A fast, private readability checker
This readability checker evaluates your English text and provides instant feedback on how difficult it is to read. By analyzing sentence length, word length, and syllable counts, it calculates a variety of standard metrics, including the widely used Flesch reading ease and Flesch-Kincaid grade level.
Because all processing happens directly in your browser, this reading level checker is entirely private. Your text is never uploaded to a server or stored in a database. You can safely analyze unreleased articles, confidential legal documents, internal corporate communications, or academic drafts without worrying about data privacy.
Understanding your readability score
Readability formulas were developed to help writers, educators, and publishers match texts to the right audience. While they all aim to measure text complexity, they approach the math slightly differently. This tool calculates six of the most established indices:
Flesch Reading Ease. This is the most common readability score. It grades text on a scale from 0 to 100. A score between 60 and 70 is considered "Standard" and is easily understood by 13- to 15-year-olds. Scores closer to 100 are very easy to read, while scores below 30 are best suited for university graduates. The formula relies heavily on the average number of syllables per word and words per sentence.
Flesch-Kincaid Grade Level. Developed for the U.S. Navy, this formula translates the Flesch Reading Ease score into a U.S. school grade level. A score of 8.5 indicates that an eighth grader would understand the document. For most public-facing content, a grade level of 7 to 9 is ideal.
Gunning Fog Index. The Fog index estimates the years of formal education a person needs to understand the text on the first reading. It places a heavy emphasis on "complex words"—defined as words with three or more syllables.
SMOG Index. Short for "Simple Measure of Gobbledygook," the SMOG index is widely considered the gold standard for healthcare and medical writing. Like Gunning Fog, it focuses on polysyllabic words, but it calculates the square root of complex words across a sample of sentences to determine the grade level.
Coleman-Liau Index and ARI. Unlike Flesch and Fog, which rely on counting syllables, the Coleman-Liau Index and the Automated Readability Index (ARI) rely on character counts. Because characters are faster and more accurate for computers to count than syllables, these formulas were designed for automated processing. They look at the average number of characters per word and words per sentence to output a U.S. grade level.
When to use a reading level checker
Writing clearly is essential, but "clear" means different things depending on your audience. Using a readability checker helps you objectively measure your writing against industry standards.
Copywriting and Content Marketing. Online readers skim. If your blog post, landing page, or email newsletter is too dense, readers will bounce. Marketers generally aim for a Flesch reading ease score of 60 or higher to ensure their message is accessible to the broadest possible audience.
Education and Publishing. Teachers, curriculum designers, and children's book authors use grade-level scores to ensure their materials match their students' reading abilities. If you are writing a textbook for middle schoolers, checking the Flesch-Kincaid grade level ensures you aren't using overly complex vocabulary.
Healthcare and Government. Medical instructions, public health notices, and government forms must be understood by everyone. Many health literacy guidelines require patient materials to be written at a 6th to 8th-grade reading level. The SMOG index is particularly useful here for identifying jargon-heavy medical texts.
Technical and Legal Writing. While technical manuals and contracts naturally have a higher reading level, they shouldn't be unnecessarily confusing. Analyzing these documents helps writers spot run-on sentences and excessive legalese, allowing them to simplify the structure without losing the technical meaning.
Tips for improving your text
If your readability score is lower than you want (meaning the text is too hard to read), you can usually fix it by adjusting two key metrics provided at the bottom of the tool:
- Lower your words per sentence. Long, winding sentences are the primary cause of poor readability. Look for sentences that contain multiple clauses joined by "and," "but," or "because." Break them into two or three shorter, punchier sentences.
- Lower your syllables per word. Big words slow readers down. Review your text for complex words (three or more syllables) and replace them with simpler alternatives. For example, use "use" instead of "utilize," "help" instead of "facilitate," or "start" instead of "commence."
As you edit your text in the input box, the scores will update in real time. If you need to check the overall length of your revised document, you can use the Word Counter or Character Counter. To identify specific words you might be overusing, try pasting your text into the Word Frequency Counter.