Claude 4.5 Opus vs GPT-5.5 Instant
Claude 4.5 Opus is cheaper on output tokens, while GPT-5.5 Instant offers a larger context window. Choose Claude 4.5 Opus or GPT-5.5 Instant based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude 4.5 Opus | GPT-5.5 Instant |
|---|---|---|
| Provider | AI/ML API | ZenMux |
| Input / 1M tokens | $5.29 | $5.00 |
| Output / 1M tokens | $26.45 | $30.00 |
| Context window | 200K | 400K |
| Parameters | — | — |
| Open weights | No | No |
| Released | Nov 2025 | May 2026 |
| SWE-bench Verified score | 76.8 | — |
| GPQA Diamond score | — | 82.5 |
| LMArena (Chatbot Arena) Elo score | — | 1419 |
| Epoch Capabilities Index score | — | 142 |
| LMArena Vision Elo score | — | 1250 |
FAQ
Is Claude 4.5 Opus or GPT-5.5 Instant cheaper?
Claude 4.5 Opus is cheaper on output tokens ($26.45 vs $30.00 per 1M).
Which has the larger context window, Claude 4.5 Opus or GPT-5.5 Instant?
GPT-5.5 Instant has the larger context window (400K tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.