What is a good Flesch Reading Ease score?

Higher is easier: 90+ is very easy, 60–70 is standard (8th–9th grade, a good target for general audiences), and below 30 is very difficult (college graduate level).

What's the difference between the metrics?

Flesch Reading Ease is a 0–100 score (higher = easier). Flesch–Kincaid Grade and Gunning Fog both estimate the US school grade needed to understand the text.

How are syllables counted?

With a well-known heuristic based on vowel groups and common word endings. It's an estimate — accurate enough for scoring but not a dictionary lookup.

Is my text sent anywhere?

No. All analysis happens locally in your browser.

Readability Score

Measure how easy your text is to read with Flesch–Kincaid and Gunning Fog — computed in your browser

Text

Paste the passage to analyze

Examples

Score short, simple sentences

Input

The cat sat on the mat. The dog ran.

Output

{
  "words": 9,
  "sentences": 2,
  "syllables": 9,
  "fleschReadingEase": 117.7,
  "fleschKincaidGrade": 0,
  "gunningFog": 1.8,
  "easeBand": "Very easy (5th grade)"
}

Short sentences and mostly one-syllable words produce a high reading-ease score and low grade estimates.

Compare technical wording

Input

Readability tools help teams write clear documentation.

Output

{
  "words": 7,
  "sentences": 1,
  "syllables": 15,
  "fleschReadingEase": 18.4,
  "fleschKincaidGrade": 12.4,
  "gunningFog": 14.2,
  "easeBand": "Very difficult (college graduate)"
}

The single sentence is short, but the heuristic counts enough syllables to produce a difficult reading-ease band.

See the lower bound for dense vocabulary

Input

Consequently, the multifaceted infrastructure necessitated comprehensive reconfiguration.

Output

{
  "words": 7,
  "sentences": 1,
  "syllables": 27,
  "fleschReadingEase": 0,
  "fleschKincaidGrade": 32.7,
  "gunningFog": 37.1,
  "easeBand": "Very difficult (college graduate)"
}

The raw Flesch calculation is below zero, so the displayed reading-ease value is clamped to 0 while the grade estimates remain high.

About this tool

Readability Score estimates how difficult an English passage is to read using Flesch Reading Ease, Flesch–Kincaid Grade and Gunning Fog. It also reports word, sentence and syllable counts, then maps the Flesch score to a plain-English band such as Very easy, Standard or Very difficult.

The component uses a lightweight browser-side heuristic: words are ASCII letter sequences with optional apostrophes, sentences are split at periods, exclamation marks and question marks, and syllables are estimated from vowel groups with common English endings removed. Flesch Reading Ease is clamped to 0–121.22, while the grade and Fog values are prevented from going below zero.

Results update as you type and are best used for comparing drafts consistently. The heuristic is designed for English prose, not as a substitute for editorial judgment or a full linguistic analysis, and all processing stays in the browser.

How to use

Paste the passage
Replace the sample text in the Text area with the English copy, documentation or UI wording you want to inspect.
Read the score summary
Review Flesch Reading Ease and its band, then compare the Flesch–Kincaid Grade and Gunning Fog Index shown below it.
Check the counts
Use Words, Sentences and Syllables to spot whether a score changed because of sentence length, word choice or the syllable heuristic.
Revise and compare
Shorten long sentences or replace unnecessarily complex words, then paste the revision and compare the new metrics with the previous draft.

Use cases

Editing developer documentation

Compare a setup guide before and after revision to see whether shorter sentences and simpler vocabulary make the instructions easier to scan.

Reviewing UI and onboarding copy

Check labels, help text and onboarding paragraphs for unexpectedly high grade estimates before handing them to users.

Comparing release-note drafts

Paste two versions of a release note and use the metrics as a consistent signal while preserving the technical meaning.

Teaching readability trade-offs

Use the counts and three scores to show how sentence length and multi-syllable words affect common readability formulas.

Common mistakes

Mistake:Treating the score as a definitive judgment of writing quality.

Fix:Use the numbers as a comparison signal. Technical terms, necessary names and deliberate tone can raise a score without making the copy wrong.

Mistake:Using the heuristic for non-English text or mixed scripts.

Fix:The word matcher and syllable estimator are built around ASCII English words, so use an appropriate language-specific analyzer for other languages.

Mistake:Leaving sentence-ending punctuation out of a multi-sentence draft.

Fix:The component splits sentences at ., ! and ? followed by whitespace or the end of the text. Add normal punctuation so sentence length is measured as intended.

Mistake:Comparing passages with very different lengths as if the scores were equally stable.

Fix:Very short passages can swing sharply from one word or punctuation change. Use a representative section and combine the score with manual review.

Frequently asked questions

Letter Frequency Analysis: How Frequency Stats Crack Substitution Ciphers

What the letter distribution in English looks like, how to use it to break a Caesar cipher, and what word and line stats reveal that individual letters miss.