Readability Score Checker

Analyze your text's reading level using 6 industry-standard formulas. Instant results, 100% in your browser.

Your Text
Paste text above to analyze its readability.

How to Use the Readability Score Checker

  1. Paste your text into the input area. The analysis updates automatically as you type.
  2. Choose a formula — Flesch-Kincaid for standard grade level, Gunning Fog for complex word analysis, or All Scores to see every metric.
  3. Read the gauge — the green zone (60-70) represents standard readability for most audiences.
  4. Review statistics — sentence count, word count, syllable count, and averages help you understand what's driving the score.
  5. Revise and re-test — to improve readability, break up long sentences and replace complex words with simpler alternatives.

Understanding the Readability Formulas

Flesch Reading Ease

The oldest and most widely used formula, developed by Rudolf Flesch in 1948. Scores range from 0 (very difficult) to 100 (very easy). The formula is 206.835 − 1.015 × (words/sentences) − 84.6 × (syllables/words). Most web content should target 60-80. Legal and technical documents often score below 30. Easy children's books score 90+.

Flesch-Kincaid Grade Level

Converts the Flesch Reading Ease score into a US school grade level. A score of 8.0 means a typical 8th grader can understand the text. The New York Times averages around grade 10. Twitter posts average grade 5. Academic journal articles often exceed grade 16. Most content marketing experts recommend writing at grade 6-8 for maximum reach.

Gunning Fog Index

Developed by Robert Gunning in 1952. Uses sentence length and percentage of "complex" words (words with 3 or more syllables) to estimate grade level. The formula: 0.4 × (words/sentences + 100 × complex_words/words). Scores above 17 indicate college-graduate level. Fog scores above 12 are considered hard to read for most audiences.

Coleman-Liau Index

Unlike other formulas, Coleman-Liau uses character counts rather than syllable counts, making it easier to compute algorithmically. It was designed for use on computer-parsed text. The formula estimates grade level from letters per 100 words and sentences per 100 words. It tends to produce slightly different results from syllable-based formulas on texts with many long words but short syllable counts.

SMOG Index

The Simple Measure of Gobbledygook (SMOG) was developed by G. Harry McLaughlin in 1969. It counts polysyllabic words (3+ syllables) in 30 sentences and estimates the years of education needed to understand the text. SMOG is considered one of the most accurate measures for healthcare and medical communications and is recommended by the US Centers for Disease Control for health literacy assessments.

Automated Readability Index (ARI)

The ARI uses characters per word and words per sentence. It was developed for real-time monitoring of typewritten output. The ARI tends to be more conservative (higher grade estimates) than Flesch-Kincaid for texts with short, multi-syllable technical words. Formula: 4.71 × (chars/words) + 0.5 × (words/sentences) − 21.43.

Tips for Improving Readability

  • Break sentences longer than 20 words into two shorter sentences
  • Replace three-syllable words with one- or two-syllable synonyms where possible
  • Use active voice instead of passive voice
  • Prefer common, everyday words over formal or technical jargon
  • Add subheadings every 200-300 words to give readers natural break points
  • Use bullet points and numbered lists for multi-part information

Frequently Asked Questions

A Flesch Reading Ease score of 60-70 is considered standard and targets a 7th-8th grade reading level. Scores above 70 are easy to read. Scores below 30 are very difficult (academic or legal text). Most web content should aim for 60-80 to reach the widest possible audience.
Flesch-Kincaid Grade Level uses average sentence length and syllables per word to estimate the US grade level needed to understand the text. Gunning Fog uses sentence length and the percentage of complex words (3+ syllables) and tends to produce slightly higher grade estimates. Both measure similar things but with different weightings.
For general audience blog posts, aim for grade 6-8 (Flesch-Kincaid). For technical or professional audiences, grade 10-12 is acceptable. For popular consumer content, grade 5-7 maximizes accessibility. Publications like Time magazine typically write at grade 10, while Reader's Digest targets grade 8.
The SMOG (Simple Measure of Gobbledygook) index measures how many years of education a reader needs to understand a piece of writing. It focuses specifically on polysyllabic words (3+ syllables) and is considered one of the most accurate readability formulas for health communications and medical documents.
Each formula weighs linguistic features differently. Flesch-Kincaid emphasizes syllable count and sentence length. Gunning Fog focuses on complex (polysyllabic) words. Coleman-Liau uses character counts instead of syllables. ARI counts characters per word and words per sentence. The variation reflects different theories about what makes text difficult to read.