Writing & Text Utility
Reading Level Calculator
Estimate Flesch Reading Ease and Flesch-Kincaid Grade Level with disclosed counting heuristics.
Estimate reading level
Method
The calculator uses the published Flesch Reading Ease formula 206.835 − 1.015 × average sentence length − 84.6 × average syllables per word, and the Flesch-Kincaid Grade Level formula 0.39 × average sentence length + 11.8 × average syllables per word − 15.59. Microsoft Support documents these formulas. This implementation estimates sentences and syllables locally, so its counts can differ from other software.
Worked example
For This sentence has seven simple words now., the local heuristic detects 7 words, 1 sentence, and 9 syllables, producing a Reading Ease near 91.0 and Grade Level near 2.3.
When this is useful
Readability estimates can help compare drafts, simplify instructions, and spot unusually dense prose. They are most useful as one editorial signal rather than a substitute for audience testing or subject-matter review.
Privacy
The text and all intermediate counts stay in the browser. This page does not send the passage to a readability API.
Limitations
The formulas estimate readability from sentence and syllable averages. The syllable counter is an English heuristic, not a pronunciation dictionary, and can miscount names, abbreviations, technical words, and words with irregular pronunciation. Scores are estimates, not guarantees of comprehension.
Reference
Formula reference: Microsoft Support — readability and level statistics.
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FAQ
Is the grade level an exact comprehension score?
No. Readability formulas estimate surface text difficulty from sentence length and syllable density; they do not test a specific reader’s comprehension or subject knowledge.
Why might this differ from Microsoft Word?
The formulas are the same, but this browser tool uses its own transparent syllable and sentence heuristics, so counts can differ for names, abbreviations, and unusual pronunciation.
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