What is readability and what does this Readability Checker do?
Readability measures estimate how difficult a text may be to read using sentence and word characteristics. This checker reports Flesch Reading Ease, Flesch-Kincaid Grade Level, Automated Readability Index, Coleman-Liau, Gunning Fog and SMOG when the sample supports it.
How to use Readability Checker
Paste a representative passage rather than only a title.
Review the sample caution before interpreting scores.
Compare the named measures and supporting sentence or complex-word metrics.
Inspect long sentences and export the report for editorial review.
Key features
- Six named readability measures where mathematically appropriate
- Reading-ease and grade-level interpretations kept separate
- Average sentence and word length context
- Complex-word and long-sentence indicators
- Short-sample and SMOG reliability cautions
Input guide
Use a complete English passage that represents the final audience and purpose. Around 100 words and several sentences provide more stable comparison than a fragment; SMOG is withheld until at least 30 sentences are available. Syllables are estimated and may differ for names or specialized vocabulary.
How to understand your results
Flesch Reading Ease increases as the measured text becomes easier under that formula. The grade-level measures estimate different aspects of word and sentence complexity, so they need not agree. Supporting metrics show the observed inputs, and the caution explains when the sample is too short.
Worked example
A short public notice uses familiar words. It gives one action in each sentence.
The formulas generally report easier reading than a passage with long sentences and many multisyllabic terms, but the short-sample caution remains important.
Common use cases
- Review public instructions or help content
- Compare two versions of an article or report
- Check whether a classroom passage suits its intended audience
- Identify long sentences before a manual edit
Readability Checker guidance and best practices
- Use multiple measures as signals rather than chasing one target.
- Judge terminology against the intended audience; necessary technical words are not automatically bad.
- Pair formula results with user testing, peer review and factual editing.
Limitations, assumptions and cautions
- Readability formulas do not measure accuracy, organization, prior knowledge or visual design.
- Syllable estimation is deterministic but not perfect.
- A grade estimate is not an official reading level or a guarantee of comprehension.
Privacy and processing
Runs in your browser.
Runs in your browser. The passage is processed locally and is not sent to an AI or readability service.
Related tools
These live writing tools use the same consistent text foundation for adjacent questions.
Readability Checker FAQs
Clear guidance for choosing and using the catalogue responsibly.
What does a readability checker measure?
It estimates text difficulty from measurable features such as sentence length, characters or syllables per word and the share of complex words.
What is Flesch Reading Ease?
It is a named measure that combines sentence length and estimated syllables per word; higher values generally indicate easier reading under the formula.
What is Flesch-Kincaid Grade Level?
It converts sentence and syllable characteristics into an approximate US school-grade value. It is an estimate, not a reader assessment.
Why can different readability formulas give different results?
They use different inputs and calibrations. Comparing several measures reveals a range rather than one supposedly definitive score.
How much text should I use for a reliable readability check?
Use a representative passage of at least about 100 words and several sentences when possible. SMOG conventionally needs 30 sentences.
What makes a sentence difficult to read?
Length, clause structure, unfamiliar terminology and information density can all matter, although a formula observes only some of these features.
Does a lower grade level always mean better writing?
No. The appropriate level depends on audience, purpose and required terminology. Oversimplifying can remove necessary meaning.
Can I use this for academic or technical writing?
Yes, but interpret the measures against the knowledge expected in that field rather than a general-audience target.
Does my text stay in my browser?
Yes. The readability calculations run locally.
Can ScholarTool guarantee that every reader will understand my text?
No. Comprehension depends on readers, context, design and prior knowledge as well as wording.