Key Takeaways
GPT-5.3 Codex wins:
- Cheaper input tokens
- Larger context window
- Higher intelligence benchmark
- Better at coding
o3 wins:
- Cheaper output tokens
- Faster response time
- Better at math
Price Advantage
GPT-5.3 Codex
Benchmark Advantage
GPT-5.3 Codex
Context Window
GPT-5.3 Codex
Speed
o3
Pricing Comparison
Benchmark Comparison
Context & Performance
Capabilities
Feature Comparison
| Feature | GPT-5.3 Codex | o3 |
|---|---|---|
Vision (Image Input) | ||
Tool/Function Calls | ||
Reasoning Mode | ||
Audio Input | ||
Audio Output | ||
PDF Input | ||
Prompt Caching | ||
Web Search |
License & Release
| Property | GPT-5.3 Codex | o3 |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | OpenAI |
| Released | Feb 2026 | Apr 2025 |
GPT-5.3 Codex Modalities
Input
textimage
Output
text
o3 Modalities
Input
imagetextfile
Output
text