Readability Checker — Flesch Score & Grade Level

Key takeaways

Both scores use only two inputs: average sentence length (words per sentence) and average word length (syllables per word). Shorter sentences and shorter words raise ease and lower grade.
For a general web audience, aim for a Reading Ease of 60–70 and a grade of 7–9. Technical docs can sit lower; consumer pages should sit higher.
Fixing the three longest sentences usually moves the score more than swapping individual words.
Answer engines quote short, self-contained statements. Open with the direct answer and phrase subheadings as the questions readers ask.

How are the Flesch scores calculated?

Rudolf Flesch published the Reading Ease formula in 1948 ("A new readability yardstick", Journal of Applied Psychology). J. Peter Kincaid and colleagues re-weighted the same two inputs into a US grade level in 1975, in a research report for the US Navy, and the grade formula later became a US military standard for technical manuals. The checker applies both formulas exactly:

Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)
Grade level  = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59

Words per sentence and syllables per word are averages over the whole text. Reading time uses 230 words per minute.

Counting words and sentences is mechanical. Counting syllables is not: English spelling doesn't map cleanly to sound, so every readability tool estimates syllables with rules rather than a dictionary. This one counts vowel groups, then corrects for silent endings ("make", "jumped"), consonant + le ("table"), and vowel pairs that are usually split ("media", "being"). It gets the occasional word wrong by one syllable, which is why different tools give slightly different scores for the same text.

What is a good Flesch Reading Ease score?

Reading Ease	Description	Approx. school level	Typical text
90–100	Very easy	5th grade	Children's books, short conversational copy
80–90	Easy	6th grade	Consumer marketing, chat-style help articles
70–80	Fairly easy	7th grade	Most popular blog posts and news
60–70	Plain English	8th–9th grade	A good target for most web pages
50–60	Fairly difficult	10th–12th grade	Technical blog posts, B2B landing pages
30–50	Difficult	College	Academic writing, API documentation
0–30	Very difficult	College graduate	Legal contracts, scientific papers

Bands follow Flesch's original interpretation table. Scores can go below 0 or above 100 for extreme text.

The grade level reads the other way round: lower is easier. A grade of 8 means a typical US eighth-grader could follow the text. It isn't a judgment of your readers — busy experts skim too, and they prefer plain text as much as anyone.

How to use the readability checker

1.Paste the text of a page or draft. Markdown works: ## headings are checked for the answer-engine tips and left out of the sentence count; list items count as their own sentences.
2.Read the Reading Ease and grade level, then look at the average sentence length. Over 20 words on average is the most common reason for a low score.
3.Open the longest sentences. Split each one at its "and", "which" or "because", or move a side point into its own sentence.
4.Check the answer-engine tips: does the first sentence answer the page's question directly, and are the subheadings phrased as questions?
5.Re-paste after editing. Aim to move the score into the band that fits your audience, not to maximize it.

How does readability affect AI answers and featured snippets?

Search features and AI assistants that quote web pages tend to lift a single passage that answers the question on its own. A page that opens with "In today's fast-moving world…" gives them nothing to quote; a page whose first sentence is "Bounce rate is the share of visits that view only one page" does. The same goes for subheadings: a ## phrased as the question a reader would type makes it obvious which section answers which query. These are the two structural checks the tool runs. There is no published rule that a particular Flesch score earns a citation — readability helps because clear, self-contained sentences are easier to extract, not because engines compute the formula.

Common readability mistakes

Chasing a score instead of the reader. Replacing every precise term with a vague short word raises the score and lowers the quality. Keep the jargon your audience actually uses.
Scoring a whole page with navigation and footers pasted in. Menu labels and buttons have no closing punctuation, so they distort the sentence count — paste the body text only.
Ignoring the longest sentences. One 60-word sentence in a short answer drags the average more than a dozen slightly long words.
Warm-up openings. "Have you ever wondered…" delays the answer and gives answer engines nothing to quote.
Topic-label subheadings. "Pricing" tells the reader less than "How much does it cost?", and matches fewer questions.
Treating the score as exact. Syllable counts are estimated, so compare versions of your own text with the same tool rather than comparing numbers across tools.

Checking whether readers actually read it

A readability score predicts whether people can read a page; behavior shows whether they did. VisitTrack records active time on page and how far each visitor scrolled, shown per page in the Pages tab (see script configuration). To know whether readers reach a specific section, add a scroll-depth event to it, and to see which AI crawlers fetch the page for their answers, set up AI crawler tracking. Rewrite, re-score, then compare scroll depth before and after.

Frequently asked questions

What is a good readability score for a website?

A Flesch Reading Ease of 60–70, which is roughly an 8th–9th grade level, suits most web pages. Consumer and help content can aim higher (70–80); developer documentation and B2B technical pages often sit at 40–60 without being a problem, as long as sentences stay short.

What is the difference between Flesch Reading Ease and Flesch-Kincaid grade level?

They use the same two inputs — words per sentence and syllables per word — with different weights. Reading Ease is a 0–100 scale where higher is easier; the Flesch-Kincaid grade estimates the US school grade needed to understand the text, so lower is easier.

Why do different readability tools give different scores?

Mostly because of syllable counting and sentence splitting. Every tool estimates syllables with its own rules and treats abbreviations, lists, headings and numbers differently. The formulas are the same, so compare drafts with one tool rather than comparing numbers across tools.

Does readability affect SEO rankings?

Google doesn't use a readability formula as a ranking factor. Readability matters indirectly: clear, direct text is easier to quote in featured snippets and AI answers, and keeps visitors reading instead of leaving.

How is reading time calculated?

Word count divided by 230 words per minute, a common estimate for adults reading on screen. Dense technical text is read more slowly and skimmed content faster, so treat it as a guide for labels like "5 min read".

Is my text sent to a server?

No. The checker runs entirely in your browser; the text you paste is never uploaded or stored.

Does it work for languages other than English?

The Flesch formulas and the syllable rules are calibrated for English. Other languages have their own adapted formulas, so scores for non-English text won't be meaningful here.

Readability checker: Flesch score, grade level and answer-engine tips