Claude Opus 4.5 vs o3
Anthropic Claude Opus 4.5 | OpenAI o3 | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Nov 24 2025 | Apr 16 2025 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given 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. | 90%Best | 26% |
Coding SWE-Bench VerifiedReal 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. | 80.9% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 87% | — |
| Timeline | ||
| Release gap | o3 shipped 222 days before Claude Opus 4.5 | |
Which is better: Claude Opus 4.5 or o3?
Claude Opus 4.5 leads o3 on 1 of the 1 benchmark they both report (BullshitBench v2). o3 shipped 222 days before Claude Opus 4.5, 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, Claude Opus 4.5 leads at 90% vs o3 at 26%.
Frequently asked questions
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
o3 was released by OpenAI on Apr 16 2025.
Other comparisons
Claude Opus 4.5 vs Gemini Omnio3 vs Gemini OmniClaude Opus 4.5 vs Muse Spark 1.1o3 vs Muse Spark 1.1Claude Opus 4.5 vs Grok 4.5o3 vs Grok 4.5Claude Opus 4.5 vs DeepSeek-V4-Proo3 vs DeepSeek-V4-ProClaude Opus 4.5 vs Mistral Medium 3.5o3 vs Mistral Medium 3.5Claude Opus 4.5 vs Kimi K2.7 Codeo3 vs Kimi K2.7 Code