Plagiarism Checker – Scan Text for Copied Content

Catch plagiarism before it becomes a problem. Our advanced plagiarism detector scans billions of sources to identify matching text, paraphrased content, and AI-generated material.

Check Your Writing for Plagiarism Without Limits

Unlimited Plagiarism Checks

No limits on plagiarism checks — run scans as many times as you need

Detailed Feedback

See clear originality feedback so you can adjust your writing before submission

More Than Just a Plagiarism Checker

Every plan includes access to the AI Humanizer and an AI Detector

How Our Plagiarism Checker Is Different

GPTinf's checker runs a custom-built code that catches what others miss. Most tools only find exact copied words. But our plagiarism detector catches paraphrasing, AI content, and hidden matches across 70+ billion sources.

What makes it stand out:

Finds paraphrased text that keeps the same ideas but changes the words
Spots when ChatGPT or other AI tools copied from existing sources
Scans research papers and journals, not only Google results
Analyzes what your text means, not just matching words

You don't get basic word-matching technology. We designed the tool specifically to find the sophisticated copying techniques writers use. Check for plagiarism with a tool that was built to catch real problems.

What Our Plagiarism Detector Does

70+ Billion

Sources we compare your text against

Our plagiarism detector checks your content against web pages, academic journals, and archived sources to find exact matches, paraphrased text, and AI-generated plagiarism.

Catch Plagiarism Before You Publish

Used by writers and professionals to protect their work

London School of Economics and Political Science

Research papersBlog posts and articlesMarketing copyProfessional reportsCreative writing

Works with any text you need to verify

How to Check for Plagiarism with GPTinf?

Step 1

Upload Your Content

01Sign up

Enter your email to unlock free plagiarism detection

02Paste the Text

Start by adding the text you want to scan for potential plagiarism

Step 2

Run the Check

01Click "Check for Plagiarism"

Hit the button at the bottom and let the tool analyze

02Get Your Results

The detector reviews the text and shows you what it found

Step 3

Review & Take Action

01Get Detailed Report

A simple 0-100% indicator shows how unique the content is

02Take Action

Rewrite flagged pieces and verify you've reduced similarity scores

Polish Your Content

Tools Writers Rely On for Stronger Writing

Get everything you need to verify originality, write quality content, and submit with confidence. Check for plagiarism, detect AI-generated text, and ensure your work is truly yours.

Many students use AI paraphrasers, but not all tools effectively transform AI-generated text or ensure it remains undetectable.

AI Detector

Run your text through the AI Detector to see where your writing has AI-like patterns, so you know which parts need a second look

Using a reliable AI paraphraser is essential for avoiding robotic sentence structure and unnatural phrasing in text.

Paraphraser

Clean up AI-heavy passages so they read like something you would actually say. The tool untangles stiff sentences, weird rhythm, and copy-paste vibes

Good writing needs flow. When sentences don't connect naturally, even strong arguments lose impact.

Plagiarism checker

A plagiarism checker scans text against a vast database to identify exact matches and paraphrased content.

Submit With Confidence, Not Plagiarism

Use our free plagiarism checker to verify every citation and paraphrase before turning in your work.

FAQs - Plagiarism Checker Questions Answered

What is the best plagiarism checker for students who need accurate results?: GPTinf’s plagiarism checker is reliable and scans over 70 billion web pages and academic sources. This is very effective and can detect plagiarism that other software may overlook. While other plagiarism checkers are limited to searching for exact plagiarism, we are able to detect mosaic plagiarism, paraphrasing, and AI-written content. Students can check the plagiarism of any 500-word work after registration. A plagiarism percentage and source links are included.
How does the plagiarism checker identify duplicate content?: The tool has several layers of scanning to detect plagiarism quickly. When you use the free plagiarism checker online, the tool will divide your content into small chunks and scan them against online sources, journals, and archives. It will search for similarity in meaning as well as exact similarity. This makes the tool a duplicate content checker as well as an originality checker. GPTinf can detect parts of your content that have been paraphrased and may use different wording, even if the meaning remains similar.
Does a match mean that I am plagiarizing?: Not all matches signal plagiarism. The similarity detector scans overlapping text, but context is also significant. Correctly cited quotations, phrases that exist in your area of study, and generic terms may turn up in your matches without implying that you plagiarized. When running the detector, focus on the exact text that has been highlighted. Matches consisting of a few words, usually between 3-5, in general terms, do not constitute plagiarism. Extended passages that match other people’s work without a quote constitute a possible case of plagiarism.
Is this truly a free online plagiarism checker, or do I need the premium option?: The plagiarism checker on GPTinf has a free version that can be used for a considerable set of features without any charge. The free version has a word limit of 500 words per search, with an account created, thus making it a free plagiarism checker for students writing essays. The free copy of the report gives information on the percentage of similarity, although premium versions provide a lot of extra features.
What kinds of plagiarism can the scanner detect?: GPTinf's plagiarism detection tool recognizes multiple categories of plagiarism. Verbatim plagiarism involves copying text word-for-word without citation. Mosaic plagiarism mixes copied phrases with original writing. Paraphrase plagiarism occurs when you reword someone's ideas without attribution — the checker tool to find this analyzes semantic meaning, not just matching words. Self-plagiarism happens when you reuse your own previously published work. Source-based plagiarism includes improper citations and fabricating references. Finally, AI-assisted plagiarism involves using language models to generate content from existing sources. The plagiarism checker offers detection for all these types simultaneously.
How accurate is this checker compared to other free tools?: The reason why GPTinf’s checker is more comprehensive compared to free checkers is that it uses a more extensive database of sources. It checks 70 billion sources, which is greater compared to what free checkers can check. It does not check word-for-word similarity alone to determine originality. When it finds something, it provides you with links to check it manually.
What do I do if the checker shows a high similarity ratio?: If you notice that you get a high similarity index, look at what it points out. For instance, an index such as 30% could be acceptable if it consists mostly of correctly cited quotations and technical terms. Download your index and examine each section that it points out. Identify whether the section contains acceptable citations, paraphrased information that requires citation, and copied information that has been passed off as original work. For the paraphrased portions, use the software to help you rewrite them in clearer language. Include citations for those portions that contained other people’s ideas even when you did not use their quotations.
Does this checker have AI-based content capabilities?: Yes. The checker targets AI writing. It checks for indicators that suggest the writing was probably done by an AI, including patterns of sentence structure and patterns of word choices. With an AI checker, you are able to see two scores: one similarity percentage and one AI probability score. This makes it easier to determine when writing assistance becomes a problem.
Is this tool applicable to professional writing and not just academic papers?: It is a resounding yes. This tool is used by writers, marketers, journalists, and businesses to check the authenticity of work before releasing it. This tool is used to detect similar content which may affect the search engine optimization of the work. It is used to check if the work has been plagiarized. This is done by the news teams and authors.
Why this plagiarism checker stands out among the free ones?: There are many reasons why it’s a good free option. It has an extensive database of 70 billion sources, unlike the small indexes other free software relies on. It can identify paraphrasing, mosaic, as well as exact plagiarism. It has AI detection to identify content created by computers. It provides a free scan up to 500 words after you register.

Ethical Use Policy

GPTinf is designed to help you improve your own writing – refining clarity, structure, and quality. It's a tool for learning better writing techniques and enhancing professional communication. Use it to analyze and polish content you've created, not to deceive or circumvent rules.

Prohibited uses include:

academic dishonesty, cheating or plagiarism
creating fake documents or credentials
evading detection systems to deceive institutions
impersonation, and any unlawful or deceptive activity

You are responsible for how you use GPTinf. Follow your institution's or employer's policies on AI tools and be transparent when required. We may suspend access if our tools are misused. GPTinf refines writing not helps you cheat.