Is Originality AI Accurate? 16 of 16 AI Texts Caught

Is Originality AI accurate? In our October 2026 test, Originality 5.0 scored all 16 AI generated texts between 88% and 97% Likely AI and all 12 human texts between 0% and 5% Likely Original, the cleanest result of the six detectors we have run through the same 28 texts. It also caught all four texts we had rewritten with Grammarly's Humanizer, which Grammarly's own detector had scored 0%.

I've spent nearly 20 years in AI development and digital marketing, and this is our second full test of Originality.ai this year. The July 2026 run found it slipping on edited text and flagging some human writing. This October retest uses the fixed 28 text set behind our AI detector accuracy hub, so every number below can be compared text for text with GPTZero, ZeroGPT, Solvely, JustDone and Grammarly. We paid for the scans with two free accounts and Originality had no part in the test.

My Main Points:

• Originality 5.0 scored 16 of 16 AI texts Likely AI, with a low of 88% and a high of 97%. The average was 93.4%.
• No human text was flagged. The 12 human texts averaged 2.5% and the highest, an economics paper introduction, scored 5%.
• Disguised AI text did not get through. Student voice rewrites with typos scored 88% to 94%, where Grammarly scored them 0% to 48%.
• Four AI texts rewritten by Grammarly's Humanizer scored 88%, 92%, 88% and 88%. Only GPTZero matched that.
• Against five other detectors on the same texts, Originality tied GPTZero and Solvely on catching AI and had the second lowest human scores after GPTZero.
• The July 2026 over sensitivity we reported did not show up in October. The 5.0 model looks better calibrated, with the usual warning that no single score is proof.

In this review I'll show the October scores by text type, the comparison with the other five detectors, the Grammarly Humanizer result, what changed since July, and what the free and paid plans cost.

Originality AI Accuracy on 28 Texts in October 2026

Originality 5.0 separated AI and human writing with a wide margin. The five plain Claude Opus 5.5 texts scored 95, 94, 96, 95 and 95. The five plain Claude Fable 5.1 texts scored 95, 96, 97, 94 and 95. The three disguised Opus texts, written in a hurried student voice or with typos injected by a script, scored 90, 90 and 94, and the three disguised Fable texts scored 88, 91 and 90. Every one of the 16 carried the Likely AI label.

The human side was just as clean. The four academic introductions scored 5, 4, 4 and 4. The three developer documentation sections scored 0, 1 and 2. The two personal blog posts scored 2 and 2, and the three essays by non native English learners, the group most often hurt by false positives, scored 2, 2 and 2. All 12 carried the Likely Original label.

Text group	Count	Originality 5.0 scores	Average
Plain Opus 5.5	5	95, 94, 96, 95, 95	95.0%
Plain Fable 5.1	5	95, 96, 97, 94, 95	95.4%
Disguised Opus 5.5	3	90, 90, 94	91.3%
Disguised Fable 5.1	3	88, 91, 90	89.7%
Human academic	4	5, 4, 4, 4	4.3%
Human technical docs	3	0, 1, 2	1.0%
Human personal blog	2	2, 2	2.0%
Human non native essays	3	2, 2, 2	2.0%

How We Tested Originality AI

Originality was tested on October 31, 2026 in its web app, on two Free accounts with 100 credits each, using the default "Originality 5.0" model with Deep Scan off and only the AI Score selected. The app checks the Plagiarism Score by default on every new scan and bills it separately, so we unchecked it each time. Each text cost 3 or 4 credits at 1 credit per 100 words, rounded up.

The 28 texts are the same set we use for every detector: 12 human texts published before 2022 (four academic introductions, three developer docs, two personal blog posts, three essays by non native English learners), 10 plain AI texts from Claude Opus 5.5 and Claude Fable 5.1, and six disguised AI texts written in a hurried student voice or with typos injected by a script. Each runs 280 to 390 words. We recorded the document level percentage and the Likely AI or Likely Original label. The app also offers a "5.0 Max" model and a Deep Scan at 20 credits per scan; neither was used, so the results here are what a default scan returns.

Originality AI vs GPTZero, ZeroGPT, Solvely, JustDone and Grammarly

Originality tied for first on catching AI and came second on leaving humans alone. The GPTZero and ZeroGPT numbers come from the Basic Scan at gptzero.me and the free checker at zerogpt.com on October 22, 2026. Counting a text as caught when it scores 50% or more, Originality, GPTZero and Solvely each caught 16 of 16 AI texts, ZeroGPT caught 10 and Grammarly caught 8. On the human side, GPTZero gave all 12 texts a flat 0%, Originality topped out at 5%, Grammarly at 15%, ZeroGPT at 24.9% and Solvely at 27.2%, with Solvely labeling four human texts "Moderate AI".

Detector	AI texts at 50%+ (of 16)	Lowest AI score	Highest human score	Human texts at 0%
Originality 5.0	16	88%	5%	1 of 12
GPTZero	16	100%	0%	12 of 12
Solvely	16	62.2%	27.2%	8 of 12
ZeroGPT	10	7.4%	24.9%	9 of 12
Grammarly	8	0%	15%	10 of 12

The JustDone numbers come from a different, earlier run and are not in the table: in our 2026 test JustDone sat at roughly 59% to 61% on clear AI, the weakest of the group. Originality's scores sit in a tighter band than GPTZero's. GPTZero returns 100% or 0% on almost everything, while Originality returned 88% to 97% on AI text and 0% to 5% on human text, which gives you a sense of confidence rather than a verdict. For a content team that has to decide where to look closer, the graded score is more useful.

Can Originality AI Detect Humanized AI Text?

Originality caught every humanized text we gave it. In our Grammarly test we took four plain AI texts and rewrote them with Grammarly's Humanizer, accepting every suggestion. Grammarly's own detector then scored all four 0% and ZeroGPT scored them 0%, 7.7%, 0% and 26.4%. Originality 5.0 scored the same four rewrites 88%, 92%, 88% and 88% Likely AI, and GPTZero scored them 100% with a "Possible AI Paraphrasing" label.

This matters more than the headline accuracy number. Almost nobody submits raw AI output. The common case is AI text that has been run through a rewriting tool, and that is where ZeroGPT and Grammarly fall apart. Originality and GPTZero are the two detectors in our set that still see the AI underneath a Humanizer pass.

What Changed Since Our July 2026 Test

So is Originality AI accurate now, or was July the truer picture? Our July 2026 test found about 88% to 90% accuracy on clear AI text, around 85% on text heavily edited with Fable 5 and GPT 5.6 Sol and seeded with human style mistakes, and a tendency to flag some fully human writing as AI. The October run on the fixed 28 text set found none of that over sensitivity: the highest human score was 5%.

Two things changed between the runs. Originality shipped its 5.0 model, which is what the app selects by default now, and our method moved from a mixed bag of samples to the fixed 28 text set with published, pre 2022 human sources. The two runs are not directly comparable, and the July warning still stands as a principle: a detector tuned to catch more AI can start catching innocent writers. On this set, with this model, it did not. We will keep rerunning the same texts as models change.

Originality AI Pricing and the Free Plan

Originality.ai sells credits, and the Free plan is enough for a small test. On October 31, 2026 its pricing page listed three plans: Free at $0 with 10,000 words (100 credits, one time), Pro at $12.95 a month with 200,000 words (2,000 credits) a month, and Enterprise at $136.58 a month with 1.5 million words a month, with the yearly discount shown. One credit covers 100 words and each scan is rounded up, so a 331 word text costs 4 credits. Pro adds Deep Scan, Bulk Scan, shared reports, PDF export and file upload; Enterprise adds API access and a one year scan history.

A full 28 text run like ours costs about 109 credits for the AI score alone, so it does not quite fit in one Free account, which is why we used two. Turning on the Plagiarism Score doubles the bill per scan, and Deep Scan costs 20 credits per text.

What Originality AI Does Beyond AI Detection

Originality bundles seven scan types in the same editor: AI Score, Plagiarism Score, Content Quality Score, Readability Score, Guideline Checker, Grammar and Spelling, and Fact and Hallucination. The plagiarism checker compares text against published content and, being a matching task rather than a prediction, is more dependable than any AI score. The fact checking layer flags claims and checks whether cited sources resolve, which catches the fabricated references that AI drafts produce. We did not score those layers in this test. For a publisher, they are a large part of the reason to pay for the tool.

Should You Trust Originality AI?

Is Originality AI accurate enough to trust? It is the detector we would reach for first, with GPTZero as the second opinion. On our set it caught every AI text, cleared every human text, and saw through a Humanizer rewrite, and it did all three at once, which no other detector in our tests managed except GPTZero.

• Publishers and agencies screening writers: this is the job it was built for. A score above 80% on a submission is worth a conversation; a score under 10% is reassuring.
• Teachers and institutions: no detector score is proof, and Originality pitches its own plans at individuals, agencies and publishers rather than schools. Use it as one signal and keep draft history as the real evidence.
• Writers worried about false positives: on our 12 human texts it never went above 5%, including essays by non native English learners. That is a strong record, and still not a guarantee for your text.
• Anyone checking paraphrased or humanized AI: Originality and GPTZero are the two that caught it. Grammarly and ZeroGPT did not.

FAQ

Is Originality AI accurate?

Yes, on our October 2026 test it was the most accurate of six detectors. Originality 5.0 scored all 16 AI texts between 88% and 97% Likely AI and all 12 human texts between 0% and 5%, with every human text labeled Likely Original.

Does Originality.ai flag human writing as AI?

Not in our October 2026 test. The highest score on 12 human texts was 5% on an academic introduction, and essays by non native English learners scored 2%. Our July 2026 run saw some human text flagged, so the newer 5.0 model looks better calibrated, but no detector is proof on its own.

Can Originality.ai detect humanized or paraphrased AI text?

It caught all four texts we rewrote with Grammarly's Humanizer, scoring them 88% to 92% Likely AI. Grammarly's own detector scored the same four texts 0% and ZeroGPT scored them 0% to 26.4%.

How does Originality.ai compare to GPTZero?

On the same 28 texts both caught 16 of 16 AI texts and flagged 0 of 12 human texts. GPTZero gave every human text a flat 0% while Originality gave them 0% to 5%, and both caught the Grammarly Humanizer rewrites. They are the two strongest detectors we have tested.

Is Originality.ai free?

The Free plan gives 100 credits once, which is about 10,000 words at 1 credit per 100 words, rounded up per scan. On October 31, 2026 the pricing page listed Pro at $12.95 a month for 200,000 words and Enterprise at $136.58 a month for 1.5 million words, with the yearly discount shown.

Final Thoughts

Originality 5.0 passed the same test that caught Grammarly out a day earlier: 16 of 16 AI texts caught, 0 of 12 human texts flagged, and all four Humanizer rewrites seen through. The July 2026 worry about false positives did not repeat on this set. Pair it with GPTZero for anything that matters, keep your drafts as proof of authorship, and treat any score as a reason to look rather than a verdict.

We run these tests because we build language model systems for clients and need to know how their output reads to the tools that screen it. If your team needs AI writing checks built into its own review process, our AI development services team can design and build that workflow.