Claude Opus 4.5vso1-preview
Claude Opus 4.5 | o1-preview | |
|---|---|---|
| Specifications | ||
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view. | — | 128k |
| API pricingUSD per 1M tokens · lower wins | ||
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it. | $5.00 | $15.00 |
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one. | $25.00 | $60.00 |
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again. | $0.50 | $7.50 |
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. | $5.00Amazon Bedrock | — |
Cheapest outputLowest output rate across third-party providers, excluding the lab itself. May come from a different provider than the cheapest input. | $25.00Amazon Bedrock | — |
| Benchmarks | ||
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 87% | 73.3% |
| BenchmarksPublished by one model only | ||
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. | 90% | — |
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. | 80.9% | — |
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Nov 24 2025 | Sep 12 2024 |
| Access | Proprietary | Proprietary |
Other comparisons
Frequently asked questions
Claude Opus 4.5 leads o1-preview on 1 of the 1 benchmark they both report (GPQA Diamond). Claude Opus 4.5 is cheaper on both input and output: $5.00 vs $15.00 per million input tokens, and $25.00 vs $60.00 per million output tokens. o1-preview shipped 438 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 GPQA Diamond, Claude Opus 4.5 leads at 87% vs o1-preview at 73.3%.
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
o1-preview was released by OpenAI on Sep 12 2024.
Claude Opus 4.5 leads on GPQA Diamond — Claude Opus 4.5 87% vs o1-preview 73.3%.
Claude Opus 4.5 is cheaper on both input and output: $5.00 vs $15.00 per million input tokens, and $25.00 vs $60.00 per million output tokens. Rates are pay-as-you-go API prices verified on August 18, 2026.