Claude Opus 5.5 vs GPT-6 Astra
Claude Opus 5.5 (Anthropic) and GPT-6 Astra (OpenAI) compared on price, context window, speed and independent benchmarks. Claude Opus 5.5 both scores higher on the Artificial Analysis Intelligence Index (57.6 vs 52.7) and is cheaper on a blended basis — 2.5× less than GPT-6 Astra.
| Claude Opus 5.5 | GPT-6 Astra | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input $/1M | $4.00 | $10.0 |
| Output $/1M | $20.0 | $50.0 |
| Blended $/1M (3:1) | $8.00 | $20.0 |
| Cached input $/1M | $0.20 | $1.00 |
| Context window | 1M | 1.1M |
| Knowledge cutoff | 2026-06 | 2026-04 |
| License | proprietary | proprietary |
| Speed (tok/s) | 85 | 58 |
| Artificial Analysis Intelligence Index | 57.6 | 52.7 |
| LMArena Elo | — | 1444 |
| GPQA Diamond | — | 96.1% |
| Humanity's Last Exam | 61.4% | 54.7% |