Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | GPT-5.5 (medium) | Claude Opus 4.5 (Reasoning) |
|---|---|---|
| Input ($/M tokens) | $5 | $5 |
| Output ($/M tokens) | $30 | $25 |
Data from Artificial Analysis API — 12 benchmarks
Claude Opus 4.5 (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $10.00/M tokens vs $11.25/M for GPT-5.5 (medium).
GPT-5.5 (medium) wins 7 out of 12 benchmarks compared to 4 for Claude Opus 4.5 (Reasoning). See the detailed benchmark chart above for per-category results.
GPT-5.5 (medium) generates tokens faster at 67 tok/s vs 62 tok/s. GPT-5.5 (medium) also has lower time-to-first-token (5.29s vs 10.70s).
Choose based on your priorities: Claude Opus 4.5 (Reasoning) for lower cost, GPT-5.5 (medium) for stronger benchmark performance, and GPT-5.5 (medium) for faster generation. For latency-sensitive apps, check the TTFT comparison above.