Readability Score
Score a piece of writing for reading ease and grade level.
What you provide
How this calculation works
All three formulas here work from two things: how long your sentences are, and how many syllables your words have. Flesch reading ease puts the result on a 0 to 100 scale where higher is easier, Flesch-Kincaid converts the same inputs into a US school grade, and Gunning fog counts words of three syllables or more instead of averaging syllables. Because they agree on the inputs and differ on the weighting, seeing all three together tells you whether a poor score comes from sentence length or from vocabulary.
What the results mean
- Flesch reading ease
- Higher is easier. Around 60 to 70 is plain English that most adults read without effort. Newspapers sit near 60, academic writing often below 30.
- Flesch-Kincaid grade
- The US school year needed to read the text comfortably. Grade 8 to 10 is a sensible target for a general audience, and technical documentation naturally runs higher.
- Sentences over 25 words
- Usually the fastest thing to fix. Splitting the longest few sentences moves every score more than swapping vocabulary does.
Common problems and fixes
- The score is poor but the writing seems fine
- Check what is driving it before rewriting anything. Technical terms your readers already know are counted as difficult because they have several syllables, and a page about photovoltaic installation will always score badly on that basis. If sentence length is reasonable and the long words are the subject matter, the score is measuring the topic rather than the prose.
- Lists and headings are skewing the numbers
- Fragments without full stops get merged into whichever sentence follows them, which inflates average sentence length. Score the body paragraphs on their own for a truer picture, and treat a page that is mostly lists as something these formulas were never designed to measure.
Frequently asked questions
Is readability a ranking factor?
Not directly. Search engines have never confirmed one, and there is no target score to hit. What does matter is whether people find what they came for and stay, and writing that takes three readings to parse works against that. Treat the score as a prompt to look at your longest sentences, not as a number to optimise.
What score should I aim for?
It depends entirely on who is reading. Consumer content aimed at a wide audience is usually comfortable around 60 to 70 on Flesch ease, or grade 8 to 10. Documentation for engineers can sit at grade 12 or above without any complaint from its readers. Writing for the audience beats writing for the formula.
Why do the three scores disagree?
They weight the same inputs differently. Gunning fog is more sensitive to long words because it counts them directly, while Flesch-Kincaid averages syllables across everything. A gap between them usually means the text has a small number of very long words rather than uniformly complex vocabulary.
Put this on your own site
Free to embed, no attribution required beyond the source link the frame carries itself. It runs entirely in your visitor's browser, sets no cookies and loads no third-party script.
<iframe src="https://runthetests.com/embed/readability-checker/" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:8px" title="Readability Score" loading="lazy"></iframe>
Preview it at https://runthetests.com/embed/readability-checker/. Embedded pages are marked noindex, so yours stays the canonical copy — not this one.