Pick GPTZero if you're a teacher or student — it's built for education, has a free tier, keeps false positives lower on student writing, and gives you a writing-history replay as evidence. Pick Originality.ai if you run or edit web content — it's more accurate on marketing copy, clearly ahead on paraphrased text, and bundles plagiarism and fact-checking into every scan. They're the two best detectors in 2026, aimed at different problems.
At a glance
| GPTZero | Originality.ai | |
|---|---|---|
| Best for | Teachers, students, schools | Marketers, publishers, SEO teams |
| Raw AI accuracy | ~92% (95.7% RAID) | ~94% (97% study) |
| Paraphrase accuracy | Moderate | Best-in-class (96.7% RAID) |
| False positives | 6–8% | 5.7% |
| Free tier | Yes — 10,000 words/mo | No (PAYG from $30) |
| Paid entry price | $14.99/mo (150k words) | $14.95/mo (2,000 credits) |
| Standout extra | Writing-history replay, LMS | Plagiarism + fact-check in one scan |
Accuracy: close on raw text, split on paraphrase
On raw, unedited AI text both are excellent — GPTZero around 92% (95.7% on RAID), Originality.ai around 94% (97% in one empirical study). The gap opens on paraphrased and "humanized" text, which is where real cheating happens. Originality.ai posted a field-best 96.7% on the RAID paraphrase benchmark; GPTZero, like most tools, drops more sharply there.
On false positives the two are close — GPTZero at 6–8%, Originality.ai at 5.7% — but the context differs. GPTZero is calibrated to be cautious with student writing, while Originality.ai runs a touch hotter on non-native English. Neither is proof; both are signals.
GPTZero: the classroom detector
GPTZero wins on transparency and evidence. It highlights suspect sentences, states its confidence honestly, and — the killer feature — replays how a Google Doc was actually written, showing organic typing versus a giant paste. For an academic integrity case, that timeline beats any raw score. It has a real 10,000-word free tier, an LMS integration, and flat, easy-to-understand word limits.
Where it lags: it's weaker on paraphrased text and on Claude-generated content, and its plagiarism check is gated to the Premium plan. Full details in our GPTZero review.
Originality.ai: the publisher's detector
Originality.ai wins on raw accuracy and, decisively, on paraphrase — the exact case most people use to try to beat a detector. It rolls AI detection, plagiarism, fact-checking, and readability into one scan, with a team dashboard and an API for CMS pipelines. If your job is vetting freelance web copy at volume, this is the tool.
Where it lags: the credit system takes a minute to learn, there's no free tier, and it's a poor fit for grading students. Full details in our Originality.ai review and pricing guide.
Pricing
GPTZero is friendlier for casual use: a free 10,000-word tier, then Essential $14.99 (150k words), Premium $23.99 (300k words + plagiarism), and Professional $45.99. Originality.ai has no free tier — $30 pay-as-you-go for 3,000 credits, Base $14.95/mo for 2,000 credits (1 credit = 100 words), and Pro $179/mo for agencies.
At the entry level GPTZero is cheaper because of the free tier and flat word count. For an agency scanning tens of thousands of words a month with plagiarism included, Originality.ai's bundled scan can be better value despite the credit math.
Which should you pick?
Choose GPTZero if you're an educator, a school, or a student checking your own work — the free tier, transparency, LMS, and writing-history evidence are built for exactly that. Choose Originality.ai if you're a marketer, editor, or publisher vetting web content — higher accuracy, best-in-class paraphrase detection, and plagiarism plus fact-check in one pass. If you can only run one across a mixed team, Originality.ai is the more accurate all-rounder; if the stakes involve a person's grade or job, GPTZero's evidence trail makes it the more defensible choice.
Still comparing? See the full field in our best AI detectors ranking.
Frequently Asked Questions
Is GPTZero or Originality.ai more accurate?
Originality.ai is more accurate on web and marketing content and clearly ahead on paraphrased text (96.7% RAID). GPTZero is strong on raw AI text and better calibrated for student writing with lower false positives. Both land in the mid-90s on raw text and slip on mixed content.
Which is cheaper, GPTZero or Originality.ai?
GPTZero has a free 10,000-word tier and flat plans from $14.99/month. Originality.ai has no free tier and runs on credits from $14.95/month for 2,000 credits, plus a $30 pay-as-you-go pack. For casual use GPTZero is cheaper; for high-volume web scanning they're close.
Which should a teacher use?
GPTZero. It's built for education, with lower false positives on student writing, a free tier, LMS integration, and a writing-history replay that provides real evidence. Originality.ai is tuned for web publishing and runs hotter on student and non-native text.
Which is better for a content agency?
Originality.ai. It's more accurate on marketing copy, leads on paraphrased text, and bundles plagiarism and fact-checking into each scan with a team dashboard and API — everything an editorial operation needs to vet freelance work.
Do either detect paraphrased AI text reliably?
Originality.ai is the best available at it (96.7% on RAID), but no detector is fully reliable on heavily rewritten text. GPTZero drops more on paraphrase. Treat any single result on humanized content with extra caution.
Can I use both together?
Yes, and for high-stakes decisions running text through both is smart — agreement between two independent detectors is a stronger signal than either alone. Even then, combine the result with drafts, writing history, and human judgment.
Which handles GPT-5.6 and Claude better?
Both detect raw GPT-5.6 well. Originality.ai holds up better across Claude and mixed content, while GPTZero can slip on Claude-generated text. Both vendors update models frequently, so the gap shifts over time.