GPT-5.5 Instant vs GPT-6 Astra
GPT-5.5 Instant (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 143).
- GPT-6 Astra ranks higher for coding (94th vs 77th percentile).
| Attribute | GPT-5.5 Instant | GPT-6 Astra |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 143 | 169 |
| Coding | 77 | 94 |
| Math | 7 | 96 |
| Reasoning & Knowledge | 32 | 99 |
| Agentic & Tools | 16 | 96 |
| Specifications | ||
| Developer | OpenAI | OpenAI |
| Family | GPT | GPT |
| Released | May 5, 2026 | Sep 3, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | — | 1.1M |
| Price — $/M input | — | $10.00 |
| Price — $/M output | — | $50.00 |
| Inputs | — | file, image, text |
| Outputs | — | text |
| Benchmarks | ||
| AIME 2024/2025 | 68% | 100% |
| GPQA Diamond | 83% | 96% |
| Humanity's Last Exam | 20% | 55% |
| SciCode | 53% | 56% |
| SimpleQA Verified | 38% | 76% |
| τ²-bench | 49% | — |
| APEX | — | 47% |
| ARC-AGI | — | 99% |
| ARC-AGI-2 | — | 95% |
| WebDev Arena | — | 1797 |
| WeirdML | — | 93% |
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 Instant better than GPT-6 Astra?
On Epoch AI's Capabilities Index, GPT-6 Astra scores higher (169) than GPT-5.5 Instant (143). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is better for coding, GPT-5.5 Instant or GPT-6 Astra?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, GPT-6 Astra ranks higher — 94th vs 77th 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.