Benchmark Data · March 2026 · 2,400 Samples
AI Detector Accuracy Benchmarks
2,400 samples, 6 detectors, 5 content categories, no vendor relationships.
| # | Tool | Accuracy | False Pos. | False Neg. | Latency | Pricing | Score |
|---|---|---|---|---|---|---|---|
| #1 | Originality.aioriginality.ai | 91% |
7% | 11% | 420ms | paid | 4.6/5 |
| #2 | GPTZerogptzero.me | 87% |
10% | 15% | 380ms | freemium | 4.1/5 |
| #3 | Copyleakscopyleaks.com | 79% |
12% | 22% | 510ms | freemium | 3.7/5 |
| #4 | Sapling AIsapling.ai | 76% |
17% | 24% | 610ms | freemium | 3.2/5 |
| #5 | Writer.comwriter.com | 84% |
8% | 18% | 290ms | paid | 3.9/5 |
| #6 | Hive Moderationthehive.ai | 88% |
9% | 12% | 340ms | paid | 4.2/5 |
Methodology
Test Corpus
2,400 samples between 150 and 600 words. Human-written (1,200): 240 samples each from academic writing, journalism, marketing copy, technical documentation, and creative writing. AI-generated (1,200): 300 samples each from Claude 3.5 Sonnet, GPT-4o, Gemini 1.5 Pro, and Llama 3.1 70B.
Measurement
Overall accuracy = (TP + TN) / 2,400. FPR = false positives / 1,200 human samples. FNR = false negatives / 1,200 AI samples. Latency = median of 100 API calls on a 200-word sample.
Bypass Findings
14 humanizer tools tested against 6 detectors. Bypass rates: 23–91%. Average accuracy drop on humanized content: 31 percentage points. Originality.ai showed best resistance (91% to 67%). GPTZero dropped furthest (87% to 54%).
Independence
No affiliate relationships, commercial agreements, or advance vendor notification. API access paid at standard rates.
Results by Content Type
Academic writing: GPTZero leads in this category at 91% on essay formats. All detectors showed elevated false positive rates on STEM disciplines due to naturally low perplexity in domain-specific language.
Journalism and news: Most consistently detectable — average 86%. Hive Moderation achieved 92% on news content specifically.
Marketing copy: Hardest category. Average 79% detection. AI-generated marketing language is statistically similar to human marketing copy, making it the toughest classification challenge.
Technical documentation: Highest false positive rates. Sapling AI flagged 31% of human technical docs as AI. Even Originality.ai FPR rose to 12% on technical content.
Bypass Study Findings
14 humanizer tools tested against 6 detectors. Bypass rates: 23%–91%. Average accuracy drop on humanized content: 31 percentage points. Originality.ai was most resistant (91% → 67%). GPTZero dropped furthest (87% → 54%, near chance level). No detector was fully robust against all humanizers. For a detailed technical explanation of how these tools work, see our how AI detection works guide.
Limitations
Corpus used 150–600 word samples. Tested at a single point in time — detectors update models regularly. Non-native English speaker writing was not separately measured. Tested at default sensitivity thresholds only. We plan to expand the corpus in upcoming quarterly benchmarks.
Frequently Asked Questions
Common questions about AI detector accuracy and our benchmark methodology.
The most accurate AI detector in our benchmark is Originality.ai at 91% accuracy. The average across all 6 tested tools is 84%. Accuracy varies significantly by content type — journalism is most detectable (86% average) while marketing copy is hardest (79% average). See our full comparison table for all metrics.
A false positive occurs when an AI detector incorrectly flags human-written text as AI-generated. In our benchmark, false positive rates ranged from 7% (Originality.ai) to 17% (Sapling AI). For academic integrity contexts, FPR is the most critical metric — a high FPR means more innocent writers wrongly accused.
Yes. We tested 14 humanizer tools against 6 detectors and found bypass rates ranging from 23% to 91%. Average accuracy dropped 31 percentage points on humanized text. Originality.ai showed best resistance. Read more in our how AI detection works guide.
We tested 2,400 samples: 1,200 human-written texts across 5 content types and 1,200 AI-generated samples from GPT-4o, Claude 3.5, Gemini 1.5 Pro, and Llama 3.1 70B. All tools tested at default settings. No affiliate relationships or vendor notification. API access paid at standard rates.
GPTZero is most widely used in education — 87% accuracy, free tier with 10,000 words per month, and sentence-level highlighting. For institutions using LMS platforms, Copyleaks offers direct Canvas, Moodle, and Blackboard integration. See our guide for educators.