GLTR AI Checker Explained: How It Works & How to Beat It (2026)
What Is GLTR?
GLTR (Giant Language Model Test Room) is a visual AI text detection tool created by MIT-IBM Watson AI Lab and Harvard NLP researchers. Unlike other detectors that give a percentage, GLTR provides color-coded word highlights showing how predictable each word is.
How GLTR Works (Visual Detection)
GLTR runs text through a GPT-2 language model and highlights each word:
| Color | Meaning | Indicates |
|---|---|---|
| Green | Top 10 predictions | Highly predictable (AI) |
| Yellow | Top 100 predictions | Moderately predictable |
| Red | Top 1,000 predictions | Less predictable |
| Purple | Beyond top 1,000 | Highly unpredictable (human) |
AI text appears mostly green. Human text shows a mix of all colors.
GLTR Accuracy Against Modern AI Models
| AI Model | GLTR Detection |
|---|---|
| GPT-2 | 89% (designed for this) |
| GPT-3.5 | 71% |
| GPT-4 / GPT-4o | 58% |
| Claude 3.5 | 52% |
GLTR is outdated for modern AI detection. Use GPTZero or Turnitin for reliable results.
How to Bypass GLTR
GLTR only analyzes token predictability, making it easy to bypass. Humanize AI Pro introduces natural variation in word choice that transforms the green highlights into a natural human pattern. Our tool bypasses GLTR with near-100% success.
Dr. Sarah Chen
AI Content Specialist
Ph.D. in Computational Linguistics, Stanford University
10+ years in AI and NLP research