Claude Opus 5.5 vs GPT-6 Astra
Claude Opus 5.5 (Anthropic) and GPT-6 Astra (OpenAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Opus 5.5 is cheaper on input tokens — $4.00 vs $10.00 per 1M.
- GPT-6 Astra has a larger context window (1.1M vs 1M tokens).
- Claude Opus 5.5 ranks higher for coding (100th vs 93th percentile).
| Attribute | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | — | 169 |
| Coding | 100 | 93 |
| Math | — | 95 |
| Reasoning & Knowledge | 100 | 99 |
| Agentic & Tools | — | 93 |
| Specifications | ||
| Developer | Anthropic | OpenAI |
| Family | Claude | GPT |
| Released | Sep 22, 2026 | Sep 3, 2026 |
| Parameters | — | — |
| Availability | — | API access |
| Context window | 1M | 1.1M |
| Price — $/M input | $4.00 | $10.00 |
| Price — $/M output | $20.00 | $50.00 |
| Inputs | text, image, file | file, image, text |
| Outputs | text | text |
| Benchmarks | ||
| Humanity's Last Exam | 61% | 55% |
| SciCode | 67% | 56% |
| AIME 2024/2025 | — | 100% |
| APEX | — | 65% |
| ARC-AGI | — | 99% |
| ARC-AGI-2 | — | 95% |
| GPQA Diamond | — | 96% |
| SimpleQA Verified | — | 76% |
| WebDev Arena | — | 1800 |
| WeirdML | — | 94% |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Which is cheaper, Claude Opus 5.5 or GPT-6 Astra?
Claude Opus 5.5 is cheaper on input tokens at $4.00 per million, versus $10.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Opus 5.5 or GPT-6 Astra?
GPT-6 Astra supports up to 1.1M tokens, compared with 1M for the other.
Which is better for coding, Claude Opus 5.5 or GPT-6 Astra?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Claude Opus 5.5 ranks higher — 100th vs 93th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.