Readability Checker

Readability Checker — Analyze Text Difficulty and Grade Level

Our free readability checker analyzes your text using seven industry-standard readability formulas and gives you a comprehensive picture of how difficult your writing is to read. Paste any text — a blog post, essay, email, product description, or document — and instantly see your Flesch Reading Ease score, Flesch-Kincaid grade level, Gunning Fog Index, SMOG, Coleman-Liau, ARI, and Dale-Chall scores, along with actionable suggestions for improvement.

Readability Formulas Explained

Flesch Reading Ease

Developed by Rudolf Flesch in 1948, the Flesch Reading Ease formula is the most widely used readability metric. It scores text on a 0–100 scale based on average sentence length and average syllables per word. The US Department of Defense requires all military documents to score at least 70. The insurance industry in many states requires policy documents to score above 45.

Flesch-Kincaid Grade Level

Developed for the US Navy, the Flesch-Kincaid Grade Level formula uses the same inputs as Reading Ease but outputs a US school grade level instead of a 0–100 score. A grade level of 8.0 means the text is appropriate for an 8th grader. Most popular newspapers target a grade level of 7–9 to reach the widest possible audience.

Gunning Fog Index

Created by Robert Gunning in 1952, the Fog Index estimates the years of formal education needed to understand text on first reading. It penalizes "complex words" — words of three or more syllables. Most business writing guidelines recommend a Fog Index below 12. Time magazine targets around 11.

SMOG Index

SMOG (Simple Measure of Gobbledygook) was developed by G. Harry McLaughlin in 1969 as a more accurate alternative to Flesch-Kincaid for health materials. It counts polysyllabic words (3+ syllables) across 30 sample sentences. It is widely used by the US healthcare industry for patient education materials.

Coleman-Liau Index

Unlike most readability formulas that count syllables, the Coleman-Liau Index uses character counts — specifically the average number of letters per 100 words and the average number of sentences per 100 words. This makes it easier to calculate programmatically and useful for analyzing very large texts.

Automated Readability Index (ARI)

The ARI was developed in 1967 and uses characters per word and words per sentence. Like Coleman-Liau, it counts characters rather than syllables, making it suitable for automated analysis. It outputs a US grade level from 1 to 14+.

Dale-Chall Readability Score

The Dale-Chall formula uses a list of approximately 3,000 words that are familiar to 80% of US 4th graders. Words not on this list are considered "difficult." The score is calculated from the proportion of difficult words and average sentence length. It is considered particularly accurate for materials targeting adult readers.

Readability Score Comparison

Target Readability by Content Type

How to Improve Text Readability

Shorten Your Sentences

Sentence length is the single biggest driver of readability scores. A sentence over 25 words is difficult for most readers to parse in one reading. Aim for an average sentence length of 15–20 words. Vary your sentence length — short punchy sentences interspersed with medium ones create better rhythm than uniform sentence lengths.

Choose Simple Words Over Complex Ones

Every readability formula penalizes long, multi-syllabic words. Replace complex words with simpler alternatives where meaning is not lost: "utilize" → "use", "demonstrate" → "show", "approximately" → "about", "commence" → "start", "terminate" → "end". This does not mean dumbing down content — it means communicating clearly.

Use Active Voice

Passive voice constructions ("The report was written by the team") are longer and harder to process than active voice ("The team wrote the report"). Active voice reduces word count, clarifies who is doing what, and improves readability scores.

Break Up Long Paragraphs

Long paragraphs — more than 5–6 lines — create a visual wall of text that discourages reading, especially on screens. Break paragraphs at logical points. Use subheadings every 3–4 paragraphs to help readers scan and navigate.

Frequently Asked Questions

What readability level should a blog post be?

For general audiences, aim for a Flesch Reading Ease score of 60–70 (Flesch-Kincaid grade level 8–9). This is the reading level of most popular newspapers and general interest magazines. Content in this range is accessible to the majority of adult readers while still sounding professional.

Does Google use readability scores for SEO?

Google does not directly use readability scores as a ranking factor. However, readability is correlated with user experience signals that do affect rankings: lower bounce rate, longer time on page, and more pages per session. Content that is genuinely easy to read tends to perform better in search.

What is the reading level of a newspaper?

Most major US newspapers target a Flesch-Kincaid grade level of 7–9 (Flesch Reading Ease 60–70). The New York Times averages around grade 10–11. Tabloid newspapers typically target grade 6–7 for maximum accessibility.

How many syllables count as a complex word?

In most readability formulas including the Gunning Fog Index, a complex word is defined as any word with three or more syllables. Proper nouns and compound words are sometimes excluded depending on the formula variant being used.

Is higher or lower readability better?

It depends entirely on your audience. A higher Flesch Reading Ease score means easier text — better for general audiences, marketing, and consumer content. A lower score means more complex text — appropriate for academic, legal, and technical content targeting educated specialists. Match your score to your readers, not to an arbitrary target.