: 0.4 times the two added together | Gunning, 1952, as given in DuBay, 2004 |
The Automated Readability Index is 0.50 × words per sentence + 4.71 × characters per word - 21.43. When it and the Flesch-Kincaid grade are far apart, the text probably holds something one of them reads badly. Web addresses and long numbers raise the index, because each is one word of many characters. So do words that are long on the page and short to say, such as "through" and "strengths".
The calculator does not report SMOG or the Gunning Fog Index. SMOG is defined on a sample of 30 sentences, which most pasted copy does not have. Gunning published his formula in a 1952 book that Convertica has not read in the original, so it is described here from a secondary source and not calculated.
Related tools and guides
Reading level is one check on a page's copy. These pages cover the others.
See all free tools and how they fit together.
Flesch-Kincaid calculator FAQ
What is a Flesch-Kincaid calculator?
A Flesch-Kincaid calculator is a tool that scores how easy English text is to read with two published formulas. It counts the words, sentences and syllables in the text, then reports a Flesch Reading Ease score, where higher is easier, and a Flesch-Kincaid Grade Level, which is a US school grade.
Is this Flesch-Kincaid calculator free?
Yes. The Flesch-Kincaid calculator is free, with no sign-up and no limit on how often you use it. It runs entirely in your browser, so the text you paste is not sent to a server or stored anywhere.
What is the Flesch Reading Ease formula?
Flesch Reading Ease = 206.835 - 1.015 × (words / sentences) - 84.6 × (syllables / words). Rudolf Flesch published it in 1948. Longer sentences and longer words both lower the score, and a higher score means easier text.
What is the Flesch-Kincaid Grade Level formula?
Flesch-Kincaid Grade Level = 0.39 × (words / sentences) + 11.8 × (syllables / words) - 15.59. J. Peter Kincaid and three colleagues fitted it for the US Navy in 1975 from Flesch's formula, so that the result is a US school grade and needs no conversion table.
What is a good Flesch-Kincaid score?
There is no single good Flesch-Kincaid score. The formulas measure sentence length and word length, and whether that length suits a text depends on who reads it. Judge a score against your own readers and against your own earlier version, not against a target taken from another audience.
What does a Flesch Reading Ease score of 60 mean?
On Rudolf Flesch's own table, a score from 60 to 70 is text that students in 8th and 9th grade should find easy, and 60 is the lowest score he counted as Plain English. A score of 60 tells you about sentence and word length. It does not tell you whether the text is clear.
What does a Flesch-Kincaid grade level of 12 mean?
A grade level of 12 means the formula estimates the text suits a reader in the 12th grade of a US school, the last year of high school. It is an estimate from sentence length and syllables alone, and the Navy report behind the formula says readability formulas are accurate only to within about one grade level.
Can a Flesch score be above 100 or below 0?
Yes. The formula has no limits built in. One-syllable words in one-word sentences score 121.2, the highest possible, and long sentences of long words score below zero. Flesch himself reported a score of minus 6 for the US Internal Revenue Code.
How does the calculator count syllables?
It estimates them. It counts the groups of vowels in each word, removes silent endings such as the e in make, splits vowel pairs that are said as two sounds, and checks a list of exceptions. Abbreviations, figures and symbols count as one syllable each, which is Flesch's own rule.
Why is my score different in Microsoft Word or another tool?
Because tools count differently. Two tools can use the same formula and still disagree on where a sentence ends, whether a heading is a sentence, and how many syllables a word or a number has. Differences of a few points are normal, so compare drafts within one tool.
Does the calculator work for languages other than English?
No. Both formulas were fitted to English text, and the syllable rules follow English spelling. Text in another language gets a number, but the number does not mean what the scale says. The calculator warns you when most of the text is not in the Latin alphabet.
Does a higher readability score increase conversions?
A readability score cannot tell you that. It measures the text, not the visitor. Easier text may help a page that asks people to understand an offer quickly, but only a test on your own traffic shows whether a rewrite changes orders or leads.
How do I lower my Flesch-Kincaid grade level?
Shorten your longest sentences and replace long words with shorter ones that mean the same. Those are the only two things the formula measures. Keep the terms your readers expect, and stop when an edit would cost them a fact they came for.