Claude 3.5 Sonnet (upgraded)vsClaude Opus 4.5
Claude 3.5 Sonnet (upgraded) | Claude Opus 4.5 | |
|---|---|---|
| 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 | ||
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. | 49% | 80.9% |
| 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% |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | — | 87% |
| Overview | ||
| Company | Anthropic | Anthropic |
| Release date | Oct 22 2024 | Nov 24 2025 |
| Access | Proprietary | Proprietary |
Frequently asked questions
Claude Opus 4.5 leads Claude 3.5 Sonnet (upgraded) on 1 of the 1 benchmark they both report (SWE-Bench Verified). 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 3.5 Sonnet (upgraded). Claude 3.5 Sonnet (upgraded) shipped 398 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 SWE-Bench Verified, Claude Opus 4.5 leads at 80.9% vs Claude 3.5 Sonnet (upgraded) at 49%.
Claude 3.5 Sonnet (upgraded) was released by Anthropic on Oct 22 2024.
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
Claude Opus 4.5 leads on SWE-Bench Verified — Claude 3.5 Sonnet (upgraded) 49% vs Claude Opus 4.5 80.9%.
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 3.5 Sonnet (upgraded). Rates are pay-as-you-go API prices verified on August 18, 2026.