How to use Readability Score
- Paste or type the English text you want to measure. Headings, list items and captions all count as part of the sample.
- The scores update as you type, with the full answer under them.
- Compare the grade numbers with the audience you are writing for, then read the longest sentences yourself.
- Change one thing at a time, such as splitting a sentence, and watch which score moves.
Example: Readability Score
Check the reading level of a short product description.
Options
- Which formulas run
- Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index. Each weighs sentence length and word difficulty differently, which is why they rarely agree exactly.
- What this page leaves out
- Word, character and reading-time counts belong to the Word Counter, so they are not repeated here. This page reports the figures the formulas actually use, such as average sentence length and syllables per word.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
What a readability score actually measures
Every formula here reduces a text to two habits: how long its sentences are and how hard its words are. Long sentences and long words raise the grade, short ones lower it. That is why a score can improve while the writing gets no clearer: swapping long words for short ones until the number drops tells you nothing about whether the sentence makes sense. Treat a score as a prompt to look at particular sentences rather than as a verdict on the text, and treat the formulas as rough instruments outside the English school and military writing they were built for.
Questions about Readability Score
Why do the formulas disagree?
They weigh the same two things differently. Flesch-Kincaid and the Fog index count long words, SMOG counts words of three or more syllables, and Coleman-Liau and ARI count characters instead of syllables. A passage of short but technical words can score well on one and badly on another.
Why is the SMOG score blank?
SMOG is defined on a sample of 30 sentences or more. Below that the number swings so widely that showing it would mislead, so the page leaves it out and says so.
Is my text uploaded?
No. Every formula runs in this browser and the text never leaves the device. Closing the page discards it.
Which grade should I aim for?
Pick the grade from your readers rather than from a target someone else set. A grade 8 result suits a general audience and a grade 12 result suits a specialist one. The score only measures sentence and word difficulty, so the useful next step is to read the longest sentences yourself.
Can I paste a whole book?
The box takes up to 100,000 characters, which is roughly 15,000 words. Longer text has to be measured in sections, and splitting it changes the sentence statistics, so compare sections that are the same kind of writing.