Plagiarism Detector: Fast & Robust Checker for Windows

Free online tool · No sign-up · Instant results

Free Online AI & Plagiarism Checker

Paste any text and instantly see how much was AI-generated — and whether it's plagiarized. Works in 40 languages, including English and Romanian.

100% free No sign-up AI + plagiarism in one Instant

Dual-model ensemble

Binoculars + ModernBERT working together for robust, hard-to-fool detection.

40 languages

English, Romanian and 38 more — most AI checkers are English-only.

AUC 0.9884

Published accuracy, measured across 22 different AI generators.

Try the online checker → [ See our accuracy benchmark → ]

PAN 2026 · CLEF Conference · Generative AI Detection

Award-Winning AI Detection

The team behind Plagiarism Detector placed 3rd out of 32 international teams at the PAN 2026 “Voight-Kampff” Generative AI Detection challenge — a leading academic benchmark for telling human writing apart from AI-generated text, held at the CLEF 2026 conference.

3rd

overall, out of 32 teams worldwide

#1 in the field

0.996

ROC-AUC — the highest detection score of any team

0.000

false-positive rate — never flagged human writing as AI

View the official results See our research & track record →

Independently evaluated on the TIRA platform; results published in the CLEF 2026 proceedings. Research by the Plagiarism-Detector.com team with Zhytomyr State University.

Supported Operating Systems:

New · Originality Reports

Similarity Coefficients, built in: CS1 · CS2 · CIT

Plagiarism Detector now reports the three similarity coefficients used across Romanian higher education — right inside every Originality Report. CS1 and CS2 grade matched text by fragment length; CIT separates quoted and cited material — so your results line up with your faculty's requirements at a glance.

CS1

of the text is matched in fragments of 5 words or longer.

CS2

is matched in fragments of 25 words or longer — the stricter borrowed-passage test.

CIT

is identified as quotations / citations, scored separately from similarity.

CS1, CS2 and CIT follow the similarity-coefficient definitions used in Romanian university anti-plagiarism regulations, within the national Ministry of Education framework applied across Romanian higher education since 2012.

Watch Plagiarism Detector Promo:

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Plagiarism Detector runs Checks against following Sources:

Internet (Google & Bing) + SciPap DB

Our Scientific Papers DB Check: SciPap

Your Custom DB Check [via PDAS add-in]

Your Local Folder of Documents Check

A Document Pair Check

Combined (Hybrid) Sources Check

Plagiarism Detector Features:

1. Your documents remain fully confidential:

Our servers do not store checked texts in any manner!
Your document is processed only at your own PC!
You control your originality reports, and only you!
Your privacy is our top priority!
No 3rd parties!

2. You pay only once! No hidden fees:

Demo is free to download - try before you buy!
License is a one-time purchase!
Flat, fair license pricing!
No recurrent charges!
No subscription!

3. This app is made to specifically tackle Plagiarism:

Many years of devoted development!
Multiple check types and functions!
Originality Reports management!
Anti-cheating engine!
No grammar check, no spellcheck, no scam!

Zero data retention

Follow the data. It comes back to you.

Plagiarism Detector reads your document on your own PC. Only short search phrases ever leave the application - the matching pages are pulled back to your machine and compared there. We never receive your file, so there is nothing for us to store, share or train on.

phrases out public pages in nothing written to our servers

Test it yourself - download the free demo

Want proof? Put a sentence nobody has ever published into a test document, check it with Plagiarism Detector, then search the web for that sentence a day later. It will not be there.

On-premise: PDAS

Everything inside your perimeter

One server, your own corpus, and every workstation checking against it over the local network. PDAS - the Plagiarism Detector Accumulator Server - indexes the documents you give it and answers every Plagiarism Detector seat on site. The line to the outside can simply be cut.

traffic inside your network optional internet link can be fully disconnected

Request on-site deployment

PDAS is an add-on to licensed Plagiarism Detector seats.
Our team will size the server with you before you buy.

We are happy to serve our Corporate Clients:

Panca Budi Development University

Medan

Secondary School of Technical Professions Šiška

Ljubljana

National University of Theatre and Film I.L. Caragiale

Bucharest

Polytechnic University of Queretaro

Santiago De Querétaro

Autonomous University of the State of Quintana Roo

Chetumal

Academy of Economic Studies of Moldova

Chișinău

Scientific and Educational Innovation Center of Social Transformations

Chernihiv

Muntinlupa City University - Sherwin Esteron

Muntinlupa

Hyperion University of Bucharest

Bucuresti

Minds At Work Ltd

Budapest

Languages for Plagiarism Detection:

English - is supported by Plagiarism Detector!

[ More >> ]

Plagiarism Detector: Why Choose It?

1. Unmatched Accuracy and Speed: Plagiarism Detector's cutting-edge algorithms enable it to provide results quickly without sacrificing accuracy. Our state-of-the-art technology guarantees comprehensive scans of your writing, pinpointing instances of plagiarism with unparalleled accuracy, even at the most subtle levels.

2. User-Friendly Interface: Plagiarism Detector's user-friendly interface accommodates users of all skill levels. There has never been an easier or more effective way to perform plagiarism checks, whether you're a professional, student, or teacher.

3. Extensive Coverage: Word documents, PDFs, and text files are just a few of the file types that Plagiarism Detector provides extensive coverage for. Whether you're examining research articles, academic papers, or web content, our technology guarantees careful examination to protect the uniqueness of your work.

4. Content Security and Privacy: At Plagiarism Detector, we take your content security and privacy very seriously. Your sensitive data is always safe with us because our application runs safely offline. You may confidently conduct plagiarism checks since you know that your data is protected from illegal access.

Our users say:

It helped me a lot, I find the software exciting because it always improves something, I have had experience with other software, but yours is the most complete. And it recognizes things that others do not, this is more faithful to the academic reality.

Rossi Rodriguez

23, Researcher

Thanks for your amazing work! The new update is the best! Congrats!

Alex Grumezescu

21, Student

Excellent program!

Nico Josea

50, ScientistResearcher

Your program is quite efficient, congratulations!

Marcelo Arnez

51, Professor\Researcher

It helps me a lot!

Dawit Yosef

24, ScientistResearcher

Thanks a lot fantastic support as ever I will activate the software as soon as possibile!

Massimiliano Giannini

37, Researcher

I’ll be honest, actually the program works just fine and overall does a pretty good job!

Addi Christea

52, ProfessorResearcher

This program is more than wonderful and I praise it throughout all universities and educational platforms in Egypt!

Ibrahim Elbaz

40, ProfessorResearcher

You are in a good company - thousands of satisfied clients:

Discover the Originality:

Become one of the thousands of content users who depend on Plagiarism Detector to keep their work original. Our application gives you the ability to safeguard your work and observe the values of honesty and integrity, whether you're aiming for academic success, encouraging creativity in the workplace, or maintaining ethical standards in all of your professional pursuits.

Free Plagiarism Detection

Are you curious about the advantages of using Plagiarism Detector? Discover the power of authenticity by utilizing our free plagiarism checker today. Make sure your work stays authentic and unique by thoroughly scanning it to identify any instances of plagiarism.

Download Plagiarism Detector Right Now!

Are you prepared to take command of your content integrity? Now that you've downloaded Plagiarism Detector, see the difference for yourself. Give yourself the resources you require to thrive in your scholastic, professional, and artistic efforts while maintaining individuality and integrity.

Frequently Asked Questions

What is Plagiarism Detector?

Plagiarism Detector is a desktop plagiarism checking software for Windows that scans documents against billions of online sources, the ScIPaP academic paper database, and a private PDAS document accumulator to identify copied, paraphrased, and AI-generated content. It supports 12+ file formats including DOC, DOCX, PDF, and TXT, and generates detailed Originality Reports with similarity percentages, highlighted matches, and clickable source URLs.

How does Plagiarism Detector work?

Plagiarism Detector works by extracting text from your documents and comparing it against five search engines — Google, Bing, Yahoo, DuckDuckGo, and the ScIPaP academic paper database — to find matching content across over 4 billion web pages. The software uses advanced fingerprinting algorithms to detect exact matches, paraphrased passages, and mosaic plagiarism, then generates an Originality Report that highlights every matched segment with its source URL and similarity score.

Is Plagiarism Detector free?

Plagiarism Detector offers a free demo download that lets you test all features with limited document checks. Full licenses — Lite, Personal, Pro, and Portable — are one-time purchases starting at $49 with no monthly or annual subscription fees. Every license includes lifetime access to minor updates, the UACE Anti-Cheating Engine, AI Content Detector, and multi-format document support.

What makes Plagiarism Detector different from online checkers?

Unlike online plagiarism checkers, Plagiarism Detector runs entirely on your desktop, so documents never leave your computer — ensuring complete privacy and data security. It checks against five search engines simultaneously instead of one, includes offline Document Pair Comparison, accumulates results in a local PDAS database for cross-reference checking, and provides the UACE Anti-Cheating Engine that detects Unicode character substitution tricks that web-based tools miss.

Does Plagiarism Detector detect AI-generated content?

Yes. Plagiarism Detector includes a built-in AI Content Detector that identifies text generated by ChatGPT, GPT-4, Claude, Gemini, and other large language models. AI detection runs automatically alongside every plagiarism check in a single scan, so you get both plagiarism and AI-generated content results without needing a separate tool or paying an additional fee.

Welcome to Plagiarism Detector, the Complete Content Integrity Solution!

Discover the Power of Authenticity with Plagiarism Detector:

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