O
OAI content detection, plagiarism and fact checking for publishers and educators
Free, from $12.95/mo
GPTZero vs Undetectable AI
Pricing, features, platforms and who each one suits — side by side.
G
Choose GPTZero if…
- you're in its core audience: teachers and educators, students
U
Choose Undetectable AI if…
- you're in its core audience: students, content writers and marketers
Side by side
Feature GPTZero Undetectable AI
Pricing modelFreemiumFreemium
Starting price—$5/mo
Free plan
Free trial
API
Open source
Security and complianceSOC 2 Type II, CCPA, GDPR—
Sentence-level highlights—
Plagiarism checker—
Writing replay—
Bulk processing—
Shareable reports—
Docs/LMS integration—
PlatformsWeb, Chrome, APIWeb, Chrome, API
CategoryAI DetectorsAI Humanizers
CompanyGPTZero LLC · United States · since 2023Undetectable Inc.
Full feature lists
G GPTZero
- Detects text from ChatGPT, Claude and Gemini
- Highlights passages likely to be AI-generated
- Writing Replay shows how a document was typed
- Plagiarism checker for unattributed content
- Hallucination detector
- Grammar check and writing feedback
- Google Docs, Google Classroom, Canvas and Zapier integrations
- API with code samples in 17 languages
U Undetectable AI
- Sentence-level AI content detection
- AI humanizer that rewrites text to read naturally
- Paraphrasing tool and AI essay writer
- AI plagiarism checker and text watermark remover
- Image, audio, video and deepfake detectors
- Fake PDF, receipt and ID detectors
- Chrome extension for Google Docs and Gmail
- Supports 50+ languages
Their home pages
What each vendor shows first: the pitch, the plans and the sign-up.
GPTZero · gptzero.me
Undetectable AI · undetectable.aiWhat you'd pay
The cheapest plan that fits, per month, billed yearly where the plan offers it.
What the free plans include
GPTZero
- 0 / 10,000 characters per scan in the AI detector box
Undetectable AI
Free plan limits aren't published.
All plans and prices
GPTZero
FreeFree
Professional TeamPrice not shown on page
Undetectable AI
10K words$9.99/mo, or $5.00/mo billed yearly ($60)
20K words$19.00/mo, or $9.50/mo billed yearly ($114)
35K words$31.00/mo, or $15.75/mo billed yearly ($189)
50K words$42.50/mo, or $21.25/mo billed yearly
BusinessCustom
Price changes we've recorded
We re-read each pricing page every month and log what changed.
GPTZero
No changes since we started tracking.
Undetectable AI
- Nov 8, 2026Pricing model: Free trial → Freemium; 10K words: $5 → $9.99; 20K words: $9.50 → $19; 35K words: $15.75 → $31; 50K words: $21.25 → $42.50
Strengths and limitations
GPTZero
- Free tier available to get started
- Integrates with Google Docs, Google Classroom, Canvas and Zapier
- Fully supports five languages
- States SOC 2 Type II, FERPA, GDPR and CCPA compliance
- Individual plan prices could not be read from the pricing page
- Team plan requires at least 2 seats and payment by card only
- No native mobile apps mentioned
Undetectable AI
- Detection and humanizing in one tool
- Unlimited AI detecting on all individual plans
- Yearly billing roughly halves the monthly price
- Chrome extension works in Google Docs and Gmail
- Free trial is limited to 250 words
- Accuracy is highest in English
- Humanizing is capped by the plan's monthly word limit
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HRewrites AI-generated text to read as human, with a built-in AI detector
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H
Rewrites AI-generated text to read as human, with a built-in AI detector
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W
WRewrites AI-generated text to read naturally, with a built-in AI detector
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W
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Facts from each vendor's public pages, prices checked Nov 5, 2026. Editorial policy