Free Sentence Structure Analyzer
Review English sentence boundaries, length, readability estimates and common writing patterns. Adjust thresholds, filter findings and export sentence-level reports privately.
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How to review English sentence length and readability
Inspect sentence boundaries, word counts and English readability estimates. Adjust length thresholds, filter review notes and export a sentence-level report privately.
- Paste or import English text, or choose a sample.
- Set the long and short sentence thresholds and optional grammar or passive-voice checks.
- Review sentence rows, adjust the filter or sorting and inspect notes in the original context.
- Copy the report or download TXT, JSON or CSV. Edit the source text and review the updated analysis.
When a sentence-level review helps
Long, tangled sentences are one of the main reasons readers give up on a page. This analyzer splits your text into sentences, counts the words in each and flags the ones worth a second look. It is useful for blog drafts, policy pages, student essays, product documentation and emails that need to be clear on the first read.
Editors can sort by length to find the worst offenders first. Teachers can show a class how sentence length affects readability. Writers of plain-language content can set a stricter long sentence threshold, such as 20 words, and work down the list.
Text up to 50,000 characters is analyzed in the browser, and results update as you edit.
Worked example with the abbreviations sample
Choose the Abbreviations and numbers sample: Dr. Rivera reviewed the report. The estimated cost is 3.14 dollars per unit. We can finish the next stage tomorrow. The tool finds 3 sentences and 21 words. It does not break the text after Dr. or inside 3.14, so the sentence rows have 5, 9 and 7 words.
With the default thresholds, long above 25 words and short below 4, none of the rows is flagged. The estimated reading time is 6 seconds at 220 words per minute, because 21 divided by 220 times 60 is 5.7, rounded up.
The tool estimates 30 syllables. Flesch Reading Ease is 206.835 minus 1.015 times 7 words per sentence minus 84.6 times 30 divided by 21 syllables per word, which gives 78.9. The estimated grade is 0.39 times 7 plus 11.8 times 1.43 minus 15.59, which rounds to 4.0.
What the review notes mean
Each row can collect notes. Long sentence and Short segment follow your thresholds. No terminal punctuation appears when a segment does not end with a period, question mark or exclamation point. Dependent opening flags a segment that starts with because, although, unless, while or if and contains no comma. Possible comma splice looks for patterns like a comma followed by they are.
A clause density note appears when a sentence has three or more linking words such as and, but, which or because. With the optional checks on, common grammar rule findings and possible passive voice notes are added. Higher Flesch scores mean easier text; a score near 60 to 70 is often described as plain English.
Common mistakes to avoid
Do not treat every flag as an error. A headline, a list item or a deliberate fragment can be correct without terminal punctuation. Read the note in context and decide.
Avoid judging readability from a few sentences. The formulas are unstable on short samples, names and technical terms. If your text uses line breaks for lists or headings, turn on Treat every line as a separate segment so each line is reviewed on its own.
Finally, remember that a shorter sentence is not automatically a better one. Varying length keeps prose from sounding choppy, so use the flags to find problems rather than to force every sentence under a number.
Useful tips and limitations
- Readability scores are English estimates and do not measure factual accuracy or writing quality.
- Short sentences, fragments and passive voice can be appropriate in context.
- Sort by Longest first and rewrite the top three sentences; that often improves a draft more than many small edits.
- Download the CSV to track word counts per sentence across several drafts in a spreadsheet.
Common questions
Does the sentence checker prove that a sentence is incorrect?
No. It identifies length thresholds and common writing patterns for review. Notes are suggestions rather than definitive grammatical judgments.
How does the tool separate sentences around abbreviations?
It uses punctuation and common English abbreviation rules, with optional line boundaries. Unusual abbreviations, dialogue and complex documents may need manual review.
Are sentence readability scores suitable for every language?
No. Flesch and grade estimates here use approximate English syllable counts. They are not reliable language-independent measures.
Does the exported sentence report include every analyzed row?
Yes. Exports include the complete analyzed report rather than just the current filtered or paginated view. The input limit is 50,000 characters.
Can I change what counts as a long sentence?
Yes. Set the long threshold from 5 to 200 words; the short threshold must stay below it.
What does Segments to review count?
It counts the sentences that have at least one review note or rule finding under the current settings.
Which reading speed is used for the time estimate?
The estimate assumes 220 words per minute and rounds up to the next whole second.
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