---
title: "Readability Score and SEO: What It Measures and Misses"
description: "What a readability score like Flesch Reading Ease measures, why Google doesn't rank on it, why it still matters, and how to raise a low score sensibly."
image: "https://www.blackseoanalyzer.com/static/images/black-seo-analyzer-og-image.png"
canonical: "https://www.blackseoanalyzer.com/en/blog/why-your-readability-score-actually-matters-and-its-not-what-you-think"
language: "en"
---

# Why Your Readability Score Matters, and What It Doesn't Measure

By [Seth Black](https://www.blackseoanalyzer.com/en/about) · Published November 01, 2026

A readability score estimates how hard a piece of text is to read from two things: how long its sentences are and how long its words are. Google doesn’t use a readability score as a ranking factor, and it doesn’t measure whether your page is accurate, useful or well organized. It matters anyway, because a low score is a cheap, reliable early warning that real readers will struggle, and readers who struggle leave.

## What does a readability score actually measure?

The most common one is the Flesch Reading Ease score, from Rudolf Flesch in 1948. The formula:

```text
206.835 - 1.015 x (words / sentences) - 84.6 x (syllables / words)
```

That’s all of it. Longer sentences lower the score. Words with more syllables lower the score. Nothing else goes in: not meaning, not structure, not whether the reader already knows the terms. The usual bands:

| Score | Reading level | Typical text |
| --- | --- | --- |
| 90 to 100 | Very easy | Children’s books |
| 70 to 90 | Easy | Conversational web copy |
| 60 to 70 | Plain English | Most good journalism |
| 30 to 60 | Difficult | Academic and technical writing |
| 0 to 30 | Very difficult | Legal and scientific papers |

Flesch-Kincaid Grade Level, Gunning Fog, SMOG and Coleman-Liau are variations on the same idea, using sentence length plus either syllables, long words or letters per word. They mostly agree with each other, which tells you they’re measuring the same two things.

## Is readability score an SEO ranking factor?

No. Google’s documentation has no readability score in it. What it does say, in the [SEO starter guide](https://developers.google.com/search/docs/fundamentals/seo-starter-guide), is that good content is “easy-to-read and well organized”, and it tells you to “Break up long content into paragraphs and sections, and provide headings to help users navigate your pages.” Its guide to [helpful content](https://developers.google.com/search/docs/fundamentals/creating-helpful-content) asks whether the content has “spelling or stylistic issues”.

So readability matters to Google the way it matters to readers, not as a number. A formula can’t tell Google your page is good, and Google isn’t computing Flesch scores to find out.

## Why does a readability score matter, then?

Because it catches a real problem early and for free.

**Readers skim.** People land on a page with a question. Long sentences full of four-syllable words make them work to find the answer, and a reader who can’t find it goes back to the results. Whatever Google measures about that, you’ve lost the visit.

**It’s a proxy for clarity in your own writing.** A sentence that runs 45 words usually holds two or three ideas that would each be clearer alone. Readability formulas are blunt, but they reliably point at those sentences.

**It scales.** You can’t read 3,000 pages. You can compute a score for 3,000 pages and read the 50 worst. That’s the real use: triage across a site, not a grade for one page.

**Answers get quoted.** Featured snippets and AI assistants lift a sentence or two that answers a question. A short, plain sentence that states the answer is easier to lift than one buried in a 60-word paragraph. That’s a structural point, not a formula point, but low-scoring pages tend to fail it.

## What a readability score doesn’t measure

This is the part that gets lost when a plugin turns the score into a red light:

- **Whether it’s right.** A wrong answer in short words scores well.
- **Whether it answers the query.** Readable text about the wrong thing is still the wrong thing.
- **Structure.** Headings, lists, tables and the order of ideas matter more than sentence length, and the formula sees none of them.
- **Audience.** “Canonicalization” is four or five syllables and exactly the right word for a technical SEO. Replacing it with a vaguer, shorter phrase makes the text worse for the people reading it.
- **Code and data.** Commands, URLs, product names and numbers confuse syllable counters and sentence splitters.

Chasing a target score is the same mistake as chasing a target word count, which I argued about at length in [word count is a vanity metric](https://www.blackseoanalyzer.com/en/blog/word-count-is-a-vanity-metric-fight-me). Google says there’s no magical word count, and there’s no magical readability score either.

## How to calculate it yourself

The formula is short enough to run anywhere. This Python version uses a vowel-group syllable count, which is the common approximation:

```python
import re

def syllables(word):
    word = word.lower()
    count = len(re.findall(r"[aeiouy]+", word))
    if word.endswith("e"):
        count -= 1
    return max(count, 1)

def flesch_reading_ease(text):
    sentences = re.findall(r"[^.!?]+[.!?]", text)
    words = re.findall(r"[a-zA-Z]+", text)
    if not sentences or not words:
        return 0.0
    syl = sum(syllables(w) for w in words)
    return 206.835 - 1.015 * (len(words) / len(sentences)) - 84.6 * (syl / len(words))

print(round(flesch_reading_ease(open("page.txt").read()), 1))
```

Feed it the visible body text, not the HTML, or the navigation and footer will skew the result.

## How bseoa measures readability

bseoa computes the Flesch Reading Ease score on each page’s content text (paragraphs, headings, list items, table cells and main content areas) using the same formula and a vowel-group syllable count like the one above. A page scoring below 60 gets the [low readability](https://www.blackseoanalyzer.com/en/technical-seo/content-analyzer/low-readability) warning, with the score attached.

Two honest limits. Sentences are split on periods, question marks and exclamation points, so headings and list items without terminal punctuation run together into one long “sentence” and pull the score down. And the syllable count is an approximation, as every automated one is. Treat the warning as “read this page”, not as a verdict. If you want the triage list for your own site, the [14-day free trial](https://www.blackseoanalyzer.com/en/free-trial) crawls every page with no page limit, and each low readability warning carries the page’s score, so you can sort by it and read the worst first.

## How to raise a low score without dumbing it down

1. **Split long sentences.** Anything over 25 words is a candidate. One idea per sentence.
2. **Put the answer first.** The first two sentences under a heading should answer the heading.
3. **Use the precise word, then stop.** Keep the technical term your reader expects; cut the filler around it (“in order to”, “it is important to note that”).
4. **Use lists and tables for parallel items.** Five options in one sentence become a list.
5. **Phrase headings as questions people ask.** It helps readers skim and helps the answer get quoted; see [Google says SEO for AI is the same as SEO for search](https://www.blackseoanalyzer.com/en/blog/google-says-seo-for-ai-is-the-same-as-seo-for-search).

Then read it out loud. If you run out of breath, so does your reader.

-Sethers

About the author

[Seth Black](https://www.blackseoanalyzer.com/en/about)

Seth is a software engineer and engineering leader who builds bseoa, a Rust-based technical SEO crawler with a GUI and CLI. He writes about the crawling, rendering and indexing problems he runs into on real sites.

[LinkedIn](https://www.linkedin.com/in/seth-black-tx/) · [GitHub](https://github.com/sethblack) · [YouTube](https://www.youtube.com/@SethBlack)

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I use AI to generate images for my posts and for general editing, updates, and ironically SEO purposes. I used to draw all of the images for my personal blog (taleas) myself, but as the volume of content I produce has increased, I've turned to AI tools to help create visuals that complement my writing. I go out of my way to generate images that look strange, and don't represent real people. If you ever want to chat about my use of AI, please reach out.

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