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GPT-4 Detector

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Detect text generated by GPT-4, GPT-4o, and GPT-4 Turbo

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GPT-4 represents a significant leap in AI writing quality over GPT-3.5, which makes it considerably harder to detect. GPT-4 output features more varied sentence structures, richer vocabulary, and more natural paragraph flow compared to its predecessor. However, it still carries telltale patterns: a tendency toward comprehensive coverage of topics, balanced "on the other hand" argumentation, and a subtle but consistent preference for certain transitional constructions. GPT-4o and GPT-4 Turbo share these core characteristics while adding even more fluency.

Coda One's GPT-4 Detector is specifically calibrated for these advanced models. Our statistical model measures sentence length distribution with higher sensitivity -- GPT-4's variation is more natural than GPT-3.5's but still measurably different from genuine human writing, which tends to be more erratic and unpredictable. The pattern model identifies GPT-4-specific constructions: its characteristic way of building paragraphs with topic-support-elaboration structure, its preference for certain academic-sounding phrases, and its tendency to conclude sections with synthesizing statements.

The per-sentence analysis is especially valuable for GPT-4 detection. Unlike GPT-3.5, which produces uniformly detectable text, GPT-4 output shows more variation between sentences -- some sentences may appear genuinely human while others carry strong AI signatures. Our color-coded sentence breakdown reveals these patterns, helping you identify the most AI-characteristic sections. The tool is 100% free with unlimited scans, no account needed.

Frequently Asked Questions

Is GPT-4 harder to detect than GPT-3.5?
Yes, significantly. GPT-4 produces more natural sentence variation, richer vocabulary, and less formulaic structure. Detection scores for GPT-4 text are typically 10-20 percentage points lower than equivalent GPT-3.5 content. However, our multi-model approach still identifies GPT-4's characteristic patterns -- they're subtler but present. The per-sentence analysis becomes especially important for GPT-4 detection.
Does this detect GPT-4o and GPT-4 Turbo specifically?
Yes. GPT-4, GPT-4 Turbo, and GPT-4o share the same foundational writing patterns despite performance differences. GPT-4o may produce slightly more conversational text, but the underlying statistical fingerprints -- sentence complexity, vocabulary distribution, structural preferences -- remain detectable by our analysis models.
What score range indicates GPT-4 use?
Raw GPT-4 output typically scores 60-85% on our detector (compared to 75-95% for GPT-3.5). Scores above 60% with GPT-4 strongly suggest AI generation. Between 40-60% may indicate GPT-4 with some editing or custom instructions. The per-sentence breakdown provides more reliable insight than the overall score alone for GPT-4 content.
Can GPT-4 with custom instructions evade detection?
Custom instructions can alter GPT-4's surface style, but deeper patterns persist. Even with instructions to "write casually" or "avoid AI-sounding language," GPT-4 maintains characteristic sentence structure distributions and vocabulary selection patterns. Our statistical model catches these deep patterns that survive stylistic instructions.
How does GPT-4 detection compare to Claude detection?
GPT-4 and Claude have different AI fingerprints. GPT-4 tends toward balanced argumentation and comprehensive coverage; Claude tends toward nuanced hedging and multi-perspective analysis. Our detector is trained on patterns from both models. The detection difficulty is similar for both, though the specific patterns flagged will differ.

Also Available For

Teachers Students Academic Writing Publishers Chatgpt Claude Gemini Deepseek Journalism Hr

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