Claude Opus 4.5vsClaude Sonnet 4
Claude Opus 4.5 | Claude Sonnet 4 | |
|---|---|---|
| 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 | — |
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 | — |
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 | — |
| 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. | 90% | 30% |
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% | 72.7% |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 87% | 75.4% |
| Overview | ||
| Company | Anthropic | Anthropic |
| Release date | Nov 24 2025 | May 22 2025 |
| Access | Proprietary | Proprietary |
Frequently asked questions
Claude Opus 4.5 leads Claude Sonnet 4 on 3 of the 3 benchmarks they both report (BullshitBench v2, SWE-Bench Verified, GPQA Diamond). Only Claude Opus 4.5 has a verified first-party API price: $5.00 per million input tokens and $25.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude Sonnet 4. Claude Sonnet 4 shipped 186 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 Claude Sonnet 4 at 30%. On SWE-Bench Verified, Claude Opus 4.5 leads at 80.9% vs Claude Sonnet 4 at 72.7%. On GPQA Diamond, Claude Opus 4.5 leads at 87% vs Claude Sonnet 4 at 75.4%.
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
Claude Sonnet 4 was released by Anthropic on May 22 2025.
Claude Opus 4.5 leads on SWE-Bench Verified — Claude Opus 4.5 80.9% vs Claude Sonnet 4 72.7%.
Claude Opus 4.5 leads on GPQA Diamond — Claude Opus 4.5 87% vs Claude Sonnet 4 75.4%.
Only Claude Opus 4.5 has a verified first-party API price: $5.00 per million input tokens and $25.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude Sonnet 4. Rates are pay-as-you-go API prices verified on August 18, 2026.