Key Takeaways
GPT-5 Codex wins:
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Better at math
GPT-5.1 wins:
- No clear advantages in compared metrics
Price Advantage
GPT-5 Codex
Benchmark Advantage
GPT-5 Codex
Context Window
GPT-5.1
Speed
GPT-5 Codex
Pricing Comparison
Price Comparison
| Metric | GPT-5 Codex | GPT-5.1 | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $1.25 | $1.25 | Tie |
| Output (per 1M tokens) | $10.00 | $10.00 | Tie |
| Cache Read (per 1M) | $0.13 | $0.13 | Tie |
Both models have similar overall pricing.
GPT-5 Codex Providers
No provider data available
GPT-5.1 Providers
No provider data available
Benchmark Comparison
6
Benchmarks Compared
6
GPT-5 Codex Wins
0
GPT-5.1 Wins
Benchmark Scores
| Benchmark | GPT-5 Codex | GPT-5.1 | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 44.6 | 27.4 | |
Coding Index Code generation & understanding | 38.9 | 27.3 | |
Math Index Mathematical reasoning | 98.7 | 38.0 | |
MMLU Pro Academic knowledge | 86.5 | 80.1 | |
GPQA Graduate-level science | 83.7 | 64.3 | |
LiveCodeBench Competitive programming | 84.0 | 49.4 |
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
GPT-5.1
400,000
tokens
Speed Performance
| Metric | GPT-5 Codex | GPT-5.1 | Winner |
|---|---|---|---|
| Tokens/second | 186.2 tok/s | 70.0 tok/s | |
| Time to First Token | 7.04s | 0.76s |
GPT-5 Codex responds 166% faster on average.
Capabilities
Feature Comparison
| Feature | GPT-5 Codex | GPT-5.1 |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | GPT-5 Codex | GPT-5.1 |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | OpenAI |
| Released | Sep 2025 | Nov 2025 |
GPT-5 Codex Modalities
Input
textimage
Output
text
GPT-5.1 Modalities
Input
imagetextfile
Output
text