Readability is simply a measure of how easy your writing is to read — and it matters far more than most writers realise. A blog post, school essay, product description, or office email that is hard to parse loses readers fast, no matter how good the ideas inside it are. Studies consistently show plain, straightforward writing keeps people on the page longer, while dense sentences send them clicking away.
This readability checker scores any text you paste using the Flesch Reading Ease formula, one of the oldest and most trusted readability measures, developed in the 1940s and still used by publishers, educators, and government plain-language guidelines. You get a score from 0 to 100 plus an estimated school grade level, each explained in plain English so you know exactly what to do next.
The tool is a favourite with bloggers polishing posts, students checking essays, marketers tightening copy, and anyone writing in English as a second language. Because it runs entirely in your browser, your draft never leaves your device — paste with confidence, even for unpublished or sensitive work.
One honest note: no formula can judge ideas, tone, or accuracy. A score is a useful signal about sentence structure and word choice, not a verdict on your writing quality. Use it to spot heavy passages, then trust your own judgment about what your readers actually need.
How it works
The Flesch Reading Ease score comes from a simple equation: 206.835 minus 1.015 times the average sentence length, minus 84.6 times the average syllables per word. In plain terms, the formula penalises two things — long sentences and long words. Short sentences built from short words score near 100 (very easy), while long sentences packed with multi-syllable words sink toward 0 (very difficult).
To apply it, the tool first splits your text into sentences and words, then estimates syllables for each word by counting vowel groups — a standard heuristic that handles most English words well, though it can stumble on unusual names or technical terms. From those counts it computes the score and maps it to a difficulty label and a Flesch-Kincaid grade level, which estimates the years of schooling needed to read the text comfortably.
For most online writing, a score between 60 and 70 hits the sweet spot of plain, comfortable English. Scores above 80 suit young readers or very broad audiences; scores below 50 are normal for academic or legal writing but will strain casual readers. The grade level works the same way — a level of 8 means a typical 13 to 14-year-old could follow it.
How to use this tool
- Paste or type your text into the input box — a few sentences minimum works best.
- Click the check button to see your Flesch Reading Ease score and grade level.
- Read the plain-English explanation of what your score means for your audience.
- Edit long sentences or heavy words, then re-check to watch the score move.
- Repeat until the score sits in the range that suits your readers.
- Publish with confidence once the text reads smoothly.
Practical tips
- Split sentences before swapping words: breaking one long sentence in two usually lifts your score more than any vocabulary change.
- Watch for nominalisations — 'make a decision' beats 'effectuate a determination' for both score and human readers.
- Do not chase 90+ for adult topics; oversimplified writing can sound patronising. Match the score to your audience, not to perfection.
- Check competitors' top-ranking articles too — matching their readability range helps your content feel equally approachable.
Frequently asked questions
What is a good Flesch Reading Ease score?
For most online writing, aim for 60 to 70 — plain English that a typical adult reads comfortably. Scores of 80 to 90 suit broad or younger audiences, while 30 to 50 is normal for academic, legal, or technical writing. There is no universally perfect score; the right target depends on who you are writing for.
What does the grade level mean?
The Flesch-Kincaid Grade Level estimates the years of schooling needed to understand the text. A grade level of 8 means a student around 13 to 14 years old should follow it comfortably. Most public-facing content aims for grade 8 to 10, while specialist material legitimately scores higher. Matching the level to your audience keeps reading effortless rather than exhausting.
Is my text uploaded anywhere?
No. The checker runs entirely in your web browser using JavaScript — your text never leaves your device and is never stored or transmitted. That makes it safe for unpublished drafts, client work, exam answers, or anything else you would rather keep private. You can check sensitive material with complete confidence.
Why did my score change after small edits?
Because the formula is sensitive to sentence length and word length, even small changes matter — splitting one long sentence in two, or replacing a few four-syllable words with shorter ones, can move the score several points. That sensitivity is actually useful: it shows you exactly which edits lighten the reading load.
Does it work for languages other than English?
Not reliably. The Flesch formulas were calibrated on English sentence and syllable patterns, and the syllable-counting heuristic assumes English spelling. Scores for Hindi, Spanish, or other languages will be misleading. For non-English text, look for readability formulas designed for that language. Applying English formulas to other languages produces numbers that mean nothing at all.
My text is very short. Can I trust the score?
Treat short-text scores cautiously. With only one or two sentences, a single long word or one lengthy sentence swings the average dramatically, so the result is noisy. The formula was designed for passages of at least 100 words — the longer your sample, the steadier and more meaningful the score.
Note: Readability scores come from simple formulas, so treat them as a rough guide rather than a verdict on your writing quality.