Claude 3.5 Sonnet (upgraded)vsClaude Sonnet 4
Claude 3.5 Sonnet (upgraded) | Claude Sonnet 4 | |
|---|---|---|
| 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% | 72.7% |
| 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. | — | 30% |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | — | 75.4% |
| Overview | ||
| Company | Anthropic | Anthropic |
| Release date | Oct 22 2024 | May 22 2025 |
| Access | Proprietary | Proprietary |
Frequently asked questions
Claude Sonnet 4 leads Claude 3.5 Sonnet (upgraded) on 1 of the 1 benchmark they both report (SWE-Bench Verified). Claude 3.5 Sonnet (upgraded) shipped 212 days before Claude Sonnet 4, 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 Sonnet 4 leads at 72.7% vs Claude 3.5 Sonnet (upgraded) at 49%.
Claude 3.5 Sonnet (upgraded) was released by Anthropic on Oct 22 2024.
Claude Sonnet 4 was released by Anthropic on May 22 2025.
Claude Sonnet 4 leads on SWE-Bench Verified — Claude 3.5 Sonnet (upgraded) 49% vs Claude Sonnet 4 72.7%.
Other comparisons
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