Claude Opus 4.5 vs GPT OSS 20B
GPT OSS 20B is cheaper on output tokens, while Claude Opus 4.5 offers a larger context window. Choose Claude Opus 4.5 or GPT OSS 20B based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude Opus 4.5 | GPT OSS 20B |
|---|---|---|
| Provider | Anthropic | Neon |
| Input / 1M tokens | $5.00 | $0.07 |
| Output / 1M tokens | $25.00 | $0.30 |
| Context window | 200K | 131K |
| Parameters | — | 21B |
| Open weights | No | Yes |
| Released | Nov 2025 | Aug 2025 |
| LiveBench score | 76.0 | — |
| LMArena (Chatbot Arena) Elo score | 1451 | — |
| GPQA Diamond score | 86.0 | — |
| FrontierMath score | 20.7 | — |
| LMArena WebDev Elo score | 1494 | — |
| Epoch Capabilities Index score | 150 | — |
| SWE-bench Multilingual score | 70.7 | — |
| SWE-bench Verified score | 79.2 | — |
FAQ
Is Claude Opus 4.5 or GPT OSS 20B cheaper?
GPT OSS 20B is cheaper on output tokens ($0.30 vs $25.00 per 1M).
Which has the larger context window, Claude Opus 4.5 or GPT OSS 20B?
Claude Opus 4.5 has the larger context window (200K tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.