Plagiarism Checker X vs Plagius

Plagiarism Checker X is Windows desktop software for checking documents and text against published web pages for plagiarism and similarity. Its online checker compares content with more than 16 billion pages. Bulk Comparison examines multiple documents in repositories, while Side-By-Side Difference places content in two windows to locate matching text. An AI detector indicates whether writing may have come from an AI tool or a human. A readability checker analyzes reading levels, extracts keywords and assesses difficulty. Reports mark matches with colors and references and can export to Word, PDF or Excel. The software accepts Word, PDF, text and other textual formats. Its interface is available in English, Spanish, French, German, Italian, Dutch and Portuguese, with content support for hundreds of languages. The maker says documents remain on the user’s computer and customer content is not copied, stored or sold. Basic is free with limited words and a daily search limit. Professional costs $39.95, paid once; Business costs $147.95, paid once.

Plagius Desktop analyzes academic papers and other documents for possible plagiarism, checking the internet or local files. It supports Word, PDF, OpenOffice, PPT, HTML, RTF, and plain-text formats. Reports can identify suspicious phrases and sources, display URLs with similarity percentages, estimate suspected-plagiarism percentages, and show analysis-quality indicators; results can be opened in a browser or exported as HTML. Its V5 AI detector analyzes paragraphs in context and returns an AI-generation probability and confidence level. The site says it recognizes signals from more than 15 models, including Gemini 3.7, GPT 5.6, and Claude 5. Professional desktop plans add local and network-share searches, batch analysis, direct URL analysis, and file comparisons. The maker says desktop analysis is performed locally, but external searches may send text fragments, usually 7 to 13 words, to search engines. AI detection may send isolated paragraphs to Plagius servers, where excerpts are deleted within up to 48 hours. A free demo runs analysis but reveals only some results. Plagius One is browser-based and initially limited to invited users. Plagius Basic costs $6.90, paid once; its license lasts 30 days and is for one Windows computer. The maker cautions that automated results need manual review and cannot alone confirm plagiarism.