Paperpal (paperpal.com) is an AI writing assistant launched by Cactus Communications in September 2022.[1] Catering to academics, Paperpal offers a variety of AI writing tools including AI detection, grammar checking, proofreading, and manuscript reviews.
This is a review of Paperpal’s AI detector only and is not a reflection of their other services.
Pros
- Sentence-by-sentence breakdowns
- Easy-to-use, well-designed interface
- Detailed reports
Cons
- 1/7 against LLMs
- 2/8 against humanizers
- 2 false positives found
Features
- AI detector: Identifies non-human writing.
- Plagiarism checker: Recognizes unoriginal writing.
- Writing assistant: Generates content and offers suggestions.
- Grammar checker: Reviews writing for spelling and grammar errors.
- Translator: Provides AI translating services.
- Essay writer: Drafts outlines and assists.
- Paper checker: Reviews and improves uploaded manuscripts.
- Chrome extension
- MS Word Add-on
- Google Docs Add-on
Pricing Plans
| Free | Prime |
| No credit card required. | $25/month or $97.30/year |
| 5 AI detections/day (1.2k words/scan) | Unlimited detections (10k words/scan) |
| Limited access to AI assistant, editor, chat, plagiarism, research. | Full access to all AI writing features including faster speeds for suggestions. |
Test #1: Paperpal vs. LLMs
For our first test, we ran text written by various AI models through Paperpal’s detector to see if it could detect basic AI writing. We enter the prompt below into each LLM to generate a scannable article.
Please create a 500-word article about the invention of the wheelbarrow that is 100% factually correct. Remove all em dashes and ensure that the text reads as human as possible in order to pass AI detectors.
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| LLM | Test Result | Proof |
| ChatGPT – 5.4 Thinking Model | 38% AI
❌ |
 |
| Claude – Sonnet 4.6 Extended | 63% AI
✅ |
 |
| Google Gemini – Thinking |
35% AI ❌ |
 |
| Deepseek – Deepthink | 20% AI
❌ |
 |
| Perplexity – Free Model | 34% AI
❌ |
 |
| Grok – Auto | 39% AI
❌ |
 |
| Meta | 1% AI
❌ |
 |
Test #2: Paperpal vs. Humanizers
For our second test, we took the only AI article that didn’t beat Paperpal’s detector and ran it through eight different AI humanizers. The humanized articles were then entered into Paperpal’s detector to see what it could pick up.
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| AI Humanizer | Test Result | Proof |
| Humanize.ai (humanized text) |
20% AI
❌ |
 |
| StealthGPT (humanized text) |
14% AI
❌ |
 |
| WriteHuman.ai (humanized text) |
6% AI
❌ |
 |
| Undetectable.ai (humanized text) |
56% AI
🟡 |
 |
| StealthWriter.ai (humanized text) |
11% AI
❌ |
 |
| WalterWrites.ai (humanized text) |
53% AI
🟡 |
 |
| Grammarly (humanized text) |
38% AI
❌ |
 |
| Quillbot (humanized text) |
7% AI
❌ |
 |
Test #3: False-Positives + Plagiarism
A false positive in this case is when Paperpal detects AI writing in 100% human-written articles. Ten human-written excerpts from various online articles and books were used for this test. We also tested Paperpal to see if it could pick up plagiarism.
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| Article URL | Test Result | AI Detection | Plagiarism |
| War and Peace (excerpt) | 3% AI – 94% Plagiarized
✅ |
 |
 |
| Self-Reliance (essay) | 1% AI – 100% Plagiarized
✅ |
 |
 |
| Nat. Geo (article) | 7% AI – 100% Plagiarized
✅ |
 |
 |
| Wikipedia (“Ralph Waldo Emerson”) | 2% AI – 74% Plagiarized
✅ |
 |
 |
| NBC (article) | 22% AI – 79% Plagiarized
✅ |
 |
 |
| Reuters (article) | 2% AI – 92% Plagiarized
✅ |
 |
 |
| Politico (article) | 30% AI – 26% Plagiarized
✅ |
 |
 |
| New York Post (article) | 38% AI – 6% Plagiarized
✅ |
 |
 |
| Johns Hopkins (article) | 71% AI – 90% Plagiarized
❌ |
 |
 |
| NIH (article) | 100% AI – 100% Plagiarized
❌ |
 |
 |
Is Paperpal Accurate?
Paperpal has good reviews on Trustpilot, with an overall score of 4.2 stars. However, a lot of the reviews are evaluating quality of the research assistant. Some complain about the accuracy of the AI detector and how it will flag their human writing as AI.
Frequently Asked Questions
Are sentence-by-sentence breakdowns provided?
Yes, completed scans provide a granular look at which sentences read as AI, human, and mixed.[2]
Is document scanning included?
Yes, documents can be uploaded in .xlsx, .pdf, and .docx formats.[3]
Is image scanning provided?
Yes, images can be uploaded and scanned in .png, .jpg, .jpeg, .gif, .webp formatting.[4]
Are reports shareable?
No, reports aren’t directly shareable from a Paperpal account but they can be downloaded immediately in PDF format and shared as needed.
Does Paperpal provide certifications?
No, there’s no certifications attached to the detection results guaranteeing their accuracy. In fact, the results include a disclaimer that states “Results are estimates of writing patterns, not proof of AI use.”
Are AI detections used for internal training?
No, Paperpal states explicitly that their AI models are trained on independent data sets, so AI detections and other uploaded documents are not used for internal training.[5]
Sources
- https://paperpal.com/blog/news-updates/an-analysis-of-how-paperpal-outperforms-other-ai-writing-tools
- https://paperpal.com/tools/ai-detector
- https://support.paperpal.com/support/solutions/articles/3000128485-which-file-formats-are-supported-by-the-file-upload-option-
- https://support.paperpal.com/support/solutions/articles/3000128485-which-file-formats-are-supported-by-the-file-upload-option-
- https://support.paperpal.com/support/solutions/articles/3000123164-will-my-data-be-used-for-training-paperpal-ai-