Content Score & Readability Checker
Flesch reading ease and grade level, plus the structural things a writer can act on: long sentences, passive voice, adverbs and paragraph length.
# Reading ease 67.3 (plain English: what most web writing aims for)
# Grade level 7.8, meaning a reader at about that US school grade
Words 63
Sentences 4
Paragraphs 2
Words per sentence 15.8
Syllables per word 1.46
# What to look at
Long sentences 1 over 25 words (25%)
Passive looking 0 sentences (0%)
Adverbs ending in ly 1 (1.6% of words)
Transition words 1 (1.6% of words)
Paragraphs over 150 0
# Longest sentences
39 words A child theme inherits everything from its parent, so an update to the parent leaves your changes alone, wh…
# Reading ease and grade level are Flesch and Flesch-Kincaid, whose arithmetic is fixed.
# The syllable count behind both is an estimate, so treat the grade as give or take one.
# Passive voice detection is rough: it counts "is interesting" and misses irregular participles.Output is valid and updates as you type.
Fix the highlighted fields to update the output.
Two published readability scores, and the structural things behind them that a writer can actually change.
How to use
- Paste the draft. Body copy, not the whole page: navigation and footers skew every count.
- Read the grade level as a range. The arithmetic is fixed but the syllable count behind it is an estimate, so treat it as give or take one.
- Work down the list of things to look at. Long sentences first: they move the score more than any word choice.
- Read the quoted sentences. A number tells you there is a problem; the sentence tells you where it is.
Example
# Reading ease 70.7 (easy: comfortable for most readers)
# Grade level 6.9, meaning a reader at about that US school grade
Words 57
Sentences 4
Words per sentence 14.3
Syllables per word 1.44
# What to look at
Long sentences 1 over 25 words (25%)
Passive looking 0 sentences (0%)
Adverbs ending in ly 1 (1.8% of words)
Transition words 1 (1.8% of words)Fourteen words a sentence with one long outlier is a normal shape for web prose. Splitting the outlier would move the reading ease by several points on its own.
Pitfalls
- Readability scores measure sentence and word length, and nothing else. A page of short sentences saying nothing scores beautifully.
- The syllable count is a heuristic. “Created” is three syllables and most estimators say two, which is why the grade is a range rather than a number.
- Both formulas were built for English school texts in the 1940s and 1970s. They transfer roughly to web prose and not at all to other languages.
- Passive voice detection here is rough by design: it counts “is interesting” as passive and misses irregular participles like “was written”. Use it to find candidates, not as a verdict.
- Adverbs are not a fault. The count is high when prose leans on them; “quickly deleted” is usually better as “deleted”.
- Aiming for a grade level is a trap. Write for the reader you have: a plugin developer reading about hooks is not served by primary school prose.
- Google has no readability signal. Clear writing helps people, who then behave in ways search engines do measure.
- Code blocks, lists and headings wreck the counts. Paste prose; measure the rest by eye.
Compatibility
Reading ease uses Flesch’s formula, 206.835 − 1.015 × (words / sentences) − 84.6 × (syllables / words). Grade level uses Flesch-Kincaid, 0.39 × (words / sentences) + 11.8 × (syllables / words) − 15.59. Both are public domain and unchanged; the only variable between implementations is how syllables are counted. Sentence splitting handles common abbreviations and decimals. Everything runs in your browser.