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Introduction:

Word-, sentence-, and syllable-based metrics form the backbone of modern readability analysis. They help you quantify lexical variety, sentence complexity, and overall text density, enabling objective comparisons between drafts or against style guides.

This tool accepts pasted passages or locally uploaded plain-text files, then instantly calculates counts, lexical density, and two readability indices. A reactive engine updates statistics, frequency tables, and an interactive bar chart as you type or tweak the display parameters.

Marketers, teachers, and editors rely on such dashboards to target age-appropriate language, trim redundancy, and uncover over-used words; *avoid pasting confidential material unless essential*.

Technical Details:

Concept Overview

Readability scoring couples average sentence length (ASL) and average syllables per word (ASW) to gauge comprehension effort. Higher ASL and ASW inflate cognitive load; lower values promote clarity. The tool additionally computes lexical density—the ratio of unique words to total words—to reveal vocabulary diversity.

Core Equations

Flesch Reading Ease (FRE) and Flesch-Kincaid Grade (FKG) are calculated as:

FRE=206.8351.015×ASL84.6×ASW FKG=0.39×ASL+11.8×ASW15.59

Interpretation Bands

FRE ScoreDifficulty
90–100Very Easy
80–89Easy
70–79Fairly Easy
60–69Standard
50–59Fairly Difficult
30–49Difficult
0–29Very Confusing

Scores above 60 suggest material suited to a broad audience; values below 50 often require specialist knowledge or editorial simplification.

Variables & Parameters

  • Text – raw passage supplied via textarea or file.
  • top N – number of high-frequency words displayed and charted.
  • CSV Actions – copy or download statistics and frequencies.

Worked Example

Sample of 95 words across 5 sentences with 143 syllables:

ASL=955=19 ASW=143951.51 FRE=206.8351.015×1984.6×1.5160.20 FKG9.58

Assumptions & Limitations

  • Counts rely on standard Latin word boundaries.
  • Hyphenated compounds are treated as single words.
  • Syllable estimation
  • uses heuristic rules; irregular words may miscount.
  • Readability formulas target English prose; results weaken for other languages.

Edge Cases & Error Sources

  • Empty input yields zeroed metrics.
  • Single long sentence inflates grade level.
  • All-caps or numeric strings skew syllable detection.
  • Excessive punctuation fragments sentences incorrectly.

Scientific Validity & References

Formulas stem from Rudolf Flesch’s readability research and the U.S. Navy training manual (1975). Subsequent validation appears in Applied Linguistics and Journal of Technical Writing studies.

Privacy & Compliance

No personal or sensitive data leaves your browser; processing is entirely local.

Step-by-Step Guide:

Follow these steps to obtain instant insights:

  1. Paste text into the field or drag & drop a plain-text file.
  2. Review live statistics in the Statistics tab.
  3. Open Word Frequency to see ranked counts; adjust top N as needed.
  4. Switch to Charts for a visual bar plot of the same data.
  5. Copy or download CSV files for further analysis or reporting.
  6. Use Clear Text to reset and begin a new session.

FAQ:

Is my data stored?

No, all processing occurs locally; nothing is transmitted.

Why do counts differ from word processors?

Definitions of word and sentence boundaries vary; this tool follows strict regex rules, so totals may shift slightly.

What is lexical density?

It is the percentage of unique tokens, indicating vocabulary variety within a passage.

How accurate are syllable estimates?

Heuristics handle common patterns, but rare or loanwords can introduce ±5 % error.

Can I analyse non-English text?

You can, yet readability formulas are calibrated for English and may misrepresent complexity in other languages.

Glossary:

ASL
Average words per sentence.
ASW
Average syllables per word.
Lexical Density
Unique-word ratio, expressed as %.
FRE
Flesch Reading Ease score.
FKG
Flesch-Kincaid Grade estimate.

Files are processed locally in your browser; nothing is uploaded.

Embed this tool into your website using the following code: