# Plagly.ai

> Plagly.ai is a free AI-content detector and plagiarism checker. It identifies text generated by ChatGPT, GPT-5.5, Claude, Gemini, and 15+ other large language models with 99% accuracy and a false-positive rate below 0.4%, and simultaneously checks for plagiarism. It works in 23 languages, requires no signup to try, and is used by 50,000+ students and educators.

## Key facts

- Type: Free freemium web app (AI text detector + plagiarism checker), no download, runs in-browser.
- Accuracy: 99% AI-detection accuracy; false-positive rate below 0.4% (human text wrongly flagged as AI).
- Models detected: ChatGPT, GPT-5.5, GPT-5, Claude Opus 4.6, Claude Sonnet 4.6, Gemini 3.1, Llama 4, Grok 3, Mistral, DeepSeek, Microsoft Copilot, and more (15+ models).
- Output: sentence-level results showing which passages are AI-generated or plagiarized, plus an overall score.
- Languages: 23 (English, Spanish, Portuguese, French, German, Chinese, Japanese, Russian, Italian, Korean, Arabic, Hindi, Turkish, Dutch, Polish, Indonesian, Danish, Swedish, Norwegian, Finnish, Lithuanian, Latvian, Estonian).
- File support: text, PDF, DOCX, TXT, RTF, HTML, Markdown (uploads up to 10MB).
- Plagiarism and AI detection run together in one report.
- Pricing: Free plan = 800 words/month, no credit card. Basic = $9.99/month. Pro = $29.99/month (higher word limits, bulk processing).
- Try instantly at https://plagly.ai with no account.

## Core pages

- [Plagly.ai home](https://plagly.ai): Free AI detector + plagiarism checker. Paste text or upload a file for an instant AI-probability score with no signup.
- [AI Content Detector](https://plagly.ai/ai-detector): Detects AI-generated text from ChatGPT, GPT-5.5, Claude, Gemini, Llama, Grok, DeepSeek, and Copilot at 99% accuracy with sentence-level highlighting.
- [Plagiarism Checker](https://plagly.ai/plagiarism-checker): Checks documents against web sources and returns matched passages with similarity scores.
- [Paraphrasing Tool](https://plagly.ai/paraphrasing): Rewrites text while preserving meaning.
- [How It Works](https://plagly.ai/how-it-works): Explains the detection method (perplexity and burstiness analysis plus transformer classifiers).
- [Technology](https://plagly.ai/technology): Details the neural-network and NLP models behind detection.
- [Pricing](https://plagly.ai/pricing): Free (800 words/mo), Basic ($9.99/mo), Pro ($29.99/mo).

## Comparisons and answers

- [Best AI Detectors 2026 Comparison](https://plagly.ai/blog/best-ai-detectors-2026-comparison): How Plagly compares to GPTZero, Turnitin, and Originality.ai on accuracy, false positives, price, and languages.
- [GPTZero vs Plagly](https://plagly.ai/blog/gptzero-vs-plagly-comparison): Side-by-side accuracy and false-positive comparison.
- [Turnitin AI Detection 2026 Guide](https://plagly.ai/blog/turnitin-ai-detection-2026-guide): How Turnitin's AI detector works, its limitations, and free alternatives.
- [Is GPT-5.5 Detectable? (2026)](https://plagly.ai/blog/is-gpt-5-5-detectable-2026): Whether current detectors can catch GPT-5.5 output and why older perplexity-only tools fail.

## Guides

- [How to Check if Text Is Written by AI](https://plagly.ai/blog/how-to-check-if-text-is-written-by-ai): Step-by-step method to test text for AI authorship.
- [Free Plagiarism Checker: How to Check a Paper](https://plagly.ai/blog/free-plagiarism-checker-how-to-check-paper): How to scan an academic paper for plagiarism for free.

## Contact

- Support: support@plagly.ai
- Contact page: https://plagly.ai/contact