About this tool
A readability checker that runs entirely in your browser. Paste a paragraph, a lesson plan, a draft email, an article, or a chapter, and the tool reports an estimated US reading grade level along with six classic readability scores. The big number at the top of the widget is the headline answer; the individual formulas underneath show how much they agree, and the text statistics below explain where the numbers came from.
It is free, has no signup, and loads no analytics. The entire tool is a small static page; your text is not transmitted, stored, or logged anywhere. If you keep the tab open you can use it offline.
How it works — and what each score means
Every formula on this page combines two basic signals: sentence length (words per sentence) and vocabulary load (syllables per word, share of long words, or letters per word, depending on the formula). The longer the sentences and the heavier the vocabulary, the higher the reading level.
Flesch Reading Ease — a 0 to 100 score where higher is easier. Roughly: 90+ is a children's book, 60 to 70 is Plain English aimed at the general public, 30 to 50 reads as college-level, and under 30 reads as graduate-level. Calculated from average words per sentence and average syllables per word.
Flesch-Kincaid Grade Level — the same two signals as Flesch Reading Ease, recast as a US school grade. A score of 8.0 means a typical 8th grader can read it; a score of 12.0 maps to a high-school senior. This is the formula the US Department of Defense adopted for technical manuals in 1978 and is probably the most widely cited reading-level number in the English-speaking world.
Gunning Fog Index — published by Robert Gunning in 1952. Combines average sentence length with the percentage of "complex" words (words with three or more syllables). Originally designed for business writing; useful when you want to flag jargon-heavy prose. Aim for a Fog score under 12 for general-audience writing.
SMOG Index — "Simple Measure of Gobbledygook," published by G. Harry McLaughlin in 1969. Counts polysyllabic words (three or more syllables) and scales by the square root of the count per thirty sentences. SMOG is the favored formula in healthcare and patient-education research because it predicts comprehension better than the alternatives on consumer health text. It is most reliable on samples of at least thirty sentences; on shorter samples treat it as approximate.
Coleman-Liau Index — published in 1975 by Meri Coleman and T. L. Liau. Uses letters per 100 words instead of syllables. The trade-off: it is more robust to syllable-counting errors but slightly less sensitive to vocabulary load. Reports a US school grade.
Automated Readability Index (ARI) — published in 1967 by Senter and Smith. Like Coleman-Liau, it uses letters per word instead of syllables, so it can be computed without a syllable dictionary. Reports a US school grade.
A note on syllable counting. Counting syllables in English exactly requires a pronunciation dictionary. This tool uses an approximate heuristic: lowercase the word, count contiguous vowel groups, then subtract a trailing silent "e", a silent past-tense "-ed" (except after t or d, where the "ed" is voiced), and a silent plural "-es" after most consonants. The minimum syllable count is always one. Most English words are handled correctly; irregular spellings and proper names can be off by a syllable. For that reason the displayed scores are best read as a sanity check rather than a final grade.
Practical guidance for teachers and writers
For most classroom and workplace contexts, a single rule of thumb works well: aim a grade or two below your audience's actual reading level. Readers have to spend energy decoding the text before they can think about its content, so writing at the audience's peak ability leaves nothing in the tank for understanding.
Some specific targets worth knowing:
- Grade 5–6 — typical newspaper, popular fiction, a well-written children's chapter book.
- Grade 7–8 — Plain English, popular non-fiction, most blog posts, business email.
- Grade 9–12 — high-school textbooks, magazine features, college essays.
- Grade 13–16 — undergraduate coursework, professional journalism, white papers.
- Grade 16+ — graduate textbooks, academic papers, legal contracts.
If you are writing for students: the readability score should be at or near the average grade of your class. A reading passage two grades above the average is challenging but useful; four grades above is frustrating and stops being instructional. For struggling readers, drop one or two grades below their assigned level so they spend cognitive effort on the content, not the decoding.
If you are writing for the general public: aim for Flesch Reading Ease in the 60s or higher (Plain English). Most adult readers comfortably read at about an 8th-grade level even when they have more education than that — they read at that level on purpose, because it is faster and less work.
If you are writing for specialists: a high grade-level score is fine when your readers already know the vocabulary. The danger is when the score is high because the sentences are long, not because the vocabulary is precise. Shorter sentences with the same technical terms will lower the score and improve comprehension at no cost to precision.
How to lower a score that is too high:
- Break long sentences into shorter ones.
- Swap long Latinate words for shorter Germanic ones — "use" for "utilize", "show" for "demonstrate", "buy" for "purchase".
- Replace abstract nouns with verbs: "we made a decision" becomes "we decided".
- Cut sentences that only restate the previous one.
- Read it aloud — anywhere you stumble is where the score is high.
For more classroom-focused utilities, see the teacher tools hub; for the rest of AnchorKite's free utilities, see all tools.
Frequently asked questions
What reading level is my text?
Paste any text into the box at the top of this page and the tool reports an estimated US grade level along with six classic readability scores. Grade 6 is a typical newspaper, grade 8 is a popular magazine or business email, grade 12 is a college essay, and grade 16+ reads as graduate or professional. If you only want a single number, look at the big estimate in the top card; the individual formulas underneath show how much they agree.
What is a good Flesch Reading Ease score?
It depends on your audience. For mass-market writing aimed at the general public, aim for 60 to 70 — what Flesch called Plain English, roughly 8th- to 9th-grade level. A children's book usually scores 80 to 100. A scientific paper might score 30 or below. Marketing teams often target 60+; legal and medical disclaimers usually fall in the 0–30 range, which is part of why people complain about them.
How is reading grade level calculated?
Each formula combines two signals: how long the sentences are (words per sentence) and how heavy the vocabulary is (syllables per word, or in the case of Gunning Fog and SMOG, the share of words with three or more syllables). Coleman-Liau and ARI use letters per word as a proxy for vocabulary instead of syllables, which makes them easier to compute by hand and less sensitive to syllable-counting errors. The overall estimate shown on this page is the average of the five grade-level formulas.
Is this readability checker accurate?
It is accurate to the same degree the underlying formulas are accurate, which is: pretty good as a sanity check, not a substitute for a real human reader. The formulas were designed in the 1940s through 1970s for English prose. They get tripped up by lists, code samples, dialogue, headings, abbreviations, and short text under a few sentences. Syllable counting in particular uses an approximate heuristic — most English words are handled correctly, but irregular spellings can be off by a syllable. Treat the scores as a guideline, not a grade.
Does this tool send my text anywhere?
No. The entire analysis runs in your browser using a small vanilla JavaScript file. No network requests are made, no analytics are loaded, and your text is never stored or transmitted. You can verify this by opening your browser's network tab while typing — nothing fires. The page works offline if you've loaded it once.
Which formula should I trust if they disagree?
When the six scores agree, you have a reliable read on the text's difficulty. When they disagree, the disagreement is itself the signal — usually it means one formula is being thrown off by the kind of text (very short, very long, list-heavy, dialogue-heavy). For general English prose, the Flesch-Kincaid Grade Level and Gunning Fog are widely used; SMOG is favored in healthcare; Coleman-Liau and ARI are more robust to syllable-counting errors. The averaged grade estimate at the top blends all five so a single outlier can't dominate.