GPT-5.1 (high) vs GPT-5 Codex (high)
Comparing 2 AI models · 5 benchmarks · OpenAI
Most Affordable
Op
GPT-5.1 (high)
$1.25/1M
Highest Intelligence
Op
GPT-5.1 (high)
87.3% GPQA
Best for Coding
Op
GPT-5.1 (high)
57.5 Coding Index
Price Difference
1.0x
input cost range
Composite Indices
Intelligence, Coding, Math
Standard Benchmarks
Academic and industry benchmarks
Benchmark Winners
5 tests
Op
GPT-5.1 (high)
4
- GPQA
- MMLU Pro
- HLE
- LiveCodeBench
Op
GPT-5 Codex (high)
1
- AIME 2025
| Metric | Op GPT-5.1 (high) | Op GPT-5 Codex (high) |
|---|---|---|
| Pricing Per 1M tokens | ||
| Input Cost | $1.25/1M | $1.25/1M |
| Output Cost | $10.00/1M | $10.00/1M |
| Blended Cost 3:1 input/output ratio | $3.44/1M | $3.44/1M |
| Specifications | ||
| Organization Model creator | OpenAI | OpenAI |
| Release Date Launch date | Nov 13, 2025 | Sep 23, 2025 |
| Performance & Speed | ||
| Throughput Output speed | 273.7 tok/s | 230.7 tok/s |
| Time to First Token (TTFT) Initial response delay | 8572ms | 16550ms |
| Latency Time to first answer token | 8572ms | 16550ms |
| Composite Indices | ||
| Intelligence Index Overall reasoning capability | 69.7 | 68.5 |
| Coding Index Programming ability | 57.5 | 53.5 |
| Math Index Mathematical reasoning | 94.0 | 98.7 |
| Standard Benchmarks | ||
| GPQA Graduate-level reasoning | 87.3% | 83.7% |
| MMLU Pro Advanced knowledge | 87.0% | 86.5% |
| HLE Hard language evaluation | 26.5% | 25.6% |
| LiveCodeBench Real-world coding tasks | 86.8% | 84.0% |
| MATH 500 Mathematical problems | — | — |
| AIME 2025 Advanced math competition | 94.0% | 98.7% |
| AIME (Original) Math olympiad problems | — | — |
| SciCode Scientific code generation | 43.3% | 40.9% |
| LCR Code review capability | 75.0% | 69.0% |
| IFBench Instruction-following | 72.9% | 74.1% |
| TAU-bench v2 Tool use & agentic tasks | 81.9% | 86.8% |
| TerminalBench Hard CLI command generation | 42.6% | 35.5% |
Key Takeaways
GPT-5.1 (high) offers the best value at $1.25/1M, making it ideal for high-volume applications and cost-conscious projects.
GPT-5.1 (high) leads in reasoning capabilities with a 87.3% GPQA score, excelling at complex analytical tasks and problem-solving.
GPT-5.1 (high) achieves a 57.5 coding index, making it the top choice for software development and code generation tasks.
All models support context windows of ∞+ tokens, suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Op
GPT-5.1 (high)
- Cost-sensitive applications
- High-volume processing
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
Op