GPT-5.5 vs GPT-6 Astra
GPT-5.5 (OpenAI) and GPT-6 Astra (OpenAI) compared on benchmarks, pricing, context window, and use-case rankings.
- GPT-6 Astra leads on overall intelligence (ECI 169 vs 159).
- GPT-5.5 is cheaper on input tokens — $5.00 vs $10.00 per 1M.
- GPT-6 Astra ranks higher for coding (95th vs 84th percentile).
| Attribute | GPT-5.5 | GPT-6 Astra |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 159 | 169 |
| Coding | 84 | 95 |
| Math | 73 | 96 |
| Reasoning & Knowledge | 83 | 99 |
| Agentic & Tools | 84 | 96 |
| Specifications | ||
| Developer | OpenAI | OpenAI |
| Family | GPT | GPT |
| Released | Apr 23, 2026 | Sep 3, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | 1.1M | 1.1M |
| Price — $/M input | $5.00 | $10.00 |
| Price — $/M output | $30.00 | $50.00 |
| Inputs | file, image, text | file, image, text |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 84% | 100% |
| APEX | 39% | 47% |
| ARC-AGI | 95% | 99% |
| ARC-AGI-2 | 85% | 95% |
| FrontierMath | 52% | — |
| FrontierMath Tier 4 | 35% | — |
| GPQA Diamond | 91% | 96% |
| GSO (code optimization) | 40% | — |
| Humanity's Last Exam | 46% | 55% |
| SciCode | 56% | 56% |
| SimpleBench | 69% | — |
| SimpleQA Verified | 63% | 76% |
| SWE-bench Verified | 81% | — |
| Terminal-Bench | 85% | — |
| WebDev Arena | 1508 | 1797 |
| WeirdML | 85% | 93% |
| τ²-bench | 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
Is GPT-5.5 better than GPT-6 Astra?
On Epoch AI's Capabilities Index, GPT-6 Astra scores higher (169) than GPT-5.5 (159). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, GPT-5.5 or GPT-6 Astra?
GPT-5.5 is cheaper on input tokens at $5.00 per million, versus $10.00 (representative OpenRouter pricing).
Which has a larger context window, GPT-5.5 or GPT-6 Astra?
GPT-5.5 supports up to 1.1M tokens, compared with 1.1M for the other.
Which is better for coding, GPT-5.5 or GPT-6 Astra?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, GPT-6 Astra ranks higher — 95th vs 84th percentile among the models tracked on Model Beat.
Want a different match-up? Open the compare tool to add or swap models.
More comparisons
Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.