Last update: 4. November 2025
Calculating the readability online - online tools
This page lists online tools that you can use to analyze your texts. It is easy, you just copy and paste your text into a window, sometimes also a URL can be specified. The most tools are limited to texts in English. If a language is not mentioned in the description of a tool, only a readability analysis of English texts gives valid results.
Please note the data privacy statements of some websites. Your data may be stored or even given away to third parties without your allowance. Thanks to Karen Smiley for this information.
Many programs were excluded from this page, these are at the bottom of this page. One reason is that the overviews I used are listing SEO tools, and readability is only one aspect.
Testing readability online tools
Maybe you would like a test of all tools? I found none on the web, so I have started to develop a test and to publish it. I also added some remarks so that you can get an impression on the software. Also some entries were removed, e.g. ClickHelp removed the readability formulas, and CIRTC redirects to readabilityformulas.com.
The readability formulas are often named by the authors. You should know that there are some formulas that have different versions: Dale-Chall, Spache, Coleman-Liau, Automated readability index (ARI). Also Flesch's formulas have been adapted for special purposes from different authors. Often you will find that the version of the formula is not mentioned. Some sites collect your texts, but most give no information what happens with your data.
The following features are tested if they are correct or if they exist:- Which formulas are used in the analyses?
- Are the implications of each readabilty formula explained?
- Which parts of the text are analyzed? text, file, URL
- Are subanalyses (e.g. paragraph) possible?
- Is a selection by age or text genre possible?
- number of grammatical sentences
- average length of sentences in words
- number of words
- number of unknown words, hard words, depending on the readability formula
- number of syllables if readability formulas use them
- results of the appropriate readability formulas
- Interpretation of the results
- remarks: topics like restrictions, data storage and the like
- The Gettysburg address - the hypens between words were separated from the words before and afther the hypens
- A story that contains different flexions of verbs to test if the number of unknown words (Dale/Chall, Spache) is correct.
- An article from CNN dated from October 2025
All texts were manually counted, so one can compare the correct results with the results from the websites and the desktop applications. I am currently compling these tests.
Also some problems occured. Some websites just didn't work, I disabled my adblocker, and I also tried different browsers: Firefox, Edge, and Opera.
Counting words also seems to be a problem. The Gettysburg address contains of four dashes, and in American typography the dashes are not separated using blanks. For the test I inserted blanks before and after the dashes.
| Autocrit |
website:
Autocrit
formulas supported: new Dale-Chall, Spache revised, Flesch-Kincaid, Linsear Write, Flesch reading ease, lexical density test
results: all readability formulas except Dale-Chall and spache in the free version, number of words, char/words, syllables/word
output all formulas are given and explained, free basic version
remarks: Autocrit has interacting tools and compares your text with other authors or text genres. The newer version of Dale-Chall and Spache are not available in the basic free ersion. You have to register to use the basic functions. All advanced features must be paid with reasonalable prices.
| Cathoven |
website:
Cathoven Readability Checker
formulas supported: Flesch reading ease, Flesch-Kindcaid grade, Gunning FOG,SMOG, ARI, Coleman-Liau, Linsear Write, Dale-Chall, McAlpine
country/state: no imprint, e-mail only via contact form
results: results of the readability formulas, school levels (US),
output readability consensus that seems to be a mixture of all formulas, word count, sentence, count, average sentence length, results can be downloaded, the text can be edited for another analysis
remarks: This design is clear, but it is not clear which version of Dale-Chall and Coleman-Liau were used. The formulas are not described, also the implications are not mentioned. Texts may have up to 250 words in the free version, after registration this limit vanishes - but I could not verify this because the veryfication of my e-mail address failed. I wrote an e-mail to the support that hasn't been answered yet (3 days).
| CefrLex |
website:
CefrLex
formulas supported: no readability formulas
results: contains common words for 2nd language learns in different languages; all words of the text are classified in levels from A1 to C1
output: llanguage level of each words of the text
remarks: the output is very impressing and useful
| Character Calculator (CC) |
website:
Character Calculator (CC)
formulas supported: Flesch reading ease, Flesch-Kincade grade, SMOG, Gunning Fog, Dale-Chall, syllable counter user data are stored for one week. Only english texts
results: Character Calculator is an online tool for counting characters, words, sentences, and paragraphs. It also includes a Dale-Chall Readability Calculator to score your content. SMOG score and grade provided, which is not the same.
output: Flesch reading ease, Flesch-Kincade grade, SMOG, Gunning Fog, Dale-Chall
remarks:The input data are stored on US servers, the website is operated from Turkey, the data are deleted after one week.
Character counter counts more than words, sentences, and paragraphs. If you open the menu (left top), readability formulas are available. The values and their interpreation are shown. It is not clear, which version of Dale-Chall and Coleman-Liau are used. The implications of the readability formulas are discussed at the bottom of the page. The design is somehow cumbersome, you have to enter your text several times depending of what you do. Also some menu items appear twice. More annoying, some modules count different. The gettysburg address sometimes has 272 or 276 words, also the number of characters are different. Obviously dashes are counted as words.
| CheckReadability |
website:
CheckReadability
formulas supported: ARI, Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, Smog, Coleman-Liau, Linsear Write, Forcast, new Dale-Chall
results: values of the implemented readability formulas and their interpretation
output: Flesch reading ease, Flesch-Kincade grade, SMOG, Gunning Fog, Dale-Chall
remarks: All formulas are displayed with the results of the text, so one can test if the counting are correct. One can read more details on the formulas and how to interpret the results. The tonline tool is easy to use and has a nice user interface. The version of the Coleman-Liau formula is not mentioned, but the formula is shown.
No information on the owner of the website or if data are stored or passed to other companies.
| Clickhelp |
website:
Clickhelp
formulas supported: ARI, Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, Smog, Coleman-Liau, SMOG, Linsear Write, Forcast
results: Flesch-Kincaid Grade Level, Coleman-Liau, Flesch Reading Ease, Gunning Fog, Automated Readability Index, Linsear Write, SMOG, FORCAST Grade, New Dale-Chall, Average Grade
output: Flesch-Kincaid Grade Level, Coleman-Liau, Flesch Reading Ease, Gunning Fog, Automated Readability Index, Linsear Write, SMOG, FORCAST Grade, New Dale-Chall, Average Grade, also text metrics
remarks: The readability online tool is no longer available.
| Datayze |
website:
Datayze
formulas supported: ARI, Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, Smog, Coleman-Liau, SMOG, Linsear Write, Forcast
results: Flesch Reading Ease, Gunning Fog, Flesch-Kincaid, SMOG, Dale-Chall, Fry readability grade level
output: all readability values are calculated by paragraph, not the whole text. It is not specified, which version of Dale-Chall is used.
remarks: Datazye has a detailed user interface that shows you what the results will be. It also allows the analyses of chapters and the whole text. It is also possible to sort the results by the values of the readability formulas and save them to a file. The implications of readability formulas are described.
The chapters are detected automatically if a line ends which can lead to too many paragraphs. After reformatting the text the results did change.
Obviously every end of line (EOL) is regarded as the end of a sentence. Abbrevations like Prof. or Dr. were tackled correctly (no end of sentence point).
The results for the number of words, number of syllables and number of difficult words are not shown. The interpretation of the values are shown in extra pop-up windows.
User data stored up to one year, but not given away. Minimum file size 30 sentences, not standardized.
The owner is known, but contact is only possible via a contact form.
| Editpad |
website:
Editpad
formulas supported: Flesch-Kincaid Reading Ease and grade level, Coleman-Liau, Ari
results: all values of readability formulas, Flesch's formulas are mixed up, version of Coleman-Liau not specified
output: all readability values, number of sentences and syllables
remarks: Editpad offers the results of readability formulas and a lot of other tools like plagiarism checker, paraphrasing tool or story generator. You can cut and paste the text into a window or load a file. The number of words do differ: the gettysburg text has 272 words and 276 words in the results table. The longest sentence is shown. The formulas and their implications are explained, the interpretation consist of one word only - average.
The website has no imprint, contact is only possible via contact form or e-mail.
| Good calculators |
website:
Good calculators
formulas supported: Flesch Reading Ease and Flesch-Kincaid, formula given
results: all readability formulas
output: all the formulas given, words/sentence, syllables/word, senences, words
remarks: Good calculators offers a lot of calculators, some for calculating readability formulas: Flesch Reading Ease und Flesch-Kincaid. The results are explained. The number of words and sentces are given, the number of syllables not. The implications of the formulas are not mentioned esplicitly.
| Gorby |
website:
Gorby
formulas supported: ARI, Coleman-Liau, Dale-Chall, Flesch Reading Ease, Flesch-Kincaid, Smog, Gunning Fog, Spache
results: all readability formulas
output: words, sentences, longest and shortest sentence, unique words (types), words/sentence, chars/word, sentences, words, characters(with and without spaces), number of syllables missing
remarks: find readability scores at left menu, all formulas are explained and all values inserted so one can see which values where used for the computation. Difficult words are shown also within the complete text. However, it is not clear which versions of Dale-Chall and Spache were used.
You have to install a kind of desktop app separate from your browser as a so called Progressive Web App that is not supported e.g. by Firefox.
However, the results are calculated and explained. In the free version the results of ARI, Dale-Chall, Flesch-Kincaid, Coleman-Liau, Flesch Reading Ease, and Gunning FOG are shown.
If you find yourself through the menu, you get a lot of information about the implications of each readability formula.
| GoWinston.ai |
website:
GoWinston.ai
formulas supported: Flesch-Kincaid only
results: the analysis didn't work: There was an error.
output could not be tested
remarks: The website is available in English, French, Spanish, German, Portugese and Chinese. GoWinston.ai doesn't work und returns an error message. Disabling the ad-blocker didn't help. Also using other browsers (Firefox, Edge and Opera) didn't fix the problem.
| Gunning Fog calculator |
website:
Gunning Fog calculator
formulas supported: Gunning Fog Index only
results: Gunning Fog Index
output: long words are shown in blue, sentence boundaries are shown in red, index value shown as well as number of wentences and words
remarks: Nice idea, but abbrevation or multiple points are not excluded, so the number of sentences is biased - too high which lowers the readability results and so the text seems to be easier than it really is.
| Health Literacy Editor |
website:
Health Literacy Editor
formulas supported: reading grade, formula unclear
results: all formulas
output: highlights unfamiliar words, passive voice, density, TTR, long words more than 2 syllables, long sentences, uncommon words (e.g. erotic words)
remarks: The Health Litery Editor calculates Flesch-Kincaid grade although this is not mentioned. Characters, words, and sentences are counted and their numbers shown, polysyllables are highlighted.
| Hemingway |
website:
Hemingway
formulas supported: Flesch Reading Ease
results: Flesch Reading Ease
output: Highlights complex sentences in yellow, marks passive voice in green, points out adverbs in blue, suggests simpler words for complex ones in purple, flags very hard-to-read sentences in red
remarks: You have to remove the example text first before you can analyze your own text. If you want to paste your text into the window, the shortcut of Windows doesn't work, you have to use Hemingway's menu. Only the grade is shown, sentences that are hard or very hard to read are highlighted. Other information or text statistics are given if you open a menu at the right side of the screen.
| infyways |
website:
infyways
formulas supported: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI, Linsear Write
results: all readability formulas (see above)
output: words, letters, complex words
remarks: The same company offers another tool named Text Analyzer Tool. Tests whow that both programs differ in number of letters and sentences. Infysys only gives the results of the readability formulas and the interpretation. It is also possible to check a webpage.
| Juicy Studios online readability tester |
website:
Juicy Studios online readability tester
formulas supported: Gunning Fog, Flesch Reading Ease, Flesch-Kincaid
results: all readability formulas (see above)
output: sentences, words, words/sentence, words with 1, 2, 3, 4 and more syllables. % of words with 3 syllables and more, all readability formulas explained including the formula
remarks: Juicystudio calculates Gunning's Fog, Flesch Reading Ease, and Flesch-Kincaid grade level. The interpretation of the results and the formulas are provided. You can test your own text if it is on a webpage, it is not possible to cut and paste some text. The site redirets you to Webfx. The sample texts were copied to a website, so a test was possible. The site seems to be outdated, dates are from 2013 although the copyright notice says 2000-2025.
| myessaywriter.ai |
website:
myessaywriter.ai
formulas supported: Flesch-Kincaid, Gunning Fog, Smog, Ari, Coleman-Liau
results: could not be tested
output: could not be tested
remarks: There is a limit of 1500 words, and you have to sign-up for free first. Nice: Selection of the readability formulas by age of the recipients. Your data are encrypted and never passed to third parties.
| NHS Medical Document Readability Tool |
website:
NHS Medical Document Readability Tool
formulas supported: result of unknown formula (reading age UK)
results: unknown readability formula
output: complex, passive, sentences and words, long words in different colours, metrics: words, sentences, avg words/sentence, sentences/paragraph, characters
remarks: NHS medical tool calculates the UK grade, whatever this is. Complex and long words (4 syllables and more), complex sentences and sentences with passive voice are shown in different colours. Unfortunately they are not counted. It also remains unclear what complex words are, the explanation given is that these words can be substitutrd by easier words.
| Okapi |
website:
Okapi
formulas supported: Spache wordlist from 1974, Dale-Chall (4 and more) and Spache (1-3)
results: due to access problems none
output: complex, passive, sentences and words, long words in different colours, metrics: words, sentences, avg words/sentence, sentences/paragraph, characters
remarks: Okapi allows sample up to 200 words only. Depending of the age of the audience, you must choose a readability formula, either Dale-Chall or Spache. Also links to the original word lists are provided. One can declare a ; or a : as a end of sentence marker, or mark known words with * and \ to separate a sentence into two sentences. Abbrevations can be marked also so that these are not regarded as end of sentence. The test failed, it just didn't work, and I used three different browsers.
| Originality.ai |
website:
Originality.ai
formulas supported: Flesch Kincaid Reading Ease and Grade Level, ARI, Coleman-Liau, Gunning Fog, SMOG, Power, Sumner, Kearl, Forcast, Dale-Chall, Spache, Linsear Write
results: all readability formulas
output: all formulas are given
remarks: You cannot test the program without sign-up. Linsear Write is not standardized nor explained, no definition of difficult words, which versions of Dale-Chall and Spache were used.
| Prepostseo |
website:
Prepostseo
formulas supported: Flesch Kincaid Reading Ease and Grade Level, ARI, Coleman-Liau
country/state: Enzipe Software House, Faisalabad, Pakistan
results: all readability formulas
output: sentences, syllables, words, keywords, unique words, total chars (without spaces) chars/words, words/sentence, syllalbes/word, syllables/sentence, longest sentences, limited word frequencies called density also for collocations
remarks: limit 5000 words. the keywords are not defined, nice text metrics and collocatinos containing two or three words.
| Readability calculator |
website:
Readability calculator
formulas supported: Coleman Liau index, Flesch Kincaid Grade Level, ARI (Automated Readability Index), SMOG
country/state: unknown yet
results: all readability formulas
output: text metrics: characters, words, sentences, chars/word, syllables/word, words/sentence, list of sentences for rewrite
remarks: a quick and easy to use tool
| Readable.com |
website:
Readable.com
formulas supported: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog in the free online version, many more in the full version but only for English texts: Smog, Ari, Spache (verison not mentioned), new Dale-Chall, Powers-sumner-Kearl, Raygor readability graph, Fry Readability graph, IELTS, CEFR, Lix, Rix, Forcast, Linsear Write (misspelled Lensear)
country/state: Added Bytes Ltd, Hassocks, UK
results: all readability formulas including explanations
output: count words, sentences, paragraphs, sentences > 30 syllables, words > 12 letters, adverbs, cliché (overused phrases), some phenomena are coloured: grey: long words, blue underline: grammar issue, red underline: spelling issue
remarks: export requires a trial vesion (free for 7 days), results are exported in CSV and PDF format, text can be exported in word, open document, pdf, html, latex. The are also word analyzers for different word lists so one can see the known words: Dale-Chall, Dolch, Ogden, Spache and Fry. The full version has even more readability formulas. Remarkable: there is a typo Lensear instead of Linsear. The company also offers an API that returns the results. In total: a nice website that has lots to offer.
| ReadabilityFormula |
website:
ReadabilityFormula
formulas supported: Flesch-Kincaid, Ari, Coleman-Liau, Flesch Reading Ease, Gunning fog, Smog, Linsear write, Forcast, Fry Graph, Raygor graph, new Dale-Chall, Fry Sight, Spache
country/state: Brian Scott
results: all readability formulas, with formulas and all values inserted so one check the calculation, options are available for sentence count, inflected words, compound words, proper nouns (familiar/unfamiliar), handle numbers, URLs, e-mail addresses
output: text metrics: characters, words, sentences, paragraphs, hard words, long sentences, adverbs, hard adjectives, nominals, passive words, weak verbs
remarks: Many formulas and useful options, the output shows many details how to check the validity of the results. Als text metrics give a lot of explanation, although many of these are not explained, e.g. long sentences, hard adjectives etc. These are shown in extra tabs.
| Sitechecker |
website:
Sitechecker
formulas supported: Gunning Fog, Flesch Reading Ease
country/state: Cyber Circus Limited, Gibraltar
results: all readability formulas
output: text metrics: characters, words, sentences, pages, suggestion which sentences to fix
remarks: a quick and easy to use tool, but only two formulas
| Spanish Readability |
website:
Spanish Readability
formulas supported: Fernández Huerta, The Szigriszt-Pazos Perspicuity, Inflesz Scale, Gutiérrez de Polini, Miguel Muñoz Baquedano and José Muñoz Urra, Spanish SMOG Formula (SOL), Flesch-Kincaid Grade Level (SOL), Spaulding Readability Formula, Crawford's Readability Score, García López Readability FormulaSpanish Fry Graph
country/state: unknown yet
results: all readability formulas and their formulas including values so you can check the calcution.
output: text metrics: characters, letters, syllables, words, sentences, paragraphs, Spaulding rare words, words/sentence, longest words, syllables/word, words with 1, 2, 3 and 4+ syllables
remarks: A specialized site for Spanish texts. Sentences must end with a sentence marker like .?! Personal data are not sold or rented to third parties.
| STORYToolz |
website:
STORYToolz
formulas supported: Flesch-Kincaid, ARU, Coleman-Liau, Fleschreading ease, Lix, Smog
country/state: Chuck Heintzelman
results: all readability formulas
output: text metrics: chars, words /chars/word, syllables/word, sentences, words/sentence, short sentences (<7), long sentences (>22), paragraphs, sentences/paragraph, Questions, paassive sentences, longest and shortest sentence in words
remarks: You can analyse up to 5120 words. Output can be exported as PDF, Excel, or CSV file
| Textinspector |
website:
Textinspector
formulas supported: Flesch-Kincaid, Flesch Reading Ease, Gunning Fog
country/state: Weblingua Ltd, UK
results: all readability formulas
output: text metrics: overall percentage difficulty, lexical diversity voc-d, sentences, token (words), academic words percentage, Percentage of words at B1 CEFR level ttr, numbers, syllables, words with more tahn 2 syllables, syllables/sentence, words/sentence, syllalbes/words
remarks: There is a limit of 250 words for guests, if you have bigger text you have to pay. The most expensive plan allows files up to 13,000 words only. The data are cleared from the server after 6 hours. The company also offers the use of an API.
| Voyant Tools |
program:
Voyant Tools
author: who knows
distributor:
Voyant
documentation:
Voyant
download: test none, online tools
operating system: browser based app
description: These tools provide an analysis of text via file, URL, or clipboard. A readability index is calculated, but which one is not documented. It generates word lists, phrases, collocations, word grapes, word density. All words are in lower case, the following languages are supported; Arabic, Bosnian, Croatian, Czech, English, French, German, Hebrew, Italian, Japanene, Portuguese, Russian, Serbian, Spanish.
| WebFx |
website:
WebFx
formulas supported: Flesch-Kincaid, Gunning, Coleman Liau, ARI, and SMOG
country/state: Guatemala, Phillipines, and USA
results: all readability formulas
output: text metrics: number of complex words and average words per sentence
remarks: This is a nice and easy to use tool with some goodies. You can enter a text from the clipboard, a file name (HTML will be stripped). WebFx may share users’ data with TeamAI.
| Wrise free readability checker |
website:
Wrise free readability checker by Rob Truslove, Wrise
formulas supported: Flesch-Kincaid, Flesch Reading Ease, Gunning Fog, SMOG, Dale-Chall Fry Readability grade
country/state: Bury, UK
results: all readability formulas
output: text metrics: words, sentences, words/sentence, characters/word, syllables/word, percent of difficult words (estimated)
remarks: This tool is very fast and has a nice dsign. The version of Dale-Chall is not mentioned.
| Wordcalc |
website: Wordcalc
formulas supported: Flesch-Kincaid Reading Ease, Gunning Fog, Coleman-Liau, SMOG, ARI, New Dale Chall , Spache
country/state:
results: all readability formulas
output: text metrics: no
remarks: Another easy to use tool that also explains the formulas itself and how to interpret the results. Also a syllable counter is offered, but this often counts one syllable too many. Also abbrevations points are not considered. If this algorithm is really used by the readability checker, your results may be biased.
Excluded software - under construction
The lists that are the basis of this section are SEO tools, and not all links use readability formulas for SEO purposes. Programs were excluded if there is no online tool available, or if only one formula is used. The following lists includes the links and the reasons why these programs were excluded.
Copywritely Flesch-Kincaid only, therefore excluded
Ginger Writing Assitant no online tool to check a text with readability formulas
Grammarly Flesch reading ease only. User data may be used for internal and external purposes therefore not included may retain random samples of de-identified text to help us improve the algorithms underlying our software and services” but “do not share the texts that you check with Grammarly with any third parties” and “have not sold, do not sell, and will not sell customer data”
Junia.ai tries to improve the readability uses Flesch reading ease, no online tool to check a text with readability formulas
Language Tool no online tool to check a text with readability formulas, verifies facts using AI for many languages
Links Assistant no online tool to check a text with readability formulas
Longshot AI no online tool to check a text with readability formulas
Okapi with current link. The online tool has a limit of 200 words. The connection to the internet is insecure. Only new Dale-chall and Spache readability formulas are im0plemented, and you select one formula from a menu dependent of the age of the readers (children).
Outwrite only afte registration you can evalute what this tool is usefule for. It seems that readability formulas are also used, but there is no further information which ones.
Searchmetrics (Conductor) no online tool to check a text with readability formulas
Surfer SEO no online tool to check a text with readability formulas
ProWritingAid no online tool to check a text with readability formulas, but tools for avoiding complex sentences or passive voice, style inconsistency checks, sentence length analysis, word choice suggestions.
Readability analyzer no online tool to check a text with readability formulas. However, you can download a*.zip file.
Readability pro the results show the grades, but not the values of each formula for Flesch-Kincaid, Gunning fog, SMOG.