Flesch Reading Ease is a readability score between 0 and 100 that measures how easy a piece of text is to read. Higher scores mean simpler, more accessible writing. Lower scores indicate dense, complex prose that demands more effort from the reader. The formula was developed by Austrian-American linguist Rudolf Flesch and published in the Journal of Applied Psychology in 1948 — and despite being nearly 80 years old, it remains the most widely used automated readability measure in the English-speaking world, built into Microsoft Word's readability statistics and referenced in federal plain-language guidelines.
For roofing contractors, law firms, and other service businesses putting content on the web, the score matters for one reason that most SEO advice gets wrong: it is not a Google ranking signal, but it is a strong predictor of whether a real human visitor will actually read what you wrote.
The formula behind the number
The Flesch Reading Ease formula uses two variables: average sentence length (ASL) and average syllable count per word (ASW).
Score = 206.835 − (1.015 × ASL) − (84.6 × ASW)
Where:
- ASL = total words ÷ total sentences
- ASW = total syllables ÷ total words
The constants — 206.835, 1.015, and 84.6 — were derived from statistical analysis of English text samples in Flesch's original research and are fixed. You do not adjust them. Every readability tool that claims to use Flesch Reading Ease is running this exact calculation.
What the formula tells you: long sentences hurt your score, and long words hurt it even more (the syllable coefficient of 84.6 is roughly 83 times more punishing than the sentence-length coefficient of 1.015). A passage full of three- and four-syllable terminology — "compensation," "comprehensive," "mitigation," "implementation" — will score poorly even if the sentences are short. This is why legal and medical content routinely scores below 30, not because lawyers write long sentences, but because the vocabulary is inherently polysyllabic.
What each score range means
Readable.com's score-band table maps the 0–100 range to approximate reading difficulty and the school-grade level most readers who can handle that text have reached:
| Score | Difficulty | Approximate reading level | |-------|-----------|--------------------------| | 90–100 | Very Easy | 5th grade | | 80–89 | Easy | 6th grade | | 70–79 | Fairly Easy | 7th grade | | 60–69 | Standard | 8th–9th grade | | 50–59 | Fairly Difficult | Some high school | | 30–49 | Difficult | College level | | 0–29 | Very Difficult | Professional or graduate |
Most online marketing content targets the 60–70 range. That is not dumbing things down — it is writing the way people actually read on a screen, in short bursts, while distracted. A score below 50 on a service-business blog post is a signal that you are writing the way you were trained to write in college, not the way someone scanning your site on a phone will absorb information.
Does Flesch Reading Ease affect Google rankings?
No, not directly. Search Engine Journal's review of Google's stated ranking factors notes that John Mueller confirmed Google does not evaluate a site's readability score, and a Portent analysis of more than 750,000 pieces of content found no statistical correlation between a page's reading level and its position in search results. If you are chasing a specific Flesch score to move up in rankings, you are optimizing a metric that Google is not measuring.
Where it does matter is what happens after someone arrives on your page. Readability is a friction variable. If your service page for commercial roof replacement is written at a 32 (graduate-level difficulty), most visitors are not going to read it — they are going to skim the first two sentences, feel the cognitive load, and hit the back button. Google interprets that signal. Pogo-sticking and short dwell times tell the algorithm that the page did not satisfy the intent, even if the page technically answered the question. Readability does not help you rank — but poor readability can cause you to lose a ranking you already have.
Where roofing contractors and service businesses go wrong
The two most common readability problems in home service content are not the ones most people expect.
Problem 1: Industry vocabulary used as if the reader already knows it. A roofing contractor writing "the TPO membrane's seam weld integrity degrades with improper HVAC penetration flashing" is writing for a peer, not a homeowner. The words are accurate. The score is probably in the 20s. The homeowner who found this page searching "flat roof leaking around AC unit" will not read past the first sentence. Replace the jargon with the plain version — "the seam holding your flat roof together weakens when the flashing around your air conditioner isn't sealed correctly" — and the score jumps to the 60s without losing accuracy.
Problem 2: Long qualification chains in sentences. Service businesses, especially in legal and home improvement, hedge everything. "It is important to note that while there are various factors that may influence the ultimate outcome of your claim, including but not limited to the specific circumstances involved, the timeline in which the damage occurred, and the nature of your policy's coverage provisions..." That sentence scores in the low 20s. Break it into two sentences, cut the qualifications by half, and you are in the 50s. The information is the same. The reader is no longer exhausted.
How to check your score
You do not need a paid tool. Three free options:
Microsoft Word: Paste your text into a document, then enable readability statistics under Options → Proofing → "Show readability statistics." Run spell-check and the Flesch score appears automatically.
Hemingway App (hemingwayapp.com): Paste text and get an immediate reading grade level, sentence-complexity highlights, and passive voice flagging. The app does not display the raw 0–100 Flesch score — it shows a grade level instead — but the grade level maps to the bands above.
Screaming Frog SEO Spider: Screaming Frog's readability feature crawls your site and reports Flesch Reading Ease scores at the page level. Useful for auditing an entire site rather than individual posts.
Common mistakes
Chasing the score instead of the reader. You can inflate a Flesch score mechanically by using short words and short sentences that add up to nothing. "It is good. Roofs keep you dry. We fix roofs. Call us." That scores 100. It is useless content. The score is a signal, not the goal. Optimize for the score only when a low score is symptom of a real clarity problem.
Treating all content the same. A technical data sheet for a commercial roofing system targeting procurement engineers should score differently than a homeowner-facing FAQ. Context matters. The right target score depends on who is reading it.
Ignoring the syllable driver. Most people who try to improve their score focus on sentence length because that is easier to see. But the syllable coefficient in the formula is 84 times more powerful than the sentence-length coefficient. Replacing "approximately" with "about," "compensation" with "pay," and "demonstrate" with "show" will move your score faster than splitting sentences.
Real example
A roofing contractor in Colorado Springs came to TBS with a website full of technically accurate content that was not converting. Their service pages were averaging a Flesch score of around 38 — solidly in the "difficult" band. Nothing was wrong with the facts. The writing just required the kind of sustained attention people do not give to websites. We rewrote their core service pages targeting a 65 score, keeping every specific claim and credential, just restructuring the language. Time-on-page increased. Bounce rate dropped. The pages that had ranked on page two for eighteen months moved to page one within ninety days — not because readability is a ranking factor, but because better user signals broke a stubborn ranking plateau.
Key takeaways
- Flesch Reading Ease scores text on a 0–100 scale using sentence length and syllable count per word
- The formula is 206.835 − 1.015 × ASL − 84.6 × ASW — syllable count per word has 83 times more influence than sentence length
- Score bands: 90–100 very easy, 60–69 standard, below 30 difficult professional-level text
- Google does not use Flesch Reading Ease as a ranking signal — confirmed by John Mueller and supported by large-scale content studies
- Poor readability creates friction that drives visitors away; better user signals can unlock rankings that good content alone isn't delivering
- Free tools: Microsoft Word, Hemingway App, Screaming Frog
Want a content audit that goes beyond the score? See how TBS approaches content quality or get in touch directly.