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Readability Checker
Real-time readability analysis with Flesch-Kincaid, Gunning Fog, Coleman-Liau, and SMOG indices. Grade-level targeting and difficulty visualization. 100% client-side.
What is a Readability Checker?
A readability checker is a free tool that tells you how easy your writing is to understand. Paste in your text, and it looks at your sentence length, word choice, and syllable count. Then it runs that information through well-known formulas such as Flesch-Kincaid, Gunning Fog, Coleman-Liau, and SMOG.
You get a score and a grade level. That number tells you who can actually read your content without struggling.
Here's what a readability checker can do for you:
- Show your content's grade level in seconds
- Compare several readability formulas at once
- Flag sentences or words that are harder to read than they need to be
- Help you write for your readers, not for yourself
No sign-up. No downloads. Just paste your text and get your results right away.
Flesch Reading Ease
What this means:
90–100: Very Easy (5th grade)
80–89: Easy (6th grade)
70–79: Fairly Easy (7th grade)
60–69: Standard (8th–9th grade)
50–59: Fairly Difficult (10th–12th)
30–49: Difficult (College)
0–29: Very Difficult (Graduate)
Composite Grade Level
Target audience grade
Average of all four indices:
1–5: Elementary (ages 6–11)
6–8: Middle School (ages 11–14)
9–12: High School (ages 14–18)
13–16: Undergraduate (ages 18–22)
17+: Graduate / Professional
Flesch-Kincaid
U.S. school grade level
Formula & Context:
0.39×(words/sentences) + 11.8×(syllables/words) − 15.59
Widely used in U.S. education and government. A score of 8.0 means an 8th grader should understand it on first reading.
Gunning Fog
Years of education needed
Formula & Context:
0.4 × [(words/sentences) + 100×(complex words/words)]
"Complex" = 3+ syllables (ignoring standard suffixes). A score of 12 means a high school senior can interpret the content safely.
Coleman-Liau
Characters per word based
Formula & Context:
0.0588×L − 0.296×S − 15.8
L = letters per 100 words, S = sentences per 100 words. Calculates character ratios directly, bypassing arbitrary syllable counts entirely.
SMOG Index
Years of education (polysyllables)
Simple Measure of Gobbledygook:
1.0430 × √(complex words × 30/sentences) + 3.1291
Highly reliable metric for medical and security compliance messaging constraints. Requires a floor size of 3 completed sentences.
Avg Sentence Length
Words per sentence
Context:
Total words ÷ total sentences. Shorter sentences dramatically improve readability loops across mass audiences.
Complex Words
Words with 3+ syllables
Definition:
Polysyllabic strings containing 3 or more distinct vowel sound allocations, intentionally ignoring matching target capitalization arrays.
Difficulty Spectrum
How to read this spectrum:
The marker shows where your text falls on the readability scale. Left = easier (lower grade level), Right = harder (higher education needed). The numbered scale below shows the Flesch Reading Ease score (0–100) and corresponding U.S. grade level.
How to Check Readability Online (And Why It Matters)
Most of us write the way we think. That usually means long sentences and bigger words than our readers want. A readability checker catches this before your reader does.
Checking your readability score isn't about making your writing sound simple or dumbed down. It's about making sure your message actually gets through to the people reading it.
What does a readability score measure?
A readability score looks at a few things in your writing:
- Sentence length: Shorter sentences are usually much easier to follow.
- Word length: Words with fewer syllables tend to be quicker to read.
- Word choice: Common words score better than rare or highly technical ones.
Common Grade Targets
| Content Type | Target Grade Level |
|---|---|
| Blogs and general content | 6th–8th grade |
| Marketing and landing pages | 6th–7th grade |
| News articles | 8th–10th grade |
| Technical or academic writing | College level |
Frequently asked questions
Scores run from 0 to 100, and higher means easier to read. A score between 60 and 70 is easy enough for a 13 to 15 year old to follow, which works well for most web content.
They come from the same formula but show the result differently. Flesch Reading Ease gives you a score out of 100. Flesch-Kincaid Grade Level turns that into a U.S. school grade, like "8th grade."
For most content meant for the public, lower is better. It means more people can read it without extra effort.
Not directly, but it helps. Clearer content tends to keep readers on the page longer and lowers bounce rates, both of which support better rankings.
Not accurately. Most readability formulas, including the ones used here, were built for English and don't hold up well in other languages.
Yes. It's completely free, works right in your browser, and doesn't need a sign-up or download.
This tool focuses purely on readability scoring, and it shows you several formulas at once instead of just one. It's a quick way to check your score without extra editing features getting in the way.
No. All analysis happens locally in your browser using 100% client-side execution. Nothing is sent to a server, saved, or logged. Your privacy is absolute with zero server communication.