Claude Sonnet 3.5 vs Claude Sonnet 4.5
Both have similar output pricing, while Claude Sonnet 4.5 offers a larger context window. Choose Claude Sonnet 3.5 or Claude Sonnet 4.5 based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude Sonnet 3.5 | Claude Sonnet 4.5 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input / 1M tokens | $3.00 | $3.00 |
| Output / 1M tokens | $15.00 | $15.00 |
| Context window | 200K | 1M |
| Parameters | — | — |
| Open weights | No | No |
| Released | Jun 2024 | Sep 2025 |
| SWE-bench Multimodal score | 12.2 | — |
| LiveBench score | — | 67.9 |
| SWE-bench Verified score | — | 74.8 |
| SWE-bench Multilingual score | — | 67.0 |
| LMArena (Chatbot Arena) Elo score | — | 1438 |
| LMArena WebDev Elo score | — | 1393 |
| GPQA Diamond score | — | 82.3 |
| FrontierMath score | — | 15.2 |
| Epoch Capabilities Index score | — | 147 |
FAQ
Is Claude Sonnet 3.5 or Claude Sonnet 4.5 cheaper?
Claude Sonnet 3.5 and Claude Sonnet 4.5 have comparable output pricing.
Which has the larger context window, Claude Sonnet 3.5 or Claude Sonnet 4.5?
Claude Sonnet 4.5 has the larger context window (1M tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.