Readability Checker

This readability checker goes beyond a simple grade level — it shows exactly which sentences are making your text hard to read, similar to the Hemingway App. Whether you are writing for a general audience, students, or professionals, use this tool to identify and simplify the most complex parts of your writing.

Step 1: Paste Your Text and Set a Target Audience

Paste your article, blog post, essay, or email into the text area. Use the Target Audience dropdown to select who you are writing for — General Public (grade 8), Children (grade 5), Academic (grade 12), or Technical (grade 14). The tool will flag sentences that exceed your target level with a red ring overlay.

Step 2: Read the 5 Readability Scores

The tool calculates five industry-standard formulas: Flesch-Kincaid Grade Level (most common, translates to U.S. school grade), Gunning Fog Index (years of education needed), Coleman-Liau Index (uses character counts for more stable results), Automated Readability Index (ARI) (character-based, used in U.S. military training), and SMOG Index (Simple Measure of Gobbledygook, popular in healthcare writing). Comparing all five gives you a robust picture of your text's complexity.

Step 3: Review the Sentence Highlighting

The Sentence Analysis section color-codes every sentence. Green sentences are easy (grade 6 or below). Yellow are moderate (grade 7-10). Orange are hard (grade 11-14). Red are very hard (grade 15+). Adverbs appear in purple. Sentences with detected passive voice have a blue underline. Hover over any sentence to see its exact grade level.

Step 4: Fix Difficult Words

The Difficult Words section lists every polysyllabic word (3+ syllables) in your text with its syllable count. These are the words most likely to slow readers down. For each difficult word, consider whether a simpler synonym exists. For example, "demonstrate" (3 syllables) can become "show" (1 syllable). Reducing difficult words is one of the fastest ways to lower your grade level score.

Step 5: Check Adverbs and Passive Voice

Adverbs (words ending in -ly) and passive voice constructions are writing style indicators. High adverb counts often signal weak verbs — replacing "walked quickly" with "sprinted" is both shorter and stronger. Passive voice ("was written by") is not always bad, but overuse in non-academic writing feels distant. Target fewer than 3% adverbs and limit passive constructions to technical or formal writing only.

Readability Targets by Content Type

General web content and blogs: target Flesch-Kincaid grade 6-8 (Reading Ease 60-70). Children's content: grade 3-5. Business communication: grade 8-10. Academic papers: grade 12+. Newspapers like the New York Times average grade 10-12. Healthcare patient education materials should target grade 6 or below for maximum comprehension.

Understanding Readability Scores in Depth

Each of the five readability formulas in this tool measures text complexity differently, and knowing what each one captures helps you use them more effectively:

Flesch-Kincaid Grade Level is the most widely used formula in American education and is built into Microsoft Word. It calculates grade level from average sentence length and average syllables per word. A score of 8.0 means an 8th grader can read the text comfortably. It's well-validated against actual reading comprehension tests but can be gamed by writing short sentences with long words.

Gunning Fog Index estimates the years of formal education a reader needs to understand the text on first reading. It specifically counts "hard words" — words of 3+ syllables (excluding proper nouns and compound words). The Wall Street Journal targets a Fog index of 11; Time Magazine targets 10. A score above 18 is considered unreadable by most of the public.

SMOG Index (Simple Measure of Gobbledygook) is the standard in healthcare communication. The U.S. Department of Health and Human Services recommends that patient education materials score below SMOG grade 8. Unlike other formulas, SMOG only counts polysyllabic words and is specifically calibrated to predict 100% reading comprehension — not just comfortable reading.

Coleman-Liau Index uses character counts rather than syllable counts, making it more stable for short texts where syllable detection can be unreliable. It's favored by computational linguists because it doesn't require a syllabification algorithm. Higher character density per word correlates with more complex vocabulary regardless of syllable structure.

Automated Readability Index (ARI) was developed for the U.S. military to assess training materials. It also uses characters per word (not syllables) and produces scores that closely match Flesch-Kincaid in practice. It's used in military and aviation contexts where accuracy of comprehension is critical.

Target Reading Levels by Audience

Different audiences expect — and can handle — different levels of text complexity. Here are practical targets for common use cases:

General public / news articles: Flesch-Kincaid grade 6–8. This range reaches the widest possible adult audience. The average American reads at a 7th–8th grade level; writing at a 10th-grade level loses roughly 30% of readers.

Medical patient materials: grade 5–6 (SMOG below 8). The American Medical Association and National Institutes of Health both recommend grade 6 maximum for patient education materials. Studies show comprehension drops sharply above grade 8 for patients under stress or with lower health literacy.

Academic and peer-reviewed papers: grade 12+ is expected and appropriate. Academic writing uses domain-specific technical vocabulary that signals expertise to the intended audience. However, abstract sections should target grade 10–12 for broader discoverability.

Marketing copy and landing pages: grade 7–8. Marketing copy that reads at grade 12+ feels academic and distant; grade 5 or below can feel condescending. Grade 7–8 is persuasive, accessible, and drives action.

Children's books by age: early readers (ages 5–7) target grade 1–2; middle-grade (ages 8–12) targets grade 3–6; young adult (ages 12–17) targets grade 6–9.

How to Improve Your Writing's Readability

The fastest ways to lower your grade level without losing meaning or authority:

Shorten your sentences. The average sentence in readable web writing is 15–20 words. If a sentence runs over 30 words, find the natural split point and cut it in two. Sentence length is the most powerful lever in most readability formulas.

Use simpler words. Replace "utilize" with "use," "terminate" with "end," "facilitate" with "help," "commence" with "start," "methodology" with "method." Technical writing is the exception — use domain terms when the audience expects them.

Write in active voice. Passive voice ("the report was written by the team") is typically longer and more abstract than active voice ("the team wrote the report"). Active voice is also usually more direct and engaging.

One idea per paragraph. Complex ideas buried in multi-idea paragraphs force readers to track multiple threads simultaneously. Break paragraphs at each new idea — even if the paragraphs end up being just 2–3 sentences.

Reading Level for SEO

Google has stated publicly that it does not use readability as a direct ranking signal. However, readability affects SEO indirectly through user behavior. Content written at too high a grade level shows higher bounce rates, lower dwell time, and lower scroll depth — all behavioral signals that correlate with lower rankings. Content written at the right level for the search intent keeps users engaged, which is what Google is actually measuring. For informational searches (how-to, what is), matching the reading level to the audience's expertise is a core content quality factor. For product and transactional pages, lower grade levels (6–8) consistently outperform higher ones in conversion rate testing.

For a detailed walkthrough, see our guide: How to Check Your Writing's Reading Level.