Claude Opus 4.5 vs GPT-5.1 Codex High: Specs & Benchmark Comparison
| Characteristic | Claude Opus 4.5 | GPT-5.1 Codex High |
|---|---|---|
| Company | Anthropic | OpenAI |
| Release Date | November 23, 2025 | November 11, 2025 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 200K | 400K |
| Context (output) | 64K | 128K |
| Input Price / 1M | $5.00 | $1.25 |
| Output Price / 1M | $25.00 | $10.00 |
| Average Score | 0.9 | 1.0 |
Verdict
GPT-5.1 Codex High leads in 2 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: Claude Opus 4.5 — 0.9, GPT-5.1 Codex High — 1.0.
API Cost
GPT-5.1 Codex High is 2.7x cheaper: input $1.25/1M vs $5.00/1M tokens.
Context Window
GPT-5.1 Codex High supports a larger context: 400K vs 200K tokens.
Recency
Both models were released around the same time: 11/23/2025 and 11/11/2025.
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The Claude Opus 4.5 and GPT-5.1 Codex High comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Claude Opus 4.5 or GPT-5.1 Codex High page. See also the complete list of AI model comparisons.