If you have ever run your writing through a readability checker, you have likely seen a number between 0 and 100 called the Flesch Reading Ease score. But what does that number actually mean? Many writers know that higher is easier and lower is harder, but the nuance of what a score of 60, 70, or 30 tells you about your text is often overlooked.
In this article, we will take a deep technical look at the Flesch formula, decode the 60–70 range, walk through examples at different score levels, and discuss when you should aim higher or lower. By the end, you will understand readability scores well enough to use them as a practical tool rather than a vanity metric.
The Flesch Reading Ease Formula
Rudolf Flesch developed the Reading Ease formula in 1948 as a way to measure how difficult a piece of text is to read. The formula is based on two variables: average sentence length and average syllables per word.
The Formula
The Flesch Reading Ease score is calculated as follows:
Score = 206.835 − (1.015 × ASL) − (84.6 × ASW)
Where:
- ASL = Average Sentence Length (total words divided by total sentences)
- ASW = Average Syllables per Word (total syllables divided by total words)
Let us break down what this means in practice. The constant 206.835 represents the theoretical maximum score. Every sentence you add beyond one word reduces the score by approximately 1.015 points per word of average length. Every syllable per word beyond one syllable reduces the score by approximately 84.6 points on average.
Because the syllable penalty is weighted so heavily, the single biggest factor in lowering your readability score is multisyllabic vocabulary — not long sentences, as many people assume.
What Contributes to a 60–70 Score
A Flesch score of 60 to 70 falls in the “Plain English” range. This is the zone most newspapers and general-interest publications target. Let us examine what sentence and word characteristics produce this score.
Typical Metrics in the 60–70 Range
| Metric | Typical Value | Interpretation |
|---|---|---|
| Average sentence length | 15–20 words | Sentences are long enough for nuance but short enough to follow easily |
| Average syllables per word | 1.4–1.6 | Mostly short words with occasional longer terms |
| Percentage of multisyllabic words | 10–15% | About one in seven or eight words has three or more syllables |
| Total words per 100-word sample | 100 | (Baseline measurement unit) |
To give you a concrete sense, here is a sample paragraph scoring in the 60–70 range:
“Most readers prefer simple language. When you write clearly, they understand your message faster. Short words and short sentences both help. You do not need to use complex vocabulary to sound professional. The best writing is the kind the reader does not have to work through twice.”
This paragraph averages about 13 words per sentence and 1.3 syllables per word, yielding a score of approximately 68.
Examples at Different Score Levels
Seeing the same topic written at different Flesch levels makes the scoring system concrete. Below is the same idea expressed at four different readability levels.
Score 80–90 (Easy / Very Conversational)
“You should write in a way that is easy to read. Keep your sentences short. Use small words. Your readers will thank you. They will enjoy what you write more.”
Characterised by: Very short sentences (8–12 words), mostly one- to two-syllable words. Suitable for children’s books or social media copy.
Score 60–70 (Plain English)
“When you write in plain English, your readers understand you more quickly. Aim for sentences of around 15 to 20 words. Use familiar words instead of fancy ones. This approach works well for most business communication.”
Characterised by: Moderate sentence length, occasional multisyllabic words. Suitable for newspapers, blogs, and most professional writing.
Score 30–50 (Fairly Difficult)
“Achieving clarity in written communication necessitates deliberate consideration of sentence structure and lexical selection. Writers who prioritise accessibility tend to engender greater comprehension among their readership. This is particularly relevant in academic and technical contexts.”
Characterised by: Longer sentences (20–25 words), many multisyllabic words. Suitable for academic journals or technical documentation aimed at specialists.
Score 0–30 (Very Difficult)
“The implementation of optimal readability protocols requires a multifaceted approach to syntactic construction and vocabulary deployment. Practitioners in specialised domains frequently employ terminological specificity that substantially elevates the cognitive load imposed upon the reader.”
Characterised by: Very long sentences (25+ words), dense vocabulary. Suitable for legal documents or highly specialised academic papers.
When to Target Higher or Lower Scores
Not everything needs to score in the 60–70 range. The right target depends on your audience and your goals.
Target 70–80 When
- Writing for a general consumer audience.
- Creating email newsletters.
- Writing social media posts.
- Producing content for mobile readers.
- Writing instructions or how-to guides.
Target 60–70 When
- Writing blog posts for a professional audience.
- Creating business reports or proposals.
- Drafting marketing copy for B2B products.
- Writing news articles.
- Preparing internal corporate communications.
Target 30–50 When
- Writing for an expert audience who expects technical precision.
- Creating academic papers or textbooks.
- Drafting legal contracts (though plain language is increasingly preferred).
- Writing detailed technical documentation for specialists.
Limitations of the Flesch Score
The Flesch Reading Ease score is a useful tool, but it has significant limitations that every writer should understand.
What the Score Does Not Measure
- Coherence and organisation. A paragraph can score well on readability but be completely disjointed in its ideas. The score does not know whether your argument flows logically.
- Jargon. The formula counts syllables, not word familiarity. A word like “amortisation” has five syllables and will lower the score, but so will “unquestionably” — a word most readers know. The score treats them identically.
- Sentence variety. Alternating short and long sentences creates rhythm and keeps readers engaged. The Flesch score works on averages and cannot reward good stylistic variation.
- Context and formatting. Bullet points, subheadings, and white space improve readability dramatically, but the Flesch formula only looks at words and sentences.
- Reader motivation. A highly motivated reader (someone who needs the information) will push through difficult text that a casual reader would abandon. The score does not account for this.
How to Use the Score Wisely
Treat the Flesch score as a diagnostic tool, not a grading system. If your score is in the 30s and you are writing a blog post for the general public, that is a signal to simplify. But if your score is in the 30s and you are writing a peer-reviewed journal article, that may be appropriate. The score tells you about the text. You need to decide whether that matches your purpose.
The best approach is to write naturally, then check your score with a tool like the CopyRefine Readability Score tool. If the number surprises you, investigate which sentences or words are causing the issue. Sometimes replacing three or four long words with shorter synonyms can shift an entire paragraph into the right range without changing your meaning.
Final Thoughts on the 60–70 Range
The 60–70 Flesch range is a sweet spot for most professional writing because it balances clarity with authority. You sound knowledgeable without sounding pretentious. You provide enough depth without making the reader work too hard. But the score is a guide, not a commandment. Write for your audience, use the score to check yourself, and never sacrifice meaning for the sake of a number.