Readability Checker

Score your writing with Flesch Reading Ease, grade level and Gunning Fog — live as you type.

Reading ease
Grade level
Gunning fog
Words / sentence
Syllables / word
Complex words
Paste some text to see how readable it is.

🔒 Runs entirely in your browser — nothing you type is uploaded or stored on a server.

The Readability Checker measures how easy your writing is to read, using the same formulas professional editors and content teams rely on. Paste your text and it instantly computes your Flesch Reading Ease score, Flesch-Kincaid grade level and Gunning Fog index, along with the raw ingredients — average words per sentence, syllables per word and the share of complex words — plus a plain-English verdict on who will find your text comfortable to read.

Readability has direct, practical consequences. Web readers skim; text pitched above their comfortable level gets abandoned. Most successful web content sits around 8th–9th grade level (a Flesch score of 60–70), and plain-language guidelines for government, healthcare and finance often require it. Checking your score takes seconds and tells you immediately whether your draft is clear prose or an academic wall of text.

The scores update live as you edit, so you can watch the numbers improve as you shorten sentences and swap long words for short ones. Everything is calculated in your browser — your draft is never uploaded — and the tool works for anything from a tweet-length blurb to a full article, though scores are most reliable with at least 50 words.

How to use

  1. Paste your draft into the box — at least a paragraph gives meaningful scores.
  2. Read the Reading Ease score: higher is easier, with 60–70 the sweet spot for general audiences.
  3. Check the grade level — it estimates the school grade a reader needs to follow the text comfortably.
  4. Look at words-per-sentence and complex words to see why a score is high or low.
  5. Edit the text and watch the scores update live until you hit your target.

Examples

Blog post check
A draft scoring 45 (difficult) with 28 words per sentence tells you to split long sentences; a few edits later it reads 65 and the verdict says “plain English”.
Simplifying an email
Before sending a company-wide announcement, check it scores at least 60 so everyone — not just specialists — reads it easily.
Grading a study text
A teacher pastes a handout and sees grade level 11.3 — too hard for a 7th-grade class — and simplifies vocabulary until it fits.
Marketing copy
Landing-page copy at grade 6–8 converts better; the checker confirms your headline and body sit in that range.

Frequently asked questions

What is the Flesch Reading Ease score?
A 0–100 scale computed from sentence length and syllables per word. Higher means easier: 90+ reads like a comic, 60–70 is plain English, below 30 is academic. It was developed by Rudolf Flesch and is still the most widely used readability measure.
What does the grade level mean?
The Flesch-Kincaid grade estimates the US school grade needed to understand the text — an 8.0 means a typical 8th grader can follow it. Most popular novels and news sites sit between grades 7 and 9.
What is the Gunning Fog index?
Another grade-level estimate that weights “complex words” (three or more syllables) heavily. A fog index of 12 or under is a common target for professional writing; above 17 is postgraduate territory.
How are syllables counted?
With a well-tested heuristic based on vowel groups and common word endings. English spelling makes perfect syllable counting impossible without a full dictionary, so scores can differ slightly from other tools — trends and targets remain accurate.
How much text do I need?
The formulas assume normal prose, so very short samples swing wildly. Aim for at least 50 words — a few paragraphs give stable, trustworthy scores.
Is my draft uploaded?
No. All scoring happens in your browser. Your text is never sent to a server, so unpublished drafts stay private.