League fixture
GPT-6 Astra vs Claude Opus 5.5.
Title clash — 1st vs 2nd — decided by the data: category winners, tale of the tape and head-to-head benchmarks.
League fixture: Title clash — 1st vs 2nd. In Season Zero, fixture results are decided by the data — the category winners above. When voted fixtures launch, results blend 60% benchmark / 40% crowd per the published rulebook.
Verdict by category
| Category | Claude Opus 5.5 | GPT-6 Astra | Winner |
|---|---|---|---|
| League Score | 98.7 | 99.8 | GPT-6 Astra |
| Coding (SWE-bench %) | — | — | — |
| Reasoning (GPQA %) | — | 96.0 | — |
| Context (tokens) | 1000000 | 1050000 | GPT-6 Astra |
| Speed (tok/s) | 75.6 | — | — |
| Price (blended $/1M) | $8.00 | $20.00 | Claude Opus 5.5 (cheaper) |
Tale of the tape
| Spec | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Released | Sep 22, 2026 | Sep 3, 2026 |
| League Score | 99 | 100 |
| Context | 1,000,000 tokens | 1,050,000 tokens |
| Max output | 128,000 | 128,000 |
| $/1M input | $4.00 | $10.00 |
| $/1M output | $20.00 | $50.00 |
| Weights | Closed | Closed |
| Speed | 75.6 t/s | — |
Head-to-head benchmarks (shared only)
| Benchmark | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| LiveBench overall | 85.1 | 85.6 |
Cost at three workloads
| Workload | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Light — 1M in / 250K out | $9.00 | $22.50 |
| Standard — 10M in / 2.5M out | $90.00 | $225.00 |
| Long-context — 50M in / 5M out | $300.00 | $750.00 |
The pick
Pick Claude Opus 5.5 if you want the lower running cost.
Pick GPT-6 Astra if you want the higher overall League Score; you need the bigger context window.
All figures from the model database — sources and dates on each model page. Cost your own workload or compare a different pair.