Claude Sonnet 4.5 vs Claude 4 Sonnet
Claude 4 Sonnet is cheaper on output tokens, while Claude Sonnet 4.5 offers a larger context window. Choose Claude Sonnet 4.5 or Claude 4 Sonnet based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude Sonnet 4.5 | Claude 4 Sonnet |
|---|---|---|
| Provider | Anthropic | NanoGPT |
| Input / 1M tokens | $3.00 | $2.99 |
| Output / 1M tokens | $15.00 | $14.99 |
| Context window | 1M | 200K |
| Parameters | — | — |
| Open weights | No | No |
| Released | Sep 2025 | Sep 2025 |
| LiveBench score | 67.9 | 60.6 |
| SWE-bench Verified score | 74.8 | 76.4 |
| 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 | — |
| SWE-bench Multimodal score | — | 35.6 |
FAQ
Is Claude Sonnet 4.5 or Claude 4 Sonnet cheaper?
Claude 4 Sonnet is cheaper on output tokens ($14.99 vs $15.00 per 1M).
Which has the larger context window, Claude Sonnet 4.5 or Claude 4 Sonnet?
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.