Best Plagiarism Checker Software

PlagiarismRemover.AI is an AI-powered platform that rewrites copied or AI-generated content to remove plagiarism while preserving the original meaning, structure, and readability. Instead of simple word swapping, it produces context-aware rewrites that read naturally and are designed to pass major plagiarism and AI-detection tools.

It handles essays, research papers, reports, blog posts, marketing copy, and more, supports 16 languages, and includes an AI humanizer for refining machine-generated text. Because it runs in the browser and is optimized for mobile, users can clean up content on any device without installing software. A free tier makes it accessible to students, writers, educators, and professionals who need original, submission-ready content.

Originality AI is a content integrity platform built to help writers, publishers, educators, marketers, and agencies verify whether text is AI-generated, plagiarized, or in need of quality improvements. More than a basic AI detector, it combines AI detection with plagiarism checking, content quality scoring, readability analysis, grammar checking, fact checking, and bulk scanning tools. That makes it especially useful for teams that need to review large volumes of content before publishing or submission. Originality AI also offers a Chrome extension, WordPress plugin, Moodle plugin, and API, so it fits into workflows across Google Docs, websites, classrooms, and enterprise content systems. Its main value is helping users publish with more confidence by identifying AI-written or heavily AI-edited text, while also improving originality, clarity, and factual accuracy. For organizations managing writers or student submissions, it provides shareable reports, scan history, team controls, and document replay features that help demonstrate authorship and content integrity. Read Originality AI Reviews

Justdone AI is an all-in-one AI writing and content optimization platform built for students, educators, researchers, marketers, and anyone who needs to create polished text faster. It combines an AI detector, AI humanizer, plagiarism checker, paraphraser, summarizer, grammar checker, fact checker, citation generator, and AI quiz generator in one workspace. The platform is especially valuable for users who want to refine AI-generated content, improve writing quality, check originality, and speed up research-driven tasks without switching between multiple tools. Justdone AI also includes AI chat features for working with PDF, DOC, TXT, or website content, plus a Chrome extension for writing support across the web. Its main value is workflow efficiency: you can draft, analyze, rewrite, and validate content from one dashboard. For users who care about originality, clarity, and productivity, Justdone AI offers a practical toolkit that helps save time while improving writing confidence. Read Justdone AI Reviews

Quetext is a plagiarism and AI content detection platform built around its proprietary DeepSearch technology and ColorGrade originality interface, which highlight matched passages and flag likely paraphrased content. It targets students, teachers, writers, and professionals who need to verify originality before submitting or publishing text. Beyond detection, Quetext includes an AI writing tutor called AITutorMe, a citation generator, and grammar and spell check tools.

Quetext offers a free plan with a 1,000-word limit for both plagiarism and AI checks, along with paid Essential, plagiarism-only, and AI-detector-only individual plans billed monthly with annual discounts. Bundle tiers and a usage-based Professional plan serve teams and high-volume users, with API access available on several paid tiers.

Copyscape is a long running plagiarism and duplicate content detection service built for website owners, writers, editors, and digital marketers who want to confirm their content is not copied elsewhere online. The free tier runs a basic search using search engine indexes, while Copyscape Premium adds copy and paste checking, PDF and Word uploads, batch searches of up to 10,000 pages, a Private Index for comparing against unpublished content, and an API returning results in JSON, XML, or HTML.

Premium is billed pay per search rather than as a flat subscription, costing 3 cents per search of up to 200 words plus 1 cent per additional 100 words. A separate product, Copysentry, continuously monitors the web for copies of a site's pages and emails alerts, with Standard and Professional tiers priced monthly per 10 pages monitored.

DupliChecker is a web based plagiarism checker that scans up to 25,000 words per search using AI based technology and partial match detection at the paragraph level, so it can catch reworded or restructured copying rather than only exact matches. It accepts copy and paste, URL, and file upload input across formats including doc, docx, odt, pdf, rtf, and txt, and can import files directly from Google Drive and Dropbox. A free AI content detector, grammar checker, and paraphrasing tool are bundled alongside the core checker.

A limited free version is available without signup, while paid access is sold in weekly, monthly, and yearly tiers offering larger word counts and search quotas, plus a Plagiarism API for integrating real time checks into other websites.

PlagScan was a German built plagiarism checker, later acquired by Turnitin, that detected overlapping text of three or more consecutive words using Microsoft Bing search results plus a database of academic and scientific journals. Reports highlighted exact matches in red and rewritten phrases in blue, and the platform let users exclude specific URLs, sources, or phrases from a scan. It supported document upload, copy and paste, and URL submission, along with an API for automated LMS integration.

As of the end of 2024, PlagScan stopped selling private individual plans, and remaining credits had to be used by December 31, 2024. Historical private pricing ranged from $5.99 for entry level plans up to around $22.99 per month for Enterprise, with higher Platinum tiers reaching several hundred dollars. Organizations are now directed to Turnitin's other academic integrity products.

iThenticate is a Turnitin owned plagiarism and similarity checking service built for researchers, authors, and publishers who need to verify originality before publication. It compares manuscripts and grant proposals against a large database of scholarly content accessed through Crossref's network of more than 1,500 publishers, along with CORE open access metadata and ProQuest theses and dissertations. Features include Match Groups for organizing similar sources, a Flags Panel that detects manipulated characters, bulk upload, and side by side comparison.

Pricing is credit based rather than subscription. A Single plan covering one manuscript up to 25,000 words costs $125, a Multiple plan for up to three manuscripts or 75,000 words costs $300, and larger organizations can request custom pricing. Individual plans do not include AI content detection.

Unicheck was a cloud based plagiarism and similarity detection service aimed at schools, universities, and businesses, known for fast scans, citation recognition across APA, MLA, Harvard, Chicago, and Turabian formats, and an AI powered authorship verification tool that could flag inconsistent writing within a single document. It integrated with popular learning platforms such as Canvas, Moodle, Google Classroom, and Schoology, and supported a wide range of file formats and archives.

Turnitin acquired Unicheck and shut the standalone product down on January 1, 2025, ending private and cloud plans and directing former customers toward Turnitin Similarity instead. The historical Personal and Cloud Business plans both started at $15 for the first 100 pages, with custom pricing for K-12 and higher education accounts.

Grammarly's plagiarism checker is a feature within the broader Grammarly writing assistant rather than a standalone product. It scans documents against billions of web pages and ProQuest's academic databases, then returns a plagiarism score along with a list of matching sources. The feature works alongside Grammarly's grammar, style, and AI writing suggestions inside its browser extension, desktop app, and web editor.

Plagiarism checking is available only on Grammarly's paid Pro and Business plans; it is not included in the free tier. Pro is billed monthly or at a lower effective rate with annual billing, while Business plans are billed per seat annually and add team management and analytics. Grammarly does not offer a separate discounted plan specifically for a standalone plagiarism checker.