What is a Readability Checker?

A readability checker is a tool that analyzes your text and tells you how easy or difficult it is to read. It uses proven formulas developed by linguists and educators to calculate a readability score based on factors like sentence length, word complexity, and syllable count.

How it works: This tool calculates six different readability metrics to give you a comprehensive analysis of your content's accessibility and clarity.

Six Readability Metrics Explained

Flesch Reading Ease

The most widely used formula, scoring from 0 (very hard) to 100 (very easy)

Flesch-Kincaid Grade

Converts readability into a U.S. school grade level

Gunning Fog Index

Estimates years of formal education needed to understand the text

SMOG Index

Particularly useful for health and medical documents

Coleman-Liau Index

Uses character count rather than syllables

Automated Readability Index

Combines character and word analysis

Who Should Use This Tool?

This readability checker is valuable for anyone who writes for an audience:

Content Writers

Ensure blog posts and articles match your target audience

Copywriters

Create marketing copy that converts by being easy to understand

Technical Writers

Verify documentation is accessible to your users

Educators

Check if teaching materials match students' reading levels

Healthcare Professionals

Make patient information clear and understandable

Business Professionals

Write clearer emails, reports, and proposals

Your Text Stays Private

All readability analysis happens entirely in your browser:

100% Privacy Guaranteed:

No server processing - Your text never leaves your device
No data storage - Nothing is saved or logged
No tracking - We don't collect any usage data

Table of Contents

1. What is a Readability Checker?
2. How to Use the Readability Checker
3. Features and Readability Formulas
4. Frequently Asked Questions

How to Use the Readability Checker

Checking your text's readability takes just a few seconds. Follow these simple steps to analyze your content and get actionable insights.

Enter Your Text

Paste or type your text into the input area. The tool works best with at least 100 words to provide accurate scores. You can analyze:

Blog posts and articles
Marketing copy and landing pages
Emails and business documents
Educational materials
Any written content

Review Your Scores

The tool instantly calculates and displays:

Main Readability Score - Your Flesch Reading Ease score with color-coded feedback
Grade Level - The education level needed to understand your text
Text Statistics - Word count, sentences, average sentence length, and complex word percentage

Check Detailed Scores

Click on Detailed Scores to see all six readability formulas. Hover over the info icons to learn what each score means and how to interpret it.

Follow Improvement Tips

The tool automatically shows tips based on your text analysis:

Green tips - Things you're doing well
Orange warnings - Areas that could be improved
Blue suggestions - General recommendations

Tips for Better Readability

Best Practices:

Shorten sentences - Aim for an average of 15-20 words per sentence
Use simpler words - Replace complex words with everyday alternatives
Break up paragraphs - Shorter paragraphs are easier to scan
Use active voice - "We analyzed the data" instead of "The data was analyzed"
Read aloud - If you stumble, your readers might too

Features and Readability Formulas

This tool provides comprehensive readability analysis using multiple scientific formulas. Each formula measures text difficulty from a different angle.

Flesch Reading Ease

The most popular readability formula, developed by Rudolf Flesch in 1948. It produces a score from 0 to 100:

90-100: Very Easy 5th Grade

80-89: Easy Conversational

70-79: Fairly Easy 7th Grade

60-69: Standard 8th-9th Grade

50-59: Fairly Difficult High School

30-49: Difficult College

0-29: Very Confusing Graduate

Flesch-Kincaid Grade Level

Developed for the U.S. Navy in 1975, this formula translates readability into a U.S. school grade level. A score of 8.0 means an 8th grader can understand the text.

This formula was specifically designed to help the U.S. Navy assess the readability of technical manuals and ensure they matched the reading abilities of enlisted personnel.
— U.S. Navy Research, 1975

Practical Use: A Flesch-Kincaid Grade Level of 8.0 indicates that someone who has completed 8th grade should be able to understand the content. Most consumer-facing content should aim for grades 6-10.

Gunning Fog Index

Created by Robert Gunning in 1952, this formula estimates the years of formal education needed. A Fog Index of 12 means the text requires a high school senior's reading ability.

High Fog Index

Complex Text (Fog 15+)

Long, complex sentences
Many multi-syllable words
Requires college education
Limited audience reach

Low Fog Index

Clear Text (Fog 8-12)

Shorter, clearer sentences
Simple, everyday words
Accessible to most readers
Broader audience reach

SMOG Index

SMOG (Simple Measure of Gobbledygook) was developed in 1969 and is particularly useful for health literacy. It's the preferred formula for medical and healthcare documents.

Healthcare Standard: The SMOG Index is recommended by the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) for evaluating patient education materials.

Why SMOG for Healthcare: Medical information must be clearly understood to ensure patient safety and compliance. SMOG provides a more conservative estimate, ensuring materials are truly accessible to the intended audience.

Coleman-Liau Index

Unlike other formulas, Coleman-Liau uses character count instead of syllables. This makes it useful for comparing texts across different languages and for automated analysis.

Cross-Language Analysis

Character-based counting works consistently across languages with different syllable structures

Fast Processing

Character counting is computationally simpler than syllable counting, enabling real-time analysis

Automated Readability Index (ARI)

ARI combines character count with word count to estimate grade level. It was designed for real-time monitoring of typewritten text readability.

The Automated Readability Index was developed in 1967 for the U.S. Air Force to assess the readability of technical manuals in real-time as they were being typed.
— U.S. Air Force Research, 1967

Modern Applications: Today, ARI is widely used in automated content analysis systems, educational software, and content management platforms for instant readability feedback.

Multi-Language Support

The tool adapts its formulas for different languages:

German

Flesch-Amstad formula with German syllable rules

Spanish

Fernández Huerta adaptation

French

Kandel-Moles formula

More Languages

Italian, Dutch, Portuguese, Polish, Russian with adapted formulas

Frequently Asked Questions

What is a good readability score?

For general audiences, aim for a Flesch Reading Ease score between 60-70 (standard difficulty). This corresponds to an 8th-9th grade reading level. Most popular newspapers and magazines write at this level.

Industry Standard: The Associated Press, USA Today, and most major news outlets target a Flesch Reading Ease score of 60-70 to ensure broad accessibility.

What readability score should I target for my content?

It depends on your audience:

Content Type	Target Score	Reading Level	Example
Children's content	80-100	Very easy	Elementary
General public	60-70	Standard	News articles
Technical documentation	50-60	Fairly difficult	User manuals
Academic papers	30-50	Difficult	Research
Legal documents	0-30	Very difficult	Contracts

Why are there so many different formulas?

Each formula was developed for different purposes and measures slightly different aspects of readability. Using multiple formulas gives you a more complete picture of your text's difficulty level. The average grade level shown combines all formula results.

Why Multiple Metrics Matter: A single formula might miss important aspects of readability. By combining multiple approaches, you get a more reliable and balanced assessment of your content's accessibility.

Are readability formulas accurate?

Readability formulas measure structural complexity (sentence length, word length, syllables) but cannot evaluate meaning, organization, or visual presentation. They are useful guidelines but should not be the only measure of content quality.

Important Limitation: Readability scores cannot assess context, tone, cultural references, or whether the content actually makes sense. Use them as one tool among many for evaluating content quality.

What formulas CAN measure:

Sentence length and complexity
Word difficulty (syllable count)
Text structure patterns

What formulas CANNOT measure:

Content accuracy or quality
Logical flow and organization
Visual design and formatting
Cultural context and idioms

What counts as a complex word?

A complex word is any word with three or more syllables. For example, "information" (4 syllables) is complex, while "data" (2 syllables) is not. Reducing complex words improves readability.

Complex Words

3+ Syllables

in-for-ma-tion (4)
com-mu-ni-cate (4)
im-por-tant (3)
nec-es-sa-ry (4)

Simple Words

1-2 Syllables

da-ta (2)
tell (1)
key (1)
need-ed (2)

How is the grade level calculated?

The grade level is the average of five formulas: Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and ARI. This provides a more balanced estimate than any single formula.

Calculation Method: By averaging multiple formulas, we reduce the impact of any single formula's limitations and provide a more reliable overall assessment of reading difficulty.

Does the tool work with languages other than English?

Yes. The tool supports multiple languages including German, Spanish, French, Italian, Dutch, Portuguese, Polish, and Russian. Each language uses adapted formulas with language-specific syllable counting rules.

Language-Specific Adaptations: Each supported language has customized syllable counting rules and formula adjustments to account for linguistic differences in word structure and sentence patterns.

Is my text stored or shared?

No. All analysis happens in your browser using JavaScript. Your text is never sent to any server, never stored, and never shared with third parties.

Complete Privacy:

Client-side processing only
No server uploads
No data logging
No third-party tracking
Works offline after initial load

Why is my score different from other readability checkers?

Small differences in syllable counting can lead to slightly different scores. This tool uses rule-based syllable counting which is approximately 85-90% accurate. The scores are reliable for practical use but may differ slightly from dictionary-based tools.

Why Scores Vary: Different tools may use different syllable counting methods, text preprocessing approaches, or formula implementations. Small variations (±5 points) are normal and don't significantly affect the practical interpretation of your content's readability.

Focus on Trends: Rather than obsessing over exact scores, pay attention to whether your content falls within your target range and how changes to your writing affect the scores.