GPT-6 Astra vs Claude Opus 5.5
GPT-6 Astra is from OpenAI, released September 3, 2026. Claude Opus 5.5 is from Anthropic, released September 22, 2026.
- LMArena Elo1476 vs 1504. Claude Opus 5.5 is 1.9% ahead on LMArena Elo.
- Input per 1M$10 vs $4. Claude Opus 5.5 costs 60% less per million input tokens.
- Output per 1M$50 vs $20. Claude Opus 5.5 costs 60% less per million output tokens.
- Context window1,050,000 vs 1M. GPT-6 Astra takes 4.8% more context in one request.
Prices are the vendors’ published API rates; Elo is LMArena’s text board. Each figure is dated on its model page.
Interactive Comparison
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$10 / $50 per 1M tokens | $4 / $20 per 1M tokens | |
|---|---|---|
| Identity | ||
| Developer | OpenAI | Anthropic |
| Released | Sep 2026 | Sep 2026 |
| Status | GA | GA |
| Licence | Proprietary | Proprietary |
| Self-hostable | No | No |
| Cost | ||
| Blended $/1M tokensinput × 0.75 + output × 0.25 | $20.000 / 1M tokens | $8.000 / 1M tokens |
| Input price | $10.000 / 1M tokens | $4.000 / 1M tokens |
| Output price | $50.000 / 1M tokens | $20.000 / 1M tokens |
| Cached input | $1 per 1M tokens | $0.20 per 1M tokens |
| Batch discount | 50% (Batch and Flex) | 50% ($2 / $10 per 1M tokens) |
| Capacity | ||
| Context window | 1,050,000 tokens | 1M tokens |
| Max output | 128k tokens | 128k tokens |
| Capability | ||
| Vision in | Yes | Yes |
| Audio in | No | No |
| Function calling | — | Yes |
| Structured output | — | Yes |
| Extended reasoning | — | Yes |
| Web search | — | Yes |
| Code execution | — | Yes |
| Access | ||
| API | Yes | Yes |
| Chat app | Yes | Yes |
| Cloud marketplaces | — | Amazon Bedrock, Google Cloud, Microsoft Foundry |
| Fine-tuning | — | No |
| Measured quality | ||
| LMArena Elo | 1476 (checked Oct 2026) | 1504 (checked Oct 2026) |
| LMArena rank | Rank 30 | Rank 4 |
| GPQA Diamond | 96 | — |
| Elo per dollarLMArena Elo ÷ blended $/1M tokens | 74 | 188 |
