Great readability.
Better engagement.
More conversions.

Readable will quickly test the readability, spelling and grammar of your text and show you how and where to make improvements.

Test Your Readability


The proportion of the public who can read your content if it has a readability grade of 8 or lower.


The average reader's attention span, in seconds, in 2022. About the same time it takes a typical person to read this single box of content.


The increase in the number of people who will finish reading your content if its readability is improved from grade 12 to grade 5.

We're delivering accurate readability analysis for organizations including:

Harvard University
Princeton University
American Red Cross

Let's get started. How can we help?


Website Readability

Trustworthy readability algorithms verified by over 1,000 automated tests and hand-calculated scores.

Website Readability


Scoring Text or Files

Check and improve the readability, spelling and grammar of text, emails or files.

Text Scoring


API and Integrations

Add powerful readability, spelling and grammar checking functionality into your own content management software.

Readability API

Anna Bolton
Anna Bolton
Conversion Copy Co.


People tune out and hit the back button when they don't understand what you write. Even if I use the most persuasive copywriting techniques, if I'm not clear, my clients will lose leads and sales. That's why I use Readable to match my copy with my audience's reading level.

It's one of my top conversion optimization tools! "

Are you engaging your audience with readable content?

Find out for free

Readable Works With ...

Your text
Paste your text into our web-based software to get instant analysis and recommended improvements.

Your files
Score all your text files, including Word documents, Open Office, PDFs, Markdown and even eBooks.

Your website
Analyse an entire website, using its sitemap or RSS feed, in just a few minutes.

Your email marketing
Send your test email campaigns to your own unique email address and receive a full readability report.

Your spreadsheets
Upload text or URLs in bulk to score large amounts of content at once.

Readable Tells You ...

Your readability scores
Readability analysed with the world's most respected and trusted readability formulas.

Your text quality
We check spelling and grammar as well as looking for use of adverbs, passive voice and cliches.

Your tone and sentiment
Monitor the sentiment and tone of your content to ensure a consistent voice.

Your keyword density
Monitor keyword density of your content so it looks on-topic to search engines.

You can have confidence
Our scores are backed up by established readability algorithms and verified by over 10,000 automated tests and hand-calculated scores.

Readable Integrates Into ...

Your CMS
Build readability right into your website CMS or other software with our powerful API.

Your favorite tools
Make readability scoring available everywhere with Dropbox and Slack applications.

What is a readability score?

A readability score is a computer-calculated index which can tell you what level of education someone will need to be able to read a piece of text easily.

Readable uses tried and tested readability formulas, as well as our own proprietary scoring systems, to analyse the readability of your website or text and recommend ways to improve upon it.

To ensure your content is readable by 85% of the general public, you should aim for a readability score of Grade 8 or better.

Typical factors used for readability scoring include:

  • Average sentence length
  • Syllable count
  • Percentage of multi-syllable words
  • Average word length
  • Familiarity of words
  • Complexity of sentences

Are you engaging your audience with readable content?
Find out for free, today!

Get Started

The readability formulas that power Readable

Flesch Reading Ease

Flesch Reading Ease will tell you what level of education someone will need to be able to read a piece of text easily.

The Reading Ease formula usually generates a score between 0 and 100 (though scores outside of that range are possible). Unlike most of the other algorithms we use, a higher score is better when it comes to the Flesch Reading Ease.

Flesch Reading Ease is probably the most widely recognised readability scoring formulas, and has been incorporated into law in several countries and US states as a reliable measure of readability of text.

Flesch-Kincaid Grade Level

In the mid 1970's the Flesch Reading Ease was amended so that it could be used by the US Navy. From those changes and enhancements, the Flesch-Kincaid Grade Level was created. It works in the same way, but produces a Grade Level rather than a score between 0 and 100.

Flesch-Kincaid Grade Level classifications are based on:

  • Sentence length as judged by the average number of words in a sentence
  • Word length as judged by the average number of syllables in a word.

Gunning Fog Index

The Gunning Fog Index is principally used as a tool to help writers keep their texts clear and simple and was developed by Robert Gunning Associates in 1944, experienced newspapers and publishing consultants.

The Gunning Fog formula generates a grade level, typically between 0 and 20. The formula estimates the years of formal education the reader requires to understand the text on first reading.

So, if a piece of text has a grade level readability score of 6 then this should be easily readable by those educated to 6th grade in the US schooling system (i.e., 11-12 year olds).

Automated Readability Index

The Automated Readability Index was developed in the 1960s by the US Air Force Medical Division as a way to analyse the readability of technical manuals, reports and training documents. Originally created to tap in to the real-world usage of typewriters to produce manuals at the time, it focusses on letter and word counting rather than syllable density.


IELTS and CEFR are related measures used by international language students to classify the profficiency of English speech. They can also be used to analyse the difficulty of a piece of text, and their scores are based on prebuilt lists of familiar words. A word like "the" will score better than a word like "xylophone", because it is used more often in English.

Coleman-Liau Index

Developed in 1975, the Coleman-Liau Index remains one of the most commonly used readability formulas. It scores on understandability and approximates the US grade level needed to comprehend the text.

A distinctive feature of the Coleman-Liau Index is that the formula doesn't involve any counting of syllables. Instead, it was designed to easily calculate text by concentrating on characters per word.

SMOG Index

The SMOG Index may be our favourite name of any readability score - it stands for Simple Measure of Gobbledygook, and true to its name it is based on the number of polysyllabic words in the text. Any word with three or more syllables is counted as difficult, and the density of those words in the text is what determines the SMOG score.

"SMOG should be the preferred measure of readability when evaluating consumer-oriented healthcare material." – Journal of the Royal College of Physicians of Edinburgh

Spache and New Dale-Chall

The Spache and New Dale-Chall scores both work in the same way, calculating readability for a specific and narrow audience based on lists of familiar words. The greater the number of unfamiliar words in a piece of text, the worse the score. Spache is great for calculating readability scores for text aimed at children up to the fourth grade, and Dale-Chall is better suited to grades four through to ten.

7 Days Free Readability Scoring

Try Readable for 7 days entirely free, or cancel any time if you don't love it.