Model Comparison
GPT-5.1 Codex (high)
vs. Claude Opus 5 (Adaptive Reasoning, Xhigh Effort)
Comparing 2 AI models · 10 benchmarks · OpenAI, Anthropic
Recommended Pick
AnClaude Opus 5 (Adaptive Reasoning, Xhigh Effort)7 metric winsStrongest on: Throughput, Reasoning, Intelligence
Best Value
GPT-5.1 Codex (high)
100.0 value score
67.1 reasoning / $3.44/1M
Lowest Price
GPT-5.1 Codex (high)
$1.25/1M input price
Best Reasoning
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort)
68.8 reasoning score
Blends available reasoning benchmarks
Best for Coding
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort)
77.0 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Best value
GPT-5.1 Codex (high) has the strongest quality-to-price mix at 100.0 out of 100 value points.
Price gap
GPT-5.1 Codex (high) is 4.0x cheaper on input tokens than Claude Opus 5 (Adaptive Reasoning, Xhigh Effort).
Reasoning gap
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort) leads GPT-5.1 Codex (high) by 1.7 points on reasoning.
Top-pick rationale
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort) wins 7 measurable categories, including Throughput, Reasoning, Intelligence, GPQA.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
GPT-5.1 Codex (high)
OpenAI
TTFT
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Time
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tok/s
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Tokens
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Cost
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Claude Opus 5 (Adaptive Reasoning, Xhigh Effort)
Anthropic
TTFT
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Time
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tok/s
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Tokens
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Cost
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Which answer was more useful?
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Full Comparison
| Metric | Op GPT-5.1 Codex (high) | Top Pick An Claude Opus 5 (Adaptive Reasoning, Xhigh Effort) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $1.25/1M | $5.00/1M |
| Output Cost | $10.00/1M | $25.00/1M |
| Blended (3:1) | $3.44/1M | $10.00/1M |
| Specifications | ||
| Organization | OpenAI | Anthropic |
| Release Date | Nov 13, 2025 | Jul 24, 2026 |
| Performance & Speed | ||
| Throughput | — | 56.9 tok/s |
| TTFT | — | 22357ms |
| Latency | — | 22357ms |
| Composite Indices | ||
| Value Score | 100.0 | 35.2 |
| Reasoning Score | 67.1 | 68.8 |
| Intelligence | 34.7 | 60.1 |
| Coding | — | 77.0 |
| Math | 95.7 | — |
| Standard Benchmarks | ||
| GPQA | 86.0% | 93.7% |
| MMLU Pro | 86.0% | — |
| HLE | 23.4% | 52.5% |
| LiveCodeBench | 84.9% | — |
| AIME 2025 | 95.7% | — |
| SciCode | 40.2% | 55.0% |
| LCR | 67.3% | 68.7% |
| IFBench | 70.0% | — |
| TAU-bench v2 | 83.0% | — |
| TerminalBench Hard | 34.8% | — |
Key Takeaways
GPT-5.1 Codex (high) offers the best value at $1.25/1M,making it ideal for high-volume applications and cost-conscious projects.
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort) has the strongest reasoning profile with a 68.8 reasoning score,combining the available reasoning-heavy benchmarks.
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort) reaches a 77.0 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
GPT-5.1 Codex (high)
- Cost-sensitive applications
- High-volume processing
Claude Opus 5 (Adaptive Reasoning, Xhigh Effort)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
