Flesch Reading Ease Score Calculator
Score any piece of writing on a 0–100 readability scale using the Flesch Reading Ease formula. Writers, editors, and UX teams use it to ensure content matches their target audience's reading level.
About this calculator
The Flesch Reading Ease score quantifies how easy a text is to read based on two linguistic factors: average sentence length and average number of syllables per word. The formula, developed by Rudolf Flesch in 1948, is: Score = 206.835 − (1.015 × (totalWords / totalSentences)) − (84.6 × (totalSyllables / totalWords)). Scores range from 0 to 100 — a score of 90–100 is considered very easy (e.g., children's books), 60–70 is plain English suitable for general audiences, and scores below 30 represent very difficult academic or legal text. The 1.015 coefficient penalises long sentences, while the 84.6 coefficient heavily penalises multi-syllable words, reflecting their greater cognitive load. Content marketers, instructional designers, and government agencies rely on this score to make writing more accessible.
How to use
Take a short paragraph with 100 words, 5 sentences, and 150 syllables. Plug the values into the formula: Score = 206.835 − (1.015 × (100 / 5)) − (84.6 × (150 / 100)). Step 1: 100 / 5 = 20 (average words per sentence); 1.015 × 20 = 20.3. Step 2: 150 / 100 = 1.5 (average syllables per word); 84.6 × 1.5 = 126.9. Step 3: 206.835 − 20.3 − 126.9 = 59.635. A score of ~60 lands in the
Frequently asked questions
What does a Flesch Reading Ease score of 60 actually mean?
A score of 60 falls in the 'Standard' range, meaning the text is suitable for 13–15-year-olds and most general adult audiences — comparable to a popular magazine or news website. Scores between 60 and 70 are the sweet spot for consumer-facing web content because most adults can read it comfortably without cognitive strain. Scores below 30 are typical of legal contracts or medical research papers, which deliberately use technical language for specialist audiences. When writing for the general public, aiming for a score above 60 maximises comprehension and engagement.
How can I improve the Flesch Reading Ease score of my writing?
The two most effective levers are shortening sentences and choosing simpler words. Break long, multi-clause sentences into two or three shorter ones, which directly reduces the sentence-length penalty. Replace polysyllabic words with one- or two-syllable alternatives wherever meaning is preserved — for example, 'use' instead of 'utilise' or 'help' instead of 'facilitate'. Avoiding passive voice and unnecessary adverbs also tends to produce shorter, crisper sentences. Running text through the calculator iteratively as you edit is a practical way to watch your score improve in real time.
Why is the Flesch Reading Ease formula weighted so heavily toward syllable count?
The 84.6 coefficient for syllables per word is much larger than the 1.015 coefficient for sentence length because multi-syllabic words impose a far greater cognitive burden on readers than slightly longer sentences do. Flesch derived these weightings empirically from readability research conducted in the 1940s, correlating passage scores with reader comprehension test results. Words with three or more syllables (polysyllabic words) require more mental effort to decode, particularly for readers with lower literacy levels. This is why a text full of short sentences but loaded with jargon can still score very low on readability.