Claude Opus 4vsGPT-5-Codex
Claude Opus 4 | GPT-5-Codex | |
|---|---|---|
| API pricingUSD per 1M tokens · lower wins | ||
Cheapest inputLowest input rate across third-party providers, excluding the lab itself. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page. | $15.00Google | — |
Cheapest outputLowest output rate across third-party providers, excluding the lab itself. May come from a different provider than the cheapest input. | $75.00Google | — |
| Benchmarks | ||
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 34% | 39% |
| BenchmarksPublished by one model only | ||
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 72.5% | — |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 79.6% | — |
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | May 22 2025 | Sep 15 2025 |
| Access | Proprietary | Proprietary |
Other comparisons
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Frequently asked questions
GPT-5-Codex leads Claude Opus 4 on 1 of the 1 benchmark they both report (BullshitBench v2). Claude Opus 4 shipped 116 days before GPT-5-Codex, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
On BullshitBench v2, GPT-5-Codex leads at 39% vs Claude Opus 4 at 34%.
Claude Opus 4 was released by Anthropic on May 22 2025.
GPT-5-Codex was released by OpenAI on Sep 15 2025.