Flesch-Kincaid reading level checker
Paste any text and instantly get your Flesch-Kincaid grade level, reading ease score and Gunning Fog Index.
The history of readability formulas
Readability measurement began as a practical problem. In 1948, Austrian-born writing consultant Rudolf Flesch published his Reading Ease formula to help journalists write for wider audiences — the Associated Press adopted it to keep newspaper writing accessible. In 1975, J. Peter Kincaid recalculated it for the US Navy, which needed to match technical manuals to the reading levels of recruits; his version reports a school grade instead of a 0–100 score, and the pair became known as Flesch-Kincaid. The formulas analyze just two things — sentence length and syllables per word — yet predict comprehension well enough that Microsoft Word, Google Docs and most writing tools still use them today, and some US states require insurance policies to meet minimum Flesch scores by law.
Flesch-Kincaid Grade Level explained
The Flesch-Kincaid Grade Level translates readability into the US school grade system. A score of 8 means an eighth grader can understand the text. Most newspapers target grades 6 to 8. Plain language guidelines for government documents often specify grade 8 or below. Technical documentation and academic papers commonly score at grade 12 or above. The Flesch-Kincaid formula uses average sentence length and average syllables per word to produce a grade level.
Flesch Reading Ease explained
The Flesch Reading Ease score is the other half of the Flesch-Kincaid system. It ranges from 0 to 100 — higher means easier. A score of 90 to 100 is very easy, understood by an average 11-year-old. A score of 60 to 70 is standard, appropriate for 13 to 15 year olds and the target for most web content. A score of 30 to 50 is difficult — college level. Below 30 is very confusing and suitable only for academic journals and legal documents.
Gunning Fog Index explained
The Gunning Fog Index estimates the years of formal education required to understand text on first reading. It weights heavily toward complex words — those with three or more syllables. A score of 12 corresponds to a US high school senior. A score of 17 corresponds to a college graduate. The Wall Street Journal targets a Fog Index of around 11. Time magazine aims for 10. If your Fog Index is above 12 for general web content, reducing complex words will have the biggest impact.
Frequently asked questions
What is a good Flesch Reading Ease score?
For most writing aimed at a general audience, 60 to 70 is the sweet spot — standard prose comfortably readable by 13-to-15-year-olds and, by extension, nearly every adult. Above 70 reads as easy and conversational, which suits marketing copy and consumer help content. Scores of 30 to 50 signal college-level difficulty, and below 30 is dense academic or legal territory that general readers will abandon. Rather than chasing 100, match the score to your audience: a research summary can sit at 45 while a product page should not.
What reading level should my blog post be?
Target grade 6 to 8 on the Flesch-Kincaid scale, which corresponds to a Reading Ease of roughly 60 to 70. That is not "dumbing down" — most newspapers write at this level, because it lets readers absorb ideas at full speed instead of decoding sentences. Content written at this level also tends to perform better for SEO: visitors stay longer and bounce less when reading feels effortless. Reserve higher grade levels for genuinely specialist audiences who expect technical vocabulary.
How do I lower my reading level score?
Two changes do most of the work: shorten sentences toward a 15-to-20-word average, and swap multi-syllable words for plain synonyms — "use" not "utilize", "show" not "demonstrate", "buy" not "purchase". Beyond that, prefer active voice, break long paragraphs, and avoid nominalizations ("decide" rather than "make a decision"). Re-check the score after each editing pass; watching the grade level fall sentence by sentence is the fastest way to build a plain-language instinct.
What reading level does the average adult read at?
Literacy research consistently places the average US adult's comfortable reading level around 7th to 8th grade, and roughly one in five adults reads below a 6th-grade level. Health and government agencies write to this reality — the NIH recommends patient materials at a 6th-to-7th-grade level, and plain-language laws hold federal documents to similar standards. This is why "write for grade 8" is the default advice for any content meant for the general public.
Are readability formulas accurate?
They are reliable indicators, not judges of quality. Formulas measure only structure — sentence length and word length — so they cannot detect jargon made of short words, muddled logic, or graceful long sentences. A grade-8 score does not guarantee clear writing, and Hemingway would score "easy" while saying profound things. Use the scores as a smoke alarm: a grade level far above your audience is a real problem worth fixing, while small score differences between drafts mean little.