Key Takeaways
GPT-5 Codex wins:
- Larger context window
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Better at math
- Supports vision
o3 Mini wins:
- Cheaper input tokens
- Cheaper output tokens
- Has reasoning mode
Price Advantage
o3 Mini
Benchmark Advantage
GPT-5 Codex
Context Window
GPT-5 Codex
Speed
GPT-5 Codex
Pricing Comparison
Price Comparison
| Metric | GPT-5 Codex | o3 Mini | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $1.25 | $1.10 | o3 Mini |
| Output (per 1M tokens) | $10.00 | $4.40 | o3 Mini |
| Cache Read (per 1M) | $125000.00 | $550000.00 | GPT-5 Codex |
Using a 3:1 input/output ratio, o3 Mini is 44% cheaper overall.
GPT-5 Codex Providers
OpenAI $1.25 (Cheapest)
o3 Mini Providers
OpenAI $1.10 (Cheapest)
Vercel $1.10 (Cheapest)
Azure $1.10 (Cheapest)
Benchmark Comparison
8
Benchmarks Compared
5
GPT-5 Codex Wins
0
o3 Mini Wins
Benchmark Scores
| Benchmark | GPT-5 Codex | o3 Mini | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 44.5 | 25.9 | |
Coding Index Code generation & understanding | 38.9 | 17.9 | |
Math Index Mathematical reasoning | 98.7 | - | - |
MMLU Pro Academic knowledge | 86.5 | 79.1 | |
GPQA Graduate-level science | 83.7 | 74.8 | |
LiveCodeBench Competitive programming | 84.0 | 71.7 | |
Aider Real-world code editing | - | 60.4 | - |
AIME Competition math | - | 77.0 | - |
GPT-5 Codex significantly outperforms in coding benchmarks.
Cost vs Quality
X-axis:
Y-axis:
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GPT-5 Codex
Other models
Context & Performance
Context Window
GPT-5 Codex
400,000
tokens
Max output: 128,000 tokens
o3 Mini
200,000
tokens
Max output: 100,000 tokens
GPT-5 Codex has a 50% larger context window.
Speed Performance
| Metric | GPT-5 Codex | o3 Mini | Winner |
|---|---|---|---|
| Tokens/second | 314.7 tok/s | 135.2 tok/s | |
| Time to First Token | 10.95s | 17.00s |
GPT-5 Codex responds 133% faster on average.
Capabilities
Feature Comparison
| Feature | GPT-5 Codex | o3 Mini |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | GPT-5 Codex | o3 Mini |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | OpenAI |
| Released | Sep 2025 | Jan 2025 |
GPT-5 Codex Modalities
Input
textimage
Output
text
o3 Mini Modalities
Input
textfile
Output
text