Flesch Reading Ease calculator

Paste any text to get its Flesch Reading Ease score — the 0-to-100 scale where higher means easier — with the calculation shown step by step. Free, instant, and your text never leaves your browser.

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The Flesch Reading Ease formula

Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words)

Words ÷ sentences — average sentence length. Every extra word per sentence costs about one point.
Syllables ÷ words — average word length. This carries far more weight: moving from 1.3 to 1.5 syllables per word costs about 17 points.

Worked example

Here is the Flesch Reading Ease worked through for our sample bedtime story — press Try a sample story above to load it. It’s a short tale about an owl who can’t sleep, and it counts up like this:

Words: 118
Sentences: 18
Syllables: 141

206.835 − 1.015 × (118 ÷ 18) − 84.6 × (141 ÷ 118) = 99.1

So the story scores 99.1 — Very easy (5th grade).

What your score means

Score	Level	Who reads it easily
90–100	Very easy	An average 11-year-old (5th grade)
80–89	Easy	6th grade — conversational English
70–79	Fairly easy	7th grade
60–69	Plain English	8th–9th grade, ages 13–15
50–59	Fairly difficult	10th–12th grade
30–49	Difficult	College students
0–29	Very difficult	University graduates

What is a good Flesch Reading Ease score?

For writing aimed at the general public — websites, emails, instructions — aim for 60 or higher. That’s the “plain English” band most adults read without effort, whatever their education.

Children’s books sit much higher. Picture books and first readers often score above 90, and simple text can go past 100: the formula has no ceiling, so a string of short, one-syllable sentences can score 110 or more. Scores below zero are possible too, for very long sentences full of long words.

Where it comes from

Rudolf Flesch, an Austrian-born writing consultant, published the formula in 1948 as part of his campaign for plain English. It rates text purely on sentence length and word length — the two features that most reliably predicted how hard readers found a passage.

It became one of the most widely used readability measures in the world. Microsoft Word reports it alongside the Flesch-Kincaid Grade Level, and several US states require insurance policies to meet a minimum Reading Ease score so that consumers can understand them.

Limitations

The formula only sees lengths. “The cat sat on the mat” and a string of short, obscure words score the same, and it can’t tell whether ideas are clear, jargon is explained, or the text is well organised.

Syllables have to be estimated by software, and every tool counts a few words differently — so expect Reading Ease scores to differ by a few points between checkers. It was also designed for English prose: poems, lists, and headings without full stops distort the sentence count.

How to calculate Flesch Reading Ease by hand

Pick a passage of at least 100 words. Count the words, the sentences and the syllables — say each word aloud and tap out the beats if you’re unsure.

Divide words by sentences to get the average sentence length, and syllables by words to get the average syllables per word. Multiply the first by 1.015 and the second by 84.6, then subtract both from 206.835.

Two rules of thumb fall straight out of the formula: every extra word in your average sentence costs about one point, and every extra syllable per 100 words costs a little under one point (0.846).

Flesch Reading Ease vs Flesch-Kincaid Grade Level

Both formulas use exactly the same two numbers — words per sentence and syllables per word — but weight them differently. Reading Ease counts word length about 83 times as heavily as sentence length; the Grade Level only about 30 times. So vocabulary moves Reading Ease more, and sentence length moves the grade more.

That’s why there’s no exact conversion between the two. As a check, our sample bedtime story scores 99.1 on Reading Ease and grade 1.1 on Flesch-Kincaid — both saying “very easy”, from the same counts.

Frequently asked questions

Is a higher Flesch Reading Ease score better?

Higher means easier to read, which is usually what you want — but match the score to your readers. A score of 90 is right for a young child and can feel choppy in a report for specialists.

Why is my Flesch Reading Ease score over 100?

The scale isn’t capped. Text made of short sentences and one-syllable words — typical of picture books — pushes the score past 100. It just means the text is very easy.

What is the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level?

They use the same two ingredients, weighted differently. Reading Ease gives a 0–100 score where higher is easier; the Flesch-Kincaid Grade Level converts the same measurements into a US school grade, where lower is easier.

How do I improve my Flesch Reading Ease score?

Shorten your longest sentences and swap long words for everyday ones — “use” for “utilise”, “help” for “facilitate”. Because word length is weighted so heavily, simpler vocabulary usually moves the score fastest.

Why does this score differ from Microsoft Word or other checkers?

Mostly syllable counting and sentence splitting. Each tool estimates syllables with its own rules and treats headings, lists, and abbreviations differently, so a few points either way is normal.

Can Flesch Reading Ease be negative?

Yes. Very long sentences packed with long words — some legal contracts and academic abstracts — can score below zero. It just means the text is extremely hard to read.