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Sentence-level analysis - Free to use

Analyze & Optimize Your
Sentence Structure

Our AI-powered sentence structure checker labels every sentence by type and gives you a Variety Score. Free, 600 words, no sign-up.

Last updated: August 2026

0 / 600 words

Free: 0 / 3

Analyzing your sentences...

Breaking down structure, types, and variety. Usually under 15 seconds.

0 / 600 words

Free: 0 / 3

Your analysis will appear here

Paste your text on the left and click Analyze to get a full sentence breakdown.

Click the rewrite icon on any sentence to improve or vary it - free, no extra check used.

Variety Score

Simple0% Compound0% Complex0% Compound-Complex0%

Next step:

Re-analyzing your text...

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4.8/5 from 3,200 reviews

Trusted by 900K+ students & pros

Your results

How The Sentence Structure Checker Helps You

This free AI sentence checker returns three outputs in the Structure Report for every passage you run.

Sentence Type Labels

Every sentence is labeled Simple, Compound, Complex, or Compound-Complex, with its word count and a structural note below.

Simple Compound Complex Compound-Complex

Variety Score

The tool scores how well the passage mixes sentence types and gives a plain-language verdict. The guidance block tells you specifically what to adjust.

Score Summary

The report shows the percentage split across all four types, along with average words per sentence and the longest sentence in the passage.

Capabilities

What the Sentence Analyzer Tool Can Do

The online sentence fixer tool analyzes your full passage at the sentence level and returns results in under 15 seconds.

AI-Powered Sentence Analysis

The tool uses AI to classify every sentence by structure type and calculate variety across your full passage in one run.

Full Passage Support

The tool handles up to 600 words per run, covering complete paragraphs and essay sections, not just individual sentences.

Multi-Format Input

The tool accepts pasted text or uploaded files in .pdf, .doc, .docx, and .txt format with no installation required.

Pattern Detection

The tool identifies structural patterns like consecutive same-type sentences and surfaces them alongside individual sentence labels.

How it works

How to Use the Free Sentence Structure Analyzer

This sentence correction checker works in three steps to improve your writing and delivers a report in under 15 seconds.

Step 01

Copy-Paste Your Content

Paste your text or upload a .pdf, .doc, .docx, or .txt file up to 600 words. Use Try Sample to see the tool run on a demo passage.

Step 02

Hit Analyze

Click Analyze Structure. The tool examines every sentence in your text and returns the Structure Report in under 15 seconds.

Step 03

Read Your Report and Refine

The Structure Report labels every sentence by type and gives you a Variety Score. Use the rewrite icon on any sentence to improve it directly in the tool.

Use cases

Who Uses a Sentence Structure Checker

The tool checks sentence structure across any writing type.

Students and Researchers

The tool identifies which sentence types dominate a draft and flags where variety is low before academic submission.

Business Writers

The tool checks structural patterns in reports and professional emails that make passages read as flat or repetitive.

Content Writers

The tool's Variety Score shows how well articles and blog posts mix sentence types to maintain reader engagement.

Teachers

The tool analyzes sentence structure in student writing and shows exactly where variety is lacking for targeted feedback.

Journalists

The tool checks whether news articles and features rely too heavily on one sentence type, affecting how the writing reads.

Marketers

The tool's Variety Score shows whether campaign copy maintains the structural variety needed to keep readers engaged.

Polish further

Tools That Pair Well With Structure Analysis

Once you know your sentence structure, these tools help you take your writing the rest of the way.

All tools - free to start

30+ AI Writing Tools, One Free Account

From structure analysis to plagiarism checking, grammar fixing, and full essay writing - every tool is included. No credit card to sign up.

Trusted by 900K+ students & pros

Rated 4.8/5 from 3,200 reviews

1,500 free words to start

Explore All Tools

AI Content Detector Check how much of your writing reads as AI-generated.

Grammar Checker Fix grammar and punctuation inside every sentence you've analyzed.

Readability Checker See how easy your writing is to read once your structure is solid.

Paraphrasing Tool Rewrite sentences flagged for poor structure into cleaner alternatives.

Content Humanizer Make your polished sentences read naturally and pass AI detection.

AI Essay Writer Generate a complete essay draft with AI.

Questions

Frequently Asked Questions

What is a sentence structure analysis tool?

A sentence structure analysis tool breaks down your writing at the sentence level, examining how words connect to create meaning. It identifies whether each sentence is Simple, Compound, Complex, or Compound-Complex, and gives you feedback on word count and structural variety so you can write with more clarity and impact.

What are the four types of sentence structures?

The four main types are: Simple (one independent clause, "She studied hard."), Compound (two independent clauses joined by a conjunction, "She studied hard, and she passed."), Complex (one independent clause with one or more dependent clauses, "Because she studied hard, she passed."), and Compound-Complex (multiple independent clauses plus at least one dependent clause). Our tool identifies and labels each type in your writing automatically.

How many words can I analyze for free?

Use this free sentence checker to analyze up to 600 words per session with no account required. That covers most essays and article sections. Paid plans start at $9.99/month and include access to all 30+ AI writing tools, the per-sentence rewrite feature, and Download Report, which exports your Structure Report as a Word or PDF file.

Can I use this tool to improve my essay grades?

Absolutely, sentence structure is one of the most commonly cited areas for improvement in academic feedback. By understanding exactly how your sentences are built, you can identify patterns, like overusing short simple sentences or writing overly long complex ones, and refine your writing before submission. Pair it with our Grammar Checker and Readability Checker for the most complete pre-submission review.

Does it work for essays, research papers, and other assignments?

Yes. The analyzer works on any writing - essays, research papers, personal statements, articles, or single paragraphs. It is especially useful for students checking sentence variety before submitting academic work, and it pairs well with our Paraphrasing Tool for rewriting sentences that need work.

What is the difference between a sentence structure checker and a grammar checker?

A sentence structure checker identifies the type and variety of sentences in your writing. A grammar checker finds and corrects errors like subject-verb agreement, spelling, and punctuation. This tool shows you whether each sentence is Simple, Compound, Complex, or Compound-Complex and scores how well you mix types. Use the Grammar Checker separately for error correction after running a structure check.

What does the Variety Score tell me?

The Variety Score shows the percentage of sentence-type variation across your passage. A higher score means your writing uses a wider mix of Simple, Compound, Complex, and Compound-Complex sentences. The guidance block below the score tells you specifically which types are underused and what to add. It is directional feedback, not a pass or fail rating.