OpenAI GPT-5. Source: OpenAI
OpenAI has released GPT-5, its most advanced language model to date. It is built as a unified system that can switch between fast responses and deeper reasoning depending on the complexity of the user's prompt. GPT-5 offers improved accuracy, better reasoning, and more useful responses across a wide range of topics including coding, health, and creative writing.
To give developers and businesses more flexibility, OpenAI also introduced smaller versions of the model called GPT-5 Mini and GPT-5 Nano. These versions are optimized for speed and lower costs while still delivering strong performance for lighter tasks.
How GPT-5 Works as One Unified System?
One Unified System of GPT-5.
GPT-5 works as a unified system with three parts: a smart, efficient model for most questions, a deeper reasoning model for tougher problems, and a real-time router that picks the right one based on your question and how complex it is. If you ask it to "think hard," it knows to switch to the deeper model. The router keeps learning and improving by looking at how people use the system and which answers they prefer. If you hit your usage limit, smaller versions of the models take over.
Comparison between GPT-5 and GPT-4o
| Feature | GPT-5 | GPT-4o |
|---|---|---|
| Reasoning | Dynamic switching between fast and deep reasoning | Optimized for speed but less nuanced reasoning |
| Accuracy | ~45% fewer hallucinations | Higher error rates |
| Writing | Handles complex structures and formats | General writing support |
| Coding | Best-in-class on SWE-bench Verified (74.9%) | Competent but less advanced |
| Health | Higher scores on HealthBench | Lower performance in health-related queries |
| Customization | Supports verbosity and reasoning_effort | Limited user-level controls |
Evaluations of GPT-5
GPT-5 is much smarter overall, showing better results in tests, especially in math, coding, visual tasks, and health. It sets:
PhD-level science questions -> 85.7% on GPQA with thinking and no tools.
Competition math -> 94.6% on AIME 2025 without tools.
Real-world coding -> 74.9% on SWE-bench Verified.
Multimodal understanding -> 84.2% on MMMU.
Health -> 46.2% on HealthBench Hard.
API Pricing
| Model | Input | Output |
|---|---|---|
| GPT-5 | $1.25 | $10.00 |
| GPT-5 mini | $0.25 | $2.00 |
| GPT-5 nano | $0.05 | $0.40 |
| GPT-4o | $2.50 | $10.00 |
NOTE
Input token of GPT-5 is 50% cheaper than GPT-4o.
